CBMS Odoo Job Queue

'=========
Job Queue
=========

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This addon adds an integrated Job Queue to CBMS ODOO.

It allows to postpone method calls executed asynchronously.

Jobs are executed in the background by a ``Jobrunner``, in their own transaction.

Example:

.. code-block:: python

from CBMS ODOO import models, fields, api

class MyModel(models.Model):
_name = 'my.model'

def my_method(self, a, k=None):
_logger.info('executed with a: %s and k: %s', a, k)


class MyOtherModel(models.Model):
_name = 'my.other.model'

def button_do_stuff(self):
self.env['my.model'].with_delay().my_method('a', k=2)


In the snippet of code above, when we call ``button_do_stuff``, a job **capturing
the method and arguments** will be postponed. It will be executed as soon as the
Jobrunner has a free bucket, which can be instantaneous if no other job is
running.


Features:

* Views for jobs, jobs are stored in PostgreSQL
* Jobrunner: execute the jobs, highly efficient thanks to PostgreSQL's NOTIFY
* Channels: give a capacity for the root channel and its sub-channels and
segregate jobs in them. Allow for instance to restrict heavy jobs to be
executed one at a time while little ones are executed 4 at a times.
* Retries: Ability to retry jobs by raising a type of exception
* Retry Pattern: the 3 first tries, retry after 10 seconds, the 5 next tries,
retry after 1 minutes, ...
* Job properties: priorities, estimated time of arrival (ETA), custom
description, number of retries
* Related Actions: link an action on the job view, such as open the record
concerned by the job

**Table of contents**

.. contents::
:local:

Installation
============

Be sure to have the ``requests`` library.

Configuration
=============

* Using environment variables and command line:

* Adjust environment variables (optional):

- ``ODOO_QUEUE_JOB_CHANNELS=root:4`` or any other channels configuration.
The default is ``root:1``

- if ``xmlrpc_port`` is not set: ``ODOO_QUEUE_JOB_PORT=8069``

* Start CBMS ODOO with ``--load=web,queue_job``
and ``--workers`` greater than 1. [1]_


* Using the CBMS ODOO configuration file:

.. code-block:: ini

[options]
(...)
workers = 6
server_wide_modules = web,queue_job

(...)
[queue_job]
channels = root:2

* Confirm the runner is starting correctly by checking the CBMS ODOO log file:

.. code-block::

...INFO...queue_job.jobrunner.runner: starting
...INFO...queue_job.jobrunner.runner: initializing database connections
...INFO...queue_job.jobrunner.runner: queue job runner ready for db <dbname>
...INFO...queue_job.jobrunner.runner: database connections ready

* Create jobs (eg using ``base_import_async``) and observe they
start immediately and in parallel.

* Tip: to enable debug logging for the queue job, use
``--log-handler=odoo.addons.queue_job:DEBUG``

.. [1] It works with the threaded CBMS ODOO server too, although this way
of running CBMS ODOO is obviously not for production purposes.

Usage
=====

To use this module, you need to:

