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layout bt_wiki
title Bash Plugin
category Plugins
publish true
abstract Cloudify bash plugin description and configuration
pageord 100
yaml_link http://getcloudify.org/spec/bash-plugin/1.0/plugin.yaml

{%summary%} The bash plugin can be used to map node life cycle operations to bash shell scripts that are included in your blueprint. {%endsummary%}

Configuration

There are 2 modes for working with this plugin.

  • In the first mode, the nodes in the blueprint will derive from one of the predefined bash types.
  • In the second mode, you have a node that is not derived from a bash type and you map a specific interface operation to a bash shell script.

The plugin definition and predefined types can be found at:

{{page.yaml_link}}

Types (Mode 1)

The predefined types are:

  • cloudify.types.bash.app_module
  • cloudify.types.bash.app_server
  • cloudify.types.bash.db_server
  • cloudify.types.bash.message_bus_server
  • cloudify.types.bash.web_server

Usage example with cloudify.types.bash.web_server

{% highlight yaml %} imports: - {{page.yaml_link}}

blueprint: name: example nodes: - name: example_web_server type: cloudify.types.bash.web_server properties: scripts: create: scripts/create.sh configure: scripts/configure.sh start: scripts/start.sh stop: scripts/stop.sh delete: scripts/delete.sh {%endhighlight%}

In this example, it is assumed that the blueprint folder has a scripts folder in it.

Here, we map the create, configure, start, stop, delete of the cloudify.interfaces.lifecycle node interface to a matching script.

The mapping itself is done under the scripts property of the node.

{%note title=Note%} It is not mandatory to map all operations to scripts. It is perfectly valid, for example, to only map the start operation to a script. {%endnote%}

Interface mapping (Mode 2)

If you have already have a node in your blueprint, and this node does not derive from one of the predefined bash types, you can directly map an interface operation to a script.

Example mapping a node's start life cycle operation

{% highlight yaml %} imports: - {{page.yaml_link}}

types: my_custom_type: derived_from: cloudify.types.web_server interfaces: cloudify.interfaces.lifecycle: - start: bash_runner.tasks.run properties: - scripts

blueprint: name: example nodes: - name: example_web_server type: my_custom_type properties: scripts: start: scripts/start.sh {%endhighlight%}

In this example, we define a custom type my_custom_type and map its cloudify.interfaces.lifecycle.start operation to the bash plugin's single operation: bash_runner.tasks.run.

Next, we add the property scripts to the type schema so that script mapping can be configured by nodes using this type.

Finally, we map the start operation to a script located in scripts/start.sh of the blueprint folder. Similar to the way we would have done it using one of the predefined types as described in Types.

{%note title=Note%} The property name under the scripts property of the node should be the same as the interface operation name, start, in the case of the example above. {%endnote%}

Scripts API

Environment Variables

The node properties are flattened as enviroment variables when the scripts are executed.

Say the node properties are: {% highlight yaml %} blueprint: name: example nodes: - name: some node type: some_type properties: some_prop: some_value some_map: prop1: value1 prop2: value2 {%endhighlight%}

The following properties will be available to scripts:

{% highlight bash %} echo "some_prop is ${some_prop}" echo "some_map_prop1 is ${some_map_prop1}" echo "some_map_prop2 is ${some_map_prop2}" {%endhighlight%}

Output: {% highlight bash %} some_prop is some_value some_map_prop1 is value1 some_map_prop2 is value2 {%endhighlight%}

In addition, the following environment variables are also available:

  • CLOUDIFY_NODE_ID The node instance id for which this script is run for
  • CLOUDIFY_BLUEPRINT_ID The blueprint id
  • CLOUDIFY_DEPLOYMENT_ID The deployment id
  • CLOUDIFY_MANAGER_IP The manager management network ip address
  • CLOUDIFY_EXECUTION_ID The current workflow execution id
  • CLOUDIFY_LOGGING Path to helper logging functions (see below)
  • CLOUDIFY_FILE_SERVER Path to helper blueprint resource access functions (see below)
  • CLOUDIFY_FILE_SERVER_BLUEPRINT_ROOT Base URI to the blueprint folder resources on the management file server

Helper Functions

Logging

You can source the CLOUDIFY_LOGGING environment variable in your script. {% highlight bash %} source ${CLOUDIFY_LOGGING} {%endhighlight%}

This will put into scope the functions cfy_info and cfy_error that can be used to send output to be managed and accessed later.

Using them is pretty straightforward {% highlight bash %} cfy_info "This is some info message. The blueprint id is ${CLOUDIFY_BLUEPRINT_ID}" cfy_error "This is some error message. The deployment id is ${CLOUDIFY_DEPLOYMENT_ID}" {%endhighlight%}

Download Blueprint Resources

You can source the CLOUDIFY_FILE_SERVER environment variable in your script. {% highlight bash %} source ${CLOUDIFY_FILE_SERVER} {%endhighlight%}

This will put into scope the function cfy_download_resource which can be used to download resources that were included in the blueprint folder.

Say we have a folder named images in our blueprint folder and in it, a file named flower.png.

We can download this file to the current working directory, like this: {% highlight bash %} cfy_download_resource "images/flower.png" {%endhighlight%}

If you want more control over the downloaded resource, you can get your resource URL by appending it to the CLOUDIFY_FILE_SERVER_BLUEPRINT_ROOT environment variable: ${CLOUDIFY_FILE_SERVER_BLUEPRINT_ROOT}/images/flower.png.

In fact, this is exactly what cfy_download_resource does. {% highlight bash %} function cfy_download_resource() { # This only serves as an example. The actual implementation might be different. wget ${CLOUDIFY_FILE_SERVER_BLUEPRINT_ROOT}/$@ } {%endhighlight%}