Hafiz

Hafiz is a configuration aggregator that allows much easier management of config data for large scale Node.js applications.

Hafiz loads config data from the following sources:

• Config files with environment variable interpolation
• Command line arguments

Getting Started

$ npm install --save hafiz

Then, put .json config files into ./config directory in the project root.

Finally, in any of your application source files:

const hafiz = require('hafiz');

console.log(hafiz('config.key'));

Documentation

CONFIG_PATH

Hafiz loads configuration files in directories specified by CONFIG_PATH environment variable, which is a list of file system paths similar to the OS PATH variable.

An example CONFIG_PATH value on UNIX would be:

/user/test/common-config:/user/test/.myprojrc

If a path is a directory, hafiz will recursively load all config files in that directory. If path is a file, hafiz will only load that file.

If a path is relative, it is resolved relative to the project root. Hafiz uses app-root-path module to obtain the project root path.

In case of conflicts, config options loaded from paths appearing later in the config paths would overwrite all previously existing values. Hard-coded config paths (./config and ./config/$${NODE_ENV} by default) overwrite everything else.

Command Line

Any config option can be overwritten using command line arguments. For example, and option with path db.collection.name can be overwritten in the following way:

$ ./my-app.js --db.collection.name="some-value"

const hafiz = require('hafiz');

console.log(hafiz('db.collection.name')); // 'some-value'

Environment Variables

Substitution

All strings in Hafiz are automatically checked for envar substitutions. For example:

const hafiz = require('hafiz');
hafiz.set('env', '$NODE_ENV');

console.log(hafiz('env')); // 'development' (or something else)

Optional Envars

If Hafiz encounters a envar substitution, and the requested envar does not exist, an error is thrown. You can mark an envar optional in the following way:

const hafiz = require('hafiz');
hafiz.set('testing', '$?NO_SUCH_VAR');

console.log(hafiz('test')); // ''

Escaping

When you need to include the $ symbol in a string, you can escape it by including an additional $. For example, $$NOT_AN_ENVAR evaluates to $NOT_AN_ENVAR.

Default Values

Currently, support for default values is in the works.

hafiz(path, def)

Gets the config option with the specified path. If the value is not found, it will return def if one is provided; otherwise, it will throw an error.

path is determined by the location of the config file relative to one of the config roots. For example, a file /user/test/my-proj/config/a/b/data.json in the config root of /user/test/my-proj/config would have a path of a.b.data. Properties inside data.json are also accessible by further adding to the path.

hafiz.set(path, value)

Sets the specified config option to the value, overwriting any existing values.

It is worth noting that it works in a way similar to _.set() rather than _.merge(). It is therefore important that you use deep paths when neccessary.

hafiz.init(options)

Clears current config data and reinitializes the hafiz module. You would only need to manually initialize in the following circumstances:

• You need to specify additional hard-coded/dynamic config root paths other than ./config and ./config/$${NODE_ENV}
• You want to search for config files using a glob pattern other than **/*.json
• You want to use custom property path separators other than ., : and /.
• You want to immediately reload the config data.

options.append

Appends these paths to the config root paths specified by CONFIG_PATH environment variable. Supports both relative and absolute paths. Default value: [ './config', `./config/$${process.env.NODE_ENV}` ]

options.separator

Specifies a RegExp for path separators. Default value: /[\.\:\/\\]/

options.glob

Glob pattern to use when searching for config files. Default value: **/*.json

License

MIT