#. Go to ``Job Queue`` menu

Developers
~~~~~~~~~~

Delaying jobs
-------------

The fast way to enqueue a job for a method is to use ``with_delay()`` on a record
or model:


.. code-block:: python

def button_done(self):
self.with_delay().print_confirmation_document(self.state)
self.write({"state": "done"})
return True

Here, the method ``print_confirmation_document()`` will be executed asynchronously
as a job. ``with_delay()`` can take several parameters to define more precisely how
the job is executed (priority, ...).

All the arguments passed to the method being delayed are stored in the job and
passed to the method when it is executed asynchronously, including ``self``, so
the current record is maintained during the job execution (warning: the context
is not kept).

Dependencies can be expressed between jobs. To start a graph of jobs, use ``delayable()``
on a record or model. The following is the equivalent of ``with_delay()`` but using the
long form:

.. code-block:: python

def button_done(self):
delayable = self.delayable()
delayable.print_confirmation_document(self.state)
delayable.delay()
self.write({"state": "done"})
return True

Methods of Delayable objects return itself, so it can be used as a builder pattern,
which in some cases allow to build the jobs dynamically:

.. code-block:: python

def button_generate_simple_with_delayable(self):
self.ensure_one()
# Introduction of a delayable object, using a builder pattern
# allowing to chain jobs or set properties. The delay() method
# on the delayable object actually stores the delayable objects
# in the queue_job table
(
self.delayable()
.generate_thumbnail((50, 50))
.set(priority=30)
.set(description=_("generate xxx"))
.delay()
)

The simplest way to define a dependency is to use ``.on_done(job)`` on a Delayable:

.. code-block:: python

def button_chain_done(self):
self.ensure_one()
job1 = self.browse(1).delayable().generate_thumbnail((50, 50))
job2 = self.browse(1).delayable().generate_thumbnail((50, 50))
job3 = self.browse(1).delayable().generate_thumbnail((50, 50))
# job 3 is executed when job 2 is done which is executed when job 1 is done
job1.on_done(job2.on_done(job3)).delay()

Delayables can be chained to form more complex graphs using the ``chain()`` and
``group()`` primitives.
A chain represents a sequence of jobs to execute in order, a group represents
jobs which can be executed in parallel. Using ``chain()`` has the same effect as
using several nested ``on_done()`` but is more readable. Both can be combined to
form a graph, for instance we can group [A] of jobs, which blocks another group
[B] of jobs. When and only when all the jobs of the group [A] are executed, the
jobs of the group [B] are executed. The code would look like:

.. code-block:: python

from CBMS ODOO.addons.queue_job.delay import group, chain

def button_done(self):
group_a = group(self.delayable().method_foo(), self.delayable().method_bar())
group_b = group(self.delayable().method_baz(1), self.delayable().method_baz(2))
chain(group_a, group_b).delay()
self.write({"state": "done"})
return True

When a failure happens in a graph of jobs, the execution of the jobs that depend on the
failed job stops. They remain in a state ``wait_dependencies`` until their "parent" job is
successful. This can happen in two ways: either the parent job retries and is successful
on a second try, either the parent job is manually "set to done" by a user. In these two
cases, the dependency is resolved and the graph will continue to be processed. Alternatively,
the failed job and all its dependent jobs can be canceled by a user. The other jobs of the
graph that do not depend on the failed job continue their execution in any case.

Note: ``delay()`` must be called on the delayable, chain, or group which is at the top
of the graph. In the example above, if it was called on ``group_a``, then ``group_b``
would never be delayed (but a warning would be shown).


Enqueing Job Options
--------------------

* priority: default is 10, the closest it is to 0, the faster it will be
executed
* eta: Estimated Time of Arrival of the job. It will not be executed before this
date/time
* max_retries: default is 5, maximum number of retries before giving up and set
the job state to 'failed'. A value of 0 means infinite retries.
* description: human description of the job. If not set, description is computed
from the function doc or method name
* channel: the complete name of the channel to use to process the function. If
specified it overrides the one defined on the function
* identity_key: key uniquely identifying the job, if specified and a job with
the same key has not yet been run, the new job will not be created

Configure default options for jobs
----------------------------------

In earlier versions, jobs could be configured using the ``@job`` decorator.
This is now obsolete, they can be configured using optional ``queue.job.function``
and ``queue.job.channel`` XML records.

Example of channel:

.. code-block:: XML

<record id="channel_sale" model="queue.job.channel">
<field name="name">sale</field>
<field name="parent_id" ref="queue_job.channel_root" />
</record>

Example of job function:

.. code-block:: XML

<record id="job_function_sale_order_action_done" model="queue.job.function">
<field name="model_id" ref="sale.model_sale_order" />
<field name="method">action_done</field>
<field name="channel_id" ref="channel_sale" />
