.. _configuration: ============================ Configuration and defaults ============================ This document describes the configuration options available. If you're using the default loader, you must create the :file:`celeryconfig.py` module and make sure it is available on the Python path. .. contents:: :local: :depth: 2 .. _conf-example: Example configuration file ========================== This is an example configuration file to get you started. It should contain all you need to run a basic Celery set-up. .. code-block:: python ## Broker settings. BROKER_URL = 'amqp://guest:guest@localhost:5672//' # List of modules to import when celery starts. CELERY_IMPORTS = ('myapp.tasks', ) ## Using the database to store task state and results. CELERY_RESULT_BACKEND = 'db+sqlite:///results.db' CELERY_ANNOTATIONS = {'tasks.add': {'rate_limit': '10/s'}} Configuration Directives ======================== .. _conf-datetime: Time and date settings ---------------------- .. setting:: CELERY_ENABLE_UTC CELERY_ENABLE_UTC ~~~~~~~~~~~~~~~~~ .. versionadded:: 2.5 If enabled dates and times in messages will be converted to use the UTC timezone. Note that workers running Celery versions below 2.5 will assume a local timezone for all messages, so only enable if all workers have been upgraded. Enabled by default since version 3.0. .. setting:: CELERY_TIMEZONE CELERY_TIMEZONE ~~~~~~~~~~~~~~~ Configure Celery to use a custom time zone. The timezone value can be any time zone supported by the `pytz`_ library. If not set the UTC timezone is used. For backwards compatibility there is also a :setting:`CELERY_ENABLE_UTC` setting, and this is set to false the system local timezone is used instead. .. _`pytz`: http://pypi.python.org/pypi/pytz/ .. _conf-tasks: Task settings ------------- .. setting:: CELERY_ANNOTATIONS CELERY_ANNOTATIONS ~~~~~~~~~~~~~~~~~~ This setting can be used to rewrite any task attribute from the configuration. The setting can be a dict, or a list of annotation objects that filter for tasks and return a map of attributes to change. This will change the ``rate_limit`` attribute for the ``tasks.add`` task: .. code-block:: python CELERY_ANNOTATIONS = {'tasks.add': {'rate_limit': '10/s'}} or change the same for all tasks: .. code-block:: python CELERY_ANNOTATIONS = {'*': {'rate_limit': '10/s'}} You can change methods too, for example the ``on_failure`` handler: .. code-block:: python def my_on_failure(self, exc, task_id, args, kwargs, einfo): print('Oh no! Task failed: {0!r}'.format(exc)) CELERY_ANNOTATIONS = {'*': {'on_failure': my_on_failure}} If you need more flexibility then you can use objects instead of a dict to choose which tasks to annotate: .. code-block:: python class MyAnnotate(object): def annotate(self, task): if task.name.startswith('tasks.'): return {'rate_limit': '10/s'} CELERY_ANNOTATIONS = (MyAnnotate(), {…}) .. _conf-concurrency: Concurrency settings -------------------- .. setting:: CELERYD_CONCURRENCY CELERYD_CONCURRENCY ~~~~~~~~~~~~~~~~~~~ The number of concurrent worker processes/threads/green threads executing tasks. If you're doing mostly I/O you can have more processes, but if mostly CPU-bound, try to keep it close to the number of CPUs on your machine. If not set, the number of CPUs/cores on the host will be used. Defaults to the number of available CPUs. .. setting:: CELERYD_PREFETCH_MULTIPLIER CELERYD_PREFETCH_MULTIPLIER ~~~~~~~~~~~~~~~~~~~~~~~~~~~ How many messages to prefetch at a time multiplied by the number of concurrent processes. The default is 4 (four messages for each process). The default setting is usually a good choice, however -- if you have very long running tasks waiting in the queue and you have to start the workers, note that the first worker to start will receive four times the number of messages initially. Thus the tasks may not be fairly distributed to the workers. .. note:: Tasks with ETA/countdown are not affected by prefetch limits. .. _conf-result-backend: Task result backend settings ---------------------------- .. setting:: CELERY_RESULT_BACKEND CELERY_RESULT_BACKEND ~~~~~~~~~~~~~~~~~~~~~ :Deprecated aliases: ``CELERY_BACKEND`` The backend used to store task results (tombstones). Disabled by default. Can be one of the following: * database Use a relational database supported by `SQLAlchemy`_. See :ref:`conf-database-result-backend`. * cache Use `memcached`_ to store the results. See :ref:`conf-cache-result-backend`. * mongodb Use `MongoDB`_ to store the results. See :ref:`conf-mongodb-result-backend`. * redis Use `Redis`_ to store the results. See :ref:`conf-redis-result-backend`. * amqp Send results back as AMQP messages See :ref:`conf-amqp-result-backend`. * cassandra Use `Cassandra`_ to store the results. See :ref:`conf-cassandra-result-backend`. * ironcache Use `IronCache`_ to store the results. See :ref:`conf-ironcache-result-backend`. * couchbase Use `Couchbase`_ to store the results. See :ref:`conf-couchbase-result-backend`. .. warning: While the AMQP result backend is very efficient, you must make sure you only receive the same result once. See :doc:`userguide/calling`). .. _`SQLAlchemy`: http://sqlalchemy.org .. _`memcached`: http://memcached.org .. _`MongoDB`: http://mongodb.org .. _`Redis`: http://redis.io .. _`Cassandra`: http://cassandra.apache.org/ .. _`IronCache`: http://www.iron.io/cache .. _`Couchbase`: http://www.couchbase.com/ .. setting:: CELERY_RESULT_SERIALIZER CELERY_RESULT_SERIALIZER ~~~~~~~~~~~~~~~~~~~~~~~~ Result serialization format. Default is ``pickle``. See :ref:`calling-serializers` for information about supported serialization formats. .. _conf-database-result-backend: Database backend settings ------------------------- Database