Native threaded concurrency (#120)

* Converted to native threads for concurrency

* Added elegant action stopping

* Added timeout to Action DELETE requests

* Switch to thread concurrency

* Updated tests and fixed bugs

* Removed assert outside of tests

* Autofix issues in 1 files

Resolved issues in the following files via DeepSource Autofix:
1. src/labthings/wsgi.py

* Fixed legacy import

Co-authored-by: deepsource-autofix[bot] <62050782+deepsource-autofix[bot]@users.noreply.github.com>

Author: jtc42

.coveragerc

@@ -2,7 +2,7 @@
 branch = True
 source = ./src/labthings
 omit = .venv/*, ./src/labthings/wsgi.py, ./src/labthings/monkey.py, ./src/labthings/server/*, ./src/labthings/core/*
-concurrency = greenlet
+concurrency = thread
 
 [report]
 # Regexes for lines to exclude from consideration

examples/components/pdf_component.py

@@ -2,6 +2,8 @@
 import math
 import time
 
+from labthings.tasks import current_task
+
 """
 Class for our lab component functionality. This could include serial communication,
 equipment API calls, network requests, or a "virtual" device as seen here.
@@ -44,6 +46,8 @@ def average_data(self, n: int):
         summed_data = self.data
 
         for _ in range(n):
+            if current_task() and current_task().stopped:
+                return summed_data
             summed_data = [summed_data[i] + el for i, el in enumerate(self.data)]
             time.sleep(0.25)
 

poetry.lock

@@ -18,9 +18,8 @@ marshmallow = "^3.4.0"
 webargs = "^6.0.0"
 apispec = "^3.2.0"
 flask-cors = "^3.0.8"
-gevent = ">=1.4,<21.0"
-gevent-websocket = "^0.10.1"
 zeroconf = ">=0.24.5,<0.29.0"
+flask-threaded-sockets = "^0.1.0"
 
 [tool.poetry.dev-dependencies]
 pytest = "^5.4"

pyproject.toml

@@ -2,8 +2,10 @@
 
 from ..view import View
 from ..view.marshalling import marshal_with
+from ..view.args import use_args
 from ..schema import ActionSchema
 from ..find import current_thing
+from .. import fields
 
 
 class ActionQueue(View):
@@ -12,7 +14,7 @@ class ActionQueue(View):
     """
 
     def get(self):
-        return ActionSchema(many=True).dump(current_thing.actions.greenlets)
+        return ActionSchema(many=True).dump(current_thing.actions.threads)
 
 
 class ActionView(View):
@@ -38,19 +40,22 @@ def get(self, task_id):
 
         return ActionSchema().dump(task)
 
-    def delete(self, task_id):
+    @use_args({"timeout": fields.Int(missing=5)})
+    def delete(self, args, task_id):
         """
         Terminate a running task.
 
         If the task is finished, deletes its entry.
         """
+        timeout = args.get("timeout", 5)
         task_dict = current_thing.actions.to_dict()
 
         if task_id not in task_dict:
             return abort(404)  # 404 Not Found
 
         task = task_dict.get(task_id)
 
-        task.kill(block=True, timeout=3)
+        # TODO: Make non-blocking?
+        task.stop(timeout=timeout)
 
         return ActionSchema().dump(task)

src/labthings/default_views/actions.py

@@ -18,7 +18,7 @@ def get(self):
         logging.warning(
             "TaskList is deprecated and will be removed in a future version. Use the Actions list instead."
         )
-        return TaskSchema(many=True).dump(current_thing.actions.greenlets)
+        return TaskSchema(many=True).dump(current_thing.actions.threads)
 
 
 class TaskView(View):
@@ -64,7 +64,6 @@ def delete(self, task_id):
             return abort(404)  # 404 Not Found
 
         task = task_dict.get(task_id)
-
-        task.kill(block=True, timeout=3)
+        task.stop(timeout=5)
 
         return TaskSchema().dump(task)

src/labthings/default_views/tasks.py

@@ -1,4 +1,5 @@
 from flask import url_for
+from flask_threaded_sockets.flask import Sockets
 from apispec import APISpec
 
