OCR Service

This repository contains OCR Service built using Axum.

The full list of crates used can be found in the Cargo.toml file. However, here are some key ones:

• axum - A user-friendly, modular web framework built with Tokio, Tower, and Hyper.
• tesseract-rs - A library for OCR using Tesseract Rust bindings.
• image - An image processing library for Rust.
• Insta - A library for snapshot testing in Rust.
• utoipa - A library for generating OpenAPI documentation in Rust.
• opentelemetry-rust - OpenTelemetry for Rust.

Getting Started

Configure the Application

Environment Variables

You can use the .env.example file or src/config/app_config.rs to view and configure the application.

The TESSDATA_PATH environment variable allows you to specify where the Tesseract data files are stored. By default, it's set to tesseract. If you change this path, make sure to:

1. Update the environment variable in your .env file
2. If using Docker or Docker Compose, pass the same path as a build argument to ensure your data gets copied into the container correctly

Download Tesseract Data Files

The OCR Service requires the Tesseract data files to be downloaded into the tesseract directory. You can download the files manually via these repositories:

• tesseract-ocr/tessdata
• tesseract-ocr/tessdata_fast

Or by running the scripts/download-tessdata.sh script.

Starting the Application

With everything else set up, all you need to do now is:

cargo run

Running Tests

Run tests:

cargo test

Run Snapshot tests:

cargo insta test

Run and review Snapshot tests:

cargo insta test --review

Linting and Formatting

Run Clippy:

cargo clippy

Run Rustfmt:

cargo fmt

Deployment

For building and running the docker image locally:

# If using the default TESSDATA_PATH (tesseract)
docker build -t ocr-service .
docker run -p 8080:8080 ocr-service

# If using a custom TESSDATA_PATH, specify it as both a build argument and environment variable
docker build --build-arg TESSDATA_PATH=your/custom/path -t ocr-service .
docker run -p 8080:8080 -e TESSDATA_PATH=your/custom/path ocr-service

If using Docker Compose, you can specify the custom path in the compose file:

services:
    ocr_service:
        build:
            context: ../
            args:
                - TESSDATA_PATH=your/custom/path
            dockerfile: Dockerfile

Make sure the TESSDATA_PATH build argument matches the environment variable you've set in your .env file.

API Documentation

The API documentation is available at http://localhost:8080/api-docs when running locally.

curl Examples

Send a file to the /api/v1/images endpoint to process the image.

curl -X POST -F "image=@./tests/images/tessdoc-introduction.png" \
"http://localhost:8080/api/v1/images?language=eng"

Send a file to the /api/v1/images endpoint to process the image with a specific model.

curl -X POST -F "image=@./tests/images/chinese-simplified-sign.jpg" \
"http://localhost:8080/api/v1/images?language=chi_sim&model=chi_sim"

Get all available languages and models.

curl http://localhost:8080/api/v1/languages

Health Check

curl http://localhost:8080/system/health