<field name="related_action" eval='{"func_name": "custom_related_action"}' />
<field name="retry_pattern" eval="{1: 60, 2: 180, 3: 10, 5: 300}" />
</record>

The general form for the ``name`` is: ``<model.name>.method``.

The channel, related action and retry pattern options are optional, they are
documented below.

When writing modules, if 2+ modules add a job function or channel with the same
name (and parent for channels), they'll be merged in the same record, even if
they have different xmlids. On uninstall, the merged record is deleted when all
the modules using it are uninstalled.


**Job function: model**

If the function is defined in an abstract model, you can not write
``<field name="model_id" ref="xml_id_of_the_abstract_model"</field>``
but you have to define a function for each model that inherits from the abstract model.


**Job function: channel**

The channel where the job will be delayed. The default channel is ``root``.

**Job function: related action**

The *Related Action* appears as a button on the Job's view.
The button will execute the defined action.

The default one is to open the view of the record related to the job (form view
when there is a single record, list view for several records).
In many cases, the default related action is enough and doesn't need
customization, but it can be customized by providing a dictionary on the job
function:

.. code-block:: python

{
"enable": False,
"func_name": "related_action_partner",
"kwargs": {"name": "Partner"},
}

* ``enable``: when ``False``, the button has no effect (default: ``True``)
* ``func_name``: name of the method on ``queue.job`` that returns an action
* ``kwargs``: extra arguments to pass to the related action method

Example of related action code:

.. code-block:: python

class QueueJob(models.Model):
_inherit = 'queue.job'

def related_action_partner(self, name):
self.ensure_one()
model = self.model_name
partner = self.records
action = {
'name': name,
'type': 'ir.actions.act_window',
'res_model': model,
'view_type': 'form',
'view_mode': 'form',
'res_id': partner.id,
}
return action


**Job function: retry pattern**

When a job fails with a retryable error type, it is automatically
retried later. By default, the retry is always 10 minutes later.

A retry pattern can be configured on the job function. What a pattern represents
is "from X tries, postpone to Y seconds". It is expressed as a dictionary where
keys are tries and values are seconds to postpone as integers:


.. code-block:: python

{
1: 10,
5: 20,
10: 30,
15: 300,
}

Based on this configuration, we can tell that:

* 5 first retries are postponed 10 seconds later
* retries 5 to 10 postponed 20 seconds later
* retries 10 to 15 postponed 30 seconds later
* all subsequent retries postponed 5 minutes later

**Job Context**

The context of the recordset of the job, or any recordset passed in arguments of
a job, is transferred to the job according to an allow-list.

The default allow-list is empty for backward compatibility. The allow-list can
be customized in ``Base._job_prepare_context_before_enqueue_keys``.

Example:

.. code-block:: python

class Base(models.AbstractModel):

_inherit = "base"

@api.model
def _job_prepare_context_before_enqueue_keys(self):
"""Keys to keep in context of stored jobs

Empty by default for backward compatibility.
"""
return ("tz", "lang", "allowed_company_ids", "force_company", "active_test")

**Bypass jobs on running CBMS ODOO**

When you are developing (ie: connector modules) you might want
to bypass the queue job and run your code immediately.

To do so you can set `TEST_QUEUE_JOB_NO_DELAY=1` in your enviroment.

**Bypass jobs in tests**

When writing tests on job-related methods is always tricky to deal with
delayed recordsets. To make your testing life easier
you can set `test_queue_job_no_delay=True` in the context.

Tip: you can do this at test case level like this

.. code-block:: python

@classmethod
def setUpClass(cls):
super().setUpClass()
cls.env = cls.env(context=dict(
cls.env.context,
test_queue_job_no_delay=True, # no jobs thanks
))

Then all your tests execute the job methods synchronously
without delaying any jobs.

Testing
-------

**Asserting enqueued jobs**

The recommended way to test jobs, rather than running them directly and synchronously is to
split the tests in two parts:

* one test where the job is mocked (trap jobs with ``trap_jobs()`` and the test
only verifies that the job has been delayed with the expected arguments
* one test that only calls the method of the job synchronously, to validate the
proper behavior of this method only

Proceeding this way means that you can prove that jobs will be enqueued properly
at runtime, and it ensures your code does not have a different behavior in tests
and in production (because running your jobs synchronously may have a different
behavior as they are in the same transaction / in the middle of the method).
Additionally, it gives more control on the arguments you want to pass when
calling the job's method (synchronously, this time, in the second type of
tests), and it makes tests smaller.

The best way to run such assertions on the enqueued jobs is to use
``odoo.addons.queue_job.tests.common.trap_jobs()``.

Inside this context manager, instead of being added in the database's queue,
jobs are pushed in an in-memory list. The context manager then provides useful
helpers to verify that jobs have been enqueued with the expected arguments. It
