svg2png Microservice

A performant Rust microservice using Axum and resvg to easily convert SVG images to PNG format with adjustable DPI via a simple HTTP API.

Features

• High-Performance Conversion: Leverages Rust and the resvg library for efficient SVG rendering.
• Simple HTTP API: Provides a straightforward /svg-to-png endpoint for conversion.
• Adjustable DPI: Control the output resolution using the dpi query parameter.
• Health Check: Includes a /health endpoint for monitoring service status.
• Containerized: Official Docker images available on GitHub Container Registry (GHCR).
• Cross-Platform Binaries: Pre-compiled binaries available for Linux, macOS (x86_64, aarch64), and Windows via GitHub Releases.

Getting Started

There are several ways to run the svg2png service:

1. Using Docker (Recommended)

The easiest way to run the service is using the official Docker image from GHCR.

# Pull the latest image
docker pull ghcr.io/govcraft/svg2png:latest

# Run the container, mapping port 3000
docker run -d -p 3000:3000 --name svg2png ghcr.io/govcraft/svg2png:latest

# Run with a specific version tag (e.g., v0.1.0)
# docker run -d -p 3000:3000 --name svg2png ghcr.io/govcraft/svg2png:0.1.0

# Run with custom port and host binding (optional)
# docker run -d -p 8080:8080 \
#   -e SVG2PNG_PORT=8080 \
#   -e SVG2PNG_HOST=0.0.0.0 \
#   --name svg2png ghcr.io/govcraft/svg2png:latest

The service will be available at http://localhost:3000 (or the custom port you specified).

2. Using Pre-built Binaries

You can download pre-compiled binaries for your operating system from the GitHub Releases page.

1. Download the appropriate binary for your system (e.g., svg2png-linux-x86_64, svg2png-macos-aarch64, svg2png-windows-x86_64.exe).
2. Make the binary executable (on Linux/macOS): chmod +x ./svg2png-linux-x86_64
3. Run the binary: ./svg2png-linux-x86_64

The service will start using the default configuration (port 3000). You can configure it using environment variables (see Configuration).

3. Building from Source

Ensure you have a recent Rust toolchain installed.

1. Clone the repository:

   git clone https://github.com/Govcraft/svg2png.git
   cd svg2png

2. Build the release binary:

   cargo build --release

3. Run the compiled binary:

   ./target/release/svg2png

API Usage

Convert SVG to PNG

• Endpoint: /svg-to-png
• Method: POST
• Request Body: Raw SVG data (Content-Type: image/svg+xml or other, though the service primarily cares about the content being valid SVG).
• Query Parameters:
  • dpi (optional): The desired output resolution in Dots Per Inch. Must be a positive number. Defaults to 96.0 if not provided or invalid. The SVG is scaled relative to this default DPI.
• Success Response:
  • Status Code: 200 OK
  • Content-Type: image/png
  • Body: Raw PNG image data. The PNG includes a pHYs chunk indicating the physical pixel dimensions based on the requested DPI.
• Error Responses:
  • 400 Bad Request: If the request body is empty, the SVG data is invalid, or the resulting image dimensions are zero after scaling.
  • 500 Internal Server Error: If there's an internal issue creating the image buffer or encoding the PNG.

Example using curl:

# Basic conversion (defaults to 96 DPI)
curl -X POST --data-binary @your_image.svg http://localhost:3000/svg-to-png -o output.png

# Conversion with custom DPI (e.g., 300 DPI)
curl -X POST --data-binary @your_image.svg "http://localhost:3000/svg-to-png?dpi=300" -o output_300dpi.png

(Replace your_image.svg with the path to your SVG file and localhost:3000 with the correct host/port if not using defaults)

Health Check

• Endpoint: /health
• Method: GET
• Success Response:
  • Status Code: 200 OK
  • Body: Empty

Example using curl:

curl http://localhost:3000/health
# Expected output: (No body, just HTTP 200 status)

# Check status code
curl -o /dev/null -s -w "%{http_code}\n" http://localhost:3000/health
# Expected output: 200

Configuration

The service can be configured using the following environment variables:

Variable	Description	Default
SVG2PNG_HOST	The host address the server binds to.	0.0.0.0
SVG2PNG_PORT	The port the server listens on.	3000
RUST_LOG	Controls logging level and verbosity.	info
	(e.g., debug, svg2png=trace, warn)

Building

To build the project locally, ensure you have Rust installed and run:

cargo build
# For an optimized release build:
cargo build --release

Contributing

Contributions are welcome! Please refer to the contribution guidelines (if available) or open an issue/pull request on GitHub.

License

This project is licensed under the MIT License.## Sponsor

Govcraft is a one-person shop—no corporate backing, no investors, just me building useful tools. If this project helps you, sponsoring keeps the work going.