URL Examples ~~~~~~~~~~~~~~~~~~~~~ To use the database backend you have to configure the :setting:`CELERY_RESULT_BACKEND` setting with a connection URL and the ``db+`` prefix: .. code-block:: python CELERY_RESULT_BACKEND = 'db+scheme://user:password@host:port/dbname' Examples: # sqlite (filename) CELERY_RESULT_BACKEND = 'db+sqlite:///results.sqlite' # mysql CELERY_RESULT_BACKEND = 'db+mysql://scott:tiger@localhost/foo' # postgresql CELERY_RESULT_BACKEND = 'db+postgresql://scott:tiger@localhost/mydatabase' # oracle CELERY_RESULT_BACKEND = 'db+oracle://scott:tiger@127.0.0.1:1521/sidname' .. code-block:: python Please see `Supported Databases`_ for a table of supported databases, and `Connection String`_ for more information about connection strings (which is the part of the URI that comes after the ``db+`` prefix). .. _`Supported Databases`: http://www.sqlalchemy.org/docs/core/engines.html#supported-databases .. _`Connection String`: http://www.sqlalchemy.org/docs/core/engines.html#database-urls .. setting:: CELERY_RESULT_DBURI CELERY_RESULT_DBURI ~~~~~~~~~~~~~~~~~~~ This setting is no longer used as it's now possible to specify the database URL directly in the :setting:`CELERY_RESULT_BACKEND` setting. .. setting:: CELERY_RESULT_ENGINE_OPTIONS CELERY_RESULT_ENGINE_OPTIONS ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ To specify additional SQLAlchemy database engine options you can use the :setting:`CELERY_RESULT_ENGINE_OPTIONS` setting:: # echo enables verbose logging from SQLAlchemy. CELERY_RESULT_ENGINE_OPTIONS = {'echo': True} .. setting:: CELERY_RESULT_DB_SHORT_LIVED_SESSIONS CELERY_RESULT_DB_SHORT_LIVED_SESSIONS = True Short lived sessions are disabled by default. If enabled they can drastically reduce performance, especially on systems processing lots of tasks. This option is useful on low-traffic workers that experience errors as a result of cached database connections going stale through inactivity. For example, intermittent errors like `(OperationalError) (2006, 'MySQL server has gone away')` can be fixed by enabling short lived sessions. This option only affects the database backend. Specifying Table Names ~~~~~~~~~~~~~~~~~~~~~~ .. setting:: CELERY_RESULT_DB_TABLENAMES When SQLAlchemy is configured as the result backend, Celery automatically creates two tables to store result metadata for tasks. This setting allows you to customize the table names: .. code-block:: python # use custom table names for the database result backend. CELERY_RESULT_DB_TABLENAMES = { 'task': 'myapp_taskmeta', 'group': 'myapp_groupmeta', } .. _conf-amqp-result-backend: AMQP backend settings --------------------- .. note:: The AMQP backend requires RabbitMQ 1.1.0 or higher to automatically expire results. If you are running an older version of RabbitmQ you should disable result expiration like this: CELERY_TASK_RESULT_EXPIRES = None .. setting:: CELERY_RESULT_EXCHANGE CELERY_RESULT_EXCHANGE ~~~~~~~~~~~~~~~~~~~~~~ Name of the exchange to publish results in. Default is `celeryresults`. .. setting:: CELERY_RESULT_EXCHANGE_TYPE CELERY_RESULT_EXCHANGE_TYPE ~~~~~~~~~~~~~~~~~~~~~~~~~~~ The exchange type of the result exchange. Default is to use a `direct` exchange. .. setting:: CELERY_RESULT_PERSISTENT CELERY_RESULT_PERSISTENT ~~~~~~~~~~~~~~~~~~~~~~~~ If set to :const:`True`, result messages will be persistent. This means the messages will not be lost after a broker restart. The default is for the results to be transient. Example configuration ~~~~~~~~~~~~~~~~~~~~~ .. code-block:: python CELERY_RESULT_BACKEND = 'amqp' CELERY_TASK_RESULT_EXPIRES = 18000 # 5 hours. .. _conf-cache-result-backend: Cache backend settings ---------------------- .. note:: The cache backend supports the `pylibmc`_ and `python-memcached` libraries. The latter is used only if `pylibmc`_ is not installed. Using a single memcached server: .. code-block:: python CELERY_RESULT_BACKEND = 'cache+memcached://127.0.0.1:11211/' Using multiple memcached servers: .. code-block:: python CELERY_RESULT_BACKEND = """ cache+memcached://172.19.26.240:11211;172.19.26.242:11211/ """.strip() .. setting:: CELERY_CACHE_BACKEND_OPTIONS The "memory" backend stores the cache in memory only: CELERY_CACHE_BACKEND = 'memory' CELERY_CACHE_BACKEND_OPTIONS ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ You can set pylibmc options using the :setting:`CELERY_CACHE_BACKEND_OPTIONS` setting: .. code-block:: python CELERY_CACHE_BACKEND_OPTIONS = {'binary': True, 'behaviors': {'tcp_nodelay': True}} .. _`pylibmc`: http://sendapatch.se/projects/pylibmc/ .. setting:: CELERY_CACHE_BACKEND CELERY_CACHE_BACKEND ~~~~~~~~~~~~~~~~~~~~ This setting is no longer used as it's now possible to specify the cache backend directly in the :setting:`CELERY_RESULT_BACKEND` setting. .. _conf-redis-result-backend: Redis backend settings ---------------------- Configuring the backend URL ~~~~~~~~~~~~~~~~~~~~~~~~~~~ .. note:: The Redis backend requires the :mod:`redis` library: http://pypi.python.org/pypi/redis/ To install the redis package use `pip` or `easy_install`: .. code-block:: bash $ pip install redis This backend requires the :setting:`CELERY_RESULT_BACKEND` setting to be set to a Redis URL:: CELERY_RESULT_BACKEND = 'redis://:password@host:port/db' For example:: CELERY_RESULT_BACKEND = 'redis://localhost/0' which is the same as:: CELERY_RESULT_BACKEND = 'redis://' The fields of the URL is defined as folows: - *host* Host name or IP address of the Redis server. e.g. `localhost`. - *port* Port to the Redis server. Default is 6379. - *db* Database number to use. Default is 0. The db can include an optional leading slash. - *password* Password used to connect to the