Developer Guide

Development

This part of the documentation relates only to development of the plugin and not required if you only intended to use it.

The frontend part is implemented using Typescript, WebPack, ESLint and NPM. The backend is written on Golang and based on Hashicorp Plugin System. The plugin development uses docker actively and it's recommended to have at least basic understanding of docker and docker-compose, although all steps can be done without docker.

Installation and Build

First, clone the project. It has to be built with docker or with locally installed tools.

Docker Way (Recommended)

1. Install frontend dependencies

docker run --rm -v ${PWD}:/opt/gcds -w /opt/gcds node:12 npm install

2. Build frontend

docker run --rm -v ${PWD}:/opt/gcds -w /opt/gcds node:12 node node_modules/webpack/bin/webpack.js

3. Install backend dependencies

docker run --rm -v ${PWD}:/go/src/github.com/ha/gcp -w /go/src/github.com/ha/gcp/backend golang:1-alpine go mod vendor

4. Build backend (Linux version)

docker run --rm -v ${PWD}:/go/src/github.com/ha/gcp -w /go/src/github.com/ha/gcp/backend golang:1-alpine go build -o ../dist/cassandra-plugin_linux_amd64 .

Locally

If you have npm and golang installed locally, you can do the build steps without docker:

• npm install
• webpack
• cd backend && go mod vendor
• go build -i -o ./dist/cassandra-plugin_linux_amd64 ./backend

Run Grafana and Cassandra

docker-compose up -d

docker-compose includes two services:

• Grafana by itself, the plugin is mounted as a volume to /var/lib/grafana/plugins/cassandra. Verbose logging is enabled. Grafana is available at http://localhost:3000, user admin, password admin
• Apache Cassandra, host cassandra:9042, user cassandra, password cassandra. cqlsh is available via docker-compose exec cassandra cqlsh -u cassandra -p cassandra.

After the startup, the datasource should be available in the list of datasources. Also, following lines should appear in grafana logs:

# Frontend part registered
lvl=info msg="Starting plugin search" logger=plugins
lvl=info msg="Registering plugin" logger=plugins name="Apache Cassandra"
...
# Backend part is started and running
msg="Plugins: Adding route" logger=http.server route=/public/plugins/hadesarchitect-cassandra-datasource dir=/var/lib/grafana/plugins/cassandra/dist
msg="starting plugin" logger=plugins plugin-id=hadesarchitect-cassandra-datasource path=/var/lib/grafana/plugins/cassandra/dist/cassandra-plugin_linux_amd64 args=[/var/lib/grafana/plugins/cassandra/dist/cassandra-plugin_linux_amd64]
msg="plugin started" logger=plugins plugin-id=hadesarchitect-cassandra-datasource path=/var/lib/grafana/plugins/cassandra/dist/cassandra-plugin_linux_amd64 pid=23
msg="waiting for RPC address" logger=plugins plugin-id=hadesarchitect-cassandra-datasource path=/var/lib/grafana/plugins/cassandra/dist/cassandra-plugin_linux_amd64
msg="2020-01-16T22:08:51.619Z [DEBUG] cassandra-backend-datasource: Running Cassandra backend datasource..." logger=plugins plugin-id=hadesarchitect-cassandra-datasource
msg="plugin address" logger=plugins plugin-id=hadesarchitect-cassandra-datasource address=/tmp/plugin991218850 network=unix timestamp=2020-01-16T22:08:51.622Z
msg="using plugin" logger=plugins plugin-id=hadesarchitect-cassandra-datasource version=1

To read the logs, use docker-compose logs -f grafana.

Load Sample Data

docker-compose exec cassandra cqlsh -u cassandra -p cassandra -f ./test_data.cql

Testing

Docker Way (Recommended)

Backend tests: docker run --rm -v ${PWD}:/go/src/github.com/ha/gcp -w /go/src/github.com/ha/gcp/backend golang:1 go mod vendor && go test .

Locally

Backend tests: go test ./backend

Making Changes

Frontend

Run webpack with --watch option to enable watching:

• docker run --rm -v ${PWD}:/opt/gcds -w /opt/gcds node:12 node node_modules/webpack/bin/webpack.js --watch
• docker-compose restart grafana

Backend

With any changes done to backend, the binary file should be recompiled and grafana should be restarted:

• docker run --rm -v ${PWD}:/go/src/github.com/ha/gcp -w /go/src/github.com/ha/gcp golang go build -i -o ./dist/cassandra-plugin_linux_amd64 ./backend
• docker-compose restart grafana