docs: Added a report example

Also added  a test based on the example.

django_q/tests/tasks.py

@@ -35,5 +35,9 @@ def get_task_name(task):
     return task.name
 
 
+def get_user_id(user):
+    return user.id
+
+
 def result(obj):
     print('RESULT HOOK {} : {}'.format(obj.name, obj.result))

django_q/tests/test_cluster.py

@@ -1,8 +1,9 @@
 import sys
-import os
 from multiprocessing import Queue, Event, Value
 import threading
 
+from django.contrib.auth.models import User
+import os
 import pytest
 
 myPath = os.path.dirname(os.path.abspath(__file__))
@@ -32,11 +33,13 @@ def r():
 def test_redis_connection(r):
     assert r.ping() is True
 
+
 @pytest.mark.django_db
 def test_sync(r):
     task = async('django_q.tests.tasks.count_letters', DEFAULT_WORDLIST, redis=r, sync=True)
     assert result(task) == 1506
 
+
 @pytest.mark.django_db
 def test_cluster_initial(r):
     list_key = 'initial_test:q'
@@ -98,28 +101,30 @@ def test_cluster(r):
 
 
 @pytest.mark.django_db
-def test_async(r):
+def test_async(r, admin_user):
     list_key = 'cluster_test:q'
     r.delete(list_key)
     a = async('django_q.tests.tasks.count_letters', DEFAULT_WORDLIST, hook='django_q.tests.test_cluster.assert_result',
-              list_key=list_key)
+              list_key=list_key, redis=r)
     b = async('django_q.tests.tasks.count_letters2', WordClass(), hook='django_q.tests.test_cluster.assert_result',
-              list_key=list_key)
+              list_key=list_key, redis=r)
     # unknown argument
     c = async('django_q.tests.tasks.count_letters', DEFAULT_WORDLIST, 'oneargumentoomany',
-              hook='django_q.tests.test_cluster.assert_bad_result', list_key=list_key)
+              hook='django_q.tests.test_cluster.assert_bad_result', list_key=list_key, redis=r)
     # unknown function
     d = async('django_q.tests.tasks.does_not_exist', WordClass(), hook='django_q.tests.test_cluster.assert_bad_result',
-              list_key=list_key)
+              list_key=list_key, redis=r)
     # function without result
-    e = async('django_q.tests.tasks.countdown', 100000, list_key=list_key)
+    e = async('django_q.tests.tasks.countdown', 100000, list_key=list_key, redis=r)
     # function as instance
-    f = async(multiply, 753, 2, hook=assert_result, list_key=list_key)
+    f = async(multiply, 753, 2, hook=assert_result, list_key=list_key, redis=r)
     # model as argument
-    g = async('django_q.tests.tasks.get_task_name', Task(name='John'), list_key=list_key)
+    g = async('django_q.tests.tasks.get_task_name', Task(name='John'), list_key=list_key, redis=r)
     # args and kwargs and broken hook
     h = async('django_q.tests.tasks.word_multiply', 2, word='django', hook='fail.me', list_key=list_key, redis=r)
-    # check if everything has a task name
+    # args unpickle test
+    j = async('django_q.tests.tasks.get_user_id', admin_user, list_key=list_key, redis=r)
+    # check if everything has a task id
     assert isinstance(a, str)
     assert isinstance(b, str)
     assert isinstance(c, str)
@@ -128,8 +133,9 @@ def test_async(r):
     assert isinstance(f, str)
     assert isinstance(g, str)
     assert isinstance(h, str)
+    assert isinstance(j, str)
     # run the cluster to execute the tasks
-    task_count = 8
+    task_count = 9
     assert r.llen(list_key) == task_count
     task_queue = Queue()
     stop_event = Event()
@@ -187,6 +193,11 @@ def test_async(r):
     assert result_h is not None
     assert result_h.success is True
     assert result(h) == 12
+    # task j
+    result_j = fetch(j)
+    assert result_j is not None
+    assert result_j.success is True
+    assert result_j.result == result_j.args[0].id
     r.delete(list_key)
 
 

docs/examples.rst

@@ -1,10 +1,12 @@
 Examples
 --------
 
-Async emails
+Emails
-============
+======
 
-Sending an email can take a while so why not queue it::
+Sending an email can take a while so why not queue it:
+
+.. code-block:: python
 
     # Welcome mail with follow up example
     from datetime import timedelta
@@ -39,7 +41,9 @@ Since you're only telling Django Q to take care of the emails, you can quickly m
 Signals
 =======
 
-A good place to use async tasks are Django's model signals. You don't want to delay the saving or creation of objects, but sometimes you want to trigger a lot of actions::
+A good place to use async tasks are Django's model signals. You don't want to delay the saving or creation of objects, but sometimes you want to trigger a lot of actions:
+
+.. code-block:: python
 
     # Message on object change
     from django.contrib.auth.models import User
@@ -60,7 +64,9 @@ A good place to use async tasks are Django's model signals. You don't want to de
                 # tell everyone
                 async('tasks.inform_everyone', instance)
 
-The task will send a message to everyone else informing them that the users email address has changed. Note that this adds almost no overhead to the save action::
+The task will send a message to everyone else informing them that the users email address has changed. Note that this adds almost no overhead to the save action:
+
+.. code-block:: python
 
     # tasks.py
     def inform_everyone(user):
@@ -72,6 +78,7 @@ The task will send a message to everyone else informing them that the users emai
                           'from@example.com', [u.email]))
         return send_mass_mail(mails)
 
+.. code-block:: python
 
     # or do it async again
     def inform_everyone_async(user):
@@ -82,8 +89,52 @@ The task will send a message to everyone else informing them that the users emai
                   'New email', msg, 'from@example.com', [u.email])
 
 
+Of course you can do other things beside sending emails. These are just generic examples. You can use signals with async to update fields in other objects too.
+Let's say this users email address is not just on the User object, but you stored it in some other places too without a reference.
+By attaching an async action to the save signal, you can now update that email address in those other places without impacting the the time it takes to return your views.
 
 
+Reports
+=======
+
+In this example the user requests a report and we let the cluster do the generating, while handling the result with a hook.
+
+.. code-block:: python
+
+    # Report generation with hook example
+    from django_q import async
+
+    # views.py
+    # user requests a report.
+    def create_report(request):
+        async('tasks.create_html_report',
+              request.user,
+              hook='tasks.email_report')
+
+    # tasks.py
+    # report generator
+    def create_html_report(user):
+        html_report = 'We had a great quarter!'
+        return html_report
+
+    # report mailer
+    def email_report(task):
+        if task.success:
+            # Email the report
+            async('django.core.mail.send_mail',
+                  'The report you requested',
+                  task.result,
+                  'from@example.com',
+                  task.args[0].email)
+        else:
+            # Tell the admins something went wrong
+            async('django.core.mail.mail_admins',
+                  'Report generation failed',
+                  task.result)
+
+
+The hook is practical here, cause it allows us to detach the sending task from the report generation function and to report on possible failures.
+
 .. note::
 
     If you have an example you want to share, please submit a pull request on `github <https://github.com/Koed00/django-q/>`__.