diff --git a/.ci/flake8_lint_include_list.txt b/.ci/flake8_lint_include_list.txt
index 0ddc6d8a6c23..b9c3491444a9 100644
--- a/.ci/flake8_lint_include_list.txt
+++ b/.ci/flake8_lint_include_list.txt
@@ -264,35 +264,7 @@ lib/galaxy/sample_tracking/__init__.py
 lib/galaxy/sample_tracking/sample.py
 lib/galaxy/security/validate_user_input.py
 lib/galaxy/tags/
-lib/galaxy/tools/actions/
-lib/galaxy/tools/cwl/
-lib/galaxy/tools/data_manager/__init__.py
-lib/galaxy/tools/deps/
-lib/galaxy/tools/exception_handling.py
-lib/galaxy/tools/execute.py
-lib/galaxy/tools/filters/
-lib/galaxy/tools/imp_exp/export_history.py
-lib/galaxy/tools/imp_exp/__init__.py
-lib/galaxy/tools/linters/
-lib/galaxy/tools/lint.py
-lib/galaxy/tools/lint_util.py
-lib/galaxy/tools/loader_directory.py
-lib/galaxy/tools/loader.py
-lib/galaxy/tools/parameters/dataset_matcher.py
-lib/galaxy/tools/parameters/history_query.py
-lib/galaxy/tools/parameters/__init__.py
-lib/galaxy/tools/parameters/input_translation.py
-lib/galaxy/tools/parameters/sanitize.py
-lib/galaxy/tools/parameters/validation.py
-lib/galaxy/tools/parameters/wrapped_json.py
-lib/galaxy/tools/parameters/wrapped.py
-lib/galaxy/tools/parser/
-lib/galaxy/tools/special_tools.py
-lib/galaxy/tools/test.py
-lib/galaxy/tools/toolbox/
-lib/galaxy/tools/util/galaxyops/
-lib/galaxy/tools/util/__init__.py
-lib/galaxy/tools/verify/
+lib/galaxy/tools/
 lib/galaxy/util/
 lib/galaxy_utils/__init__.py
 lib/galaxy/util/sleeper.py
diff --git a/.ci/py3_sources.txt b/.ci/py3_sources.txt
index 83a46debe7a0..25e55544477f 100644
--- a/.ci/py3_sources.txt
+++ b/.ci/py3_sources.txt
@@ -40,26 +40,7 @@ lib/galaxy/quota/
 lib/galaxy/sample_tracking/
 lib/galaxy/security/
 lib/galaxy/tags/
-lib/galaxy/tools/actions/
-lib/galaxy/tools/cwl/
-lib/galaxy/tools/deps/
-lib/galaxy/tools/exception_handling.py
-lib/galaxy/tools/execute.py
-lib/galaxy/tools/lint.py
-lib/galaxy/tools/lint_util.py
-lib/galaxy/tools/linters/
-lib/galaxy/tools/loader.py
-lib/galaxy/tools/loader_directory.py
-lib/galaxy/tools/parameters/dataset_matcher.py
-lib/galaxy/tools/parameters/__init__.py
-lib/galaxy/tools/parameters/input_translation.py
-lib/galaxy/tools/parameters/sanitize.py
-lib/galaxy/tools/parameters/validation.py
-lib/galaxy/tools/parameters/wrapped_json.py
-lib/galaxy/tools/parameters/wrapped.py
-lib/galaxy/tools/parser/
-lib/galaxy/tools/test.py
-lib/galaxy/tools/toolbox/
+lib/galaxy/tools/
 lib/galaxy/tours/
 lib/galaxy/util/
 lib/galaxy/visualization/
diff --git a/lib/galaxy/tools/__init__.py b/lib/galaxy/tools/__init__.py
index 545d16104a28..72c05c470db3 100755
--- a/lib/galaxy/tools/__init__.py
+++ b/lib/galaxy/tools/__init__.py
@@ -1,7 +1,6 @@
 """
 Classes encapsulating galaxy tools and tool configuration.
 """
-
 import glob
 import json
 import logging
@@ -10,64 +9,88 @@
 import tarfile
 import tempfile
 import threading
-import urllib
-from datetime import datetime
-
 from cgi import FieldStorage
+from datetime import datetime
 from xml.etree import ElementTree
+
 from mako.template import Template
 from paste import httpexceptions
 from six import string_types
+from six.moves.urllib.parse import unquote_plus
 
-from galaxy.version import VERSION_MAJOR
-from galaxy import model
-from galaxy.managers import histories
+import galaxy.jobs
+import tool_shed.util.repository_util as repository_util
+from galaxy import (
+    exceptions,
+    model
+)
 from galaxy.datatypes.metadata import JobExternalOutputMetadataWrapper
-from galaxy import exceptions
+from galaxy.managers import histories
 from galaxy.queue_worker import (
     reload_toolbox,
     send_control_task
 )
 from galaxy.tools.actions import DefaultToolAction
-from galaxy.tools.actions.upload import UploadToolAction
-from galaxy.tools.actions.data_source import DataSourceToolAction
 from galaxy.tools.actions.data_manager import DataManagerToolAction
+from galaxy.tools.actions.data_source import DataSourceToolAction
 from galaxy.tools.actions.model_operations import ModelOperationToolAction
-from galaxy.tools.deps import views
-from galaxy.tools.deps import CachedDependencyManager
-from galaxy.tools.parameters import params_to_incoming, check_param, params_from_strings, params_to_strings, visit_input_values
+from galaxy.tools.actions.upload import UploadToolAction
+from galaxy.tools.deps import (
+    CachedDependencyManager,
+    views
+)
+from galaxy.tools.parameters import (
+    check_param,
+    params_from_strings,
+    params_to_incoming,
+    params_to_strings,
+    visit_input_values
+)
 from galaxy.tools.parameters import output_collect
-from galaxy.tools.parameters.basic import (BaseURLToolParameter,
-                                           DataToolParameter, DataCollectionToolParameter, HiddenToolParameter,
-                                           SelectToolParameter, ToolParameter)
+from galaxy.tools.parameters.basic import (
+    BaseURLToolParameter,
+    DataCollectionToolParameter,
+    DataToolParameter,
+    HiddenToolParameter,
+    SelectToolParameter,
+    ToolParameter
+)
 from galaxy.tools.parameters.grouping import Conditional, ConditionalWhen, Repeat, Section, UploadDataset
 from galaxy.tools.parameters.input_translation import ToolInputTranslator
-from galaxy.tools.test import parse_tests
-from galaxy.tools.parser import get_tool_source
+from galaxy.tools.parameters.meta import expand_meta_parameters
+from galaxy.tools.parser import (
+    get_tool_source,
+    ToolOutputCollectionPart
+)
 from galaxy.tools.parser.xml import XmlPageSource
-from galaxy.tools.parser import ToolOutputCollectionPart
+from galaxy.tools.test import parse_tests
 from galaxy.tools.toolbox import BaseGalaxyToolBox
-from galaxy.util import rst_to_html, string_as_bool
-from galaxy.util import ExecutionTimer
-from galaxy.util import listify
-from galaxy.util import unicodify
-from galaxy.tools.parameters.meta import expand_meta_parameters
+from galaxy.util import (
+    ExecutionTimer,
+    listify,
+    rst_to_html,
+    string_as_bool,
+    unicodify
+)
 from galaxy.util.bunch import Bunch
+from galaxy.util.dictifiable import Dictifiable
 from galaxy.util.expressions import ExpressionContext
 from galaxy.util.json import json_fix
 from galaxy.util.odict import odict
 from galaxy.util.template import fill_template
+from galaxy.version import VERSION_MAJOR
 from galaxy.web import url_for
 from galaxy.web.form_builder import SelectField
-from galaxy.util.dictifiable import Dictifiable
 from galaxy.work.context import WorkRequestContext
 from tool_shed.util import common_util
-import tool_shed.util.repository_util as repository_util
 from tool_shed.util import shed_util_common as suc
 
-from .loader import template_macro_params, raw_tool_xml_tree, imported_macro_paths
 from .execute import execute as execute_job
-import galaxy.jobs
+from .loader import (
+    imported_macro_paths,
+    raw_tool_xml_tree,
+    template_macro_params
+)
 
 log = logging.getLogger( __name__ )
 
@@ -475,7 +498,7 @@ def __get_job_tool_configuration(self, job_params=None):
                 if job_tool_config.params:
                     # There are job params and this config has params defined
                     for param, value in job_params.items():
-                        if param not in job_tool_config.params or job_tool_config.params[param] != job_params[param]:
+                        if param not in job_tool_config.params or job_tool_config.params[param] != value:
                             break
                     else:
                         # All params match, use this config
@@ -683,12 +706,13 @@ def __parse_legacy_features(self, tool_source):
                         self.hook_map[key] = value
                 file_name = code_elem.get("file")
                 code_path = os.path.join( self.tool_dir, file_name )
-                execfile( code_path, self.code_namespace )
+                with open(code_path) as f:
+                    exec(compile(f.read(), code_path, 'exec'), self.code_namespace)
 
