coap

README

Mainflux CoAP Adapter

Mainflux CoAP adapter provides an CoAP API for sending 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_COAP_ADAPTER_PORT	Service listening port	5683
MF_NATS_URL	NATS instance URL	nats://localhost:4222
MF_COAP_ADAPTER_LOG_LEVEL	Service log level	error
MF_COAP_ADAPTER_CLIENT_TLS	Flag that indicates if TLS should be turned on	false
MF_COAP_ADAPTER_CA_CERTS	Path to trusted CAs in PEM format
MF_COAP_ADAPTER_PING_PERIOD	Hours between 1 and 24 to ping client with ACK message	12
MF_JAEGER_URL	Jaeger server URL	localhost:6831
MF_THINGS_AUTH_GRPC_URL	Things service Auth gRPC URL	localhost:8181
MF_THINGS_AUTH_GRPC_TIMEOUT	Things service Auth gRPC request timeout in seconds	1s

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:
  adapter:
    image: mainflux/coap:[version]
    container_name: [instance name]
    ports:
      - [host machine port]:[configured port]
    environment:
      MF_COAP_ADAPTER_PORT: [Service HTTP port]
      MF_NATS_URL: [NATS instance URL]
      MF_COAP_ADAPTER_LOG_LEVEL: [Service log level]
      MF_COAP_ADAPTER_CLIENT_TLS: [Flag that indicates if TLS should be turned on]
      MF_COAP_ADAPTER_CA_CERTS: [Path to trusted CAs in PEM format]
      MF_COAP_ADAPTER_PING_PERIOD: [Hours between 1 and 24 to ping client with ACK message]
      MF_JAEGER_URL: [Jaeger server URL]
      MF_THINGS_AUTH_GRPC_URL: [Things service Auth gRPC URL]
      MF_THINGS_AUTH_GRPC_TIMEOUT: [Things service Auth gRPC request timeout in seconds]

Running this service outside of container requires working instance of the NATS service. To start the service outside of the container, execute the following shell script:

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

cd mainflux

# compile the http
make coap

# copy binary to bin
make install

# set the environment variables and run the service
MF_NATS_URL=[NATS instance URL] \
MF_COAP_ADAPTER_PORT=[Service HTTP port] \
MF_COAP_ADAPTER_LOG_LEVEL=[Service log level] \
MF_COAP_ADAPTER_CLIENT_TLS=[Flag that indicates if TLS should be turned on] \
MF_COAP_ADAPTER_CA_CERTS=[Path to trusted CAs in PEM format] \
MF_COAP_ADAPTER_PING_PERIOD: [Hours between 1 and 24 to ping client with ACK message] \
MF_JAEGER_URL=[Jaeger server URL] \
MF_THINGS_AUTH_GRPC_URL=[Things service Auth gRPC URL] \
MF_THINGS_AUTH_GRPC_TIMEOUT=[Things service Auth gRPC request timeout in seconds] \
$GOBIN/mainflux-coap

Usage

If CoAP adapter is running locally (on default 5683 port), a valid URL would be: coap://localhost/channels/<channel_id>/messages?authorization=<thing_auth_key>. Since CoAP protocol does not support Authorization header (option) and options have limited size, in order to send CoAP messages, valid authorization value (a valid Thing key) must be present in Uri-Query option.

Documentation

Overview

Package coap contains the domain concept definitions needed to support Mainflux CoAP adapter service functionality. All constant values are taken from RFC, and could be adjusted based on specific use case.

Index

• Variables
• type Client
  • func NewClient(mc mux.Client, token message.Token, l logger.Logger) Client
• type Observer
  • func NewObserver(subject string, c Client, conn *broker.Conn) (Observer, error)
• type Service
  • func New(auth mainflux.ThingsServiceClient, nc *broker.Conn) Service

Variables

var (
	ErrUnauthorized = errors.New("unauthorized access")
	ErrUnsubscribe  = errors.New("unable to unsubscribe")
)

Exported errors

var ErrOption = errors.New("unable to set option")

ErrOption indicates an error when adding an option.

Types

type Client

type Client interface {
	// In CoAP terminology, Token similar to the Session ID.
	Token() string
	SendMessage(m messaging.Message) error
	Cancel() error
	Done() <-chan struct{}
}

Client wraps CoAP client.

func NewClient

func NewClient(mc mux.Client, token message.Token, l logger.Logger) Client

NewClient instantiates a new Observer.

type Observer

type Observer interface {
	Cancel() error
}

Observer represents an internal observer used to handle CoAP observe messages.

func NewObserver

func NewObserver(subject string, c Client, conn *broker.Conn) (Observer, error)

NewObserver returns a new Observer instance.

type Service

type Service interface {
	// Publish Messssage
	Publish(ctx context.Context, key string, msg messaging.Message) error

	// Subscribes to channel with specified id, subtopic and adds subscription to
	// service map of subscriptions under given ID.
	Subscribe(ctx context.Context, key, chanID, subtopic string, c Client) error

	// Unsubscribe method is used to stop observing resource.
	Unsubscribe(ctx context.Context, key, chanID, subptopic, token string) error
}

Service specifies CoAP service API.

func New

func New(auth mainflux.ThingsServiceClient, nc *broker.Conn) Service

New instantiates the CoAP adapter implementation.