 # from apispec.ext.marshmallow import MarshmallowPlugin
@@ -19,7 +20,6 @@
 from .representations import DEFAULT_REPRESENTATIONS
 from .apispec import MarshmallowPlugin, rule_to_apispec_path
 from .td import ThingDescription
-from .sockets import Sockets
 from .event import Event
 
 from .tasks import Pool
@@ -61,7 +61,7 @@ def __init__(
 
         self.extensions = {}
 
-        self.actions = Pool()  # Pool of greenlets for Actions
+        self.actions = Pool()  # Pool of threads for Actions
 
         self.events = {}
 

src/labthings/labthing.py

@@ -1 +1,2 @@
-from ..sockets import Sockets, SocketSubscriber
+from ..sockets import SocketSubscriber
+from flask_threaded_sockets.flask import Sockets

src/labthings/server/sockets.py

@@ -1,19 +1,3 @@
-"""
-Once upon a time, based on flask-websocket; Copyright (C) 2013 Kenneth Reitz
-Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
-The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
-"""
-
-# -*- coding: utf-8 -*-
-
-from werkzeug.exceptions import NotFound
-from werkzeug.http import parse_cookie
-from flask import request
-
-from flask.helpers import _endpoint_from_view_func
-from werkzeug.routing import Map, Rule, BuildError
-
 from .representations import encode_json
 
 
@@ -25,158 +9,3 @@ def emit(self, event: dict):
         response = encode_json(event)
         # TODO: Logic surrounding if this subscriber is subscribed to the requested event type
         self.ws.send(response)
-
-
-class WsUrlAdapterWrapper(object):
-    def __init__(self, app_adapter, sockets_adapter):
-        self.__app_adapter = app_adapter
-        self.__sockets_adapter = sockets_adapter
-
-    def build(
-        self,
-        endpoint,
-        values=None,
-        method=None,
-        force_external=False,
-        append_unknown=True,
-    ):
-        try:
-            return (
-                "ws"
-                + self.__sockets_adapter.build(
-                    endpoint=endpoint,
-                    values=values,
-                    method=None,
-                    force_external=True,
-                    append_unknown=append_unknown,
-                )[4:]
-            )
-        except BuildError:
-            return self.__app_adapter.build(
-                endpoint=endpoint,
-                values=values,
-                method=method,
-                force_external=force_external,
-                append_unknown=append_unknown,
-            )
-
-    def __getattr__(self, attr):
-        fun = getattr(self.__app_adapter, attr)
-        setattr(self, attr, fun)
-        return fun
-
-
-class Sockets:
-    def __init__(self, app=None):
-        #: Compatibility with 'Flask' application.
-        #: The :class:`~werkzeug.routing.Map` for this instance. You can use
-        #: this to change the routing converters after the class was created
-        #: but before any routes are connected.
-        self.url_map = Map()
-
-        #: Compatibility with 'Flask' application.
-        #: All the attached blueprints in a dictionary by name. Blueprints
-        #: can be attached multiple times so this dictionary does not tell
-        #: you how often they got attached.
-        self.blueprints = {}
-        self._blueprint_order = []
-
-        self.view_functions = {}
-
-        if app:
-            self.init_app(app)
-
-    def __create_url_adapter(self, url_map, request):
-        if request is not None:
-            return url_map.bind_to_environ(
-                request.environ, server_name=self.app.config["SERVER_NAME"]
-            )
-        elif self.app.config["SERVER_NAME"] is not None:
-            return url_map.bind(
-                self.app.config["SERVER_NAME"],
-                script_name=self.app.config["APPLICATION_ROOT"] or "/",
-                url_scheme=self.app.config["PREFERRED_URL_SCHEME"],
-            )
-
-    def create_url_adapter(self, request):
-        adapter_for_app = self.__create_url_adapter(self.app.url_map, request)
-        adapter_for_sockets = self.__create_url_adapter(self.url_map, request)
-        return WsUrlAdapterWrapper(adapter_for_app, adapter_for_sockets)
-
-    def init_app(self, app):
-        self.app = app
-        self.app_wsgi_app = app.wsgi_app
-
-        app.wsgi_app = self.wsgi_app
-        app.create_url_adapter = self.create_url_adapter
-
-    def route(self, rule, **options):
-        def decorator(f):
-            endpoint = options.pop("endpoint", None)
-            self.add_url_rule(rule, endpoint, f, **options)
-            return f
-
-        return decorator
-
-    def add_url_rule(self, rule, endpoint, f, **options):
-        if endpoint is None:
-            endpoint = _endpoint_from_view_func(f)
-
-        methods = options.pop("methods", None)
-
-        setattr(f, "endpoint", endpoint)
-
-        self.url_map.add(Rule(rule, endpoint=endpoint, **options))
-        self.view_functions[endpoint] = f
-
-        if methods is None:
-            methods = []
-        self.app.add_url_rule(rule, endpoint, f, methods=methods, **options)
-
-    def add_view(self, url, f, endpoint=None, **options):
-        return self.add_url_rule(url, endpoint, f, **options)
-
-    def register_blueprint(self, blueprint, **options):
-        """
-        Registers a blueprint for web sockets like for 'Flask' application.
-        Decorator :meth:`~flask.app.setupmethod` is not applied, because it
-        requires ``debug`` and ``_got_first_request`` attributes to be defined.
-        """
-        first_registration = False
-
-        if blueprint.name in self.blueprints:
-            assert self.blueprints[blueprint.name] is blueprint, (
-                "A blueprint's name collision occurred between %r and "
-                '%r.  Both share the same name "%s".  Blueprints that '
-                "are created on the fly need unique names."
-                % (blueprint, self.blueprints[blueprint.name], blueprint.name)
-            )
-        else:
-            self.blueprints[blueprint.name] = blueprint
-            self._blueprint_order.append(blueprint)
-            first_registration = True
-
-        blueprint.register(self, options, first_registration)
-
-    def wsgi_app(self, environ, start_response):
-        adapter = self.url_map.bind_to_environ(environ)
-        try:
-            # Find handler view function
-            endpoint, values = adapter.match()
-            handler = self.view_functions[endpoint]
-
-            # Handle environment
-            environment = environ["wsgi.websocket"]
-            cookie = None
-            if "HTTP_COOKIE" in environ:
-                cookie = parse_cookie(environ["HTTP_COOKIE"])
-
-            with self.app.app_context():
-                with self.app.request_context(environ):
-                    # add cookie to the request to have correct session handling
-                    request.cookie = cookie
-                    # Run WebSocket handler
-                    handler(environment, **values)
-                    return []
-        except (NotFound, KeyError):
-            return self.app_wsgi_app(environ, start_response)