         # User interface hints
         uihints_elem = root.find( "uihints" )
         if uihints_elem is not None:
-            for key, value in uihints_elem.attrib.iteritems():
+            for key, value in uihints_elem.attrib.items():
                 self.uihints[ key ] = value
 
     def __parse_tests(self, tool_source):
@@ -778,12 +802,12 @@ def parse_inputs( self, tool_source ):
                 # nginx_upload_path. This logic is handled in the tool_form.mako
                 # template.
                 if self.nginx_upload and self.app.config.nginx_upload_path:
-                    if '?' in urllib.unquote_plus( self.action ):
+                    if '?' in unquote_plus( self.action ):
                         raise Exception( 'URL parameters in a non-default tool action can not be used '
                                          'in conjunction with nginx upload.  Please convert them to '
                                          'hidden POST parameters' )
                     self.action = (self.app.config.nginx_upload_path + '?nginx_redir=',
-                                   urllib.unquote_plus(self.action))
+                                   unquote_plus(self.action))
                 self.target = input_elem.get( "target", self.target )
                 self.method = input_elem.get( "method", self.method )
                 # Parse the actual parameters
@@ -909,7 +933,7 @@ def parse_input_elem( self, page_source, enctypes, context=None ):
                     group.test_param.refresh_on_change = True
                     for attr in value_from[1].split( '.' ):
                         group.value_from = getattr( group.value_from, attr )
-                    for case_value, case_inputs in group.value_from( context, group, self ).iteritems():
+                    for case_value, case_inputs in group.value_from( context, group, self ).items():
                         case = ConditionalWhen()
                         case.value = case_value
                         if case_inputs:
@@ -1136,7 +1160,7 @@ def fill_in_new_state( self, trans, inputs, state, context=None ):
         in the dictionary `inputs`. Grouping elements are filled in recursively.
         """
         context = ExpressionContext( state, context )
-        for input in inputs.itervalues():
+        for input in inputs.values():
             state[ input.name ] = input.get_initial_value( trans, context )
 
     def get_param( self, key ):
@@ -1226,8 +1250,8 @@ def handle_input( self, trans, incoming, history=None ):
         log.debug( 'Validated and populated state for tool request %s' % validation_timer )
         # If there were errors, we stay on the same page and display them
         if any( all_errors ):
-            err_data = { key: value for d in all_errors for ( key, value ) in d.iteritems() }
-            raise exceptions.MessageException( ', '.join( [ msg for msg in err_data.itervalues() ] ), err_data=err_data )
+            err_data = { key: value for d in all_errors for ( key, value ) in d.items() }
+            raise exceptions.MessageException( ', '.join( msg for msg in err_data.values() ), err_data=err_data )
         else:
             execution_tracker = execute_job( trans, self, all_params, history=request_context.history, rerun_remap_job_id=rerun_remap_job_id, collection_info=collection_info )
             if execution_tracker.successful_jobs:
@@ -1257,7 +1281,7 @@ def handle_single_execution( self, trans, rerun_remap_job_id, params, history, m
             message = 'Error executing tool: %s' % str(e)
             return False, message
         if isinstance( out_data, odict ):
-            return job, out_data.items()
+            return job, list(out_data.items())
         else:
             if isinstance( out_data, string_types ):
                 message = out_data
@@ -1308,7 +1332,7 @@ def get_static_param_values( self, trans ):
         does require input.
         """
         args = dict()
-        for key, param in self.inputs.iteritems():
+        for key, param in self.inputs.items():
             # BaseURLToolParameter is now a subclass of HiddenToolParameter, so
             # we must check if param is a BaseURLToolParameter first
             if isinstance( param, BaseURLToolParameter ):
@@ -1762,7 +1786,7 @@ def to_json( self, trans, kwd={}, job=None, workflow_building_mode=False ):
         # populates model from state
         def populate_model( inputs, state_inputs, group_inputs, other_values=None ):
             other_values = ExpressionContext( state_inputs, other_values )
-            for input_index, input in enumerate( inputs.itervalues() ):
+            for input_index, input in enumerate( inputs.values() ):
                 tool_dict = None
                 group_state = state_inputs.get( input.name, {} )
                 if input.type == 'repeat':
@@ -1855,7 +1879,7 @@ def populate_model( inputs, state_inputs, group_inputs, other_values=None ):
     # populates state from incoming parameters
     def populate_state( self, request_context, inputs, incoming, state, errors={}, prefix='', context=None ):
         context = ExpressionContext( state, context )
-        for input in inputs.itervalues():
+        for input in inputs.values():
             state[ input.name ] = input.get_initial_value( request_context, context )
             key = prefix + input.name
             group_state = state[ input.name ]
@@ -1865,7 +1889,7 @@ def populate_state( self, request_context, inputs, incoming, state, errors={}, p
                 del group_state[:]
                 while True:
                     rep_prefix = '%s_%d' % ( key, rep_index )
-                    if not any( [ incoming_key.startswith( rep_prefix ) for incoming_key in incoming.keys() ] ) and rep_index >= input.min:
+                    if not any( incoming_key.startswith( rep_prefix ) for incoming_key in incoming.keys() ) and rep_index >= input.min:
                         break
                     if rep_index < input.max:
                         new_state = { '__index__' : rep_index }
@@ -1900,7 +1924,7 @@ def populate_state( self, request_context, inputs, incoming, state, errors={}, p
                     del group_state[ -1 ]
                 while len( writable_files ) > len( group_state ):
                     new_state = { '__index__' : len( group_state ) }
-                    for upload_item in input.inputs.itervalues():
+                    for upload_item in input.inputs.values():
                         new_state[ upload_item.name ] = upload_item.get_initial_value( request_context, context )
                     group_state.append( new_state )
                 for i, rep_state in enumerate( group_state ):
@@ -2070,7 +2094,7 @@ def _prepare_json_list( self, param_list ):
 
     def _prepare_json_param_dict( self, param_dict ):
         rval = {}
-        for key, value in param_dict.iteritems():
+        for key, value in param_dict.items():
             if isinstance( value, dict ):
                 rval[ key ] = self._prepare_json_param_dict( value )
             elif isinstance( value, list ):
@@ -2087,7 +2111,7 @@ def exec_before_job( self, app, inp_data, out_data, param_dict=None ):
         json_params[ 'output_data' ] = []
         json_params[ 'job_config' ] = dict( GALAXY_DATATYPES_CONF_FILE=param_dict.get( 'GALAXY_DATATYPES_CONF_FILE' ), GALAXY_ROOT_DIR=param_dict.get( 'GALAXY_ROOT_DIR' ), TOOL_PROVIDED_JOB_METADATA_FILE=galaxy.jobs.TOOL_PROVIDED_JOB_METADATA_FILE )
         json_filename = None
-        for i, ( out_name, data ) in enumerate( out_data.iteritems() ):
+        for i, ( out_name, data ) in enumerate( out_data.items() ):
             # use wrapped dataset to access certain values
             wrapped_data = param_dict.get( out_name )
             # allow multiple files to be created
@@ -2139,7 +2163,7 @@ def exec_before_job( self, app, inp_data, out_data, param_dict=None ):
         json_params[ 'output_data' ] = []
         json_params[ 'job_config' ] = dict( GALAXY_DATATYPES_CONF_FILE=param_dict.get( 'GALAXY_DATATYPES_CONF_FILE' ), GALAXY_ROOT_DIR=param_dict.get( 'GALAXY_ROOT_DIR' ), TOOL_PROVIDED_JOB_METADATA_FILE=galaxy.jobs.TOOL_PROVIDED_JOB_METADATA_FILE )
         json_filename = None
-        for i, ( out_name, data ) in enumerate( out_data.iteritems() ):
+        for i, ( out_name, data ) in enumerate( out_data.items() ):
             # use wrapped dataset to access certain values
             wrapped_data = param_dict.get( out_name )
             # allow multiple files to be created
@@ -2192,7 +2216,7 @@ class SetMetadataTool( Tool ):
     requires_setting_metadata = False
 
     def exec_after_process( self, app, inp_data, out_data, param_dict, job=None ):
-        for name, dataset in inp_data.iteritems():
+        for name, dataset in inp_data.items():
             external_metadata = JobExternalOutputMetadataWrapper( job )
             if external_metadata.external_metadata_set_successfully( dataset, app.model.context ):
                 dataset.metadata.from_JSON_dict( external_metadata.get_output_filenames_by_dataset( dataset, app.model.context ).filename_out )
@@ -2250,7 +2274,7 @@ def exec_after_process( self, app, inp_data, out_data, param_dict, job=None, **k
         if job and job.state == job.states.ERROR:
             return
         # Job state may now be 'running' instead of previous 'error', but datasets are still set to e.g. error
-        for dataset in out_data.itervalues():
+        for dataset in out_data.values():
             if dataset.state != dataset.states.OK:
                 return
         data_manager_id = job.data_manager_association.data_manager_id
@@ -2385,7 +2409,7 @@ def produce_outputs( self, trans, out_data, output_collections, incoming, histor
         new_elements["reverse"] = reverse
 
         output_collections.create_collection(
-            self.outputs.values()[0], "output", elements=new_elements
+            next(iter(self.outputs.values())), "output", elements=new_elements
         )
 
 
@@ -2464,7 +2488,7 @@ def produce_outputs( self, trans, out_data, output_collections, incoming, histor
             new_elements[key] = value.copy()
 
         output_collections.create_collection(
-            self.outputs.values()[0], "output", elements=new_elements
+            next(iter(self.outputs.values())), "output", elements=new_elements
         )
 
