env-replacer

env-replacer is a command-line tool designed to streamline the process of replacing environment variables in configuration files. It reads variables from a .env file and substitutes placeholders within specified files or directories, ensuring smooth and safe configuration management.

Features

• Efficiently replaces ${VAR_NAME} placeholders with corresponding values from .env.
• Supports recursive replacement for all files within a directory and its subdirectories.
• Ensures safe replacement: placeholders for variables not present in the .env file remain unchanged.
• Option to output to a specified file, leaving the original file unchanged.
• Simple and lightweight, facilitating easy integration into deployment and configuration workflows.

Usage

Requirements

• Bash (Bourne Again SHell) available on Unix-like systems.

Installation

1. Clone the repository:

   git clone https://github.com/yourusername/env-replacer.git
   cd env-replacer

2. Make sure replace_env.sh has execute permissions:

   chmod +x replace_env.sh

Examples

Assume your .env file contains the following variables:

# .env

DB_PASSWORD=mysecretpassword
API_URL=https://api.example.com

1. Single File Replacement

To replace variables in a single file (configs/app.conf):

./replace_env.sh .env configs/app.conf

Contents of configs/app.conf before:

# Example config file
db_password=${DB_PASSWORD}
api_url=${API_URL}

After running replace_env.sh:

# Example config file
db_password=mysecretpassword
api_url=https://api.example.com

2. Directory Recursive Replacement

Assume the following directory structure (configs/):

configs/
├── app.conf
└── nested/
    ├── config1.conf
    └── config2.conf

To replace variables recursively in the configs/ directory:

./replace_env.sh .env configs

After running replace_env.sh, contents of configs/app.conf, configs/nested/config1.conf, and configs/nested/config2.conf will be updated accordingly.

3. Specify Output File

To specify an output file (configs/app.conf to configs/app_updated.conf):

./replace_env.sh .env configs/app.conf configs/app_updated.conf

Contents of configs/app.conf before running replace_env.sh:

# Example config file
db_password=${DB_PASSWORD}
api_url=${API_URL}

After running replace_env.sh:

# Example config file
db_password=mysecretpassword
api_url=https://api.example.com

Contents of configs/app_updated.conf after running replace_env.sh will be the same as configs/app.conf, while configs/app.conf remains unchanged.

4. Safe Replacement Example

Assume the following configuration file (configs/app_safe.conf):

# Example config file
db_password=${DB_PASSWORD}
api_url=${API_URL}
other_var=${OTHER_VAR}

To replace variables in the file while leaving undefined placeholders unchanged:

./replace_env.sh .env configs/app_safe.conf

Contents of configs/app_safe.conf before:

# Example config file
db_password=${DB_PASSWORD}
api_url=${API_URL}
other_var=${OTHER_VAR}

After running replace_env.sh:

# Example config file
db_password=mysecretpassword
api_url=https://api.example.com
other_var=${OTHER_VAR}

...

Running Tests

To ensure the script works correctly, you can run the included test script. The test script verifies single file replacement, directory recursive replacement, specifying output files, and safe replacement features.

1. Make sure test_replace_env.sh has execute permissions:

   chmod +x test_replace_env.sh

2. Run the test script:

   ./test_replace_env.sh

The test script will output the results of each test and indicate whether they passed or failed.

License

This project is licensed under the MIT License - see the LICENSE file for details.

Contributing

Contributions are welcome! Please fork the repository and submit a pull request with your improvements.