krystall0/envautoupdater repository overview

⁠EnvAutoUpdater

A lightweight .NET 9 background service that automatically keeps your local .env files in sync with their corresponding versions hosted in remote Git repositories (e.g., GitHub).

⁠📑 Table of Contents

• Features⁠
• Requirements⁠
• Configuration⁠
  • Configuration Fields⁠
  • Service Configuration⁠
  • Full Configuration Example⁠
• Deployment⁠
  • Docker Compose⁠
  • Volume Mapping⁠
  • Running Without Docker⁠
• How It Works⁠
• Behavior Details⁠
  • Variable Parsing⁠
  • Multi-line Values⁠
  • Added Variables Format⁠
  • Comment Syncing⁠
  • Backup Files⁠
• Troubleshooting⁠
• License⁠

⁠🚀 Features

• 🔄 Automatically detects outdated local .env files by comparing variable names with the remote version
• ➕ Adds missing environment variables found in the repository .env to the local file
• 💬 Preserves and syncs comments associated with each variable
• 🧩 Supports multi-line variable values (e.g., JSON strings)
• 💾 Optional backup of the original .env file before any update (.env.bak_TIMESTAMP)
• 🔗 Supports multiple services, each with its own repository URL and local file path
• 🌐 Automatically converts standard GitHub URLs to raw content URLs
• 🐳 Docker-ready with simple volume-based configuration

⁠📋 Requirements

• .NET 9 SDK⁠ (for local development/run)
• Docker⁠ and Docker Compose⁠ (for containerized deployment)

⁠⚙️ Configuration

The service is configured entirely via a config.json file located in the application's root directory. This file defines which services to monitor, how often to check for updates, and general behavior settings.

⁠Configuration Fields

⁠Service Configuration

Each entry in the services array represents a single .env file to keep in sync:

⁠Full Configuration Example

Below is a complete config.json example that monitors three different services:

{ 
	"services": 
		[ 
			{ 
			
				"name": "AuthService", 
				"repositoryEnvUrl": "https://raw.githubusercontent.com/myorg/auth-service/refs/heads/main/.env-sample", 
				"localEnvPath": "/app/envs/auth-service/.env" 
				
			}, 
			{ 
				"name": "PaymentGateway", 
				"repositoryEnvUrl": "https://github.com/myorg/payment-gateway/blob/main/.env-sample", 
				"localEnvPath": "/app/envs/payment-gateway/.env" 
			}, 
			{ 
				"name": "NotificationService", 
				"repositoryEnvUrl": "https://raw.githubusercontent.com/myorg/notifications/refs/heads/develop/.env-sample", 
				"localEnvPath": "/app/envs/notifications/.env" 
			} 
		], 
	"checkInterval": 1800, 
	"saveBackupFile": true, 
	"timezone": "Europe/Rome",
	"logLevel": "info"
}

⁠🐳 Deployment

⁠Docker Compose

The recommended way to deploy EnvAutoUpdater is via Docker Compose. Create a docker-compose.yml file:

services: 
	env-auto-updater: 
	image: krystall0/envautoupdater:latest
	container_name: env-auto-updater 
	restart: unless-stopped 
	volumes: 
		# Mount the configuration file (read-only) 
		- ./config.json:/app/config.json:ro
		# Mount the local .env directories for each monitored service.
		# The container needs read/write access to update the .env files.
		- /home/user/projects/auth-service:/app/envs/auth-service
		- /home/user/projects/payment-gateway:/app/envs/payment-gateway
		- /home/user/projects/notifications:/app/envs/notifications

Then, start the service:

docker-compose up -d

This will download the latest image, create the container, and start the EnvAutoUpdater service in detached mode. The logs can be viewed with:

docker-compose logs env-auto-updater -f

⁠Volume Mapping

Ensure that the host directories (e.g., /home/user/projects/auth-service) exist and contain the .env files you want to monitor. The container will map these directories to /app/envs/... paths.

⁠Running Without Docker

For development or testing, you can run the service directly on your machine (assuming .NET 9 SDK is installed):

1. Clone the repository:

git clone https://github.com/kRYstall9/EnvAutoUpdater.git
cd EnvAutoUpdater

1. Configure the service:

   • Edit config.json to your needs.

2. Run the service:

dotnet run

⁠🔍 How It Works

1. Read configuration — loads the list of services to monitor from config.json at each iteration (the config can be changed without restarting the container; its updated content will be read at the next iteration).
2. Read local .env — reads the local file line by line via ReadLocalEnvFile.
3. Fetch remote .env — downloads the latest .env from the configured repository URL via ReadUpdatedEnvFileFromRepository.
4. Extract variable names — parses both files via ReadEnvVariables to extract environment variable names (lines containing =).
5. Compare — checks via IsFileAlreadyUpdated if all remote variable names are already present in the local file.
6. Update — if differences are found, UpdateEnvFile:
   • Appends a clearly marked section at the bottom of the local file.
   • Adds any missing variables (commented out, preserving their original values and associated comments).
   • Updates inline comments for variables already present locally.
7. Backup (optional) — saves a .env.bak_TIMESTAMP copy before writing changes.
8. Wait — sleeps for checkInterval seconds, then repeats from step 1.

⁠📝 Behavior Details

⁠Variable Parsing

• Lines that are empty, do not contain =, or have spaces in the variable name are skipped.
• Commented-out variables (prefixed with #) are recognized and their names are extracted by stripping the # prefix.
• Duplicate variable names across the file are automatically deduplicated.

⁠Multi-line Values

Variables whose values span multiple lines (e.g., embedded JSON strings) are fully captured. The parser continues reading lines until it encounters an empty line, a comment, or a new variable assignment.

⁠Added Variables Format

New variables found in the remote .env are appended commented out at the bottom of the local file, under a clearly identifiable marker section. This ensures your existing configuration is never overwritten — you review and uncomment the new variables manually.

⁠Comment Syncing

If a variable already exists locally but its associated comments in the repository have changed, EnvAutoUpdater will:

• Remove the outdated comments above the existing variable line.
• Insert the updated comments from the repository in their place.

⁠Backup Files

• If saveBackupFile is enabled, a backup of the original .env file is saved as .env.bak_TIMESTAMP before any updates are applied. The timestamp format is yyyyMMddTHHmmss (e.g., .env.bak_20230101T120000).

⁠❓ Troubleshooting

⁠📄 License

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