Third take on the FAF replay server, this time in Rust.

Usage

See docs/usage.rst. If you want to build the documentation, you'll need sphinx and dia.

Running extra tests

To run database query unit tests, do the following:

• Setup a local FAF database. The compose.yaml file will do it for you, like so:

  docker compose up -d --quiet-pull
  

  TODO: Move this file to a shared location.
• Clear the local database and load test data:

  ./test/clear_and_populate_db.sh <DB arguments to mysql>
  

• Run cargo test as follows:

  env DB_HOST=<db_host> DB_PORT=<db_port> cargo test --features local_db_tests
  

A few tests run outside cargo test, since they manipulate process-global state. You can run them like so:

cargo build --features process_tests
./test/run_process_tests.sh

Sqlx compile-time checks

Database queries are checked for correctness at compile time. You'll need to setup a local FAF database like above and set DATABASE_URL env var to "mysql://root:[email protected]:3306/faf" for compilation to work.

Results of compile-time checking are saved to sqlx-data.json, which lets us compile on CI without setting up the DB. If you're changing DB queries, run the following command:

env DATABASE_URL="mysql://root:[email protected]:3306/faf" cargo sqlx prepare -- --lib

In order to regenerate the file.

Coverage

To do code coverage, first install lcov (from your distribution) and llvm-cov:

cargo install cargo-llvm-cov

Once this is done, run test/run_coverage.sh. Generated coverage is available under ./coverage.

If the script is complaining about "failed to find llvm-tools-preview", you can give it paths to your llvm installation, like so:

export LLVM_COV=<path to llvm-cov>
export LLVM_PROFDATA=<path to llvm-profdata>

TODOs

• More tests in src/replay.

Code improvement checklist

Code that needs no real improvement is marked with ✓.

├── accept ✓
├── config.rs ✓ (could add validation)
├── database ✓
├── error.rs ✓
├── main.rs ✓
├── metrics.rs ✓
├── process_test ✓
├── replay
│   ├── receive
│   │   ├── merger.rs
│   │   ├── merge_strategy.rs
│   │   ├── quorum_merge_strategy.rs
│   │   └── replay_delay.rs
│   ├── replay.rs ✓ (maybe more tests)
│   ├── replays.rs ✓
│   ├── save ✓
│   ├── send ✓
│   ├── streams
│   │   ├── header.rs ✓
│   │   ├── merged_replay_reader.rs
│   │   ├── merged_replay.rs
│   │   └── writer_replay.rs
│   └── runner.rs ✓
├── server
│   ├── connection.rs ✓
│   └── server.rs ✓ (maybe more tests)
├── util ✓

TL; DR the only thing that still feels bad is the whole state machine of replays.