cassandra

README

Cassandra writer

Cassandra writer provides message repository implementation for Cassandra.

Configuration

The service is configured using the environment variables presented in the following table. Note that any unset variables will be replaced with their default values.

Variable	Description	Default
MF_NATS_URL	NATS instance URL	nats://localhost:4222
MF_CASSANDRA_WRITER_LOG_LEVEL	Log level for Cassandra writer (debug, info, warn, error)	error
MF_CASSANDRA_WRITER_PORT	Service HTTP port	8180
MF_CASSANDRA_WRITER_DB_CLUSTER	Cassandra cluster comma separated addresses	127.0.0.1
MF_CASSANDRA_WRITER_DB_KEYSPACE	Cassandra keyspace name	mainflux

Deployment

  version: "2"
  cassandra-writer:
    image: mainflux/cassandra-writer:[version]
    container_name: [instance name]
    expose:
      - [Service HTTP port]
    restart: on-failure
    environment:
      MF_NATS_URL: [NATS instance URL]
      MF_CASSANDRA_WRITER_LOG_LEVEL: [Cassandra writer log level]
      MF_CASSANDRA_WRITER_PORT: [Service HTTP port]
      MF_CASSANDRA_WRITER_DB_CLUSTER: [Cassandra cluster comma separated addresses]
      MF_CASSANDRA_WRITER_DB_KEYSPACE: [Cassandra keyspace name]
    ports:
      - [host machine port]:[configured HTTP port]

To start the service, execute the following shell script:

# download the latest version of the service
go get github.com/mainflux/mainflux


cd $GOPATH/src/github.com/mainflux/mainflux

# compile the cassandra writer
make cassandra-writer

# copy binary to bin
make install

# Set the environment variables and run the service
MF_NATS_URL=[NATS instance URL] MF_CASSANDRA_WRITER_LOG_LEVEL=[Cassandra writer log level] MF_CASSANDRA_WRITER_PORT=[Service HTTP port] MF_CASSANDRA_WRITER_DB_CLUSTER=[Cassandra cluster comma separated addresses] MF_CASSANDRA_WRITER_DB_KEYSPACE=[Cassandra keyspace name] $GOBIN/mainflux-cassandra-writer

Using docker-compose

This service can be deployed using docker containers. Docker compose file is available in <project_root>/docker/addons/cassandra-writer/docker-compose.yml. In order to run all Mainflux core services, as well as mentioned optional ones, execute following command:

./docker/addons/cassandra-writer/init.sh

Usage

Starting service will start consuming normalized messages in SenML format.

Documentation

Overview

Package cassandra contains the domain concept definitions needed to support Mainflux Cassandra writer service.

Index

• func Connect(hosts []string, keyspace string) (*gocql.Session, error)
• func MakeHandler() http.Handler
• func New(session *gocql.Session) writers.MessageRepository

Functions

func Connect

func Connect(hosts []string, keyspace string) (*gocql.Session, error)

Connect establishes connection to the Cassandra cluster.

func MakeHandler

func MakeHandler() http.Handler

MakeHandler returns a HTTP API handler with version and metrics.

func New

func New(session *gocql.Session) writers.MessageRepository

New instantiates Cassandra message repository.