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+=============================
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+ Introduction to Task Queues
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+=============================
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+
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+.. contents::
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+ :local:
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+ :depth: 1
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+
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+What are Task Queues?
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+=====================
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+
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+
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+Celery Features
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+===============
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+
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+- Messaging Transports (Brokers)
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+
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+Celery requires a message broker to send and receive messages,
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+but this term has been stretched to include everything from
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+financial-grade messaging systems to you fridge (no offense)
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+
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+RabbitMQ, Redis, MongoDB, Amazon SQS, CouchDB, Beanstalk, Apache ZooKeeper,
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+or Databases (SQLAlchemy/Django ORM).
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+
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+- HA
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+
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+Both clients and workers will automatically retry in the event
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+of connection loss or failure, and some brokers support
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+HA in way of Master/Master or Master/Slave replication.
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+
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+- Multiple Serializers
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+
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+Messages can be serialized using pickle, json, yaml, msgpack or
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+even custom serializers. In addition Celery ships with a special
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+serializer that signs messages using cryptographic hashes.
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+
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+- Compression
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+
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+Messages can be compressed using zlib, bzip2 or custom
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+compression schemes defined by the user.
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+
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+Worker
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+------
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+
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+- Monitoring
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+
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+Workers emit a stream of monitoring events, that is used
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+by monitoring tools like `celery events`, `celerymon` and
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+the Django Admin monitor. Users can write custom event consumers
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+to analyze what the workers are doing in real-time.
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+
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+- Time Limits
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+
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+Tasks can be enforced a strict time to run, and this can be set as a default
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+for all tasks, for a specific worker, or individually for each task.
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+
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+.. sidebar:: Soft, or hard?
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+
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+ The time limit is set in two values, `soft` and `hard`.
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+ The soft time limit allows the task to catch an exception
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+ to clean up before it is killed: the hard timeout is not catchable
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+ and force terminates the task.
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+
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+- Autoreloading
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+
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+While developing the worker can be set to automatically reload
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+when the source code for a task changes.
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+
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+- Autoscaling
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+
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+The worker pool can be dynamically resized based on worker load,
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+and autoscaling rules can be customized by the user.
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+
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+- Memory Leak Cleanup
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+
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+Sometimes tasks contain memory leaks that are out of the
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+developers control, or the task allocated other resources
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+that cannot be cleaned up. In this case the worker supports
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+a :option:`--maxtasksperchild` argument that defines how
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+many task a given pool process can execute before it's
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+replaced by a fresh process.
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+
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+- User components
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+
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+Each worker component can be customized, and additional components
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+can be defined by the user simply by defining a new boot steps
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+that will be loaded as part of the workers dependency graph.
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