src/labthings/sockets.py

@@ -1,10 +1,8 @@
-from gevent.hub import getcurrent
-import gevent
 import time
 import logging
-from gevent.lock import BoundedSemaphore
 
-from gevent.event import Event
+import threading
+from _thread import get_ident
 
 
 class ClientEvent(object):
@@ -17,25 +15,18 @@ class ClientEvent(object):
 
     def __init__(self):
         self.events = {}
-        self._setting_lock = BoundedSemaphore()
+        self._setting_lock = threading.Lock()
 
     def wait(self, timeout: int = 5):
         """Wait for the next data frame (invoked from each client's thread)."""
-        ident = id(getcurrent())
+        ident = get_ident()
         if ident not in self.events:
             # this is a new client
             # add an entry for it in the self.events dict
             # each entry has two elements, a threading.Event() and a timestamp
-            self.events[ident] = [Event(), time.time()]
+            self.events[ident] = [threading.Event(), time.time()]
 
-        # We have to reimplement event waiting here as we need native thread events to allow gevent context switching
-        wait_start = time.time()
-        while not self.events[ident][0].is_set():
-            now = time.time()
-            if now - wait_start > timeout:
-                return False
-            gevent.sleep(0)
-        return True
+        return self.events[ident][0].wait(timeout=timeout)
 
     def set(self, timeout=5):
         """Signal that a new frame is available."""
@@ -61,10 +52,10 @@ def set(self, timeout=5):
 
     def clear(self):
         """Clear frame event, once processed."""
-        ident = id(getcurrent())
+        ident = get_ident()
         if ident not in self.events:
             logging.error(f"Mismatched ident. Current: {ident}, available:")
             logging.error(self.events.keys())
             return False
-        self.events[id(getcurrent())][0].clear()
+        self.events[get_ident()][0].clear()
         return True