database. .. setting:: CELERY_REDIS_MAX_CONNECTIONS CELERY_REDIS_MAX_CONNECTIONS ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Maximum number of connections available in the Redis connection pool used for sending and retrieving results. .. _conf-mongodb-result-backend: MongoDB backend settings ------------------------ .. note:: The MongoDB backend requires the :mod:`pymongo` library: http://github.com/mongodb/mongo-python-driver/tree/master .. setting:: CELERY_MONGODB_BACKEND_SETTINGS CELERY_MONGODB_BACKEND_SETTINGS ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ This is a dict supporting the following keys: * database The database name to connect to. Defaults to ``celery``. * taskmeta_collection The collection name to store task meta data. Defaults to ``celery_taskmeta``. * max_pool_size Passed as max_pool_size to PyMongo's Connection or MongoClient constructor. It is the maximum number of TCP connections to keep open to MongoDB at a given time. If there are more open connections than max_pool_size, sockets will be closed when they are released. Defaults to 10. * options Additional keyword arguments to pass to the mongodb connection constructor. See the :mod:`pymongo` docs to see a list of arguments supported. .. _example-mongodb-result-config: Example configuration ~~~~~~~~~~~~~~~~~~~~~ .. code-block:: python CELERY_RESULT_BACKEND = 'mongodb://192.168.1.100:30000/' CELERY_MONGODB_BACKEND_SETTINGS = { 'database': 'mydb', 'taskmeta_collection': 'my_taskmeta_collection', } .. _conf-cassandra-result-backend: Cassandra backend settings -------------------------- .. note:: The Cassandra backend requires the :mod:`pycassa` library: http://pypi.python.org/pypi/pycassa/ To install the pycassa package use `pip` or `easy_install`: .. code-block:: bash $ pip install pycassa This backend requires the following configuration directives to be set. .. setting:: CASSANDRA_SERVERS CASSANDRA_SERVERS ~~~~~~~~~~~~~~~~~ List of ``host:port`` Cassandra servers. e.g.:: CASSANDRA_SERVERS = ['localhost:9160'] .. setting:: CASSANDRA_KEYSPACE CASSANDRA_KEYSPACE ~~~~~~~~~~~~~~~~~~ The keyspace in which to store the results. e.g.:: CASSANDRA_KEYSPACE = 'tasks_keyspace' .. setting:: CASSANDRA_COLUMN_FAMILY CASSANDRA_COLUMN_FAMILY ~~~~~~~~~~~~~~~~~~~~~~~ The column family in which to store the results. e.g.:: CASSANDRA_COLUMN_FAMILY = 'tasks' .. setting:: CASSANDRA_READ_CONSISTENCY CASSANDRA_READ_CONSISTENCY ~~~~~~~~~~~~~~~~~~~~~~~~~~ The read consistency used. Values can be ``ONE``, ``QUORUM`` or ``ALL``. .. setting:: CASSANDRA_WRITE_CONSISTENCY CASSANDRA_WRITE_CONSISTENCY ~~~~~~~~~~~~~~~~~~~~~~~~~~~ The write consistency used. Values can be ``ONE``, ``QUORUM`` or ``ALL``. .. setting:: CASSANDRA_DETAILED_MODE CASSANDRA_DETAILED_MODE ~~~~~~~~~~~~~~~~~~~~~~~ Enable or disable detailed mode. Default is :const:`False`. This mode allows to use the power of Cassandra wide columns to store all states for a task as a wide column, instead of only the last one. To use this mode, you need to configure your ColumnFamily to use the ``TimeUUID`` type as a comparator:: create column family task_results with comparator = TimeUUIDType; CASSANDRA_OPTIONS ~~~~~~~~~~~~~~~~~~~~~~~~~~~ Options to be passed to the `pycassa connection pool`_ (optional). .. _`pycassa connection pool`: http://pycassa.github.com/pycassa/api/pycassa/pool.html Example configuration ~~~~~~~~~~~~~~~~~~~~~ .. code-block:: python CASSANDRA_SERVERS = ['localhost:9160'] CASSANDRA_KEYSPACE = 'celery' CASSANDRA_COLUMN_FAMILY = 'task_results' CASSANDRA_READ_CONSISTENCY = 'ONE' CASSANDRA_WRITE_CONSISTENCY = 'ONE' CASSANDRA_DETAILED_MODE = True CASSANDRA_OPTIONS = { 'timeout': 300, 'max_retries': 10 } .. _conf-ironcache-result-backend: IronCache backend settings -------------------------- .. note:: The IronCache backend requires the :mod:`iron_celery` library: http://pypi.python.org/pypi/iron_celery To install the iron_celery package use `pip` or `easy_install`: .. code-block:: bash $ pip install iron_celery IronCache is configured via the URL provided in :setting:`CELERY_RESULT_BACKEND`, for example:: CELERY_RESULT_BACKEND = 'ironcache://project_id:token@' Or to change the cache name:: ironcache:://project_id:token@/awesomecache For more information, see: https://github.com/iron-io/iron_celery .. _conf-couchbase-result-backend: Couchbase backend settings -------------------------- .. note:: The Couchbase backend requires the :mod:`couchbase` library: https://pypi.python.org/pypi/couchbase To install the couchbase package use `pip` or `easy_install`: .. code-block:: bash $ pip install couchbase This backend can be configured via the :setting:`CELERY_RESULT_BACKEND` set to a couchbase URL:: CELERY_RESULT_BACKEND = 'couchbase://username:password@host:port/bucket' .. setting:: CELERY_COUCHBASE_BACKEND_SETTINGS CELERY_COUCHBASE_BACKEND_SETTINGS ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ This is a dict supporting the following keys: * host Host name of the Couchbase server. Defaults to ``localhost``. * port The port the Couchbase server is listening to. Defaults to ``8091``. * bucket The default bucket the Couchbase server is writing to. Defaults to ``default``. * username User name to authenticate to the Couchbase server as (optional). * password Password to authenticate to the Couchbase server (optional). .. _conf-messaging: Message Routing --------------- .. _conf-messaging-routing: .. setting:: CELERY_QUEUES CELERY_QUEUES ~~~~~~~~~~~~~ The mapping of queues the worker consumes from. This is a dictionary of queue name/options. See :ref:`guide-routing` for more information. The default is a queue/exchange/binding key of ``celery``, with exchange type ``direct``. You don't have