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
MF_CASSANDRA_WRITER_DB_USER	Cassandra DB username
MF_CASSANDRA_WRITER_DB_PASS	Cassandra DB password
MF_CASSANDRA_WRITER_DB_PORT	Cassandra DB port	9042
MF_CASSANDRA_WRITER_SUBJECTS_CONFIG	Configuration file path with subjects list	/config/subjects.toml
MF_CASSANDRA_WRITER_CONTENT_TYPE	Message payload Content Type	application/senml+json

Deployment

  version: "3.7"
  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]
      MF_CASSANDRA_WRITER_DB_USER: [Cassandra DB username]
      MF_CASSANDRA_WRITER_DB_PASS: [Cassandra DB password]
      MF_CASSANDRA_WRITER_DB_PORT: [Cassandra DB port]
      MF_CASSANDRA_WRITER_SUBJECTS_CONFIG: [Configuration file path with subjects list]
      MF_CASSANDRA_WRITER_CONTENT_TYPE: [Message payload Content Type]
    ports:
      - [host machine port]:[configured HTTP port]
    volume:
      - ./subjects.yaml:/config/subjects.yaml

To start the service, execute the following shell script:

# download the latest version of the service
git clone https://gitee.com/shtemmi/iotflux

cd 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] \
MF_CASSANDRA_READER_DB_USER=[Cassandra DB username] \
MF_CASSANDRA_READER_DB_PASS=[Cassandra DB password] \
MF_CASSANDRA_READER_DB_PORT=[Cassandra DB port] \
MF_CASSANDRA_WRITER_SUBJECTS_CONFIG=[Configuration file path with subjects list] \
$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(cfg DBConfig) (*gocql.Session, error)
• func New(session *gocql.Session) writers.MessageRepository
• type DBConfig

Functions

func Connect

func Connect(cfg DBConfig) (*gocql.Session, error)

Connect establishes connection to the Cassandra cluster.

func New

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

New instantiates Cassandra message repository.

Types

type DBConfig

type DBConfig struct {
	Hosts    []string
	Keyspace string
	User     string
	Pass     string
	Port     int
}

DBConfig contains Cassandra DB specific parameters.