https://github.com/milkdrinkers/env-applier-rs
Rust CLI for replacing environment variables in config files.
https://github.com/milkdrinkers/env-applier-rs
cli config configuration devops rust rust-cli-apps rust-lang systemadministration
Last synced: about 2 months ago
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Rust CLI for replacing environment variables in config files.
- Host: GitHub
- URL: https://github.com/milkdrinkers/env-applier-rs
- Owner: milkdrinkers
- License: mit
- Created: 2025-02-03T19:41:24.000Z (4 months ago)
- Default Branch: main
- Last Pushed: 2025-02-04T11:58:41.000Z (4 months ago)
- Last Synced: 2025-02-04T12:37:52.814Z (4 months ago)
- Topics: cli, config, configuration, devops, rust, rust-cli-apps, rust-lang, systemadministration
- Language: Rust
- Homepage:
- Size: 43.9 KB
- Stars: 0
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Funding: .github/FUNDING.yml
- License: LICENSE
- Codeowners: .github/CODEOWNERS
Awesome Lists containing this project
README
CLI functionality is simple. It reads a config that specifies a list of files and nodes. The user can then apply or unapply patches.
## Command Line Usage
`env-applier-rs` or (*ea*) is a CLI tool for applying environment variables in configuration files.
### Basic Usage
```bash
ea [COMMAND] [OPTIONS]
```
### Commands
#### `apply`
Applies the configuration by replacing variables in the target files with values from the environment.
```bash
ea apply [OPTIONS]
Options:
-c, --config Path to config file
-h, --help Print help information
```
#### `deapply`
Reverts the configuration by restoring the original values in the target files.
```bash
ea deapply [OPTIONS]
Options:
-c, --config Path to config file
-h, --help Print help information
```
#### `parse`
Validates the configuration file without making any changes to the target files.
```bash
ea parse [OPTIONS]
Options:
-c, --config Path to config file
-h, --help Print help information
```
### Global Options
```bash
-h, --help Print help information
-V, --version Print version information
```
### Examples
Apply configuration using the default config file (`config.toml`):
```bash
ea apply
```
Apply configuration using a specific config file:
```bash
ea apply --config ./config.toml
```
Validate a specific config file:
```bash
ea parse --config ./some-config.toml
```
Revert changes using the default config file (`config.toml`):
```bash
ea deapply
```
### Notes
- If no config file is specified, the tool will look for the default configuration file `config.toml` in your current working directory
- The tool will load environment variables from your system, `.env` & `.env.local`
- The parse command can be used to validate config files before applying changes
### Configuration
The configuration file is what tells Env Applier what to change and where. It should be a single `Toml` file located in the *current working directory* or specified using the command argument for config.
By default `config.toml` is loaded by the CLI.
```toml
[environment]
# In this case the de-apply output would be something like "%%SOME_ENV_NAME%%"
prefix = "%%" # What env variables should be prefixed with when changes are de-applied
suffix = "%%" # What env variables should be suffixed with when changes are de-applied
[specific]
[specific.json]
[specific.toml]
[specific.properties]
[specific.yaml]
[[specific.yaml.locations]]
file = "test.yml" # The file which contains the config node
node = "database.password" # The config node to change
variable = "DB_PASS" # This is the env variable that is parsed on apply, and replaced back on de-apply
[[specific.yaml.locations]]
file = [ "test.yml", "test2.yml", ] # Allows multiple files to be updated
node = "database.host"
variable = "DB_HOST"
[[specific.yaml.locations]]
file = "test.yml"
node = [ "database.name", ] # Allow multiple nodes to be updated
variable = "DB_NAME"
[[specific.yaml.locations]]
files = "test.yml" # Alias of "file"
nodes = "server.password" # Alias of "node"
variable = "DB_PASS"
default = "%%OVERRIDE_DEAPPLY%%" # Overrides the "variable" field when de-applying
override = { exemptApply = false, exemptDeapply = false } # Exempt from applying or de-applying changes
[[specific.yaml.locations]]
files = [ "test.yml", ] # Alias of "file"
nodes = [ "database.password", "server.password" ] # Alias of "node"
variable = "DB_PASS"
default = "%%DB_CUSTOM_VARIABLE%%"
override = { exemptApply = false, exemptDeapply = false }
```
### Environment Variables
Environment variables are loaded from your system and the files `.env` & `.env.local` (*Located in your current working directory*).
`.env` files follow `.properties` format and support variable expnasion. Here is an example `.env` file which makes the following environment variables available to the program:
```properties
# SQL Database Settings
DB_NAME=database
DB_USER=root
DB_PASS=123
DB_HOST=localhost
DB_PORT=3306
# Example of variable expansion
DB_URL=mysql://$DB_USER:$DB_PASS@$DB_ADDRESS/$DB_NAME
DB_ADDRESS=$DB_HOST:$DB_PORT
```
### File Formats
| Format | Comments Support | Table Support | Array Support |
|-------------|------------------|---------------|---------------|
| **YAML** | ✅ (Using `#`) | ✅ (Maps) | ✅ (Sequences) |
| **JSON** | ❌ | ❌ | ✅ |
| **JSONC** | ✅ (Using `//`) | ❌ | ✅ |
| **TOML** | ✅ (Using `#`) | ✅ | ✅ |
| **Properties** | ✅ (Using `#`/`!`)| ❌ | ❌ |
The specs & criteria for modifications is straightforward:
- Only replaces the value of a node, it never adds entries to the file
- Does not "*reformat*" the file at all
- Respects previous whitespace/indentation/line endings
- Respects comments in applicable config formats (*Including header, footer & trailing comments*)
- Able to traverse & modify complex data structures in supported file formats
- Editing a file should never break the syntax of the config