to care about this unless you want custom routing facilities. .. setting:: CELERY_ROUTES CELERY_ROUTES ~~~~~~~~~~~~~ A list of routers, or a single router used to route tasks to queues. When deciding the final destination of a task the routers are consulted in order. See :ref:`routers` for more information. .. setting:: CELERY_QUEUE_HA_POLICY CELERY_QUEUE_HA_POLICY ~~~~~~~~~~~~~~~~~~~~~~ :brokers: RabbitMQ This will set the default HA policy for a queue, and the value can either be a string (usually ``all``): .. code-block:: python CELERY_QUEUE_HA_POLICY = 'all' Using 'all' will replicate the queue to all current nodes, Or you can give it a list of nodes to replicate to: .. code-block:: python CELERY_QUEUE_HA_POLICY = ['rabbit@host1', 'rabbit@host2'] Using a list will implicitly set ``x-ha-policy`` to 'nodes' and ``x-ha-policy-params`` to the given list of nodes. See http://www.rabbitmq.com/ha.html for more information. .. setting:: CELERY_WORKER_DIRECT CELERY_WORKER_DIRECT ~~~~~~~~~~~~~~~~~~~~ This option enables so that every worker has a dedicated queue, so that tasks can be routed to specific workers. The queue name for each worker is automatically generated based on the worker hostname and a ``.dq`` suffix, using the ``C.dq`` exchange. For example the queue name for the worker with node name ``w1@example.com`` becomes:: w1@example.com.dq Then you can route the task to the task by specifying the hostname as the routing key and the ``C.dq`` exchange:: CELERY_ROUTES = { 'tasks.add': {'exchange': 'C.dq', 'routing_key': 'w1@example.com'} } .. setting:: CELERY_CREATE_MISSING_QUEUES CELERY_CREATE_MISSING_QUEUES ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ If enabled (default), any queues specified that are not defined in :setting:`CELERY_QUEUES` will be automatically created. See :ref:`routing-automatic`. .. setting:: CELERY_DEFAULT_QUEUE CELERY_DEFAULT_QUEUE ~~~~~~~~~~~~~~~~~~~~ The name of the default queue used by `.apply_async` if the message has no route or no custom queue has been specified. This queue must be listed in :setting:`CELERY_QUEUES`. If :setting:`CELERY_QUEUES` is not specified then it is automatically created containing one queue entry, where this name is used as the name of that queue. The default is: `celery`. .. seealso:: :ref:`routing-changing-default-queue` .. setting:: CELERY_DEFAULT_EXCHANGE CELERY_DEFAULT_EXCHANGE ~~~~~~~~~~~~~~~~~~~~~~~ Name of the default exchange to use when no custom exchange is specified for a key in the :setting:`CELERY_QUEUES` setting. The default is: `celery`. .. setting:: CELERY_DEFAULT_EXCHANGE_TYPE CELERY_DEFAULT_EXCHANGE_TYPE ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Default exchange type used when no custom exchange type is specified for a key in the :setting:`CELERY_QUEUES` setting. The default is: `direct`. .. setting:: CELERY_DEFAULT_ROUTING_KEY CELERY_DEFAULT_ROUTING_KEY ~~~~~~~~~~~~~~~~~~~~~~~~~~ The default routing key used when no custom routing key is specified for a key in the :setting:`CELERY_QUEUES` setting. The default is: `celery`. .. setting:: CELERY_DEFAULT_DELIVERY_MODE CELERY_DEFAULT_DELIVERY_MODE ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Can be `transient` or `persistent`. The default is to send persistent messages. .. _conf-broker-settings: Broker Settings --------------- .. setting:: CELERY_ACCEPT_CONTENT CELERY_ACCEPT_CONTENT ~~~~~~~~~~~~~~~~~~~~~ A whitelist of content-types/serializers to allow. If a message is received that is not in this list then the message will be discarded with an error. By default any content type is enabled (including pickle and yaml) so make sure untrusted parties do not have access to your broker. See :ref:`guide-security` for more. Example:: # using serializer name CELERY_ACCEPT_CONTENT = ['json'] # or the actual content-type (MIME) CELERY_ACCEPT_CONTENT = ['application/json'] .. setting:: BROKER_FAILOVER_STRATEGY BROKER_FAILOVER_STRATEGY ~~~~~~~~~~~~~~~~~~~~~~~~ Default failover strategy for the broker Connection object. If supplied, may map to a key in 'kombu.connection.failover_strategies', or be a reference to any method that yields a single item from a supplied list. Example:: # Random failover strategy def random_failover_strategy(servers): it = list(it) # don't modify callers list shuffle = random.shuffle for _ in repeat(None): shuffle(it) yield it[0] BROKER_FAILOVER_STRATEGY=random_failover_strategy .. setting:: BROKER_TRANSPORT BROKER_FAILOVER_STRATEGY ~~~~~~~~~~~~~~~~~~~~~~~~ Default failover strategy for the broker Connection object. If supplied, may map to a key in 'kombu.connection.failover_strategies', or be a reference to any method that yields a single item from a supplied list. Example:: # Random failover strategy def random_failover_strategy(servers): it = list(it) # don't modify callers list shuffle = random.shuffle for _ in repeat(None): shuffle(it) yield it[0] BROKER_FAILOVER_STRATEGY=random_failover_strategy BROKER_TRANSPORT ~~~~~~~~~~~~~~~~ :Aliases: ``BROKER_BACKEND`` :Deprecated aliases: ``CARROT_BACKEND`` .. setting:: BROKER_URL BROKER_URL ~~~~~~~~~~ Default broker URL. This must be an URL in the form of:: transport://userid:password@hostname:port/virtual_host Only the scheme part (``transport://``) is required, the rest is optional, and defaults to the specific transports default values. The transport part is the broker implementation to use, and the default is ``amqp``, which uses ``librabbitmq`` by default or falls back to ``pyamqp`` if that is not installed. Also there are many other choices including ``redis``, ``beanstalk``, ``sqlalchemy``, ``django``, ``mongodb``, ``couchdb``. It can also be a fully qualified path to your own