even can run the jobs of its list synchronously! Details in
``odoo.addons.queue_job.tests.common.JobsTester``.

A very small example (more details in ``tests/common.py``):

.. code-block:: python

# code
def my_job_method(self, name, count):
self.write({"name": " ".join([name] * count)

def method_to_test(self):
count = self.env["other.model"].search_count([])
self.with_delay(priority=15).my_job_method("Hi!", count=count)
return count

# tests
from CBMS ODOO.addons.queue_job.tests.common import trap_jobs

# first test only check the expected behavior of the method and the proper
# enqueuing of jobs
def test_method_to_test(self):
with trap_jobs() as trap:
result = self.env["model"].method_to_test()
expected_count = 12

trap.assert_jobs_count(1, only=self.env["model"].my_job_method)
trap.assert_enqueued_job(
self.env["model"].my_job_method,
args=("Hi!",),
kwargs=dict(count=expected_count),
properties=dict(priority=15)
)
self.assertEqual(result, expected_count)


# second test to validate the behavior of the job unitarily
def test_my_job_method(self):
record = self.env["model"].browse(1)
record.my_job_method("Hi!", count=12)
self.assertEqual(record.name, "Hi! Hi! Hi! Hi! Hi! Hi! Hi! Hi! Hi! Hi! Hi! Hi!")

If you prefer, you can still test the whole thing in a single test, by calling
``jobs_tester.perform_enqueued_jobs()`` in your test.

.. code-block:: python

def test_method_to_test(self):
with trap_jobs() as trap:
result = self.env["model"].method_to_test()
expected_count = 12

trap.assert_jobs_count(1, only=self.env["model"].my_job_method)
trap.assert_enqueued_job(
self.env["model"].my_job_method,
args=("Hi!",),
kwargs=dict(count=expected_count),
properties=dict(priority=15)
)
self.assertEqual(result, expected_count)

trap.perform_enqueued_jobs()

record = self.env["model"].browse(1)
record.my_job_method("Hi!", count=12)
self.assertEqual(record.name, "Hi! Hi! Hi! Hi! Hi! Hi! Hi! Hi! Hi! Hi! Hi! Hi!")

**Execute jobs synchronously when running CBMS ODOO**

When you are developing (ie: connector modules) you might want
to bypass the queue job and run your code immediately.

To do so you can set ``TEST_QUEUE_JOB_NO_DELAY=1`` in your environment.

.. WARNING:: Do not do this in production

**Execute jobs synchronously in tests**

You should use ``trap_jobs``, really, but if for any reason you could not use it,
and still need to have job methods executed synchronously in your tests, you can
do so by setting ``test_queue_job_no_delay=True`` in the context.

Tip: you can do this at test case level like this

.. code-block:: python

@classmethod
def setUpClass(cls):
super().setUpClass()
cls.env = cls.env(context=dict(
cls.env.context,
test_queue_job_no_delay=True, # no jobs thanks
))

Then all your tests execute the job methods synchronously without delaying any
jobs.

In tests you'll have to mute the logger like:

@mute_logger('odoo.addons.queue_job.models.base')

.. NOTE:: in graphs of jobs, the ``test_queue_job_no_delay`` context key must be in at
least one job's env of the graph for the whole graph to be executed synchronously


Tips and tricks
---------------

* **Idempotency** (https://www.restapitutorial.com/lessons/idempotency.html): The queue_job should be idempotent so they can be retried several times without impact on the data.
* **The job should test at the very beginning its relevance**: the moment the job will be executed is unknown by design. So the first task of a job should be to check if the related work is still relevant at the moment of the execution.

Patterns
--------
Through the time, two main patterns emerged:

1. For data exposed to users, a model should store the data and the model should be the creator of the job. The job is kept hidden from the users
2. For technical data, that are not exposed to the users, it is generally alright to create directly jobs with data passed as arguments to the job, without intermediary models.

Known issues / Roadmap
======================

* After creating a new database or installing ``queue_job`` on an
existing database, CBMS ODOO must be restarted for the runner to detect it.

* When CBMS ODOO shuts down normally, it waits for running jobs to finish.
However, when the CBMS ODOO server crashes or is otherwise force-stopped,
running jobs are interrupted while the runner has no chance to know
they have been aborted. In such situations, jobs may remain in
``started`` or ``enqueued`` state after the CBMS ODOO server is halted.
Since the runner has no way to know if they are actually running or
not, and does not know for sure if it is safe to restart the jobs,
it does not attempt to restart them automatically. Such stale jobs
therefore fill the running queue and prevent other jobs to start.
You must therefore requeue them manually, either from the Jobs view,
or by running the following SQL statement *before starting CBMS ODOO*:

.. code-block:: sql

update queue_job set state='pending' where state in ('started', 'enqueued')

Changelog
=========

.. [ The change log. The goal of this file is to help readers
understand changes between version. The primary audience is
end users and integrators. Purely technical changes such as
code refactoring must not be mentioned here.

This file may contain ONE level of section titles, underlined
with the ~ (tilde) character. Other section markers are
forbidden and will likely break the structure of the README.rst
or other documents where this fragment is included. ]

Next
~~~~

