Config Injector

DISCLAIMER: I am not a good rust dev, if you see some stuff that could be done better you can create a pull request.

The config-injector is a Rust-based tool that processes configuration files, replacing placeholders with environment variable values. It reads files, searches for placeholders in the format {{VAR_NAME}}, and replaces them with the respective values of environment variables. If a variable is not found, it logs a warning and leaves the placeholder intact.

Prerequisites

1. Docker
2. Rust installed locally (optional if you are using Docker for cross-compilation)

Build Instructions

To build the project for Linux (even if you're on Windows), use the provided Docker environment:

1. Build the Docker Image

Run the following command to build the Docker image:

docker build -t rust-cross-compilation .

This will create a Docker image named rust-cross-compilation based on the provided Dockerfile.

2. Start Docker Container

Run the following command to start a Docker container and open an interactive shell:

docker run -it --rm -v ${PWD}:/usr/src/config-injector rust-cross-compilation /bin/bash

This mounts the current directory (${PWD}) into the container and starts an interactive shell. The directory inside the container will be /usr/src/config-injector.

3. Add the Linux Target for Cross-Compilation

Inside the Docker container, run the following command to add the necessary target for Linux cross-compilation:

rustup target add x86_64-unknown-linux-gnu

4. Build the Project for Linux

Now, compile the project for the Linux target:

cargo build --release --target x86_64-unknown-linux-gnu

This will generate the compiled binary in the path /usr/src/config-injector/target/x86_64-unknown-linux-gnu/release/config-injector.

5. Copy the Binary to Your Local Machine

To retrieve the compiled binary from the Docker container, use the following command, replacing <container_id> with the actual container ID (you can get it using docker ps):

docker cp <container_id>:/usr/src/config-injector/target/x86_64-unknown-linux-gnu/release/config-injector ${PWD}/output/config-injector

This will copy the config-injector binary from the container to a local directory (${PWD}/output).

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Usage

After building the binary, you can use the config-injector tool by following these steps:

1. Set Environment Variables

   Set the environment variables that the tool will use for substitution. For example:

   export SERVER_LICENSEKEY="your_license_key"
   export FILES_TO_PROCESS="server-data/server.cfg,txData/default/config.json"

2. Run the Binary

   Run the config-injector binary, which will replace placeholders in the specified files:

   .config-injector

   The tool will process the files specified in the FILES_TO_PROCESS environment variable. Any placeholder in the format {{VAR_NAME}} will be replaced with the corresponding environment variable value.

   If an environment variable is not found, it logs a warning and leaves the placeholder intact.

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FILES_TO_PROCESS

This environment variable specifies which files should be processed. The files are separated by commas. For example:

export FILES_TO_PROCESS="server-data/server.cfg,txData/default/config.json"

Regex Pattern

The tool searches for placeholders using the following pattern: {{VAR_NAME}}, where VAR_NAME is an uppercase environment variable name.