transport implementation. See :ref:`kombu:connection-urls` in the Kombu documentation for more information. .. setting:: BROKER_HEARTBEAT BROKER_HEARTBEAT ~~~~~~~~~~~~~~~~ :transports supported: ``pyamqp`` It's not always possible to detect connection loss in a timely manner using TCP/IP alone, so AMQP defines something called heartbeats that's is used both by the client and the broker to detect if a connection was closed. Hartbeats are disabled by default. If the heartbeat value is 10 seconds, then the heartbeat will be monitored at the interval specified by the :setting:`BROKER_HEARTBEAT_CHECKRATE` setting, which by default is double the rate of the heartbeat value (so for the default 10 seconds, the heartbeat is checked every 5 seconds). .. setting:: BROKER_HEARTBEAT_CHECKRATE BROKER_HEARTBEAT_CHECKRATE ~~~~~~~~~~~~~~~~~~~~~~~~~~ :transports supported: ``pyamqp`` At intervals the worker will monitor that the broker has not missed too many heartbeats. The rate at which this is checked is calculated by dividing the :setting:`BROKER_HEARTBEAT` value with this value, so if the heartbeat is 10.0 and the rate is the default 2.0, the check will be performed every 5 seconds (twice the heartbeat sending rate). .. setting:: BROKER_USE_SSL BROKER_USE_SSL ~~~~~~~~~~~~~~ Use SSL to connect to the broker. Off by default. This may not be supported by all transports. .. setting:: BROKER_POOL_LIMIT BROKER_POOL_LIMIT ~~~~~~~~~~~~~~~~~ .. versionadded:: 2.3 The maximum number of connections that can be open in the connection pool. The pool is enabled by default since version 2.5, with a default limit of ten connections. This number can be tweaked depending on the number of threads/greenthreads (eventlet/gevent) using a connection. For example running eventlet with 1000 greenlets that use a connection to the broker, contention can arise and you should consider increasing the limit. If set to :const:`None` or 0 the connection pool will be disabled and connections will be established and closed for every use. Default (since 2.5) is to use a pool of 10 connections. .. setting:: BROKER_CONNECTION_TIMEOUT BROKER_CONNECTION_TIMEOUT ~~~~~~~~~~~~~~~~~~~~~~~~~ The default timeout in seconds before we give up establishing a connection to the AMQP server. Default is 4 seconds. .. setting:: BROKER_CONNECTION_RETRY BROKER_CONNECTION_RETRY ~~~~~~~~~~~~~~~~~~~~~~~ Automatically try to re-establish the connection to the AMQP broker if lost. The time between retries is increased for each retry, and is not exhausted before :setting:`BROKER_CONNECTION_MAX_RETRIES` is exceeded. This behavior is on by default. .. setting:: BROKER_CONNECTION_MAX_RETRIES BROKER_CONNECTION_MAX_RETRIES ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Maximum number of retries before we give up re-establishing a connection to the AMQP broker. If this is set to :const:`0` or :const:`None`, we will retry forever. Default is 100 retries. .. setting:: BROKER_LOGIN_METHOD BROKER_LOGIN_METHOD ~~~~~~~~~~~~~~~~~~~ Set custom amqp login method, default is ``AMQPLAIN``. .. setting:: BROKER_TRANSPORT_OPTIONS BROKER_TRANSPORT_OPTIONS ~~~~~~~~~~~~~~~~~~~~~~~~ .. versionadded:: 2.2 A dict of additional options passed to the underlying transport. See your transport user manual for supported options (if any). Example setting the visibility timeout (supported by Redis and SQS transports): .. code-block:: python BROKER_TRANSPORT_OPTIONS = {'visibility_timeout': 18000} # 5 hours .. _conf-task-execution: Task execution settings ----------------------- .. setting:: CELERY_ALWAYS_EAGER CELERY_ALWAYS_EAGER ~~~~~~~~~~~~~~~~~~~ If this is :const:`True`, all tasks will be executed locally by blocking until the task returns. ``apply_async()`` and ``Task.delay()`` will return an :class:`~celery.result.EagerResult` instance, which emulates the API and behavior of :class:`~celery.result.AsyncResult`, except the result is already evaluated. That is, tasks will be executed locally instead of being sent to the queue. .. setting:: CELERY_EAGER_PROPAGATES_EXCEPTIONS CELERY_EAGER_PROPAGATES_EXCEPTIONS ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ If this is :const:`True`, eagerly executed tasks (applied by `task.apply()`, or when the :setting:`CELERY_ALWAYS_EAGER` setting is enabled), will propagate exceptions. It's the same as always running ``apply()`` with ``throw=True``. .. setting:: CELERY_IGNORE_RESULT CELERY_IGNORE_RESULT ~~~~~~~~~~~~~~~~~~~~ Whether to store the task return values or not (tombstones). If you still want to store errors, just not successful return values, you can set :setting:`CELERY_STORE_ERRORS_EVEN_IF_IGNORED`. .. setting:: CELERY_MESSAGE_COMPRESSION CELERY_MESSAGE_COMPRESSION ~~~~~~~~~~~~~~~~~~~~~~~~~~ Default compression used for task messages. Can be ``gzip``, ``bzip2`` (if available), or any custom compression schemes registered in the Kombu compression registry. The default is to send uncompressed messages. .. setting:: CELERY_TASK_RESULT_EXPIRES CELERY_TASK_RESULT_EXPIRES ~~~~~~~~~~~~~~~~~~~~~~~~~~ Time (in seconds, or a :class:`~datetime.timedelta` object) for when after stored task tombstones will be deleted. A built-in periodic task will delete the results after this time (:class:`celery.task.backend_cleanup`). A value of :const:`None` or 0 means results will never expire (depending on backend specifications). Default is to expire after 1 day. .. note:: For the moment this only works with the amqp, database, cache, redis and MongoDB backends. When using the database or MongoDB backends, `celery beat` must be running for the results to be expired. .. setting:: CELERY_MAX_CACHED_RESULTS CELERY_MAX_CACHED_RESULTS ~~~~~~~~~~~~~~~~~~~~~~~~~ Result backends caches ready results used by the client. This is the total number of results to cache before older results are evicted. The default is 5000. 