https://github.com/wissance/go-config-extender

A Package to override config with environment variables
https://github.com/wissance/go-config-extender

configuration-management docker-configuration go-configuration go-docker

Last synced: 5 months ago
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A Package to override config with environment variables

• Host: GitHub
• URL: https://github.com/wissance/go-config-extender
• Owner: Wissance
• License: apache-2.0
• Created: 2024-11-29T14:05:38.000Z (over 1 year ago)
• Default Branch: master
• Last Pushed: 2024-11-30T20:42:50.000Z (over 1 year ago)
• Last Synced: 2025-05-07T05:04:23.733Z (about 1 year ago)
• Topics: configuration-management, docker-configuration, go-configuration, go-docker
• Language: Go
• Homepage: https://wissance.github.io/go-config-extender/
• Size: 14.6 KB
• Stars: 2
• Watchers: 3
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

          
## 1. DESCRIPTION

`go-config-extender` is a utility that helps to work with config files: it loads a JSON config file and ***overrides values by setting environment variables***. This is useful when we are having, i.e., `Dockerfile` or `docker-compose`, consider that we are having application 

config file `config.json` and we have to override log level or db `username+passord` based on values in an `.env` file.

## 2. Requirements

To make this thing work, we have to do the following:

1. We have to separate *"normal"* environment variables from technical (those using for such override);

2. We should have some relation between `JSON` properties in config and env variable.

Considering these two restrictions, we decided to have a variable's name pattern that allows it to meet all these requirements.

consider following example of config:

```json

{

    "server": {

        "schema": "http",

        "address": "0.0.0.0",

        "port": 8182,

        "secret_file": "./keyfile"

    },

    "logging": {

        "level": "debug",

        "appenders": [

            {

                "type": "rolling_file",

                "enabled": true,

                "level": "debug",

                "destination": {

                    "file": "./logs/ferrum.log",

                    "max_size": 100,

                    "max_age": 5,

                    "max_backups": 5,

                    "local_time": true

                }

            },

            {

                "type": "console",

                "enabled": true,

                "level": "debug"

            }

        ],

        "http_log": true,

        "http_console_out": true

    },

    "data_source": {

        "type": "redis",

        "source": "redis:6379",

        "credentials": {

            "username": "ferrum_db",

            "password": "FeRRuM000"

        },

        "options": {

            "namespace": "ferrum_1",

            "db_number": "0"

        }

    }

}

```

And we would like to override:

1. `logging.level` -> `env` variable `__logging.level`

2. `data_source.username` -> `env` variable `__data_source.username`

3. `data_source.password` -> `env` variable `__data_source.password`

What methods this package have:

1. `LoadConfig [T any] (configFile string) (T, error)` for loading without overriding

2. `LoadConfigWithEnv [T any] (configFile string) (T, error)` for loading with override

## 3. Full example

A full example could be found in the test `TestLoadJSONConfigWithEnvOverride` [test_file](./config_loader_test.go)

In This test were set 3 variables of different types: `bool`, `int` and `float`

Real App usage will be shown later after this package Release && usage in `Ferrum Community Authorization Server`