60 lines
2.3 KiB
ReStructuredText
60 lines
2.3 KiB
ReStructuredText
=======================
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Storage drivers options
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=======================
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Storage back ends
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~~~~~~~~~~~~~~~~~
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The Message service supports several different storage back ends (storage
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drivers) for storing management information, messages and their metadata. The
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recommended storage back end is MongoDB. For information on how to specify the
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storage back ends, see :doc:`zaqar-drivers`.
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When the storage back end is chosen, the corresponding back-end options become
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active. For example, if Redis is chosen as the management storage back end, the
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options in ``[drivers:management_store:redis]`` section become active.
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Storage layer pipelines
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~~~~~~~~~~~~~~~~~~~~~~~
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A pipeline is a set of stages needed to process a request. When a new request
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comes to the Message service, first it goes through the transport layer
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pipeline and then through one of the storage layer pipelines depending on the
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type of operation of each particular request. For example, if the Message
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service receives a request to make a queue-related operation, the storage
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layer pipeline will be ``queue pipeline``. The Message service always has the
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actual storage controller as the final storage layer pipeline stage.
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By setting the options in the ``[storage]`` section of ``zaqar.conf``,
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you can add additional stages to these storage layer pipelines:
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* **Claim pipeline**
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* **Message pipeline** with built-in stage available to use:
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* ``zaqar.notification.notifier`` - sends notifications to the queue
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subscribers on each incoming message to the queue, in other words, enables
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notifications functionality.
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* **Queue pipeline**
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* **Subscription pipeline**
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The storage layer pipelines options are empty by default, because additional
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stages can affect the performance of the Message service. Depending on the
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stages, the sequence in which the option values are listed does matter or not.
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You can add external stages to the storage layer pipelines. For information how
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to write and add your own external stages, see
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`Writing stages for the storage pipelines
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<http://docs.openstack.org/developer/zaqar/writing_pipeline_stages.html>`_
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tutorial.
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Options
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~~~~~~~
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The following tables detail the available options:
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.. include:: ../tables/zaqar-storage.rst
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.. include:: ../tables/zaqar-mongodb.rst
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.. include:: ../tables/zaqar-redis.rst
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.. include:: ../tables/zaqar-sqlalchemy.rst
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