neon/compute_tools

Compute node tools

Postgres wrapper (zenith_ctl) is intended to be run as a Docker entrypoint or as a systemd ExecStart option. It will handle all the zenith specifics during compute node initialization:

• zenith_ctl accepts cluster (compute node) specification as a JSON file.
• Every start is a fresh start, so the data directory is removed and initialized again on each run.
• Next it will put configuration files into the PGDATA directory.
• Sync safekeepers and get commit LSN.
• Get basebackup from pageserver using the returned on the previous step LSN.
• Try to start postgres and wait until it is ready to accept connections.
• Check and alter/drop/create roles and databases.
• Hang waiting on the postmaster process to exit.

Also zenith_ctl spawns two separate service threads:

• compute-monitor checks the last Postgres activity timestamp and saves it into the shared ComputeState;
• http-endpoint runs a Hyper HTTP API server, which serves readiness and the last activity requests.

Usage example:

zenith_ctl -D /var/db/postgres/compute \
           -C 'postgresql://zenith_admin@localhost/postgres' \
           -S /var/db/postgres/specs/current.json \
           -b /usr/local/bin/postgres

Tests

Cargo formatter:

cargo fmt

Run tests:

cargo test

Clippy linter:

cargo clippy --all --all-targets -- -Dwarnings -Drust-2018-idioms

Cross-platform compilation

Imaging that you are on macOS (x86) and you want a Linux GNU (x86_64-unknown-linux-gnu platform in rust terminology) executable.

Using docker

You can use a throw-away Docker container (rustlang/rust image) for doing that:

docker run --rm \
    -v $(pwd):/compute_tools \
    -w /compute_tools \
    -t rustlang/rust:nightly cargo build --release --target=x86_64-unknown-linux-gnu

or one-line:

docker run --rm -v $(pwd):/compute_tools -w /compute_tools -t rust:latest cargo build --release --target=x86_64-unknown-linux-gnu

Using rust native cross-compilation

Another way is to add x86_64-unknown-linux-gnu target on your host system:

rustup target add x86_64-unknown-linux-gnu

Install macOS cross-compiler toolchain:

brew tap SergioBenitez/osxct
brew install x86_64-unknown-linux-gnu

And finally run cargo build:

CARGO_TARGET_X86_64_UNKNOWN_LINUX_GNU_LINKER=x86_64-unknown-linux-gnu-gcc cargo build --target=x86_64-unknown-linux-gnu --release