 
@@ -2499,7 +2523,7 @@ def produce_outputs( self, trans, out_data, output_collections, incoming, histor
                 new_elements[element_identifier] = element.copy()
 
         output_collections.create_collection(
-            self.outputs.values()[0], "output", elements=new_elements
+            next(iter(self.outputs.values())), "output", elements=new_elements
         )
 
 
@@ -2523,7 +2547,7 @@ def add_elements(collection, prefix=""):
 
         add_elements(hdca.collection)
         output_collections.create_collection(
-            self.outputs.values()[0], "output", elements=new_elements
+            next(iter(self.outputs.values())), "output", elements=new_elements
         )
 
 
diff --git a/lib/galaxy/tools/data/__init__.py b/lib/galaxy/tools/data/__init__.py
index f13d4c9b1b4b..8de016426b37 100644
--- a/lib/galaxy/tools/data/__init__.py
+++ b/lib/galaxy/tools/data/__init__.py
@@ -6,21 +6,20 @@
 to modify the tool configurations.
 """
 
+import hashlib
 import logging
 import os
 import os.path
 import re
 import string
-import hashlib
-
 from glob import glob
 from tempfile import NamedTemporaryFile
-from urllib2 import urlopen
 
-from galaxy import util
-from galaxy.util.odict import odict
+from six.moves.urllib.request import urlopen
 
+from galaxy import util
 from galaxy.util.dictifiable import Dictifiable
+from galaxy.util.odict import odict
 
 log = logging.getLogger( __name__ )
 
@@ -158,7 +157,7 @@ def to_xml_file( self, shed_tool_data_table_config, new_elems=None, remove_elems
             for elem in out_elems:
                 out.write( util.xml_to_string( elem, pretty=True ) )
             out.write( '</tables>\n' )
-        os.chmod( full_path, 0644 )
+        os.chmod( full_path, 0o644 )
 
     def reload_tables( self, table_names=None ):
         """
@@ -166,7 +165,7 @@ def reload_tables( self, table_names=None ):
         """
         tables = self.get_tables()
         if not table_names:
-            table_names = tables.keys()
+            table_names = list(tables.keys())
         elif not isinstance( table_names, list ):
             table_names = [ table_names ]
         for table_name in table_names:
@@ -349,7 +348,7 @@ def configure_and_load( self, config_element, tool_data_path, from_shed_config=F
                 self.filenames[ filename ] = dict( found=found, filename=filename, from_shed_config=from_shed_config, tool_data_path=tool_data_path,
                                                    config_element=config_element, tool_shed_repository=repo_info, errors=errors )
             else:
-                log.debug( "Filename '%s' already exists in filenames (%s), not adding", filename, self.filenames.keys() )
+                log.debug( "Filename '%s' already exists in filenames (%s), not adding", filename, list(self.filenames.keys()) )
             # Remove URL tmp file
             if tmp_file is not None:
                 tmp_file.close()
@@ -357,7 +356,7 @@ def configure_and_load( self, config_element, tool_data_path, from_shed_config=F
     def merge_tool_data_table( self, other_table, allow_duplicates=True, persist=False, persist_on_error=False, entry_source=None, **kwd ):
         assert self.columns == other_table.columns, "Merging tabular data tables with non matching columns is not allowed: %s:%s != %s:%s" % ( self.name, self.columns, other_table.name, other_table.columns )
         # merge filename info
-        for filename, info in other_table.filenames.iteritems():
+        for filename, info in other_table.filenames.items():
             if filename not in self.filenames:
                 self.filenames[ filename ] = info
         # save info about table
@@ -473,7 +472,7 @@ def get_column_name_list( self ):
         rval = []
         for i in range( self.largest_index + 1 ):
             found_column = False
-            for name, index in self.columns.iteritems():
+            for name, index in self.columns.items():
                 if index == i:
                     if not found_column:
                         rval.append( name )
@@ -530,7 +529,7 @@ def get_filename_for_source( self, source, default=None ):
         else:
             source_repo_info = None
         filename = default
-        for name, value in self.filenames.iteritems():
+        for name, value in self.filenames.items():
             repo_info = value.get( 'tool_shed_repository', None )
             if ( not source_repo_info and not repo_info ) or ( source_repo_info and repo_info and source_repo_info == repo_info ):
                 filename = name
@@ -637,7 +636,7 @@ def _replace_field_separators( self, fields, separator=None, replace=None, comme
                     replace = "_"
                 else:
                     replace = " "
-        return map( lambda x: x.replace( separator, replace ), fields )
+        return [x.replace( separator, replace ) for x in fields]
 
     def _deduplicate_data( self ):
         # Remove duplicate entries, without recreating self.data object
diff --git a/lib/galaxy/tools/data_manager/manager.py b/lib/galaxy/tools/data_manager/manager.py
index 44691e7fd569..aa57a35cc873 100644
--- a/lib/galaxy/tools/data_manager/manager.py
+++ b/lib/galaxy/tools/data_manager/manager.py
@@ -1,20 +1,24 @@
 import errno
 import json
+import logging
 import os
+
 from six import string_types
 
 from galaxy import util
-from galaxy.util.odict import odict
-from galaxy.util.template import fill_template
+from galaxy.queue_worker import (
+    reload_data_managers,
+    send_control_task
+)
 from galaxy.tools.data import TabularToolDataTable
 from galaxy.tools.toolbox.watcher import get_tool_conf_watcher
-from tool_shed.util import common_util
-from tool_shed.util import repository_util
-from galaxy.queue_worker import reload_data_managers
-from galaxy.queue_worker import send_control_task
+from galaxy.util.odict import odict
+from galaxy.util.template import fill_template
+from tool_shed.util import (
+    common_util,
+    repository_util
+)
 
-# set up logger
-import logging
 log = logging.getLogger( __name__ )
 
 SUPPORTED_DATA_TABLE_TYPES = ( TabularToolDataTable )
@@ -112,7 +116,7 @@ def remove_manager( self, manager_ids ):
                 # determine if any data_tables are no longer tracked
                 for data_table_name in data_manager.data_tables.keys():
                     remove_data_table_tracking = True
-                    for other_data_manager in self.data_managers.itervalues():
+                    for other_data_manager in self.data_managers.values():
                         if data_table_name in other_data_manager.data_tables:
                             remove_data_table_tracking = False
                             break
@@ -279,21 +283,21 @@ def process_result( self, out_data ):
         data_manager_dicts = {}
         data_manager_dict = {}
         # TODO: fix this merging below
-        for output_name, output_dataset in out_data.iteritems():
+        for output_name, output_dataset in out_data.items():
             try:
                 output_dict = json.loads( open( output_dataset.file_name ).read() )
             except Exception as e:
                 log.warning( 'Error reading DataManagerTool json for "%s": %s' % ( output_name, e ) )
                 continue
             data_manager_dicts[ output_name ] = output_dict
-            for key, value in output_dict.iteritems():
+            for key, value in output_dict.items():
                 if key not in data_manager_dict:
                     data_manager_dict[ key ] = {}
                 data_manager_dict[ key ].update( value )
             data_manager_dict.update( output_dict )
 
         data_tables_dict = data_manager_dict.get( 'data_tables', {} )
-        for data_table_name in self.data_tables.iterkeys():
+        for data_table_name in self.data_tables.keys():
             data_table_values = data_tables_dict.pop( data_table_name, None )
             if not data_table_values:
                 log.warning( 'No values for data table "%s" were returned by the data manager "%s".' % ( data_table_name, self.id ) )
@@ -307,7 +311,7 @@ def process_result( self, out_data ):
                 continue  # next table name
             output_ref_values = {}
             if data_table_name in self.output_ref_by_data_table:
-                for data_table_column, output_ref in self.output_ref_by_data_table[ data_table_name ].iteritems():
+                for data_table_column, output_ref in self.output_ref_by_data_table[ data_table_name ].items():
                     output_ref_dataset = out_data.get( output_ref, None )
                     assert output_ref_dataset is not None, "Referenced output was not found."
                     output_ref_values[ data_table_column ] = output_ref_dataset
@@ -316,7 +320,7 @@ def process_result( self, out_data ):
                 data_table_values = [ data_table_values ]
             for data_table_row in data_table_values:
                 data_table_value = dict( **data_table_row )  # keep original values here
-                for name, value in data_table_row.iteritems():  # FIXME: need to loop through here based upon order listed in data_manager config
+                for name, value in data_table_row.items():  # FIXME: need to loop through here based upon order listed in data_manager config
                     if name in output_ref_values:
                         self.process_move( data_table_name, name, output_ref_values[ name ].extra_files_path, **data_table_value )
                         data_table_value[ name ] = self.process_value_translation( data_table_name, name, **data_table_value )
@@ -332,13 +336,13 @@ def process_result( self, out_data ):
             for ref_file in out_data.values():
                 util.move_merge( ref_file.extra_files_path, self.data_managers.app.config.galaxy_data_manager_data_path )
             path_column_names = [ 'path' ]
-            for data_table_name, data_table_values in data_tables_dict.iteritems():
+            for data_table_name, data_table_values in data_tables_dict.items():
                 data_table = self.data_managers.app.tool_data_tables.get( data_table_name, None )
                 if not isinstance( data_table_values, list ):
                     data_table_values = [ data_table_values ]
                 for data_table_row in data_table_values:
                     data_table_value = dict( **data_table_row )  # keep original values here
-                    for name, value in data_table_row.iteritems():
+                    for name, value in data_table_row.items():
                         if name in path_column_names:
                             data_table_value[ name ] = os.path.abspath( os.path.join( self.data_managers.app.config.galaxy_data_manager_data_path, value ) )
                     data_table.add_entry( data_table_value, persist=True, entry_source=self )
@@ -346,7 +350,7 @@ def process_result( self, out_data ):
                                       noop_self=True,
                                       kwargs={'table_name': data_table_name} )
         else:
-            for data_table_name, data_table_values in data_tables_dict.iteritems():
+            for data_table_name, data_table_values in data_tables_dict.items():
                 # tool returned extra data table entries, but data table was not declared in data manager
                 # do not add these values, but do provide messages
                 log.warning( 'The data manager "%s" returned an undeclared data table "%s" with new entries "%s". These entries will not be created. Please confirm that an entry for "%s" exists in your "%s" file.' % ( self.id, data_table_name, data_table_values, data_table_name, self.data_managers.filename ) )
diff --git a/lib/galaxy/tools/deps/resolvers/resolver_mixins.py b/lib/galaxy/tools/deps/resolvers/resolver_mixins.py
index 1a330af9d877..61663e0c08b0 100644
--- a/lib/galaxy/tools/deps/resolvers/resolver_mixins.py
+++ b/lib/galaxy/tools/deps/resolvers/resolver_mixins.py
@@ -41,7 +41,7 @@ def _installed_versions(self, recipe):
             return []
 
