Writing a Cloudify Plugin

Let's create a Cloudify Plugin.

The simplest incarnation of a plugin has two components: an operation in a python script, and a blueprint.

With that in mind, let's create an operation that does nothing:

def do_nothing(**kwargs):
    pass

Save that in a file called 'tasks.py' in a folder called 'nothing_plugin'.

Let's say that you want to run this script on the manager every time you run a deployment. Let's create a node type:

node_type:
  cloudify.nothing_plugin.instance
    derived_from: cloudify.nodes.ApplicationModule
    interfaces:
      cloudify.interfaces.lifecycle:
        start:
          implementation: nothing_package.nothing_plugin.tasks.do_nothing

Now at the top of that file add:

tosca_definitions_version: cloudify_dsl_1_0

plugins:
  cloudify-plugin:
    executor: central_deployment_agent
    source: https://github.com/your-git-user/nothing_package/archive/master.zip

Save the file as 'plugin.yaml'.

Now let's create a package for this plugin. You can use the template: [https://github.com/cloudify-cosmo/cloudify-plugin-template](A Cloudify Plugin Template).

Or just make sure that you have a folder, let's call it 'nothing_package', with the following files:

./nothing_package/
./nothing_package/setup.py
./nothing_package/plugin.yaml
./nothing_package/nothing_plugin/
./nothing_package/nothing_plugin/tasks.py

Make sure that at least the following is in your setup.py file:

setup(
    name='nothing_package',
    description='does nothing',
    packages=['nothing_plugin'],
    install_requires=["cloudify-plugins-common"]
)

Now you have your plugin. Once you upload it to github, All you need to do is implement it.

If you have a manager up and running, create a new directory, and add a new file called 'blueprint.yaml'.

In the file, add the following:

tosca_definitions_version: cloudify_dsl_1_0

imports:
  - http://www.getcloudify.org/spec/cloudify/3.1/types.yaml
  - https://raw.githubusercontent.com/your-git-hub-user/nothing_package/master/plugin.yaml

node_templates:
  dont_do_anything:
    type: cloudify.nothing_plugin.instance
    interfaces:
      cloudify.interfaces.lifecycle:
        start:
          implementation: nothing_package.nothing_plugin.tasks.do_nothing

At this point the only thing left to do is run it! (On how to do that see the documentation on running uploading blueprints and creating deployments.

There is a lot of quality information scattered across the web on how to write a Cloudify Plugin. Writing a Cloudify Plugin is simple, if you know where to start. Here are some of the top places to look:

[http://getcloudify.org/guide/3.1/guide-plugin-creation.html](Plugin Authoring Guide)

[https://github.com/cloudify-cosmo/cloudify-plugin-template](A Cloudify Plugin Template)

A good example of a plugin is the script plugin, which enables you to run shell scripts.

[http://getcloudify.org/guide/3.1/plugin-script.html](Script Plugin Documentation)

[https://github.com/cloudify-cosmo/cloudify-script-plugin](Script Plugin)