ws

README

WebSocket adapter

WebSocket adapter provides an WebSocket API for sending and receiving messages through the platform.

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_WS_ADAPTER_CLIENT_TLS	Flag that indicates if TLS should be turned on	false
MF_WS_ADAPTER_CA_CERTS	Path to trusted CAs in PEM format
MF_WS_ADAPTER_LOG_LEVEL	Log level for the WS Adapter	error
MF_WS_ADAPTER_PORT	Service WS port	8180
MF_NATS_URL	NATS instance URL	nats://localhost:4222
MF_THINGS_URL	Things service URL	localhost:8181

Deployment

The service 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:
  ws:
    image: mainflux/ws:[version]
    container_name: [instance name]
    ports:
      - [host machine port]:[configured port]
    environment:
      MF_THINGS_URL: [Things service URL]
      MF_NATS_URL: [NATS instance URL]
      MF_WS_ADAPTER_PORT: [Service WS port]
      MF_WS_ADAPTER_LOG_LEVEL: [WS adapter log level]
      MF_WS_ADAPTER_CLIENT_TLS: [Flag that indicates if TLS should be turned on]
      MF_WS_ADAPTER_CA_CERTS: [Path to trusted CAs in PEM format]

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/mainflux

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

# compile the ws
make ws

# copy binary to bin
make install

# set the environment variables and run the service
MF_THINGS_URL=[Things service URL] MF_NATS_URL=[NATS instance URL] MF_WS_ADAPTER_PORT=[Service WS port] MF_WS_ADAPTER_LOG_LEVEL=[WS adapter log level] MF_WS_ADAPTER_CLIENT_TLS=[Flag that indicates if TLS should be turned on] MF_WS_ADAPTER_CA_CERTS=[Path to trusted CAs in PEM format] $GOBIN/mainflux-ws

Usage

For more information about service capabilities and its usage, please check out the WebSocket paragraph in the Getting Started guide.

Documentation

Overview

Package ws contains the domain concept definitions needed to support Mainflux ws adapter service functionality.

Index

• Variables
• type Channel
  • func NewChannel() *Channel
  • func (channel *Channel) Close()
  • func (channel *Channel) Send(msg mainflux.RawMessage)
• type Service
  • func New(pubsub Service) Service

Variables

var (
	// ErrFailedMessagePublish indicates that message publishing failed.
	ErrFailedMessagePublish = errors.New("failed to publish message")

	// ErrFailedSubscription indicates that client couldn't subscribe to specified channel.
	ErrFailedSubscription = errors.New("failed to subscribe to a channel")

	// ErrFailedConnection indicates that service couldn't connect to message broker.
	ErrFailedConnection = errors.New("failed to connect to message broker")
)

Types

type Channel

type Channel struct {
	Messages chan mainflux.RawMessage
	Closed   chan bool
	// contains filtered or unexported fields
}

Channel is used for receiving and sending messages.

func NewChannel

func NewChannel() *Channel

NewChannel instantiates empty channel.

func (*Channel) Close

func (channel *Channel) Close()

Close channel and stop message transfer.

func (*Channel) Send

func (channel *Channel) Send(msg mainflux.RawMessage)

Send method send message over Messages channel.

type Service

type Service interface {
	mainflux.MessagePublisher

	// Subscribes to channel with specified id.
	Subscribe(string, string, *Channel) error
}

Service specifies web socket service API.

func New

func New(pubsub Service) Service

New instantiates the WS adapter implementation.