         names = os.listdir(recipe_base_path)
-        return filter(lambda n: os.path.isdir(os.path.join(recipe_base_path, n)), names)
+        return [n for n in names if os.path.isdir(os.path.join(recipe_base_path, n))]
 
 
 class UsesToolDependencyDirMixin:
@@ -53,14 +53,10 @@ def _init_base_path(self, dependency_manager, **kwds):
 class UsesInstalledRepositoriesMixin:
 
     def _get_installed_dependency( self, name, type, version=None, **kwds ):
-        installed_tool_dependencies = kwds.get("installed_tool_dependencies", [])
-        for installed_tool_dependency in (installed_tool_dependencies or []):
-            name_and_type_equal = installed_tool_dependency.name == name and installed_tool_dependency.type == type
-            if version:
-                if name_and_type_equal and installed_tool_dependency.version == version:
-                    return installed_tool_dependency
-            else:
-                if name_and_type_equal:
+        installed_tool_dependencies = kwds.get("installed_tool_dependencies") or []
+        for installed_tool_dependency in installed_tool_dependencies:
+            if installed_tool_dependency.name == name and installed_tool_dependency.type == type:
+                if not version or installed_tool_dependency.version == version:
                     return installed_tool_dependency
         return None
 
diff --git a/lib/galaxy/tools/errors.py b/lib/galaxy/tools/errors.py
index 18ca67700a20..faa1dca7018c 100644
--- a/lib/galaxy/tools/errors.py
+++ b/lib/galaxy/tools/errors.py
@@ -1,9 +1,14 @@
 """
 Functionality for dealing with tool errors.
 """
-import string
-from galaxy import model, util, web
 import cgi
+import string
+
+from galaxy import (
+    model,
+    util,
+    web
+)
 from galaxy.util import unicodify
 
 error_report_template = """
diff --git a/lib/galaxy/tools/evaluation.py b/lib/galaxy/tools/evaluation.py
index e0a2e32de789..440f04e8c92c 100644
--- a/lib/galaxy/tools/evaluation.py
+++ b/lib/galaxy/tools/evaluation.py
@@ -1,33 +1,42 @@
 import json
+import logging
 import os
 import tempfile
+
 from six import string_types
 
 from galaxy import model
-from galaxy.util.object_wrapper import wrap_with_safe_string
-from galaxy.util.bunch import Bunch
-from galaxy.util.none_like import NoneDataset
-from galaxy.util.template import fill_template
-from galaxy.tools.wrappers import (
-    ToolParameterValueWrapper,
-    DatasetFilenameWrapper,
-    DatasetListWrapper,
-    DatasetCollectionWrapper,
-    SelectToolParameterWrapper,
-    InputValueWrapper,
-    RawObjectWrapper
+from galaxy.jobs.datasets import dataset_path_rewrites
+from galaxy.tools import global_tool_errors
+from galaxy.tools.parameters import (
+    visit_input_values,
+    wrapped_json,
 )
 from galaxy.tools.parameters.basic import (
-    DataToolParameter,
     DataCollectionToolParameter,
+    DataToolParameter,
     SelectToolParameter,
 )
-from galaxy.tools.parameters import wrapped_json, visit_input_values
-from galaxy.tools.parameters.grouping import Conditional, Repeat, Section
-from galaxy.tools import global_tool_errors
-from galaxy.jobs.datasets import dataset_path_rewrites
+from galaxy.tools.parameters.grouping import (
+    Conditional,
+    Repeat,
+    Section
+)
+from galaxy.tools.wrappers import (
+    DatasetCollectionWrapper,
+    DatasetFilenameWrapper,
+    DatasetListWrapper,
+    InputValueWrapper,
+    RawObjectWrapper,
+    SelectToolParameterWrapper,
+    ToolParameterValueWrapper,
+)
+from galaxy.util.bunch import Bunch
+from galaxy.util.none_like import NoneDataset
+from galaxy.util.object_wrapper import wrap_with_safe_string
+from galaxy.util.template import fill_template
 from galaxy.work.context import WorkRequestContext
-import logging
+
 log = logging.getLogger( __name__ )
 
 
@@ -150,7 +159,7 @@ def do_walk( inputs, input_values ):
             """
             Wraps parameters as neccesary.
             """
-            for input in inputs.itervalues():
+            for input in inputs.values():
                 if isinstance( input, Repeat ):
                     for d in input_values[ input.name ]:
                         do_walk( input.inputs, d )
@@ -256,7 +265,7 @@ def wrap_input( input_values, input ):
         #       tools where the inputs don't even get passed through. These
         #       tools (e.g. UCSC) should really be handled in a special way.
         if self.tool.check_values:
-            identifier_key_dict = dict((v, "%s|__identifier__" % k) for k, v in input_datasets.iteritems())  # allows lookup of identifier through HDA.
+            identifier_key_dict = dict((v, "%s|__identifier__" % k) for k, v in input_datasets.items())  # allows lookup of identifier through HDA.
             self.__walk_inputs( self.tool.inputs, param_dict, wrap_input )
 
     def __populate_input_dataset_wrappers(self, param_dict, input_datasets, input_dataset_paths):
@@ -347,7 +356,7 @@ def __populate_output_dataset_wrappers(self, param_dict, output_datasets, output
             param_dict[name].files_path = os.path.abspath(os.path.join( job_working_directory, "dataset_%s_files" % (hda.dataset.id) ))
             for child in hda.children:
                 param_dict[ "_CHILD___%s___%s" % ( name, child.designation ) ] = DatasetFilenameWrapper( child )
-        for out_name, output in self.tool.outputs.iteritems():
+        for out_name, output in self.tool.outputs.items():
             if out_name not in param_dict and output.filters:
                 # Assume the reason we lack this output is because a filter
                 # failed to pass; for tool writing convienence, provide a
@@ -407,9 +416,9 @@ def __sanitize_param_dict( self, param_dict ):
         Note: this method follows the style of the similar populate calls, in that param_dict is modified in-place.
         """
         # chromInfo is a filename, do not sanitize it.
-        skip = [ 'chromInfo' ] + self.tool.template_macro_params.keys()
+        skip = [ 'chromInfo' ] + list(self.tool.template_macro_params.keys())
         if not self.tool or not self.tool.options or self.tool.options.sanitize:
-            for key, value in param_dict.items():
+            for key, value in list(param_dict.items()):
                 if key not in skip:
                     # Remove key so that new wrapped object will occupy key slot
                     del param_dict[key]
@@ -565,7 +574,7 @@ def __write_workdir_file( self, config_filename, content, context, is_template=T
         with open( config_filename, "w" ) as f:
             f.write( value )
         # For running jobs as the actual user, ensure the config file is globally readable
-        os.chmod( config_filename, 0644 )
+        os.chmod( config_filename, 0o644 )
 
     def __register_extra_file( self, name, local_config_path ):
         """
diff --git a/lib/galaxy/tools/imp_exp/__init__.py b/lib/galaxy/tools/imp_exp/__init__.py
index 248da34f54ca..3fde45703f36 100644
--- a/lib/galaxy/tools/imp_exp/__init__.py
+++ b/lib/galaxy/tools/imp_exp/__init__.py
@@ -342,7 +342,7 @@ def get_item_tag_dict( item ):
 
         def prepare_metadata( metadata ):
             """ Prepare metatdata for exporting. """
-            for name, value in metadata.items():
+            for name, value in list(metadata.items()):
                 # Metadata files are not needed for export because they can be
                 # regenerated.
                 if isinstance( value, trans.app.model.MetadataFile ):
diff --git a/lib/galaxy/tools/imp_exp/export_history.py b/lib/galaxy/tools/imp_exp/export_history.py
index 618c63e12676..3f1ae0e19583 100644
--- a/lib/galaxy/tools/imp_exp/export_history.py
+++ b/lib/galaxy/tools/imp_exp/export_history.py
@@ -5,6 +5,7 @@
 usage: %prog history_attrs dataset_attrs job_attrs out_file
     -G, --gzip: gzip archive file
 """
+from __future__ import print_function
 
 import optparse
 import os
@@ -105,7 +106,7 @@ def main():
 
