Welcome to yaml-env-defaults 👋

Read yaml file with environment variables substitution

This is an wrapper under js-yaml library which can render environment variables values with defaults support in yml file. (like Java Spring application.yaml).

Install module for Node.js

1npm install yaml-env-defaults
2
3# or
4
5yarn add yaml-env-defaults

Usage

Import

1// ES
2import { readYamlEnvSync, readYamlEnv } from 'yaml-env-defaults';
3
4// require
5const { readYamlEnvSync, readYamlEnv } = require('yaml-env-defaults');

Reading yaml

1import { readYamlEnvSync, readYamlEnv } from 'yaml-env-defaults';
2
3// Read one yaml file synchronysly
4const config = readYamlEnvSync('../path/to/yaml-file.yml');
5
6// Read many yaml files synchronysly
7const joinedYamls = readYamlEnvSync(['first.yml', 'second.yml', 'third.yaml']);
8
9// Read yaml files with custom properties provider fn
10const propertiesMap = {
11  ENV_VAR_NAME: 'My value',
12  USERS_COUNT: 4
13};
14
15const getProperty = (key) => {
16  // without default value will be throwed error in case of missing 
17  return propertiesMap[key] || 'Default value';
18}
19
20const config = readYamlEnvSync('../path/to/yaml-file.yml', getProperty);
21
22// Custom properties for js-yaml
23const config = readYamlEnvSync('../path/to/yaml-file.yml', undefined, {
24  jsYaml: {
25    onWarning: (yaml, e) => {
26    }
27    //...
28  }
29})
30
31  // the same for readYamlEnv as async 
32  (async () => {
33    // Read one yaml file asynchronysly
34    const config = await readYamlEnv('../path/to/yaml-file.yml');
35  });
36//or
37readYamlEnv('../path/to/yaml-file.yml').then(config => config);
38

Example

config-env.yml

1foo: 1
2bar: 'text-${ENV_VAR_MY}-text-${ENV_VAR_YOUR}-text'
3
4someFoo:
5  someBar: ['${ENV_VAR_MY}', '${ENV_VAR_YOUR}']
6  yaml-array:
7    - ${ENV_VAR_MY}
8    - second
9
10someStrange: Thats/${ENV_VAR_MY}/${NAMESPACE:cloud-or-not}/${ENV_VAR_YOUR}
11
12escapedValue:
13  value: \$\{ENV_VAR_MY\}

JS output

1process.env.ENV_VAR_MY = 'Some value 2';
2process.env.ENV_VAR_YOUR = 'Another Value';
3
4const config = readYamlEnvSync(path.resolve(__dirname, 'config-env.yml'));
5// Object {
6//   "bar": "text-Some value 2-text-Another Value-text",
7//   "escapedValue": Object {
8//     "value": "\\\\$\\\\{ENV_VAR_MY\\\\}",
9//   },
10//   "foo": 1,
11//   "someFoo": Object {
12//     "someBar": Array [
13//       "Some value 2",
14//       "Another Value",
15//     ],
16//     "yaml-array": Array [
17//       "Some value 2",
18//       "second",
19//     ],
20//   },
21//   "someStrange": "Thats/Some value 2/cloud-or-not/Another Value",
22// }

More examples you can find in ./src/__fixtures__/ and ./src/__snapshots/ from tests snapshot results.

Tests coverage report

---------------------|---------|----------|---------|---------|-------------------
File                 | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s 
---------------------|---------|----------|---------|---------|-------------------
All files            |   98.46 |    83.02 |     100 |   98.11 |                   
 read-yaml-config.ts |   98.46 |    83.02 |     100 |   98.11 | 40                
---------------------|---------|----------|---------|---------|-------------------

Used Dependencies:

• js-yaml@4.1.0
• lodash@4.17.21

Author

👤 Valerii Nosikov

• Github: @vara855

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