confabulous

    2.1.0 • Public • Published

    Confabulous

    Confabulous is a hierarchical, asynchronous config loader and post processor. It can load config from command line arguments, environment variables, files, web servers, databases, and even scm systems. It's easy to extend too. You can watch config sources for changes and apply post processors to do things like decrypt secrets or unflatten key/value pairs into structured objects.

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    TL;DR

    const Confabulous = require('confabulous');
    const loaders = Confabulous.loaders;
    
    const confabulous = new Confabulous()
      .add((config) => loaders.require({ path: './conf/defaults.js' }))
      .add((config) => loaders.require({ path: './conf/production.js' }))
      .end((err, config) => {
        // Your code goes here
      });

    Merging

    Confabulous recursively merges (and subsequently freezes) configuration from multiple sources. If you want to override the default merge behaviour you can supply your own merge function, providing it is varardic and favours the right most parameter, e.g.

    function shallow(...args) {
      return Object.assign({}, ...args);
    }
    
    new Confabulous({ merge: shallow })
      .add((config) => loaders.require({ path: './conf/defaults.js' }))
      .add((config) => loaders.require({ path: './conf/production.js' }))
      .end((err, config) => {
        // Your code goes here
      });

    Loaders

    Loaders are used to load config. Out of the box you can load config from command line parameters, environment variables and files.

    args

    Loads config from command line arguments

    new Confabulous().add((config) => {
      return loaders.args();
    });

    You cannot watch command line arguments

    env

    Loads config from envrionment variables

    new Confabulous().add((config) => {
      return loaders.env();
    });

    You cannot watch environment variables

    require

    Loads config from a .js or .json file

    new Confabulous().add((config) => {
      return loaders.require({ path: './conf/defaults.js' });
    });
    Option Type Default Notes
    path string undefined The javascript or json config file to be required
    mandatory boolean true Causes an error/reload_error to be emitted if the configuration does not exist
    watch boolean undefined Watching implemented via fs.watch. Be sure to read the caveats section if you encounter problems.

    file

    Loads config from the specified file. Files are read using the specified encoding (defaults to 'utf8'). Use a post processor if you want to convert them to json.

    new Confabulous().add((config) => {
      return loaders.file({ path: './conf/defaults.js' }, [processors.json()]);
    });
    Option Type Default Notes
    path string undefined The config file to be read
    mandatory boolean true Causes an error/reload_error to be emitted if the configuration does not exist
    watch boolean undefined Watching implemented via fs.watch. Be sure to read the caveats section if you encounter problems.
    encoding string utf8 Specified the file encoding

    More Loaders

    The following loaders are proviced as separate modules

    Post Processors

    Post processes can be used to transform or validate your configuration after it's been loaded. Out of the box you can mount config at a specified key, unflatten key value pairs into structured documents, parse json, decrypt content and transform environment variables.

    mount

    Mounts the configuration at the specified key

    new Confabulous().add((config) => {
      return loaders.require({ path: './extra.json' }, [processors.mount({ key: 'move.to.here' })]);
    });

    unflatten

    Unflattens config into structured documents. Useful for command line arguments and environment variables.

    new Confabulous().add((config) => {
      return loaders.env([processors.unflatten()]);
    });

    envToProp

    Converts environment variables in the form NODE_ENV=test to nested properties in the form { node: { env: "test" } }

    new Confabulous().add((config) => {
      return loaders.env([processors.envToProp()]);
    });

    If you want to prefix your environment variables with an application discriminator you can also strip the prefix.

    new Confabulous().add((config) => {
      return loaders.env([
        processors.envToProp({ prefix: 'GS_' }), // GS_SERVER_PORT => server.port
      ]);
    });

    You can also filter environment variables to include only those you want

    new Confabulous().add((config) => {
      return loaders.env([
        processors.envToProp({ filter: /^GS_/ }), // Only include environment variables starting with GS_
      ]);
    });

    envToCamelCaseProp

    Converts environment variables in the form USER__FIRST_NAME=fred to nested properties in the form { user: { firstName: "fred" } }

    new Confabulous().add((config) => {
      return loaders.env([processors.envToCamelCaseProp()]);
    });

    If you want to prefix your environment variables with an application discriminator you can also strip the prefix.

    new Confabulous().add((config) => {
      return loaders.env([
        // GS_SERVER_PORT => server.port
        processors.envToCamelCaseProp({ prefix: 'GS_' }),
      ]);
    });

    You can also filter environment variables to include only those you want

    new Confabulous().add((config) => {
      return loaders.env([
        // Only include environment variables starting with GS_
        processors.envToCamelCaseProp({ filter: /^GS_/ }),
      ]);
    });

    json

    Parses text into JSON.

    new Confabulous().add((config) => {
      return loaders.file({ path: './config.json.encrypted' }, [processors.json()]);
    });

    decrypt

    Decrypts encrypted configuration.

    new Confabulous().add((config) => {
      return loaders.file({ path: './config.json.encrypted' }, [
        processors.decrypt({
          algorithm: 'aes-192-cbc',
          key: process.env.SECRET_KEY,
          iv: process.env.IV,
        }),
        processors.json(),
      ]);
    });

    Events

    closing

    Calling confabulous.close will emit a 'closing' event. This can be used by loaders to free up resources (e.g. close file watchers)

    loaded

    Deprecated. Pass a callback to the end function instead. Emitted when loading config for the first time.

    error

    Deprecated. Pass a callback to the end function instead. Emitted when an error occurs loading config for the first time.

    reloaded

    Emitted when confabulous successfully reloads a watched config.

    reload_error

    Emitted when confabulous encounters an error reloading a watched config

    FAQ

    Q. Why doesn't Confabulous notice new files.
    A. Because fs.watch doesn't notice them either. You can workaround by modifying some configuration watched by a different loader higher up in the confabulous stack

    Q. Why does jest emit a FSEVENTWRAP error A. Because you have configured a loader to watch for changes, but not called confabulous.close() in your test teardown

    Install

    npm i confabulous

    DownloadsWeekly Downloads

    789

    Version

    2.1.0

    License

    ISC

    Unpacked Size

    46.1 kB

    Total Files

    47

    Last publish

    Collaborators

    • cressie176
    • ulisesgascon
    • feliun
    • guidesmiths_bot