drone-plugin - argument parsing for drone plugins

This package provies an API for parsing and validating the CI_* and PLUGIN_* envvars that are used by drone to pass build context to plugins.

Installation

yarn add drone-plugin

Example

Assume the following pipeline structure for your plugin in .drone.yml

pipeline:
  my-plugin:
    image: myrepo/post-message-to-chat
    webhook: 'http://some.chatserver.com/some/path?query=string'
    timeout: 42

This module makes it easy to parse, validate and coerce those plugin parameters as well as the drone build state variables, which are passed to your plugin in the environment in upper-case variable names. It will also do the same for the CI-context metadata (variables matching /^CI_.+/).

Example:

const { argParse } = require('drone-plugin');
const { webhook, timeout = 10, ci } = argParse()
  .arg('webhook=s!', 'timeout=n')
  .parse();

const req = require('request')({
  uri: webhook,
  timeout: (timeout * 1000),
  json: {
    text: `build #${ci.buildNumber} of ${ci.repoName} ${ci.buildStatus}`
  },
});
// and so forth...

Parsing arguments and CI context

drone creates UPPER_CASE named envvars for both CI-context and plugin parameters, but for purely aesthetic reasons, this API converts them to camelCase representations, dropping the CI_ or PLUGIN_ prefix.

The argParse() function returns an instance of class Args, which has various chainable methods for informing the argument parser of the plugin arguments, their types and whether or not they are required. The parse() method returns an object that contains all of this information as well as an embedded object named drone with the CI context (all of the CI_ args).

Argument spec strings

The .arg() method can be used to declare argument(s) along with type and demand hints included after an = in the name.

| hint char | purpose | | --------- | ------------------------------- | | s | string (default when no hint) | | n | numeric | | b | boolean | | t | timestamp (seconds since epoch) | | d | date | | o | object (also {}) | | a | array (slice) also [] | | ! | flag argument as required |

The array type can be combined with a scalar type.

Example:

.arg('timeout=n', 'title=s!', 'tags=as')

The above declares two arguments:

• timeout is a numeric argument
• title is a string argument and is required
• tags is an array of strings

The step in the drone.yml file that should exist for the above example would look like this:

  myplugin:
    image: my/drone-plugin:latest
    timeout: 5
    title: hello world
    tags: [ beta, 1.0.11, latest ]

Args methods

.arg(spec[, ...])

chainable, this is detailed above. Note that you may pass a list of argument specs in one call to .arg() or you may invoke .arg() for each argument you are declaring.

These are all equivalent:

argParse().arg('name=s').arg('age=n');     //...
argParse().arg('name=s', 'age=n!');        // ...
argParse().string('name').number('age=!'); // ...

.boolean(name [,...])

.number(name [,...])

.string(name [,...])

.date(name [,...])

.object(name [,...])

chainable, declare an argument as a particular type. You may append =! to any name to indicate that it is a required parameter.

.demand(name [,...])

chainable, indicate that the named parameter is required.

.parse()

This returns an object containing all of the parsed arguments as well as an embedded object named ci that contains the drone CI-context.

Args properties

.ci

The drone environment variables, camelized and coerced.

.plugin

The plugin environment variables, camelized.

.env

An object containing both the ci and plugin variables.

See Also

• cncd-env

License

View the LICENSE file (MIT).