Plugin Module Implementation

Topics

Introduciton
Site.yml
Host
Description
Automatic port allocations
Sample plugins implemented

Introduction

The plugin module is designed to ensure clients can execute instructions in a declarative manner across different containers created. This means the user (i.e client) needs to write the instruction only once, and these instructions can be executed across different nodes in a repetitive manner.

In the scenario of this project Ansibles will be used as the way the users can create these instructions.

Setup instruction

The plugin module introduces a new path to the config file known as pluginpath. This path by defaults points to ${P2PRC}/plugin/deploy. Any file/folder inside plugin/deploy is part of the .gitginore. Plugins are detected by folder names inside the plugin/deploy.

plugin
|___ Deploy 
       |___<plugin name>
                |___ site.yml 
                |___ hosts
                |___ ports.json
                |___ description.txt 
              .
              . 
              .
              n: n number of plugins possible 

Site File Template

The site file is also known as the Ansible playbook and is incharge of executing instructions in a declarative manner. The below example specifies how to make one.

- hosts: all

  tasks:
    - name: <task name> 
      <ansible task> 
      debug:
        msg: <debug message> 

Read more about ansible tasks: https://docs.ansible.com/ansible/latest/user_guide/playbooks_intro.html#about-playbooks

Hosts file

hosts file is also known as the inventory file. This file consists of all the information required to connect to other nodes to execute Ansible instructions. In this project this file needs to be set in a certain configuration because the go code or binary will populate this file automatically with the appropriate information required to connect to local or remote containers.

[!NOTE] Add as exactly specified below:

all:
 vars:
   ansible_python_interpreter: /usr/bin/python3 // Path to your python 3 interpreter 
main:
 hosts:
   host1:
     // Note: These values will be automatically overwritten 
     // by the Go functions 
     ansible_host: 0.0.0.0 
     ansible_port: 39269
     ansible_user: master
     ansible_ssh_pass: password
     ansible_sudo_pass: password

Ports.json

The ports.json file is intended to mention the number of ports required by the plugin.

{
  "NumOfPorts": <number of ports>
}

Description file

This is a simple text file used to describe what the module does. When the client is looking at various commands via the ClI. The description is displayed along-side the plugin name.

Ex: When the flag --ViewPlugins or --vp is called

{
	"PluginsDetected": [
		{
			"FolderName": "<name of the plugin>",
			"PluginDescription": "<description of the plugin>"
		}
	]
} 

Automatic port allocations

P2PRC would be in-charge to set to the ports to various TCP ports opened. Due to this implementation the plugin being executed is copied to the tmp directory with a unique UUID.

Command: ls /tmp
output: Semantic <UUID>_<Plugin Name> 
2e6d76c4-0ed1-4b55-9385-79a58d4f0492_p2prc-vscode-browser                
7b631e08-62ee-4c1c-a2a4-c05857b9aa7d_p2prc-vscode-browser

Once the copy of the plugin is added to the /tmp directory the site.yml file inside the appropriate yaml is modified with the appropriate ports assigned to the container.

Ex:

Create container called c1 with an automatic generated TCP port 3313 (external) - 3313 (internal)
Assumption of plugin p1 exists. p1 has one server which needs to be mapped to a free open TCP port in container c1. Below shows an implementation of a sample site.yml file. ``` —
- hosts: all tasks:
- name: start vscode code server shell: sh server.sh 0.0.0.0: ``` Notice there is the following . does not belong to Ansible but rather is a way to mention where to add the external free port of the container. We use the golang template library to parse and populate the site.yml with the appropriate open ports. An array of ints which consists of open free ports are sent to the site.yml. 0 in refers to the index in the int array passed on.

After the port is automatically it’s ready to run !

---
- hosts: all
  tasks:
    - name: start vscode code server
      shell: sh server.sh 0.0.0.0:3313

Sample plugins implemented:

VSCode Plugin

Pull Plugins

The following allows us to pull plugins from a remote git repository and store them in the default plugins directory. The implementation uses a Go git library to pull the git repo and automatically save it as a folder in the plugin path.

Delete Plugins

We delete the plugin folder based on the plugin name provided as an argument on the cli command. Once the folder is deleted, the plugin manager automatically knows that the plugin does not exist anymore.

Theme Moonwalk