opwire-agent

opwire-agent

Program opwire-agent is a simple command line wrapper. It receives a request from a REST API client or a message queue broker and transports this request to a command line process (that is developed by any programming language).

• Architecture
• Configuration
  • Location
  • Structure
• Command line programs
• Contributing
• License

Architecture

Configuration

Location

Support configuration file (opwire-agent.cfg or opwire-agent.conf) from (priority in top-down order):

• --config command line argument,
• OPWIRE_AGENT_CONFIG_DIR environment variable,
• current binary directory (i.e the folder that contained opwire-agent),
• current working directory,
• XDG configuration directory (i.e $HOME/.config/opwire-agent.conf),
• Hidden configuration file in home directory (i.e $HOME/.opwire-agent.conf),
• /etc directory (i.e /etc/opwire-agent.conf).

Structure

Configuration in JSON pseudo-code:

{
  "version": "<VERSION_OF_OPWIRE_AGENT>",
  "main-resource": {
    "default": {
      "command": "<COMMAND LINE>",
      "timeout": 0 // no timeout by default
    }
  },
  "resources": {
    "<NAME_OF_RESOURCE>": {
      "default": {
        "command": "<COMMAND LINE>",
        "timeout": 30 // seconds
      }
    },
    // ...
  }
}

Example:

{
  "version": "v1.0.3",
  "main-resource": {
    "default": {
      "command": "echo 'Hello opwire-agent'"
    }
  },
  "resources": {
    "spawn": {
      "default": {
        "command": "bash",
        "timeout": 5
      }
    },
    "ps-all": {
      "default": {
        "command": "ps -All"
      }
    }
  }
}

Command line programs

Command line programs use 5 technical mechanism to communicate with outer service (i.e opwire-agent):

• Environment variables;
• Command arguments;
• Standard I/O: stdin, stdout, stderr;
• JSON encoding, decoding;
• Message logs (to log files);

Opwire development team provides a collection of command line examples in several programming languges:

• Command line example in Bash
• Command line example in Java
• Command line example in Node.js
• Command line example in PHP
• Command line example in Python
• Command line example in Perl
• Command line example in R
• Command line example in .NET

Contributing

1. Fork it
2. Create your feature branch (git checkout -b your-new-feature)
3. Commit your changes (git commit -am "Add some feature")
4. Push to the branch (git push origin your-new-feature)
5. Create new Pull Request

License

MIT

See LICENSE to see the full text.