# MQTT adapter

MQTT adapter provides an MQTT API for sending messages through the platform.
MQTT adapter uses [mProxy](https://github.com/mainflux/mproxy) for proxying
traffic between client and MQTT broker.

## 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_MQTT_ADAPTER_LOG_LEVEL                | mProxy Log level                                       | error                 |
| MF_MQTT_ADAPTER_MQTT_PORT                | mProxy port                                            | 1883                  |
| MF_MQTT_ADAPTER_MQTT_TARGET_HOST         | MQTT broker host                                       | 0.0.0.0               |
| MF_MQTT_ADAPTER_MQTT_TARGET_PORT         | MQTT broker port                                       | 1883                  |
| MF_MQTT_ADAPTER_MQTT_TARGET_HEALTH_CHECK | URL of broker health check                             | ""                    |
| MF_MQTT_ADAPTER_WS_PORT                  | mProxy MQTT over WS port                               | 8080                  |
| MF_MQTT_ADAPTER_WS_TARGET_HOST           | MQTT broker host for MQTT over WS                      | localhost             |
| MF_MQTT_ADAPTER_WS_TARGET_PORT           | MQTT broker port for MQTT over WS                      | 8080                  |
| MF_MQTT_ADAPTER_WS_TARGET_PATH           | MQTT broker MQTT over WS path                          | /mqtt                 |
| MF_MQTT_ADAPTER_FORWARDER_TIMEOUT        | MQTT forwarder for multiprotocol communication timeout | 30s                   |
| MF_NATS_URL                              | NATS broker URL                                        | nats://127.0.0.1:4222 |
| MF_THINGS_AUTH_GRPC_URL                  | Things gRPC endpoint URL                               | localhost:8181        |
| MF_THINGS_AUTH_GRPC_TIMEOUT              | Timeout in seconds for Things service gRPC calls       | 1s                    |
| MF_JAEGER_URL                            | URL of Jaeger tracing service                          | ""                    |
| MF_MQTT_ADAPTER_CLIENT_TLS               | gRPC client TLS                                        | false                 |
| MF_MQTT_ADAPTER_CA_CERTS                 | CA certs for gRPC client TLS                           | ""                    |
| MF_MQTT_ADAPTER_INSTANCE                 | Instance name for event sourcing                       | ""                    |
| MF_MQTT_ADAPTER_ES_URL                   | Event sourcing URL                                     | localhost:6379        |
| MF_MQTT_ADAPTER_ES_PASS                  | Event sourcing password                                | ""                    |
| MF_MQTT_ADAPTER_ES_DB                    | Event sourcing database                                | "0"                   |
| MF_AUTH_CACHE_URL                        | Auth cache URL                                         | localhost:6379        |
| MF_AUTH_CACHE_PASS                       | Auth cache password                                    | ""                    |
| MF_AUTH_CACHE_DB                         | Auth cache database                                    | "0"                   |


## 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:

```yaml
version: "3.7"
services:
  mqtt-adapter:
    image: mainflux/mqtt:latest
    container_name: mainflux-mqtt
    depends_on:
      - vernemq
      - things
      - nats
    restart: on-failure
    environment:
      MF_MQTT_ADAPTER_LOG_LEVEL: ${MF_MQTT_ADAPTER_LOG_LEVEL}
      MF_MQTT_ADAPTER_MQTT_PORT: ${MF_MQTT_ADAPTER_MQTT_PORT}
      MF_MQTT_ADAPTER_WS_PORT: ${MF_MQTT_ADAPTER_WS_PORT}
      MF_MQTT_ADAPTER_ES_URL: es-redis:${MF_REDIS_TCP_PORT}
      MF_NATS_URL: ${MF_NATS_URL}
      MF_MQTT_ADAPTER_MQTT_TARGET_HOST: vernemq
      MF_MQTT_ADAPTER_MQTT_TARGET_PORT: ${MF_MQTT_BROKER_PORT}
      MF_MQTT_ADAPTER_MQTT_TARGET_HEALTH_CHECK: http://vernemq:8888/health
      MF_MQTT_ADAPTER_WS_TARGET_HOST: vernemq
      MF_MQTT_ADAPTER_WS_TARGET_PORT: ${MF_MQTT_BROKER_WS_PORT}
      MF_JAEGER_URL: ${MF_JAEGER_URL}
      MF_THINGS_AUTH_GRPC_URL: ${MF_THINGS_AUTH_GRPC_URL}
      MF_THINGS_AUTH_GRPC_TIMEOUT: ${MF_THINGS_AUTH_GRPC_TIMEOUT}
      MF_AUTH_CACHE: things-redis:${MF_REDIS_TCP_PORT}
```

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

```bash
# download the latest version of the service
git clone https://github.com/mainflux/mainflux

cd mainflux

# compile the mqtt
make mqtt

# copy binary to bin
make install

# set the environment variables and run the service
MF_MQTT_ADAPTER_LOG_LEVEL=[MQTT Adapter Log Level] \
MF_MQTT_ADAPTER_MQTT_PORT=[MQTT adapter MQTT port]
MF_MQTT_ADAPTER_MQTT_TARGET_HOST=[MQTT broker host] \
MF_MQTT_ADAPTER_MQTT_TARGET_PORT=[MQTT broker MQTT port]] \
MF_MQTT_ADAPTER_MQTT_TARGET_HEALTH_CHECK=[MQTT health check URL] \
MF_MQTT_ADAPTER_WS_PORT=[MQTT adapter WS port] \
MF_MQTT_ADAPTER_WS_TARGET_HOST=[MQTT broker for MQTT over WS host] \
MF_MQTT_ADAPTER_WS_TARGET_PORT=[MQTT broker for MQTT over WS port]] \
MF_MQTT_ADAPTER_WS_TARGET_PATH=[MQTT adapter WS path] \
MF_MQTT_ADAPTER_FORWARDER_TIMEOUT=[MQTT forwarder for multiprotocol support timeout] \
MF_NATS_URL=[NATS instance URL] \
MF_THINGS_AUTH_GRPC_URL=[Things service Auth gRPC URL] \
MF_THINGS_AUTH_GRPC_TIMEOUT=[Things service Auth gRPC request timeout in seconds] \
MF_JAEGER_URL=[Jaeger service URL] \
MF_MQTT_ADAPTER_CLIENT_TLS=[gRPC client TLS] \
MF_MQTT_ADAPTER_CA_CERTS=[CA certs for gRPC client] \
MF_MQTT_ADAPTER_INSTANCE=[Instance for event sourcing] \
MF_MQTT_ADAPTER_ES_URL=[Event sourcing URL] \
MF_MQTT_ADAPTER_ES_PASS=[Event sourcing pass] \
MF_MQTT_ADAPTER_ES_DB=[Event sourcing database] \
MF_AUTH_CACHE_URL=[Auth cache URL] \
MF_AUTH_CACHE_PASS=[Auth cache pass] \
MF_AUTH_CACHE_DB=[Auth cache DB name] \
$GOBIN/mainflux-mqtt
```