apisix/doc/plugins/mqtt-proxy.md

<!--
#
# Licensed to the Apache Software Foundation (ASF) under one or more
# contributor license agreements.  See the NOTICE file distributed with
# this work for additional information regarding copyright ownership.
# The ASF licenses this file to You under the Apache License, Version 2.0
# (the "License"); you may not use this file except in compliance with
# the License.  You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
-->

[中文](mqtt-proxy-cn.md)

# Summary
- [**Name**](#name)
- [**Attributes**](#attributes)
- [**How To Enable**](#how-to-enable)
- [**Test Plugin**](#test-plugin)
- [**Disable Plugin**](#disable-plugin)


## Name

The plugin `mqtt-proxy` only works in stream model, it help you to dynamic load
balance by `client_id` of MQTT.

And this plugin both support MQTT protocol [3.1.*](http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html) and [5.0](https://docs.oasis-open.org/mqtt/mqtt/v5.0/mqtt-v5.0.html).

## Attributes

|name          |option  |description|
|---------     |--------|-----------|
|protocol_name |require |Name of protocol, shoulds be `MQTT` in normal.|
|protocol_level|require |Level of protocol, it should be `4` for MQTT `3.1.*`. it should be `5` for MQTT `5.0`.|
|upstream.ip   |require |IP address of upstream, will forward current request to.|
|upstream.port |require |Port of upstream, will forward current request to.|


## How To Enable

To enable this plugin, we need to enable the stream_proxy configuration in `conf/config.yaml` first.
For example, the following configuration represents listening on the 9100 TCP port.

```yaml
    ...
    router:
        http: 'radixtree_uri'
        ssl: 'radixtree_sni'
    stream_proxy:                 # TCP/UDP proxy
      tcp:                        # TCP proxy port list
        - 9100
    dns_resolver:
    ...
```

Then send the MQTT request to port 9100.

Creates a stream route, and enable plugin `mqtt-proxy`.

```shell
curl http://127.0.0.1:9080/apisix/admin/stream_routes/1 -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d '
{
    "remote_addr": "127.0.0.1",
    "plugins": {
        "mqtt-proxy": {
            "protocol_name": "MQTT",
            "protocol_level": 4,
            "upstream": {
                "ip": "127.0.0.1",
                "port": 1980
            }
        }
    }
}'
```

## Delete Plugin

```shell
$ curl http://127.0.0.1:2379/v2/keys/apisix/stream_routes/1 -X DELETE
```

The `mqtt-proxy` plugin has been deleted now.