the development version 3 Celery Documentation, Release 2.0.3 (stable) 1.1.1 Overview This is a high level overview of the architecture. The broker pushes tasks to the worker servers. A worker server retrieve it later, or ignore it. Result Stores Database, MongoDB, Redis, Tokyo Tyrant, AMQP (high performance). Web- hooks Your tasks can also be HTTP callbacks, enabling cross-language communication don’t want – Disable rate limits if they’re not used – Avoid launching synchronous subtasks • Performance and Strategies – Granularity – Data locality – State – Database transactions 2.1.1 Basics A

Installation Downloading and installing from source Using the development version Overview This is a high level overview of the architecture. http://cloud.github.com/downloads/ask/celery/Celery-Overview-v4 like cron, or specifying an exact date or countdown for when after the task should be executed. Performance Able to execute tasks while the user waits. Return Values Task return values can be saved to retrieve it later, or ignore it. Result Stores Database, MongoDB, Redis, Tokyo Tyrant, AMQP (high performance). Webhooks Your tasks can also be HTTP callbacks, enabling cross- language communication.

[http://www.rabbitmq.com/], but support for Redis and databases is also available. Overview This is a high level overview of the architecture. http://cloud.github.com/downloads/ask/celery/Celery-Overview-v4 like cron, or specifying an exact date or countdown for when after the task should be executed. Performance Able to execute tasks while the user waits. Return Values Task return values can be saved to retrieve it later, or ignore it. Result Stores Database, MongoDB, Redis, Tokyo Tyrant, AMQP (high performance). Webhooks Your tasks can also be HTTP callbacks, enabling cross- language communication.

broker is RabbitMQ, but support for Redis and databases is also available. 1.1.1 Overview This is a high level overview of the architecture. The broker pushes tasks to the worker servers. A worker server retrieve it later, or ignore it. Result Stores Database, MongoDB, Redis, Tokyo Tyrant, AMQP (high performance). Web- hooks Your tasks can also be HTTP callbacks, enabling cross-language communication result.AsyncResult to check if the task is done, or get its return value. Only use if you need the performance and is able live without these features. Any exceptions raised will store the return value/status

that message to a worker. A Celery system can consist of multiple workers and brokers, giving way to high availability and horizontal scaling. Celery is written in Python, but the protocol can be implemented shown that adding more than twice the number of CPU’s is rarely effective, and likely to degrade performance instead. Including the default prefork pool, Celery also supports using Eventlet, Gevent, and OOM killer, the same may happen again. 4. A task that always fails when redelivered may cause a high-frequency message loop taking down the system. If you really want a task to be redelivered in these

that message to a worker. A Celery system can consist of multiple workers and brokers, giving way to high availability and horizontal scaling. Celery is written in Python, but the protocol can be implemented shown that adding more than twice the number of CPU’s is rarely effective, and likely to degrade performance instead. Including the default prefork pool, Celery also supports using Eventlet, Gevent, and OOM killer, the same may happen again. 4. A task that always fails when redelivered may cause a high-frequency message loop taking down the system. If you really want a task to be redelivered in these

that message to a worker. A Celery system can consist of multiple workers and brokers, giving way to high availability and horizontal scaling. Celery is written in Python, but the protocol can be implemented shown that adding more than twice the number of CPU’s is rarely effective, and likely to degrade performance instead. Including the default prefork pool, Celery also supports using Eventlet, Gevent, and OOM killer, the same may happen again. 4. A task that always fails when redelivered may cause a high-frequency message loop taking down the system. If you really want a task to be redelivered in these

that message to a worker. A Celery system can consist of multiple workers and brokers, giving way to high availability and horizontal scaling. Celery is written in Python, but the protocol can be implemented shown that adding more than twice the number of CPU’s is rarely effective, and likely to degrade performance instead. Including the default prefork pool, Celery also supports using Eventlet, Gevent, and OOM killer, the same may happen again. 4. A task that always fails when redelivered may cause a high-frequency message loop taking down the system. If you really want a task to be redelivered in these

that message to a worker. A Celery system can consist of multiple workers and brokers, giving way to high availability and horizontal scaling. Celery is written in Python, but the protocol can be implemented shown that adding more than twice the number of CPU’s is rarely effective, and likely to degrade performance instead. Including the default prefork pool, Celery also supports using Eventlet, Gevent, and OOM killer, the same may happen again. 4. A task that always fails when redelivered may cause a high-frequency message loop taking down the system. If you really want a task to be redelivered in these

– Using the development version 3 Celery Documentation, Release 2.3.5 1.1.1 Overview This is a high level overview of the architecture. The broker delivers tasks to the worker nodes. A worker node don’t want – Disable rate limits if they’re not used – Avoid launching synchronous subtasks • Performance and Strategies – Granularity – Data locality – State – Database transactions • Example – blog/models server, with thousands of tasks the broker may be overloaded with queues and this will affect performance in negative ways. If you’re using RabbitMQ then each queue will be a separate Erlang process, so