Add Flask context automatically to APScheduler executors

docs/rst/usage.rst

@@ -74,12 +74,6 @@ Jobs can also be added after you app is running
 Flask Context
 -------------
 
-If you wish to use anything from your Flask app context inside the job you can use something like this
-
-.. code-block:: python
-
-    def blah():
-        with scheduler.app.app_context():
-            # do stuff
-            
+The Flask context is pushed automatically when initialising APScheduler executors, i.e. all jobs will be run inside a Flask application context.
+
 If you are making use of Flask-SQLAlchemy and performing DB operations within a job, make sure that you make a call to `db.session.commit()`, in addition to providing the Flask app context.

examples/flask_context.py

@@ -1,32 +1,20 @@
 """Example using flask context."""
 
 from apscheduler.jobstores.sqlalchemy import SQLAlchemyJobStore
-from flask import Flask
-from flask_sqlalchemy import SQLAlchemy
+from flask import Flask, current_app
 
 from flask_apscheduler import APScheduler
 
-db = SQLAlchemy()
 
-
-class User(db.Model):
-    """User model."""
-
-    id = db.Column(db.Integer, primary_key=True)  # noqa: A003, VNE003
-    username = db.Column(db.String(80), unique=True)
-    email = db.Column(db.String(120), unique=True)
-
-
-def show_users():
+def show_app_name():
     """Print all users."""
-    with db.app.app_context():
-        print(User.query.all())
+    print(f"Running example={current_app.name}")
 
 
 class Config:
     """App configuration."""
 
-    JOBS = [{"id": "job1", "func": show_users, "trigger": "interval", "seconds": 2}]
+    JOBS = [{"id": "job1", "func": show_app_name, "trigger": "interval", "seconds": 2}]
 
     SCHEDULER_JOBSTORES = {
         "default": SQLAlchemyJobStore(url="sqlite:///flask_context.db")
@@ -39,9 +27,6 @@ class Config:
     app = Flask(__name__)
     app.config.from_object(Config())
 
-    db.app = app
-    db.init_app(app)
-
     scheduler = APScheduler()
     scheduler.init_app(app)
     scheduler.start()

flask_apscheduler/scheduler.py

@@ -26,7 +26,7 @@
 from apscheduler.jobstores.base import JobLookupError
 from flask import make_response
 from . import api
-from .utils import fix_job_def, pop_trigger
+from .utils import fix_job_def, pop_trigger, with_app_context
 
 LOGGER = logging.getLogger('flask_apscheduler')
 
@@ -81,6 +81,7 @@ def init_app(self, app):
         self.app.apscheduler = self
 
         self._load_config()
+        self._apply_app_context()
         self._load_jobs()
 
         if self.api_enabled:
@@ -281,7 +282,11 @@ def run_job(self, id, jobstore=None):
         if not job:
             raise JobLookupError(id)
 
-        job.func(*job.args, **job.kwargs)
+        if self.app:
+            with self.app.app_context():
+                job.func(*job.args, **job.kwargs)
+        else:
+            job.func(*job.args, **job.kwargs)
 
     def authenticate(self, func):
         """
@@ -305,6 +310,10 @@ def _load_config(self):
         if executors:
             options['executors'] = executors
 
+        if 'executors' not in options:
+            # APScheduler adds the default 'executor' at execution time rather than at configuration time, we need it at conf time in order to apply Flask app context.
+            options['executors'] = {'default': {'type': 'threadpool'}}
+
         job_defaults = self.app.config.get('SCHEDULER_JOB_DEFAULTS')
         if job_defaults:
             options['job_defaults'] = job_defaults
@@ -370,6 +379,23 @@ def _add_url_route(self, endpoint, rule, view_func, method):
             methods=[method]
         )
 
+    def _apply_app_context(self):
+        """
+        Apply Flask application context to the scheduler executors.
+        """
+        import importlib, six
+        with self._scheduler._executors_lock:
+            for alias, executor in six.iteritems(self._scheduler._executors):
+                try:
+                    module_name = executor.__module__
+                    module = importlib.import_module(module_name)
+                except ModuleNotFoundError:
+                    LOGGER.error(f'Unable to add Flask app context to {module_name}.')
+                    continue
+
+                if 'run_job' in vars(module):
+                    vars(module)['run_job'] = with_app_context(self.app, vars(module)['run_job'])
+
     def _apply_auth(self, view_func):
         """
         Apply decorator to authenticate the user who is making the request.

flask_apscheduler/utils.py

@@ -21,6 +21,7 @@
 from apscheduler.triggers.date import DateTrigger
 from apscheduler.triggers.interval import IntervalTrigger
 from collections import OrderedDict
+from functools import wraps
 
 
 def job_to_dict(job):
@@ -162,3 +163,14 @@ def wsgi_to_bytes(data):
     if isinstance(data, bytes):
         return data
     return data.encode("latin1")  # XXX: utf8 fallback?
+
+
+def with_app_context(app, func):
+    @wraps(func)
+    def wrapper(*args, **kwargs):
+        if not app:
+            return func(*args, **kwargs)
+        with app.app_context():
+            return func(*args, **kwargs)         
+
+    return wrapper

tests/test_scheduler.py

@@ -1,9 +1,12 @@
-from flask import Flask
+from flask import Flask, current_app
 from flask_apscheduler import APScheduler, utils
 from unittest import TestCase
 import apscheduler
 from pytz import utc
 import datetime
+import sys
+import importlib
+
 
 class TestScheduler(TestCase):
     def setUp(self):
@@ -184,6 +187,27 @@ def decorated_job():
         self.scheduler.shutdown()
         self.assertFalse(self.scheduler.running)
 
+    def test_run_job(self):
+        job = self.scheduler.add_job('job2', job2)
+
+        with self.assertRaises(RuntimeError):
+            self.scheduler.run_job('job2')
+
+        job = self.scheduler_two.add_job('job2', job2)
+        self.scheduler_two.run_job('job2')
+
+    def test_apply_app_context(self):
+        now = datetime.datetime.now(utc)
+        self.scheduler_two.start()
+        job = self.scheduler_two.add_job('appctx', job2, trigger='date', next_run_time=now)
+        executor = self.scheduler_two._scheduler._executors['default']
+
+        self.assertTrue(executor.submit_job(job, [now]) is None)
+
 
 def job1():
     pass
+
+
+def job2():
+    return current_app.name

tests/test_utils.py

@@ -1,8 +1,13 @@
 from copy import deepcopy
 from flask_apscheduler import utils
+from flask import Flask
 from unittest import TestCase
+from flask_apscheduler.utils import with_app_context
 
 class TestUtils(TestCase):
+    def setUp(self):
+        self.app = Flask(__name__)
+
     def test_pop_trigger(self):
         def __pop_trigger(trigger, *params):
             data = dict(trigger=trigger)
@@ -23,3 +28,10 @@ def __pop_trigger(trigger, *params):
         __pop_trigger('interval', 'weeks', 'days', 'hours', 'minutes', 'seconds', 'start_date', 'end_date', 'timezone')
         __pop_trigger('cron', 'year', 'month', 'day', 'week', 'day_of_week', 'hour', 'minute', 'second', 'start_date', 'end_date', 'timezone')
         self.assertRaises(Exception, utils.pop_trigger, dict(trigger='invalid_trigger'))
+
+    def test_with_app_context(self):
+        def one_func():
+            return 'x'
+
+        one_func = with_app_context(self.app, one_func)
+        self.assertTrue('x' == one_func())