     # Create archive.
     status = create_archive( history_attrs, dataset_attrs, job_attrs, out_file, gzip )
-    print status
+    print(status)
 
 
 if __name__ == "__main__":
diff --git a/lib/galaxy/tools/imp_exp/unpack_tar_gz_archive.py b/lib/galaxy/tools/imp_exp/unpack_tar_gz_archive.py
index 932779c0e438..ee15bcf8cfda 100644
--- a/lib/galaxy/tools/imp_exp/unpack_tar_gz_archive.py
+++ b/lib/galaxy/tools/imp_exp/unpack_tar_gz_archive.py
@@ -5,16 +5,18 @@
 usage: %prog archive_source dest_dir
     --[url|file] source type, either a URL or a file.
 """
+from __future__ import print_function
 
+import math
+import optparse
 import os
 import sys
-import optparse
 import tarfile
 import tempfile
-import urllib2
-import math
 from base64 import b64decode
 
+from six.moves.urllib.request import urlopen
+
 # Set max size of archive/file that will be handled to be 100 GB. This is
 # arbitrary and should be adjusted as needed.
 MAX_SIZE = 100 * math.pow( 2, 30 )
@@ -25,7 +27,7 @@ def url_to_file( url, dest_file ):
     Transfer a file from a remote URL to a temporary file.
     """
     try:
-        url_reader = urllib2.urlopen( url )
+        url_reader = urlopen( url )
         CHUNK = 10 * 1024  # 10k
         total = 0
         fp = open( dest_file, 'wb')
@@ -40,7 +42,7 @@ def url_to_file( url, dest_file ):
         fp.close()
         return dest_file
     except Exception as e:
-        print "Exception getting file from URL: %s" % e, sys.stderr
+        print("Exception getting file from URL: %s" % e, file=sys.stderr)
         return None
 
 
@@ -99,4 +101,4 @@ def main(options, args):
     try:
         main(options, args)
     except Exception as e:
-        print "Error unpacking tar/gz archive: %s" % e, sys.stderr
+        print("Error unpacking tar/gz archive: %s" % e, file=sys.stderr)
diff --git a/lib/galaxy/tools/parameters/basic.py b/lib/galaxy/tools/parameters/basic.py
index e96d55cd0774..77a16d638ebc 100644
--- a/lib/galaxy/tools/parameters/basic.py
+++ b/lib/galaxy/tools/parameters/basic.py
@@ -1,29 +1,38 @@
 """
 Basic tool parameters.
 """
-
 import logging
-import re
 import os
 import os.path
-from six import string_types
+import re
 from xml.etree.ElementTree import XML
 
+from six import string_types
+
+import galaxy.model
+import galaxy.tools.parser
 from galaxy import util
-from galaxy.util import string_as_bool, sanitize_param, unicodify
+from galaxy.util import (
+    sanitize_param,
+    string_as_bool,
+    unicodify
+)
+from galaxy.util.bunch import Bunch
+from galaxy.util.dictifiable import Dictifiable
 from galaxy.util.expressions import ExpressionContext
-from sanitize import ToolParameterSanitizer
-import validation
-import galaxy.tools.parser
-from ..parser import get_input_source as ensure_input_source
-from ..parameters import history_query
-from ..parameters import dynamic_options
-from .dataset_matcher import DatasetMatcher
-from .dataset_matcher import DatasetCollectionMatcher
 from galaxy.web import url_for
-from galaxy.util.dictifiable import Dictifiable
-import galaxy.model
-from galaxy.util.bunch import Bunch
+
+from . import validation
+from .dataset_matcher import (
+    DatasetCollectionMatcher,
+    DatasetMatcher
+)
+from .sanitize import ToolParameterSanitizer
+from ..parameters import (
+    dynamic_options,
+    history_query
+)
+from ..parser import get_input_source as ensure_input_source
 
 log = logging.getLogger( __name__ )
 
@@ -798,7 +807,7 @@ def get_legal_values( self, trans, other_values ):
     def from_json( self, value, trans, other_values={} ):
         legal_values = self.get_legal_values( trans, other_values )
         workflow_building_mode = trans.workflow_building_mode
-        for context_value in other_values.itervalues():
+        for context_value in other_values.values():
             if isinstance( context_value, RuntimeValue ):
                 workflow_building_mode = True
                 break
@@ -848,7 +857,7 @@ def to_param_dict_string( self, value, other_values={} ):
         if isinstance( value, list ):
             if not self.multiple:
                 raise ValueError( "Multiple values provided but parameter %s is not expecting multiple values." % self.name )
-            value = map( str, value )
+            value = list(map( str, value ))
         else:
             value = str( value )
         if self.tool is None or self.tool.options.sanitize:
@@ -1045,7 +1054,7 @@ def from_json( self, value, trans, other_values={} ):
                         column2 = column2.strip()
                         if column2:
                             column_list.append( column2 )
-                value = map( ColumnListParameter._strip_c, column_list )
+                value = list(map( ColumnListParameter._strip_c, column_list ))
             else:
                 value = []
         else:
@@ -1097,7 +1106,7 @@ def get_column_list( self, trans, other_values ):
             if column_list is None:
                 column_list = this_column_list
             else:
-                column_list = filter( lambda c: c in this_column_list, column_list )
+                column_list = [c for c in column_list if c in this_column_list]
         return column_list
 
     def get_options( self, trans, other_values ):
@@ -1248,12 +1257,12 @@ def get_options( self, trans=None, value=None, other_values={} ):
                 options = self._get_options_from_code( trans=trans, value=value, other_values=other_values )
             else:
                 options = []
-            for filter_key, filter_value in self.filtered.iteritems():
+            for filter_key, filter_value in self.filtered.items():
                 dataset = other_values.get(filter_key)
                 if dataset.__class__.__name__.endswith( "DatasetFilenameWrapper" ):  # this is a bad way to check for this, but problems importing class ( due to circular imports? )
                     dataset = dataset.dataset
                 if dataset:
-                    for meta_key, meta_dict in filter_value.iteritems():
+                    for meta_key, meta_dict in filter_value.items():
                         if hasattr( dataset, 'metadata' ) and hasattr( dataset.metadata, 'spec' ):
                             check_meta_val = dataset.metadata.spec[ meta_key ].param.to_string( dataset.metadata.get( meta_key ) )
                             if check_meta_val in meta_dict:
@@ -1387,7 +1396,7 @@ def get_dependencies( self ):
         """
         Get the *names* of the other params this param depends on.
         """
-        return self.filtered.keys()
+        return list(self.filtered.keys())
 
     def to_dict( self, trans, other_values={} ):
         # skip SelectToolParameter (the immediate parent) bc we need to get options in a different way here
@@ -1762,8 +1771,8 @@ def to_dict( self, trans, other_values={} ):
         datatypes_registery = self._datatypes_registery( trans, self.tool )
         all_edam_formats = datatypes_registery.edam_formats if hasattr( datatypes_registery, 'edam_formats' ) else {}
         all_edam_data = datatypes_registery.edam_data if hasattr( datatypes_registery, 'edam_formats' ) else {}
-        edam_formats = map(lambda ext: all_edam_formats.get(ext, None), extensions)
-        edam_data = map(lambda ext: all_edam_data.get(ext, None), extensions)
+        edam_formats = [all_edam_formats.get(ext, None) for ext in extensions]
+        edam_data = [all_edam_data.get(ext, None) for ext in extensions]
 
         d['extensions'] = extensions
         d['edam'] = {'edam_formats': edam_formats, 'edam_data': edam_data}
diff --git a/lib/galaxy/tools/parameters/dynamic_options.py b/lib/galaxy/tools/parameters/dynamic_options.py
index 248301781d26..b32ea7518524 100644
--- a/lib/galaxy/tools/parameters/dynamic_options.py
+++ b/lib/galaxy/tools/parameters/dynamic_options.py
@@ -2,13 +2,20 @@
 Support for generating the options for a SelectToolParameter dynamically (based
 on the values of other parameters or other aspects of the current state)
 """
-
 import logging
 import os
-import validation
-from galaxy.util import string_as_bool
-from galaxy.model import User, HistoryDatasetAssociation, HistoryDatasetCollectionAssociation
+
+from six import StringIO
+
 import galaxy.tools
+from galaxy.model import (
+    HistoryDatasetAssociation,
+    HistoryDatasetCollectionAssociation,
+    User
+)
+from galaxy.util import string_as_bool
+
+from . import validation
 
 log = logging.getLogger(__name__)
 
