Mainflux Export service can send message from one Mainflux cloud to another via MQTT, or it can send messages from edge gateway to Mainflux Cloud.
Export service is subscribed to local message bus and connected to MQTT broker in the cloud.
Messages collected on local message bus are redirected to the cloud.
When connection is lost, messages from local bus are stored into Redis stream. Upon connection reestablishment Export service consumes messages from Redis stream and sends it to the Mainflux cloud.
Get the code:
go get github.com/mainflux/export
cd $GOPATH/github.com/mainflux/exportMake:
makecd build
./mainflux-exportBy default Export service looks for config file at ../configs/config.toml if no env vars are specified.
[exp]
cache_pass = ""
cache_url = "localhost:6379"
cache_db = "0"
log_level = "debug"
nats = "localhost:4222"
port = "8170"
[mqtt]
username = "<thing_id>"
password = "<thing_password>"
ca = "ca.crt"
cert = "thing.crt"
mtls = "false"
priv_key = "thing.key"
retain = "false"
skip_tls_ver = "false"
url = "tcp://mainflux.com:1883"
[[routes]]
mqtt_topic = "channel/<channel_id>/messages"
subtopic = "subtopic"
nats_topic = "export"
type = "plain"
workers = 10port- HTTP port where status ofExportservice can be fetched.
curl -X GET http://localhost:8170/version
{"service":"export","version":"0.0.1"}%To configure Redis connection settings cache_url, cache_pass, cache_db in config.toml are used.
To establish connection to MQTT broker following settings are needed:
username- Mainflux <thing_id>password- Mainflux <thing_key>url- url of MQTT broker
Additionally, you will need MQTT client certificates if you enable mTLS. To obtain certificates ca.crt, thing.crt and key thing.key follow instructions here.
Routes are being used for specifying which subscriber's topic(subject) goes to which publishing topic.
Currently only MQTT is supported for publishing. To match Mainflux requirements mqtt_topic must contain channel/<channel_id>/messages, additional subtopics can be appended.
mqtt_topic-channel/<channel_id>/messages/<custom_subtopic>nats_topic-Exportservice will be subscribed to NATS subject<nats_topic>.>subtopic- messages will be published to MQTT topic<mqtt_topic>/<subtopic>/<nats_subject>, where dots in nats_subject are replaced with '/'workerscontrol number of workers that will be used for message forwarding.type- specifies message transformation, currently onlyplainis supported, meaning no transformation.
Before running Export service edit configs/config.toml and provide username, password and url
username- matchesthing_idin Mainflux cloud instancepassword- matchesthing_keychannel- MQTT part of the topic where to publish MQTT data (channel/<channel_id>/messagesis format of mainflux MQTT topic) and plays a part in authorization.
In order for Export service to listen on Mainflux NATS deployed on the same machine NATS port must be exposed. Run mainflux using make run.
Service will look for config.toml first and if not found it will be configured with env variables and new config file specified with MF_EXPORT_CONFIG_FILE will be saved with values populated from env vars.
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 url | localhost:4222 |
| MF_EXPORT_MQTT_HOST | Mqtt url where to export | tcp://localhost:1883 |
| MF_EXPORT_MQTT_USERNAME | MQTT username, thing id in case of mainflux | |
| MF_EXPORT_MQTT_PASSWORD | MQTT password, thing key in case of mainflux | |
| MF_EXPORT_MQTT_CHANNEL | MQTT channel where to publish | |
| MF_EXPORT_MQTT_SKIP_TLS | Skip tls verification | true |
| MF_EXPORT_MQTT_MTLS | Use MTLS for authentication | false |
| MF_EXPORT_MQTT_CA | CA for tls | ca.crt |
| MF_EXPORT_MQTT_CLIENT_CERT | Client cert for authentication in case when MTLS = true | thing.crt |
| MF_EXPORT_MQTT_CLIENT_PK | Client key for authentication in case when MTLS = true | thing.key |
| MF_EXPORT_MQTT_QOS | MQTT QOS | 0 |
| MF_EXPORT_MQTT_RETAIN | MQTT retain | false |
| MF_EXPORT_CONFIG_FILE | Configuration file | config.toml |
for values in environment variables to take effect make sure that there is no MF_EXPORT_CONF file.
If you run with environment variables you can create config file:
MF_EXPORT_PORT=8178 \
MF_EXPORT_LOG_LEVEL=debug \
MF_EXPORT_MQTT_HOST=tcp://localhost:1883 \
MF_EXPORT_MQTT_USERNAME=<thing_id> \
MF_EXPORT_MQTT_PASSWORD=<thing_key> \
MF_EXPORT_MQTT_CHANNEL=<channel_id> \
MF_EXPORT_MQTT_SKIP_TLS=true \
MF_EXPORT_MQTT_MTLS=false \
MF_EXPORT_MQTT_CA=ca.crt \
MF_EXPORT_MQTT_CLIENT_CERT=thing.crt \
MF_EXPORT_MQTT_CLIENT_PK=thing.key \
MF_EXPORT_CONFIG_FILE=export.toml \
../build/mainflux-export&Service will be subscribed to NATS <nats_topic>.> subject and send messages to channels/<MF_EXPORT_MQTT_CHANNEL>/messages + / + <NatsSubject>.
For example if you are running Mainflux on a gateway if you set nats_topic="channel" you can make export service forward messages to other Mainflux instances i.e. into to the Mainflux cloud.
When message gets published to local Mainflux instance it will end on NATS as channels.<local_channel_id>.messages.subtopic, Export service will pick it up and forward it to <mqtt_topic> ending on <mqtt_topic>/channels/<local_channel_id>/messages/subtopic.
Created export.toml you can edit to add different routes and use in next run.
Configuration file for Export service can be send over MQTT using Agent service.
save, export,
mosquitto_pub -u <thing_id> -P <thing_key> -t channels/<control_ch_id>/messages/req -h localhost -p 18831 -m "[{\"bn\":\"1:\", \"n\":\"config\", \"vs\":\"save, export, <config_file_path>, <file_content_base64>\"}]"
vs="config_file_path, file_content_base64" - vs determines where to save file and contains file content in base64 encoding payload:
b,_ := toml.Marshal(export.Config)
payload := base64.StdEncoding.EncodeToString(b)
React
Typescript
Django
Laravel
Facebook
Microsoft
Google
Alibaba
D3
Tencent