# Sidecar Development Guide

If you're reading this document then you've decided to contribute to the Sidecar for Apache Cassandra.

## Building

    ./gradlew build

Packages can be built using the following Gradle commands:

    ./gradlew buildDeb
    ./gradlew buildRpm

## Project Layout

### Common

Contains the libraries which are shared between the version specific Cassandra code as well as the dependencies of Cassandra itself.

### Cassandra40

Implementation of ICassandraAdapter for Cassandra 4.0.

### Cassandra Integration Tests

Cassandra integration tests leverage Kubernetes to create Cassandra nodes and test the different implementations
of the ICassandraAdapters against real C* nodes.

The integration tests will not run by default when running `./gradlew test` since they require a bit of setup and you may not have
Kubernetes available.

#### Mac Local Setup

Running kubernetes locally on a Mac can be a bit tricky as it requires several steps.

First, install minikube: https://kubernetes.io/docs/tasks/tools/install-minikube/

There is a convenience script, located at `scripts/setup-minikube.sh`, that can be used to create the minikube environment and enable the registry for you.

You will also need Docker: https://docs.docker.com/get-docker/ to build containers locally before pushing to the minikube registry.

NOTE: If you have a registry already running you can skip the above step and instead set the SIDECAR_DOCKER_REGISTRY environment variable to the full URI of your registry..

If you're using the local option, make sure you can push to an insecure registry.
The following should be added to your docker configuration (under docker preferences -> docker engine).  Be sure to use whatever ip is reported by `minikube ip`:

    {
        "insecure-registries": ["192.168.64.16:5000"]
    }

You will need to run `minikube tunnel` to ensure your Mac can connect to the IP addresses inside the hyperkit virtual machine:

    minikube tunnel

Enter your password when prompted.  It'll redirect part of the 10.x address space to the hyperkit virtual machine.

Once all this is completed, execute `./gradlew pushAll` to create all the containers required for integration testing.

Sometimes minikube can run into issues starting up new jobs, especially if there are several running pods which failed to get cleaned up.  Running the following can help clean up the old pods:

    scripts/cleanup-pods.sh

#### Linux Setup

The most straightforward setup on Linux is to use microk8s, as this relies on non virtualized containers, which give excellent performance.

https://microk8s.io

You will need to configure the SIDECAR_DOCKER_REGISTRY environment variable.  If you're using the built in microk8's registry you should configure the following:

    export SIDECAR_DOCKER_REGISTRY="http://localhost:32000"

NOTE: The MicroK8 project uses 32000 for its registry while minikube on MacOS uses port 5000.

Please see the setup in `.circleci/setup-microk8.sh`.

#### Push containers to the registry

    ./gradlew pushAll

#### Running Integration Tests

Integration tests can be run with the following:

    ./gradlew integrationTest


#### Tests

Tests in the cassandra-integration-tests submodule should be marked as integration tests with the @CassandraIntegrationTest annotation:

    @CassandraIntegrationTest
    void myTestHere(CassandraTestContext context)
    {
        //
    }

The `CassandraTestTemplate` will handle starting up each of the Kubernetes services required for testing and inject the
`CassandraTestContext`, which will have the version, CQLSession, container, and other useful information required for testing.

### Main Project

The main project consumes the various Cassandra versions via the CassandraAdapterDelegate.  When connecting to the server,
the delegate will discover the version and choose the best `ICassandraAdapter` to match the server version.


## Testing

Our official CI for this project is CircleCI.

We strive for high quality, thoroughly tested code.

Some tests require docker to be installed locally to run Cassandra.

## Issue Tracker

File bugs or look for issues to work on in our project JIRA: https://issues.apache.org/jira/browse/CASSANDRASC

## Submitting Patches

You may open a PR against our project: http://github.com/apache/cassandra-sidecar

Please link to the PR from the JIRA ticket.  All work *must* have a corresponding JIRA ticket.  Please put the JIRA ID in the body of the pull request.