@@ -590,10 +597,9 @@ def get_fields( self, trans, other_values ):
                 options = self.parse_file_fields( open( path ) )
             else:
                 # Pass just the first megabyte to parse_file_fields.
-                import StringIO
                 log.warning( "Attempting to load options from large file, reading just first megabyte" )
                 contents = open( path, 'r' ).read( 1048576 )
-                options = self.parse_file_fields( StringIO.StringIO( contents ) )
+                options = self.parse_file_fields( StringIO( contents ) )
         elif self.tool_data_table:
             options = self.tool_data_table.get_fields()
         else:
diff --git a/lib/galaxy/tools/parameters/grouping.py b/lib/galaxy/tools/parameters/grouping.py
index 22a74d46a93b..f83d66490500 100644
--- a/lib/galaxy/tools/parameters/grouping.py
+++ b/lib/galaxy/tools/parameters/grouping.py
@@ -1,21 +1,26 @@
 """
 Constructs for grouping tool parameters
 """
-
 import logging
-log = logging.getLogger( __name__ )
-
 import os
-import StringIO
 import unicodedata
-from six import text_type
+
+from six import (
+    StringIO,
+    text_type
+)
+
 from galaxy.datatypes import sniff
-from galaxy.util import inflector
-from galaxy.util import relpath
-from galaxy.util import sanitize_for_filename
+from galaxy.util import (
+    inflector,
+    relpath,
+    sanitize_for_filename
+)
 from galaxy.util.bunch import Bunch
-from galaxy.util.expressions import ExpressionContext
 from galaxy.util.dictifiable import Dictifiable
+from galaxy.util.expressions import ExpressionContext
+
+log = logging.getLogger( __name__ )
 
 
 class Group( object, Dictifiable ):
@@ -82,7 +87,7 @@ def value_to_basic( self, value, app ):
             # Propogate __index__
             if '__index__' in d:
                 rval_dict['__index__'] = d['__index__']
-            for input in self.inputs.itervalues():
+            for input in self.inputs.values():
                 rval_dict[ input.name ] = input.value_to_basic( d[input.name], app )
             rval.append( rval_dict )
         return rval
@@ -96,7 +101,7 @@ def value_from_basic( self, value, app, ignore_errors=False ):
                 # compatibility)
                 rval_dict['__index__'] = d.get( '__index__', i )
                 # Restore child inputs
-                for input in self.inputs.itervalues():
+                for input in self.inputs.values():
                     if ignore_errors and input.name not in d:
                         # If we do not have a value, and are ignoring errors, we simply
                         # do nothing. There will be no value for the parameter in the
@@ -114,7 +119,7 @@ def get_initial_value( self, trans, context ):
         rval = []
         for i in range( self.default ):
             rval_dict = { '__index__': i}
-            for input in self.inputs.itervalues():
+            for input in self.inputs.values():
                 rval_dict[ input.name ] = input.get_initial_value( trans, context )
             rval.append( rval_dict )
         return rval
@@ -125,7 +130,7 @@ def to_dict( self, trans ):
         def input_to_dict( input ):
             return input.to_dict( trans )
 
-        repeat_dict[ "inputs" ] = map( input_to_dict, self.inputs.values() )
+        repeat_dict[ "inputs" ] = list(map( input_to_dict, self.inputs.values() ))
         return repeat_dict
 
 
@@ -150,14 +155,14 @@ def label( self ):
 
     def value_to_basic( self, value, app ):
         rval = {}
-        for input in self.inputs.itervalues():
+        for input in self.inputs.values():
             rval[ input.name ] = input.value_to_basic( value[input.name], app )
         return rval
 
     def value_from_basic( self, value, app, ignore_errors=False ):
         rval = {}
         try:
-            for input in self.inputs.itervalues():
+            for input in self.inputs.values():
                 if not ignore_errors or input.name in value:
                     rval[ input.name ] = input.value_from_basic( value[ input.name ], app, ignore_errors )
         except Exception as e:
@@ -168,7 +173,7 @@ def value_from_basic( self, value, app, ignore_errors=False ):
     def get_initial_value( self, trans, context ):
         rval = {}
         child_context = ExpressionContext( rval, context )
-        for child_input in self.inputs.itervalues():
+        for child_input in self.inputs.values():
             rval[ child_input.name ] = child_input.get_initial_value( trans, child_context )
         return rval
 
@@ -178,7 +183,7 @@ def to_dict( self, trans ):
         def input_to_dict( input ):
             return input.to_dict( trans )
 
-        section_dict[ "inputs" ] = map( input_to_dict, self.inputs.values() )
+        section_dict[ "inputs" ] = list(map( input_to_dict, self.inputs.values() ))
         return section_dict
 
 
@@ -232,7 +237,7 @@ def group_title( self, context ):
 
     def title_by_index( self, trans, index, context ):
         d_type = self.get_datatype( trans, context )
-        for i, ( composite_name, composite_file ) in enumerate( d_type.writable_files.iteritems() ):
+        for i, ( composite_name, composite_file ) in enumerate( d_type.writable_files.items() ):
             if i == index:
                 rval = composite_name
                 if composite_file.description:
@@ -249,7 +254,7 @@ def value_to_basic( self, value, app ):
             # Propogate __index__
             if '__index__' in d:
                 rval_dict['__index__'] = d['__index__']
-            for input in self.inputs.itervalues():
+            for input in self.inputs.values():
                 rval_dict[ input.name ] = input.value_to_basic( d[input.name], app )
             rval.append( rval_dict )
         return rval
@@ -262,7 +267,7 @@ def value_from_basic( self, value, app, ignore_errors=False ):
             # compatibility)
             rval_dict['__index__'] = d.get( '__index__', i )
             # Restore child inputs
-            for input in self.inputs.itervalues():
+            for input in self.inputs.values():
                 if ignore_errors and input.name not in d:  # this wasn't tested
                     rval_dict[ input.name ] = input.get_initial_value( None, d )
                 else:
@@ -273,10 +278,10 @@ def value_from_basic( self, value, app, ignore_errors=False ):
     def get_initial_value( self, trans, context ):
         d_type = self.get_datatype( trans, context )
         rval = []
-        for i, ( composite_name, composite_file ) in enumerate( d_type.writable_files.iteritems() ):
+        for i, ( composite_name, composite_file ) in enumerate( d_type.writable_files.items() ):
             rval_dict = {}
             rval_dict['__index__'] = i  # create __index__
-            for input in self.inputs.itervalues():
+            for input in self.inputs.values():
                 rval_dict[ input.name ] = input.get_initial_value( trans, context )
             rval.append( rval_dict )
         return rval
@@ -467,8 +472,8 @@ def get_filenames( context ):
             dataset.uuid = None
             # load metadata
             files_metadata = context.get( self.metadata_ref, {} )
-            metadata_name_substition_default_dict = dict( [ ( composite_file.substitute_name_with_metadata, d_type.metadata_spec[ composite_file.substitute_name_with_metadata ].default ) for composite_file in d_type.composite_files.values() if composite_file.substitute_name_with_metadata ] )
-            for meta_name, meta_spec in d_type.metadata_spec.iteritems():
+            metadata_name_substition_default_dict = dict( ( composite_file.substitute_name_with_metadata, d_type.metadata_spec[ composite_file.substitute_name_with_metadata ].default ) for composite_file in d_type.composite_files.values() if composite_file.substitute_name_with_metadata )
+            for meta_name, meta_spec in d_type.metadata_spec.items():
                 if meta_spec.set_in_upload:
                     if meta_name in files_metadata:
                         meta_value = files_metadata[ meta_name ]
@@ -478,7 +483,7 @@ def get_filenames( context ):
             dataset.precreated_name = dataset.name = self.get_composite_dataset_name( context )
             if dataset.datatype.composite_type == 'auto_primary_file':
                 # replace sniff here with just creating an empty file
-                temp_name, is_multi_byte = sniff.stream_to_file( StringIO.StringIO( d_type.generate_primary_file( dataset ) ), prefix='upload_auto_primary_file' )
+                temp_name, is_multi_byte = sniff.stream_to_file( StringIO( d_type.generate_primary_file( dataset ) ), prefix='upload_auto_primary_file' )
                 dataset.primary_file = temp_name
                 dataset.to_posix_lines = True
                 dataset.space_to_tab = False
@@ -494,7 +499,7 @@ def get_filenames( context ):
             keys = [ value.name for value in writable_files.values() ]
             for i, group_incoming in enumerate( groups_incoming[ writable_files_offset : ] ):
                 key = keys[ i + writable_files_offset ]
-                if group_incoming is None and not writable_files[ writable_files.keys()[ keys.index( key ) ] ].optional:
+                if group_incoming is None and not writable_files[ list(writable_files.keys())[ keys.index( key ) ] ].optional:
                     dataset.warnings.append( "A required composite file (%s) was not specified." % ( key ) )
                     dataset.composite_files[ key ] = None
                 else:
@@ -504,7 +509,7 @@ def get_filenames( context ):
                         dataset.composite_files[ key ] = file_bunch.__dict__
                     else:
                         dataset.composite_files[ key ] = None
-                        if not writable_files[ writable_files.keys()[ keys.index( key ) ] ].optional:
+                        if not writable_files[ list(writable_files.keys())[ keys.index( key ) ] ].optional:
                             dataset.warnings.append( "A required composite file (%s) was not specified." % ( key ) )
             return [ dataset ]
         else:
@@ -546,7 +551,7 @@ def value_to_basic( self, value, app ):
         rval = dict()
         rval[ self.test_param.name ] = self.test_param.value_to_basic( value[ self.test_param.name ], app )
         current_case = rval[ '__current_case__' ] = self.get_current_case( value[ self.test_param.name ] )
-        for input in self.cases[ current_case ].inputs.itervalues():
+        for input in self.cases[ current_case ].inputs.values():
             if input.name in value:  # parameter might be absent in unverified workflow
                 rval[ input.name ] = input.value_to_basic( value[ input.name ], app )
         return rval
@@ -557,7 +562,7 @@ def value_from_basic( self, value, app, ignore_errors=False ):
             rval[ self.test_param.name ] = self.test_param.value_from_basic( value.get( self.test_param.name ), app, ignore_errors )
             current_case = rval[ '__current_case__' ] = self.get_current_case( rval[ self.test_param.name ] )
             # Inputs associated with current case
-            for input in self.cases[ current_case ].inputs.itervalues():
+            for input in self.cases[ current_case ].inputs.values():
                 # If we do not have a value, and are ignoring errors, we simply
                 # do nothing. There will be no value for the parameter in the
                 # conditional's values dictionary.
@@ -581,7 +586,7 @@ def get_initial_value( self, trans, context ):
         rval[ self.test_param.name ] = test_value
         # Fill in state for selected case
         child_context = ExpressionContext( rval, context )
-        for child_input in self.cases[current_case].inputs.itervalues():
+        for child_input in self.cases[current_case].inputs.values():
             rval[ child_input.name ] = child_input.get_initial_value( trans, child_context )
         return rval
 
