Gemini Developers Guide

Setting Up the Environment

Before building Gemini, you need first to have ScyllaDB clusters running, for both oracle and test clusters. There are two modes for running clusters. Running single node oracle and 3 node test cluster and single node oracle and single node test cluster. The second mode is useful for debugging and development purposes, but the first mode is recommended for running tests as it mimic the production environment more closely. Everything in gemini is organized with Makefile scripts, so you can run the following commands to start the clusters:

When running scylla multi-node clusters, the script will setup prometheus and grafana for monitoring the clusters. You can access the prometheus and grafana dashboards at http://localhost:9090 and http://localhost:3000 respectively.

make scylla-setup-cluster # For starting 1 node oracle and 3 node test cluster
make scylla-shutdown-cluster # For shutting down the clusters

make scylla-setup # For starting 1 node oracle and 1 node test cluster
make scylla-shutdown # For shutting down the clusters

Building Gemini for Development

make debug-build

This will build the Gemini binary in debug mode, which is useful for development and debugging purposes. The binary will be located in the bin/ directory.

Building Gemini for Production

make build

Building Gemini Docker image

make build-docker

Running Tests

Running Unit tests

Running unit tests with -race and -tags testing to catch issues related to concurrency and to include testing tags. This is the default way to run tests in Gemini and in CI.

make test

Running Integration tests

As Gemini has two running modes for clusters (3 node and 1 node). There are two commands for integration tests:

• Running tests with 3 node test cluster

make integration-cluster-test

• Running tests with 1 node test cluster

make integration-test

• Running integration tests in Docker

make docker-integration-test

Running other tools

• Formatting the code

Using golangci-lint to format the code. (under the hood it used gofumt, goimports, and gci to format the code)

make fmt

• Linting the code Using golangci-lint to lint the code. It will run multiple linters to catch issues in the code.

make check

• Struct alignment fixes

make fieldalign

• Profiling the code

make pprof-profile # Runs pprof /debug/profile on :8080 port
make pprof-goroutine # Runs pprof /debug/goroutine on :8082 port
make pprof-block # Runs pprof /debug/block on :8083 port
make pprof-heap # Runs pprof /debug/heap on :8085 port