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https://issues.apache.org/jira/browse/STRATOS-1180?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14326999#comment-14326999
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ASF GitHub Bot commented on STRATOS-1180:
-----------------------------------------
GitHub user chamilad opened a pull request:
https://github.com/apache/stratos/pull/234
[STRATOS-1180] - Yapsy based plugin architecture for PCA
A basic plugin system where <PCA_HOME>/plugins folder can be used to drop
plugins to be picked up by the PCA. For this I've used Yapsy[1] plugin
framework.Yapsy is both simple and effective in enabling a plugin structure in
Python. It is BSD licensed so there is no conflict in licensing for
incorporating it, if the need arises.
Implementing a plugin for the PCA is simple. The plugin contract is defined
in <PCA_HOME>/plugins/contracts.py module. To write a plugin
contracts.ICartridgeAgentPlugin has to be extended. Additionally a plugin
descriptor (with yapsy-plugin extension) has to be included which will describe
and point to the plugin module file, when queried by the Yapsy framework. To
map a plugin for a certain event, the event name has to be specified in the
Description field. By this approach, it is possible to map more than one plugin
to a single event and one plugin to several events. Each plugin is run in a
separate thread, therefore, it will not be blocking the main execution.
A plugin gets a dictionary with the payload parameters and any additional
values included for specific events. This is more effective than the
environment variables approach we had for bash scripts.
A test plugin can be found in the <PCA_HOME>/plugins which demonstrates the
plugin architecture. This plugin is mapped to the MemberInitializedEvent and
the ArtifactUpdatedEvent.
PCA was tested in an OpenStack deployment for regression and functionality.
[1] - http://yapsy.sourceforge.net/
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/chamilad/stratos stratos-1180-01
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/stratos/pull/234.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #234
----
commit f4be9ce8b37f4121b461d55fd9aa0b3daf773516
Author: Chamila de Alwis <chami...@wso2.com>
Date: 2015-02-14T11:21:03Z
PCA plugin architecture with Yapsy
Dockerfile updated to install Yapsy
Refactored Exceptions
Refactored event handling
PEP style related changes
commit 6b938f65a09c082dd6ba95830e120a2832fdc020
Author: Chamila de Alwis <chami...@wso2.com>
Date: 2015-02-14T15:19:36Z
PCA -
Fixed issues in plugin execution
Added test plugin
PEP style related changes
Fixed import errors
commit 4c253ea2251d012f04e49e870087d08c17fe1803
Author: Chamila de Alwis <chami...@wso2.com>
Date: 2015-02-14T15:21:39Z
PCA - fixed PEP style hints in constants module
commit 2cb93ca72e1606859fadb40d7daa968a1afeed35
Author: Chamila de Alwis <chami...@wso2.com>
Date: 2015-02-14T19:08:20Z
PCA - A single plugin can be mapped to multiple events
commit 3528415ebc118b777837ee03e7e13647f869dd05
Author: Chamila de Alwis <chami...@wso2.com>
Date: 2015-02-19T04:58:44Z
PCA - Yapsy based plugins - Added yapsy pip install to PCA puppet module
----
> Modify extension execution structure in Python Cartridge Agent
> --------------------------------------------------------------
>
> Key: STRATOS-1180
> URL: https://issues.apache.org/jira/browse/STRATOS-1180
> Project: Stratos
> Issue Type: Task
> Components: Cartridge Agent
> Reporter: Chamila de Alwis
> Fix For: 4.1.0 RC1
>
>
> Currently we have bash scripts as extensions however if we could introduce a
> python extension layer in between that would make it much easier to implement
> extension logic.
> The current extension setup is as follows. A set of bash scripts are
> available in the <PCA_HOME>/extensions. The file name of the extension that
> should be executed for each event is defined in the agent configuration
> (agent.conf in PCA, stratos.sh in JCA). The event handler executes these bash
> scripts as new shell commands when the respective events are received.
> We can introduce a layer between the bash scripts and the python code that
> calls them. The names of the python scripts corresponding to each event can
> be defined as before.
> Additionally we can extend this behavior to the Git artifact management
> component of the PCA. The contract that the artifact management component
> should adhere to is "checkout" and "push". We can separate the current python
> code relating to these two operations in to two extension scripts.
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