61 lines
2.2 KiB
ReStructuredText
61 lines
2.2 KiB
ReStructuredText
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========
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Commands
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========
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Command Structure
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=================
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OpenStack Client uses a command form ``verb object``.
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Note that 'object' here refers to the target of a command's action. In coding
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discussions 'object' has its usual Python meaning. Go figure.
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Commands take the form::
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openstack [<global-options>] <verb> <object> [<command-local-arguments>]
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Command Arguments
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-----------------
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* All long option names use two dashes ('--') as the prefix and a single dash
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('-') as the interpolation character. Some common options also have the
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traditional single letter name prefixed by a single dash ('-').
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* Global options generally have a corresponding environment variable that
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may also be used to set the value. If both are present, the command-line
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option takes priority. The environment variable names can be derived from
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the option name by dropping the leading '--', converting all embedded dashes
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('-') to underscores ('_'), and converting the name to upper case.
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* Positional arguments trail command options. In commands that require two or
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more objects be acted upon, such as 'attach A to B', both objects appear
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as positional arguments. If they also appear in the command object they are
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in the same order.
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Implementation
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==============
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The command structure is designed to support seamless addition of extension
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command modules via entry points. The extensions are assumed to be subclasses
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of Cliff's command.Command object.
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Command Entry Points
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--------------------
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Commands are added to the client using distribute's entry points in ``setup.py``.
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There is a single common group ``openstack.cli`` for commands that are not versioned,
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and a group for each combination of OpenStack API and version that is
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supported. For example, to support Identity API v3 there is a group called
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``openstack.identity.v3`` that contains the individual commands. The command
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entry points have the form::
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"verb_object=fully.qualified.module.vXX.object:VerbObject"
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For example, the 'list user' command fir the Identity API is identified in
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``setup.py`` with::
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'openstack.identity.v3': [
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# ...
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'list_user=openstackclient.identity.v3.user:ListUser',
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# ...
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],
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