@@ -591,7 +596,7 @@ def to_dict( self, trans ):
         def nested_to_dict( input ):
             return input.to_dict( trans )
 
-        cond_dict[ "cases" ] = map( nested_to_dict, self.cases )
+        cond_dict[ "cases" ] = list(map( nested_to_dict, self.cases ))
         cond_dict[ "test_param" ] = nested_to_dict( self.test_param )
         return cond_dict
 
@@ -609,5 +614,5 @@ def to_dict( self, trans ):
         def input_to_dict( input ):
             return input.to_dict( trans )
 
-        when_dict[ "inputs" ] = map( input_to_dict, self.inputs.values() )
+        when_dict[ "inputs" ] = list(map( input_to_dict, self.inputs.values() ))
         return when_dict
diff --git a/lib/galaxy/tools/parameters/meta.py b/lib/galaxy/tools/parameters/meta.py
index 907889b028c8..79ecbfbc1843 100644
--- a/lib/galaxy/tools/parameters/meta.py
+++ b/lib/galaxy/tools/parameters/meta.py
@@ -1,10 +1,14 @@
-from galaxy.util import permutations
-from galaxy import model
-from galaxy import util
-from galaxy import exceptions
-import itertools
 import copy
+import itertools
 import logging
+
+from galaxy import (
+    exceptions,
+    model,
+    util
+)
+from galaxy.util import permutations
+
 log = logging.getLogger( __name__ )
 
 
@@ -52,10 +56,10 @@ def expand_workflow_inputs( inputs ):
     product = product or [ [ None ] ]
     linked_keys = linked_keys or [ ( None, None ) ]
     product_keys = product_keys or [ ( None, None ) ]
-    for linked_values, product_values in itertools.product( *[ zip( *linked ), itertools.product( *product ) ] ):
+    for linked_values, product_values in itertools.product( zip( *linked ), itertools.product( *product ) ):
         new_params = copy.deepcopy( inputs )
         new_keys = []
-        for ( step_id, key ), value in zip( linked_keys, linked_values ) + zip( product_keys, product_values ):
+        for ( step_id, key ), value in list(zip( linked_keys, linked_values )) + list(zip( product_keys, product_values )):
             if step_id is not None:
                 new_params[ step_id ][ key ] = value
                 new_keys.append( value[ 'hid' ] )
diff --git a/lib/galaxy/tools/parameters/output_collect.py b/lib/galaxy/tools/parameters/output_collect.py
index 4be37808550c..91a4f00401d5 100644
--- a/lib/galaxy/tools/parameters/output_collect.py
+++ b/lib/galaxy/tools/parameters/output_collect.py
@@ -1,24 +1,25 @@
 """ Code allowing tools to define extra files associated with an output datset.
 """
-import os
-import re
-import operator
 import glob
 import json
+import logging
+import operator
+import os
+import re
 
 from galaxy import jobs
 from galaxy import util
-from galaxy.util import odict
-from galaxy.util import ExecutionTimer
 from galaxy.tools.parser.output_collection_def import (
     DEFAULT_DATASET_COLLECTOR_DESCRIPTION,
     INPUT_DBKEY_TOKEN,
 )
+from galaxy.util import (
+    ExecutionTimer,
+    odict
+)
 
 DATASET_ID_TOKEN = "DATASET_ID"
 
-
-import logging
 log = logging.getLogger( __name__ )
 
 
@@ -105,7 +106,7 @@ def populate_collection_elements( self, collection, root_collection_builder, out
         filenames = self.find_files( collection, dataset_collectors )
 
         element_datasets = []
-        for filename, extra_file_collector in filenames.iteritems():
+        for filename, extra_file_collector in filenames.items():
             create_dataset_timer = ExecutionTimer()
             fields_match = extra_file_collector.match( collection, os.path.basename( filename ) )
             if not fields_match:
@@ -248,7 +249,7 @@ def collect_primary_datasets( tool, output, job_working_directory, input_ext, in
         if 'job_working_directory' in app.config.collect_outputs_from:
             for path, extra_file_collector in walk_over_extra_files( dataset_collectors, job_working_directory, outdata ):
                 filenames[ path ] = extra_file_collector
-        for filename_index, ( filename, extra_file_collector ) in enumerate( filenames.iteritems() ):
+        for filename_index, ( filename, extra_file_collector ) in enumerate( filenames.items() ):
             fields_match = extra_file_collector.match( outdata, os.path.basename( filename ) )
             if not fields_match:
                 # Before I guess pop() would just have thrown an IndexError
diff --git a/lib/galaxy/tools/search/__init__.py b/lib/galaxy/tools/search/__init__.py
index 6261781f6f4f..9c4867c71b3f 100644
--- a/lib/galaxy/tools/search/__init__.py
+++ b/lib/galaxy/tools/search/__init__.py
@@ -5,16 +5,23 @@
 import logging
 import re
 import tempfile
-
-from galaxy.web.framework.helpers import to_unicode
 from datetime import datetime
 
-from whoosh.filedb.filestore import RamStorage, FileStorage
-from whoosh.fields import KEYWORD, Schema, STORED, TEXT
-from whoosh.scoring import BM25F
-from whoosh.qparser import MultifieldParser
 from whoosh import analysis
+from whoosh.fields import (
+    KEYWORD,
+    Schema,
+    STORED,
+    TEXT
+)
+from whoosh.filedb.filestore import (
+    FileStorage,
+    RamStorage
+)
+from whoosh.qparser import MultifieldParser
+from whoosh.scoring import BM25F
 
+from galaxy.web.framework.helpers import to_unicode
 
 log = logging.getLogger( __name__ )
 
diff --git a/lib/galaxy/tools/util/galaxyops/__init__.py b/lib/galaxy/tools/util/galaxyops/__init__.py
index b7a4a5f2dd8a..7ec5e7590544 100644
--- a/lib/galaxy/tools/util/galaxyops/__init__.py
+++ b/lib/galaxy/tools/util/galaxyops/__init__.py
@@ -1,16 +1,18 @@
 """Utility functions for galaxyops"""
+from __future__ import print_function
+
 import sys
 
 
 def warn( msg ):
     # TODO: since everything printed to stderr results in job.state = error, we
     # don't need both a warn and a fail...
-    print >> sys.stderr, msg
+    print(msg, file=sys.stderr)
     sys.exit( 1 )
 
 
 def fail( msg ):
-    print >> sys.stderr, msg
+    print(msg, file=sys.stderr)
     sys.exit( 1 )
 
 
@@ -25,15 +27,15 @@ def parse_cols_arg( cols ):
         # looks something like 1,2,3,
         if cols.endswith( ',' ):
             cols += '0'
-        col_list = map( lambda x: int( x ) - 1, cols.split(",") )
+        col_list = [int( x ) - 1 for x in cols.split(",")]
         return col_list
     else:
         return BED_DEFAULT_COLS
 
 
 def default_printer( stream, exc, obj ):
-    print >> stream, "%d: %s" % ( obj.linenum, obj.current_line )
-    print >> stream, "\tError: %s" % ( str(exc) )
+    print("%d: %s" % ( obj.linenum, obj.current_line ), file=stream)
+    print("\tError: %s" % ( str(exc) ), file=stream)
 
 
 def skipped( reader, filedesc="" ):
diff --git a/lib/galaxy/tools/util/maf_utilities.py b/lib/galaxy/tools/util/maf_utilities.py
index d2e92b061d75..c50dc42747e6 100644
--- a/lib/galaxy/tools/util/maf_utilities.py
+++ b/lib/galaxy/tools/util/maf_utilities.py
@@ -3,18 +3,21 @@
 Provides wrappers and utilities for working with MAF files and alignments.
 """
 # Dan Blankenberg
+from __future__ import print_function
+
 import logging
 import os
+import resource
 import string
 import sys
 import tempfile
+from copy import deepcopy
+from errno import EMFILE
 
 import bx.align.maf
-import bx.intervals
 import bx.interval_index_file
-from errno import EMFILE
-import resource
-from copy import deepcopy
+import bx.intervals
+from six.moves import xrange
 
 assert sys.version_info[:2] >= ( 2, 4 )
 
