rusty-pixel

Image proxy that applies image transformations to the given image.

Transformations

Options

To generate an image with ratio 40/30 and with 10% margin that is resize to 200 height before

<proxy_base_url>/scale/rh200-s30x40-m10/<url>

• GET /scale/ - Scale mode
  • s<a size>x<b size> - Scale with ratio
  • r<w|h><pixels> - Resize image to max w (width) or max h (height)
  • m<percentage> - Add margin from percentage base on original size, this makes the image bigger
  • o<portrait|landscape> - Force orientation of the image
  • bw - Black and white

Resize is performed after all options.

Examples

• s40x30 - Scale by 40 / 30
• rw1000 - Resize image to width 1000
• Scale with margin
  • s40x30-m10 - Scale by 40 / 30 with added percentage margin of the shortest side

Configuration

Copy config.example.toml to config.toml. Every value can be overridden with an environment variable prefixed RP__, using a double underscore between nesting levels, for example RP__APP__API_KEY or RP__STORAGE__S3__SECRET_ACCESS_KEY. Leave the S3 credentials unset to use the AWS default credential chain.

Settings that affect throughput:

• worker_threads, the number of images processed at the same time (defaults to the CPU count)
• vips_concurrency, libvips threads per operation. Keep worker_threads * vips_concurrency close to the CPU count
• upload_concurrency, uploads in flight per process request
• max_output_dimension, largest side any output may have, requests above it are rejected
• request_timeout_secs, after which the request is abandoned and any remaining work is cancelled

Operations

The metrics listener (metrics_listen) serves:

• /metrics, Prometheus metrics including http_requests_duration_seconds, image_process_duration_seconds, image_decode_duration_seconds, image_encode_duration_seconds{format}, image_output_bytes{format}, image_upload_duration_seconds and image_queue_wait_seconds
• /healthz, liveness

Every response carries an x-request-id header which is also included in the logs for that request.

Benchmark

cargo test --release --test bench -- --ignored --nocapture posts a 4000px JPEG with eight configurations and prints p50 and p95 wall time.

Contributing

Pull Request Process

1. Ensure any install or build dependencies are not in version control.
2. Update the README.md with details of changes to the interface, this includes new environment variables, exposed ports, useful file locations and container parameters.
3. You may merge Pull Requests.
4. Delete branch after merge.