Have bootstrap_pex_env pull in contents of pexrc files

pex/pex_bootstrapper.py

@@ -3,6 +3,7 @@
 
 from __future__ import absolute_import, print_function
 
+import json
 import os
 import sys
 
@@ -173,9 +174,22 @@ def maybe_reexec_pex(compatibility_constraints=None):
   os.execv(target_binary, cmdline)
 
 
-def _bootstrap(entry_point):
+def _bootstrap(entry_point, include_pexrc=False, extra_vars=None):
   from .pex_info import PexInfo
   pex_info = PexInfo.from_pex(entry_point)
+
+  # Pull in the default ENV, which is an instance of pex.variables.Variables, which reads
+  # from the default pexrc locations.
+  if include_pexrc:
+    pex_info.update(PexInfo.from_env())
+
+  # Override env settings using extra passed-in vars
+  if extra_vars:
+    if isinstance(extra_vars, dict):
+      pex_info.update(PexInfo.from_json(json.dumps(extra_vars)))
+    elif isinstance(extra_vars, str):
+      pex_info.update(PexInfo.from_json(extra_vars))
+
   pex_warnings.configure_warnings(pex_info)
 
   from .finders import register_finders
@@ -199,9 +213,13 @@ def is_compressed(entry_point):
   return os.path.exists(entry_point) and not os.path.exists(os.path.join(entry_point, PexInfo.PATH))
 
 
-def bootstrap_pex_env(entry_point):
-  """Bootstrap the current runtime environment using a given pex."""
-  pex_info = _bootstrap(entry_point)
+def bootstrap_pex_env(entry_point, include_pexrc=False, extra_vars=None):
+  """Bootstrap the current runtime environment using a given pex.
+
+  Optionally, pexrc files from 'standard' locations can be included - see
+  pex.variables.Variables.from_rc() - or runtime-specific overrides (dict or json)
+  """
+  pex_info = _bootstrap(entry_point, include_pexrc=include_pexrc, extra_vars=extra_vars)
 
   from .environment import PEXEnvironment
   PEXEnvironment(entry_point, pex_info).activate()

tests/test_pex_bootstrapper.py

@@ -1,12 +1,16 @@
 # Copyright 2015 Pants project contributors (see CONTRIBUTORS.md).
 # Licensed under the Apache License, Version 2.0 (see LICENSE).
 
+import json
+import os
 import pytest
 
 from pex.interpreter import PythonInterpreter
-from pex.pex_bootstrapper import find_compatible_interpreters
+from pex.pex_bootstrapper import find_compatible_interpreters, _bootstrap
 from pex.testing import IS_PYPY, PY27, PY35, PY36, ensure_python_interpreter
 
+EMPTY_FIXTURE_PEX = os.path.join(os.path.dirname(__file__), 'empty_test_fixture.pex')
+
 
 @pytest.mark.skipif(IS_PYPY)
 def test_find_compatible_interpreters():
@@ -37,3 +41,47 @@ def find_interpreters(*constraints):
 
   interpreters = find_compatible_interpreters(compatibility_constraints=['<3'])
   assert set(interpreters).issubset(all_known_interpreters)
+
+
+def test_bootstrap():
+  """Simple test against an empty .pex file"""
+  pex_info = _bootstrap(EMPTY_FIXTURE_PEX)
+  # code_hash is arbitrary; it's just what was written into the test fixture.
+  # It is only here to ensure that we're actually reading the file, and not
+  # returning a defaults-only PexInfo.
+  assert pex_info.code_hash == 'da39a3ee5e6b4b0d3255bfef95601890afd80709'
+  assert pex_info.requirements == []
+  assert pex_info.zip_safe is True
+
+
+def test_bootstrap_with_vars_dict():
+  """Test that extra_vars passed in as a dict are considered"""
+  extra_vars = {
+    "pex_root": "some_dir",
+    "script": "my_dict_test_script"
+  }
+  pex_info = _bootstrap(EMPTY_FIXTURE_PEX, include_pexrc=False, extra_vars=extra_vars)
+  assert pex_info.pex_root == "some_dir"
+  assert pex_info.script == "my_dict_test_script"
+
+
+def test_bootstrap_with_vars_json():
+  """Test that extra_vars passed in as a JSON string are considered"""
+  extra_vars = {
+    "pex_root": "some_dir",
+    "script": "my_json_test_script"
+  }
+  json_vars = json.dumps(extra_vars)
+  pex_info = _bootstrap(EMPTY_FIXTURE_PEX, include_pexrc=False, extra_vars=json_vars)
+  assert pex_info.pex_root == "some_dir"
+  assert pex_info.script == "my_json_test_script"
+
+
+def test_bootstrap_with_pexrc():
+  """Test that pexrc files are considered"""
+  pass
+
+
+def test_bootstrap_with_pexrc_and_vars():
+  """Test that both pexrc files and passed-in extra_vars are considered in a suitable order"""
+  pass