0 or None means no limit, and a value of :const:`-1` will disable the cache. .. setting:: CELERY_CHORD_PROPAGATES CELERY_CHORD_PROPAGATES ~~~~~~~~~~~~~~~~~~~~~~~ .. versionadded:: 3.0.14 This setting defines what happens when a task part of a chord raises an exception: - If propagate is True the chord callback will change state to FAILURE with the exception value set to a :exc:`~@ChordError` instance containing information about the error and the task that failed. This is the default behavior in Celery 3.1+ - If propagate is False the exception value will instead be forwarded to the chord callback. This was the default behavior before version 3.1. .. setting:: CELERY_TRACK_STARTED CELERY_TRACK_STARTED ~~~~~~~~~~~~~~~~~~~~ If :const:`True` the task will report its status as "started" when the task is executed by a worker. The default value is :const:`False` as the normal behaviour is to not report that level of granularity. Tasks are either pending, finished, or waiting to be retried. Having a "started" state can be useful for when there are long running tasks and there is a need to report which task is currently running. .. setting:: CELERY_TASK_SERIALIZER CELERY_TASK_SERIALIZER ~~~~~~~~~~~~~~~~~~~~~~ A string identifying the default serialization method to use. Can be `pickle` (default), `json`, `yaml`, `msgpack` or any custom serialization methods that have been registered with :mod:`kombu.serialization.registry`. .. seealso:: :ref:`calling-serializers`. .. setting:: CELERY_TASK_PUBLISH_RETRY CELERY_TASK_PUBLISH_RETRY ~~~~~~~~~~~~~~~~~~~~~~~~~ .. versionadded:: 2.2 Decides if publishing task messages will be retried in the case of connection loss or other connection errors. See also :setting:`CELERY_TASK_PUBLISH_RETRY_POLICY`. Enabled by default. .. setting:: CELERY_TASK_PUBLISH_RETRY_POLICY CELERY_TASK_PUBLISH_RETRY_POLICY ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ .. versionadded:: 2.2 Defines the default policy when retrying publishing a task message in the case of connection loss or other connection errors. See :ref:`calling-retry` for more information. .. setting:: CELERY_DEFAULT_RATE_LIMIT CELERY_DEFAULT_RATE_LIMIT ~~~~~~~~~~~~~~~~~~~~~~~~~ The global default rate limit for tasks. This value is used for tasks that does not have a custom rate limit The default is no rate limit. .. setting:: CELERY_DISABLE_RATE_LIMITS CELERY_DISABLE_RATE_LIMITS ~~~~~~~~~~~~~~~~~~~~~~~~~~ Disable all rate limits, even if tasks has explicit rate limits set. .. setting:: CELERY_ACKS_LATE CELERY_ACKS_LATE ~~~~~~~~~~~~~~~~ Late ack means the task messages will be acknowledged **after** the task has been executed, not *just before*, which is the default behavior. .. seealso:: FAQ: :ref:`faq-acks_late-vs-retry`. .. _conf-worker: Worker ------ .. setting:: CELERY_IMPORTS CELERY_IMPORTS ~~~~~~~~~~~~~~ A sequence of modules to import when the worker starts. This is used to specify the task modules to import, but also to import signal handlers and additional remote control commands, etc. The modules will be imported in the original order. .. setting:: CELERY_INCLUDE CELERY_INCLUDE ~~~~~~~~~~~~~~ Exact same semantics as :setting:`CELERY_IMPORTS`, but can be used as a means to have different import categories. The modules in this setting are imported after the modules in :setting:`CELERY_IMPORTS`. .. setting:: CELERYD_FORCE_EXECV CELERYD_FORCE_EXECV ~~~~~~~~~~~~~~~~~~~ On Unix the prefork pool will fork, so that child processes start with the same memory as the parent process. This can cause problems as there is a known deadlock condition with pthread locking primitives when `fork()` is combined with threads. You should enable this setting if you are experiencing hangs (deadlocks), especially in combination with time limits or having a max tasks per child limit. This option will be enabled by default in a later version. This is not a problem on Windows, as it does not have `fork()`. .. setting:: CELERYD_WORKER_LOST_WAIT CELERYD_WORKER_LOST_WAIT ~~~~~~~~~~~~~~~~~~~~~~~~ In some cases a worker may be killed without proper cleanup, and the worker may have published a result before terminating. This value specifies how long we wait for any missing results before raising a :exc:`@WorkerLostError` exception. Default is 10.0 .. setting:: CELERYD_MAX_TASKS_PER_CHILD CELERYD_MAX_TASKS_PER_CHILD ~~~~~~~~~~~~~~~~~~~~~~~~~~~ Maximum number of tasks a pool worker process can execute before it's replaced with a new one. Default is no limit. .. setting:: CELERYD_TASK_TIME_LIMIT CELERYD_TASK_TIME_LIMIT ~~~~~~~~~~~~~~~~~~~~~~~ Task hard time limit in seconds. The worker processing the task will be killed and replaced with a new one when this is exceeded. .. setting:: CELERYD_TASK_SOFT_TIME_LIMIT CELERYD_TASK_SOFT_TIME_LIMIT ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Task soft time limit in seconds. The :exc:`~@SoftTimeLimitExceeded` exception will be raised when this is exceeded. The task can catch this to e.g. clean up before the hard time limit comes. Example: .. code-block:: python from celery.exceptions import SoftTimeLimitExceeded @app.task def mytask(): try: return do_work() except SoftTimeLimitExceeded: cleanup_in_a_hurry() .. setting:: CELERY_STORE_ERRORS_EVEN_IF_IGNORED CELERY_STORE_ERRORS_EVEN_IF_IGNORED ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ If set, the worker stores all task errors in the result store even if :attr:`Task.ignore_result ` is on. .. setting:: CELERYD_STATE_DB CELERYD_STATE_DB ~~~~~~~~~~~~~~~~ Name of the file used to stores persistent worker