LibstorageMgmt Plugin Developer Guide

This document is assuming you already read the user_guide.

The LSM plugin codes are located

1. Workflow.

Each plugin has its own folder in “libstoragemgmt-code/plugin’ folder. We suggest use the plugin name as folder name.

Each plugin will has a excutable file named as ‘xxx_lsmplugin’ (xxx is the name of plugin). For example: ‘abc_lsmplugin’ will be excuted by lsmd when client is calling with URI ‘abc://….’.

The lsmd already created a socket for plugin to communicate with client. The socket file descriptor will be the first argument when lsmd excuting ‘abc_lsmplugin’.

The ‘abc_lsmplugin’ will communicate with client in JSON.

We created plugin helper/runner to unifiy the code for socket handling, JSON converting and etc.

2. C Plugin

2.1 C Plugin helper

TODO: List all methods dedicate for plugin use.

2.2 Linking with LSM

3. Python Plugin

2.1 Python plugin helper

TODO: List all methods dedicate for plugin use.

TODO: Provide sample for xxx_lsmplugin

4. Installation files for new plugin

4.1 Makefile

Sample changes to Makefiles for shipping new plugin.

4.2 RPM SPEC – packaging/libstoragemgmt.spec.in

Sample changes to rpm spec file for shipping new plugin in rpm way.

5. Sample C plugin – simc

TODO: Help new commer understand how simc works.

6. Sample Python plugin – sim

The ‘sim’ plugin contains three python files:

* sim_lsmplugin
  Handing the socket creation and JSON communication.
* simulator.py
  Handling lsm.Client methods.
* simarray.py
  Handling intenral data storage.

The ‘sim’ plugin will store/load data into/from file(default is /tmp/lsm_sim_data) using ‘pickle’ python module.

There are four classes in this simulator plugin: * SimPlugin Talk to lsm.Client (python_binding/lsm/_client.py) * SimArray Talk to SimPlugin, handling internal data load/save. * SimData Talk to SimArray. Handling internal data management(create/update/delete). * SimJob Talk to SimData. Simulating ASYNC jobs.

Data is stored in a dictionary by SimData class. For example, pools are stored as:

self.pool_dict = {
    Pool.id = sim_pool,
}
sim_pool = {
    'name': Pool.name,
        .
        .
        .
}

7. Plugin test

Plugin test is located at “libstoragemgmt-code/test/plugin_test.py”.

TODO: explain how to use it.