Mainflux.mainflux/writer

Mainflux message writer

Mainflux message writer consumes channel events published on message broker, and stores them into the database.

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
MESSAGE_WRITER_DB_CLUSTER	comma-separated Cassandra contact points	127.0.0.1
MESSAGE_WRITER_DB_KEYSPACE	name of the Cassandra keyspace	message_writer
MESSAGE_WRITER_NATS_URL	NATS instance URL	nats://localhost:4222

Deployment

Before proceeding to deployment, make sure to check out the Apache Cassandra 3.0.x documentation. Developers are advised to get acquainted with basic architectural concepts, data modeling techniques and deployment strategies.

Prior to deploying the service, make sure to set up the database and create the keyspace that will be used by the service.

The service itself is distributed as Docker container. The following snippet provides a compose file template that can be used to deploy the service container locally:

version: "2"
services:
  manager:
    image: mainflux/message-writer:[version]
    container_name: [instance name]
    environment:
      MESSAGE_WRITER_DB_CLUSTER: [comma-separated Cassandra endpoints]
      MESSAGE_WRITER_DB_KEYSPACE: [name of Cassandra keyspace]
      MESSAGE_WRITER_NATS_URL: [NATS instance URL]

To start the service outside of the container, execute the following shell script:

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

cd $GOPATH/github.com/mainflux/message-writer/cmd

# compile the app; make sure to set the proper GOOS value
CGO_ENABLED=0 GOOS=[platform identifier] go build -ldflags "-s" -a -installsuffix cgo -o app

# set the environment variables and run the service
MESSAGE_WRITER_DB_CLUSTER=[comma-separated Cassandra endpoints] MESSAGE_WRITER_DB_KEYSPACE=[name of Cassandra keyspace] MESSAGE_WRITER_NATS_URL=[NATS instance URL] app