state (like revoked tasks). Can be a relative or absolute path, but be aware that the suffix `.db` may be appended to the file name (depending on Python version). Can also be set via the :option:`--statedb` argument to :mod:`~celery.bin.worker`. Not enabled by default. .. setting:: CELERYD_TIMER_PRECISION CELERYD_TIMER_PRECISION ~~~~~~~~~~~~~~~~~~~~~~~ Set the maximum time in seconds that the ETA scheduler can sleep between rechecking the schedule. Default is 1 second. Setting this value to 1 second means the schedulers precision will be 1 second. If you need near millisecond precision you can set this to 0.1. .. setting:: CELERY_ENABLE_REMOTE_CONTROL CELERY_ENABLE_REMOTE_CONTROL ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Specify if remote control of the workers is enabled. Default is :const:`True`. .. _conf-error-mails: Error E-Mails ------------- .. setting:: CELERY_SEND_TASK_ERROR_EMAILS CELERY_SEND_TASK_ERROR_EMAILS ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The default value for the `Task.send_error_emails` attribute, which if set to :const:`True` means errors occurring during task execution will be sent to :setting:`ADMINS` by email. Disabled by default. .. setting:: ADMINS ADMINS ~~~~~~ List of `(name, email_address)` tuples for the administrators that should receive error emails. .. setting:: SERVER_EMAIL SERVER_EMAIL ~~~~~~~~~~~~ The email address this worker sends emails from. Default is celery@localhost. .. setting:: EMAIL_HOST EMAIL_HOST ~~~~~~~~~~ The mail server to use. Default is ``localhost``. .. setting:: EMAIL_HOST_USER EMAIL_HOST_USER ~~~~~~~~~~~~~~~ User name (if required) to log on to the mail server with. .. setting:: EMAIL_HOST_PASSWORD EMAIL_HOST_PASSWORD ~~~~~~~~~~~~~~~~~~~ Password (if required) to log on to the mail server with. .. setting:: EMAIL_PORT EMAIL_PORT ~~~~~~~~~~ The port the mail server is listening on. Default is `25`. .. setting:: EMAIL_USE_SSL EMAIL_USE_SSL ~~~~~~~~~~~~~ Use SSL when connecting to the SMTP server. Disabled by default. .. setting:: EMAIL_USE_TLS EMAIL_USE_TLS ~~~~~~~~~~~~~ Use TLS when connecting to the SMTP server. Disabled by default. .. setting:: EMAIL_TIMEOUT EMAIL_TIMEOUT ~~~~~~~~~~~~~ Timeout in seconds for when we give up trying to connect to the SMTP server when sending emails. The default is 2 seconds. .. _conf-example-error-mail-config: Example E-Mail configuration ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ This configuration enables the sending of error emails to george@vandelay.com and kramer@vandelay.com: .. code-block:: python # Enables error emails. CELERY_SEND_TASK_ERROR_EMAILS = True # Name and email addresses of recipients ADMINS = ( ('George Costanza', 'george@vandelay.com'), ('Cosmo Kramer', 'kosmo@vandelay.com'), ) # Email address used as sender (From field). SERVER_EMAIL = 'no-reply@vandelay.com' # Mailserver configuration EMAIL_HOST = 'mail.vandelay.com' EMAIL_PORT = 25 # EMAIL_HOST_USER = 'servers' # EMAIL_HOST_PASSWORD = 's3cr3t' .. _conf-events: Events ------ .. setting:: CELERY_SEND_EVENTS CELERY_SEND_EVENTS ~~~~~~~~~~~~~~~~~~ Send events so the worker can be monitored by tools like `celerymon`. .. setting:: CELERY_SEND_TASK_SENT_EVENT CELERY_SEND_TASK_SENT_EVENT ~~~~~~~~~~~~~~~~~~~~~~~~~~~ .. versionadded:: 2.2 If enabled, a :event:`task-sent` event will be sent for every task so tasks can be tracked before they are consumed by a worker. Disabled by default. .. setting:: CELERY_EVENT_QUEUE_TTL CELERY_EVENT_QUEUE_TTL ~~~~~~~~~~~~~~~~~~~~~~ :transports supported: ``amqp`` Message expiry time in seconds (int/float) for when messages sent to a monitor clients event queue is deleted (``x-message-ttl``) For example, if this value is set to 10 then a message delivered to this queue will be deleted after 10 seconds. Disabled by default. .. setting:: CELERY_EVENT_QUEUE_EXPIRES CELERY_EVENT_QUEUE_EXPIRES ~~~~~~~~~~~~~~~~~~~~~~~~~~ :transports supported: ``amqp`` Expiry time in seconds (int/float) for when a monitor clients event queue will be deleted (``x-expires``). Default is never, relying on the queue autodelete setting. .. setting:: CELERY_EVENT_SERIALIZER CELERY_EVENT_SERIALIZER ~~~~~~~~~~~~~~~~~~~~~~~ Message serialization format used when sending event messages. Default is ``json``. See :ref:`calling-serializers`. .. _conf-broadcast: Broadcast Commands ------------------ .. setting:: CELERY_BROADCAST_QUEUE CELERY_BROADCAST_QUEUE ~~~~~~~~~~~~~~~~~~~~~~ Name prefix for the queue used when listening for broadcast messages. The workers host name will be appended to the prefix to create the final queue name. Default is ``celeryctl``. .. setting:: CELERY_BROADCAST_EXCHANGE CELERY_BROADCAST_EXCHANGE ~~~~~~~~~~~~~~~~~~~~~~~~~ Name of the exchange used for broadcast messages. Default is ``celeryctl``. .. setting:: CELERY_BROADCAST_EXCHANGE_TYPE CELERY_BROADCAST_EXCHANGE_TYPE ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Exchange type used for broadcast messages. Default is ``fanout``. .. _conf-logging: Logging ------- .. setting:: CELERYD_HIJACK_ROOT_LOGGER CELERYD_HIJACK_ROOT_LOGGER ~~~~~~~~~~~~~~~~~~~~~~~~~~ .. versionadded:: 2.2 By default any previously configured handlers on the root logger will be removed. If you want to customize your own logging handlers, then you can disable this behavior by setting `CELERYD_HIJACK_ROOT_LOGGER = False`. .. note:: Logging can also be customized by connecting to the :signal:`celery.signals.setup_logging` signal. .. setting:: CELERYD_LOG_COLOR CELERYD_LOG_COLOR ~~~~~~~~~~~~~~~~~ Enables/disables colors in logging output by the Celery apps. By default colors are enabled if 1) the app is logging to a real terminal, and not a file. 2) the app is not