@@ -51,7 +54,7 @@ def get_species_in_block( block ):
 
 
 def tool_fail( msg="Unknown Error" ):
-    print >> sys.stderr, "Fatal Error: %s" % msg
+    print("Fatal Error: %s" % msg, file=sys.stderr)
     sys.exit()
 
 
@@ -136,7 +139,7 @@ def __del__( self ):
 class RegionAlignment( object ):
 
     DNA_COMPLEMENT = string.maketrans( "ACGTacgt", "TGCAtgca" )
-    MAX_SEQUENCE_SIZE = sys.maxint  # Maximum length of sequence allowed
+    MAX_SEQUENCE_SIZE = sys.maxsize  # Maximum length of sequence allowed
 
     def __init__( self, size, species=[], temp_file_handler=None ):
         assert size <= self.MAX_SEQUENCE_SIZE, "Maximum length allowed for an individual sequence has been exceeded (%i > %i)." % ( size, self.MAX_SEQUENCE_SIZE )
@@ -161,7 +164,7 @@ def add_species( self, species ):
     def get_species_names( self, skip=[] ):
         if not isinstance( skip, list ):
             skip = [skip]
-        names = self.sequences.keys()
+        names = list(self.sequences.keys())
         for name in skip:
             try:
                 names.remove( name )
@@ -314,7 +317,7 @@ def build_maf_index_species_chromosomes( filename, index_species=None ):
         maf_reader = bx.align.maf.Reader( open( filename ) )
         while True:
             pos = maf_reader.file.tell()
-            block = maf_reader.next()
+            block = next(maf_reader)
             if block is None:
                 break
             blocks += 1
@@ -478,7 +481,7 @@ def __split_components_by_species( components_by_species, new_block ):
     empty_block = bx.align.Alignment( score=block.score, attributes=deepcopy( block.attributes ) )  # should we copy attributes?
     empty_block.text_size = block.text_size
     # call recursive function to split into each combo of spec/blocks
-    for value in __split_components_by_species( spec_dict.values(), empty_block ):
+    for value in __split_components_by_species( list(spec_dict.values()), empty_block ):
         sort_block_components_by_block( value, block )  # restore original component order
         yield value
 
@@ -612,10 +615,10 @@ def get_starts_ends_fields_from_gene_bed( line ):
 
     # Calculate and store starts and ends of coding exons
     region_start, region_end = cds_start, cds_end
-    exon_starts = map( int, fields[11].rstrip( ',\n' ).split( ',' ) )
-    exon_starts = map( ( lambda x: x + tx_start ), exon_starts )
-    exon_ends = map( int, fields[10].rstrip( ',' ).split( ',' ) )
-    exon_ends = map( ( lambda x, y: x + y ), exon_starts, exon_ends )
+    exon_starts = list(map( int, fields[11].rstrip( ',\n' ).split( ',' ) ))
+    exon_starts = [x + tx_start for x in exon_starts]
+    exon_ends = list(map( int, fields[10].rstrip( ',' ).split( ',' ) ))
+    exon_ends = [x + y for x, y in zip( exon_starts, exon_ends )]
     for start, end in zip( exon_starts, exon_ends ):
         start = max( start, region_start )
         end = min( end, region_end )
@@ -680,7 +683,7 @@ def remove_temp_index_file( index_filename ):
 
 def get_fasta_header( component, attributes={}, suffix=None ):
     header = ">%s(%s):%i-%i|" % ( component.src, component.strand, component.get_forward_strand_start(), component.get_forward_strand_end() )
-    for key, value in attributes.iteritems():
+    for key, value in attributes.items():
         header = "%s%s=%s|" % ( header, key, value )
     if suffix:
         header = "%s%s" % ( header, suffix )
@@ -714,7 +717,7 @@ def get_attributes_from_fasta_header( header ):
         # fields 0 is not a region coordinate
         pass
     if len( fields ) > 2:
-        for i in xrange( 1, len( fields ) - 1 ):
+        for i in range( 1, len( fields ) - 1 ):
             prop = fields[i].split( '=', 1 )
             if len( prop ) == 2:
                 attributes[ prop[0] ] = prop[1]
diff --git a/lib/galaxy/tools/verify/asserts/__init__.py b/lib/galaxy/tools/verify/asserts/__init__.py
index d0c8f19a8cf3..51f2c7cf31af 100644
--- a/lib/galaxy/tools/verify/asserts/__init__.py
+++ b/lib/galaxy/tools/verify/asserts/__init__.py
@@ -44,7 +44,7 @@ def verify_assertion(data, assertion_description):
 
     assert_function_args = inspect.getargspec(assert_function).args
     args = {}
-    for attribute, value in assertion_description["attributes"].iteritems():
+    for attribute, value in assertion_description["attributes"].items():
         if attribute in assert_function_args:
             args[attribute] = value
 
diff --git a/lib/galaxy/tools/verify/test_data.py b/lib/galaxy/tools/verify/test_data.py
index 01ef28bca7f0..01459a217c30 100644
--- a/lib/galaxy/tools/verify/test_data.py
+++ b/lib/galaxy/tools/verify/test_data.py
@@ -28,7 +28,7 @@ class TestDataResolver(object):
     def __init__(self, env_var='GALAXY_TEST_FILE_DIR', environ=os.environ):
         file_dirs = environ.get(env_var, None)
         if file_dirs:
-            self.resolvers = map(lambda u: build_resolver(u, environ), LIST_SEP.split(file_dirs))
+            self.resolvers = [build_resolver(u, environ) for u in LIST_SEP.split(file_dirs)]
         else:
             self.resolvers = []
 
diff --git a/lib/galaxy/tools/wrappers.py b/lib/galaxy/tools/wrappers.py
index d9801e76d5ff..7e0631eeff28 100644
--- a/lib/galaxy/tools/wrappers.py
+++ b/lib/galaxy/tools/wrappers.py
@@ -1,13 +1,16 @@
+import logging
 import os
 import pipes
 import tempfile
+
+from six import string_types
+
 from galaxy import exceptions
-from galaxy.util.none_like import NoneDataset
 from galaxy.util import odict
+from galaxy.util.none_like import NoneDataset
 from galaxy.util.object_wrapper import wrap_with_safe_string
 
-from logging import getLogger
-log = getLogger( __name__ )
+log = logging.getLogger( __name__ )
 
 # Fields in .log files corresponding to paths, must have one of the following
 # field names and all such fields are assumed to be paths. This is to allow
@@ -27,8 +30,9 @@ class ToolParameterValueWrapper( object ):
     Base class for object that Wraps a Tool Parameter and Value.
     """
 
-    def __nonzero__( self ):
+    def __bool__( self ):
         return bool( self.value )
+    __nonzero__ = __bool__
 
     def get_display_text( self, quote=True ):
         """
@@ -48,8 +52,9 @@ class RawObjectWrapper( ToolParameterValueWrapper ):
     def __init__( self, obj ):
         self.obj = obj
 
-    def __nonzero__( self ):
+    def __bool__( self ):
         return bool( self.obj )  # FIXME: would it be safe/backwards compatible to rename .obj to .value, so that we can just inherit this method?
+    __nonzero__ = __bool__
 
     def __str__( self ):
         try:
@@ -72,7 +77,7 @@ def __init__( self, input, value, other_values={} ):
         self._other_values = other_values
 
     def __eq__( self, other ):
-        if isinstance( other, basestring ):
+        if isinstance( other, string_types ):
             return str( self ) == other
         elif isinstance( other, int ):
             return int( self ) == other
@@ -144,7 +149,7 @@ def __init__( self, input, value, app, other_values={}, path_rewriter=None ):
         self.fields = self.SelectToolParameterFieldWrapper( input, value, other_values, self._path_rewriter )
 
     def __eq__( self, other ):
-        if isinstance( other, basestring ):
+        if isinstance( other, string_types ):
             return str( self ) == other
         else:
             return super( SelectToolParameterWrapper, self ) == other
@@ -193,8 +198,9 @@ def __getattr__( self, name ):
                 rval = wrap_with_safe_string( rval )
             return rval
 
-        def __nonzero__( self ):
+        def __bool__( self ):
             return self.metadata.__nonzero__()
+        __nonzero__ = __bool__
 
         def __iter__( self ):
             return self.metadata.__iter__()
@@ -206,7 +212,7 @@ def get( self, key, default=None ):
                 return default
 
         def items( self ):
-            return iter( [ ( k, self.get( k ) ) for k, v in self.metadata.items() ] )
+            return iter( ( k, self.get( k ) ) for k, v in self.metadata.items() )
 
     def __init__( self, dataset, datatypes_registry=None, tool=None, name=None, dataset_path=None, identifier=None ):
         if not dataset:
@@ -276,8 +282,9 @@ def __getattr__( self, key ):
         else:
             return getattr( self.dataset, key )
 
-    def __nonzero__( self ):
+    def __bool__( self ):
         return bool( self.dataset )
+    __nonzero__ = __bool__
 
 
 class HasDatasets:
@@ -407,7 +414,8 @@ def __iter__( self ):
             return [].__iter__()
         return self.__element_instance_list.__iter__()
 
-    def __nonzero__( self ):
+    def __bool__( self ):
         # Fail `#if $param` checks in cheetah is optional input
         # not specified or if resulting collection is empty.
         return self.__input_supplied and bool( self.__element_instance_list )
+    __nonzero__ = __bool__