* [ADD] Run jobrunner as a worker process instead of a thread in the main
process (when running with --workers > 0)
* [REF] ``@job`` and ``@related_action`` deprecated, any method can be delayed,
and configured using ``queue.job.function`` records
* [MIGRATION] from 13.0 branched at rev. e24ff4b

Bug Tracker
===========

Bugs are tracked on `GitHub Issues <https://github.com/OCA/queue/issues>`_.
In case of trouble, please check there if your issue has already been reported.
If you spotted it first, help us smashing it by providing a detailed and welcomed
`feedback <https://github.com/OCA/queue/issues/new?body=module: queue_job
version: 14.0

**Steps to reproduce**
- ...

**Current behavior**

**Expected behavior**>`_.

Do not contact contributors directly about support or help with technical issues.

Credits
=======

Authors
~~~~~~~

* Camptocamp
* ACSONE SA/NV

Contributors
~~~~~~~~~~~~

* Guewen Baconnier <guewen.baconnier@camptocamp.com>
* Stéphane Bidoul <stephane.bidoul@acsone.eu>
* Matthieu Dietrich <matthieu.dietrich@camptocamp.com>
* Jos De Graeve <Jos.DeGraeve@apertoso.be>
* David Lefever <dl@taktik.be>
* Laurent Mignon <laurent.mignon@acsone.eu>
* Laetitia Gangloff <laetitia.gangloff@acsone.eu>
* Cédric Pigeon <cedric.pigeon@acsone.eu>
* Tatiana Deribina <tatiana.deribina@avoin.systems>
* Souheil Bejaoui <souheil.bejaoui@acsone.eu>
* Eric Antones <eantones@nuobit.com>
* Simone Orsi <simone.orsi@camptocamp.com>

Maintainers
~~~~~~~~~~~

This module is maintained by the OCA.

.. image:: https://odoo-community.org/logo.png
:alt: CBMS ODOO Community Association
:target: https://odoo-community.org

OCA, or the CBMS ODOO Community Association, is a nonprofit organization whose
mission is to support the collaborative development of CBMS ODOO features and
promote its widespread use.

.. |maintainer-guewen| image:: https://github.com/guewen.png?size=40px
:target: https://github.com/guewen
:alt: guewen

Current `maintainer <https://odoo-community.org/page/maintainer-role>`__:

|maintainer-guewen|

This module is part of the `OCA/queue <https://github.com/OCA/queue/tree/14.0/queue_job>`_ project on GitHub.

You are welcome to contribute. To learn how please visit https://odoo-community.org/page/Contribute.

Internal Reference: queue_job