running on Windows. .. setting:: CELERYD_LOG_FORMAT CELERYD_LOG_FORMAT ~~~~~~~~~~~~~~~~~~ The format to use for log messages. Default is `[%(asctime)s: %(levelname)s/%(processName)s] %(message)s` See the Python :mod:`logging` module for more information about log formats. .. setting:: CELERYD_TASK_LOG_FORMAT CELERYD_TASK_LOG_FORMAT ~~~~~~~~~~~~~~~~~~~~~~~ The format to use for log messages logged in tasks. Can be overridden using the :option:`--loglevel` option to :mod:`~celery.bin.worker`. Default is:: [%(asctime)s: %(levelname)s/%(processName)s] [%(task_name)s(%(task_id)s)] %(message)s See the Python :mod:`logging` module for more information about log formats. .. setting:: CELERY_REDIRECT_STDOUTS CELERY_REDIRECT_STDOUTS ~~~~~~~~~~~~~~~~~~~~~~~ If enabled `stdout` and `stderr` will be redirected to the current logger. Enabled by default. Used by :program:`celery worker` and :program:`celery beat`. .. setting:: CELERY_REDIRECT_STDOUTS_LEVEL CELERY_REDIRECT_STDOUTS_LEVEL ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The log level output to `stdout` and `stderr` is logged as. Can be one of :const:`DEBUG`, :const:`INFO`, :const:`WARNING`, :const:`ERROR` or :const:`CRITICAL`. Default is :const:`WARNING`. .. _conf-security: Security -------- .. setting:: CELERY_SECURITY_KEY CELERY_SECURITY_KEY ~~~~~~~~~~~~~~~~~~~ .. versionadded:: 2.5 The relative or absolute path to a file containing the private key used to sign messages when :ref:`message-signing` is used. .. setting:: CELERY_SECURITY_CERTIFICATE CELERY_SECURITY_CERTIFICATE ~~~~~~~~~~~~~~~~~~~~~~~~~~~ .. versionadded:: 2.5 The relative or absolute path to an X.509 certificate file used to sign messages when :ref:`message-signing` is used. .. setting:: CELERY_SECURITY_CERT_STORE CELERY_SECURITY_CERT_STORE ~~~~~~~~~~~~~~~~~~~~~~~~~~ .. versionadded:: 2.5 The directory containing X.509 certificates used for :ref:`message-signing`. Can be a glob with wildcards, (for example :file:`/etc/certs/*.pem`). .. _conf-custom-components: Custom Component Classes (advanced) ----------------------------------- .. setting:: CELERYD_POOL CELERYD_POOL ~~~~~~~~~~~~ Name of the pool class used by the worker. .. admonition:: Eventlet/Gevent Never use this option to select the eventlet or gevent pool. You must use the `-P` option instead, otherwise the monkey patching will happen too late and things will break in strange and silent ways. Default is ``celery.concurrency.prefork:TaskPool``. .. setting:: CELERYD_POOL_RESTARTS CELERYD_POOL_RESTARTS ~~~~~~~~~~~~~~~~~~~~~ If enabled the worker pool can be restarted using the :control:`pool_restart` remote control command. Disabled by default. .. setting:: CELERYD_AUTOSCALER CELERYD_AUTOSCALER ~~~~~~~~~~~~~~~~~~ .. versionadded:: 2.2 Name of the autoscaler class to use. Default is ``celery.worker.autoscale:Autoscaler``. .. setting:: CELERYD_AUTORELOADER CELERYD_AUTORELOADER ~~~~~~~~~~~~~~~~~~~~ Name of the autoreloader class used by the worker to reload Python modules and files that have changed. Default is: ``celery.worker.autoreload:Autoreloader``. .. setting:: CELERYD_CONSUMER CELERYD_CONSUMER ~~~~~~~~~~~~~~~~ Name of the consumer class used by the worker. Default is :class:`celery.worker.consumer.Consumer` .. setting:: CELERYD_TIMER CELERYD_TIMER ~~~~~~~~~~~~~~~~~~~~~ Name of the ETA scheduler class used by the worker. Default is :class:`celery.utils.timer2.Timer`, or one overrided by the pool implementation. .. _conf-celerybeat: Periodic Task Server: celery beat --------------------------------- .. setting:: CELERYBEAT_SCHEDULE CELERYBEAT_SCHEDULE ~~~~~~~~~~~~~~~~~~~ The periodic task schedule used by :mod:`~celery.bin.beat`. See :ref:`beat-entries`. .. setting:: CELERYBEAT_SCHEDULER CELERYBEAT_SCHEDULER ~~~~~~~~~~~~~~~~~~~~ The default scheduler class. Default is ``celery.beat:PersistentScheduler``. Can also be set via the :option:`-S` argument to :mod:`~celery.bin.beat`. .. setting:: CELERYBEAT_SCHEDULE_FILENAME CELERYBEAT_SCHEDULE_FILENAME ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Name of the file used by `PersistentScheduler` to store the last run times of periodic tasks. Can be a relative or absolute path, but be aware that the suffix `.db` may be appended to the file name (depending on Python version). Can also be set via the :option:`--schedule` argument to :mod:`~celery.bin.beat`. .. setting:: CELERYBEAT_SYNC_EVERY CELERYBEAT_SYNC_EVERY ~~~~~~~~~~~~~~~~~~~~~ The number of periodic tasks that can be called before another database sync is issued. Defaults to 0 (sync based on timing - default of 3 minutes as determined by scheduler.sync_every). If set to 1, beat will call sync after every task message sent. .. setting:: CELERYBEAT_MAX_LOOP_INTERVAL CELERYBEAT_MAX_LOOP_INTERVAL ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The maximum number of seconds :mod:`~celery.bin.beat` can sleep between checking the schedule. The default for this value is scheduler specific. For the default celery beat scheduler the value is 300 (5 minutes), but for e.g. the django-celery database scheduler it is 5 seconds because the schedule may be changed externally, and so it must take changes to the schedule into account. Also when running celery beat embedded (:option:`-B`) on Jython as a thread the max interval is overridden and set to 1 so that it's possible to shut down in a timely manner. .. _conf-celerymon: Monitor Server: celerymon ------------------------- .. setting:: CELERYMON_LOG_FORMAT CELERYMON_LOG_FORMAT ~~~~~~~~~~~~~~~~~~~~ The format to use for log messages. Default is `[%(asctime)s: %(levelname)s/%(processName)s] %(message)s` See the Python :mod:`logging` module for more information about log formats.