# Plugin Development Guide

## 1. Prerequisites

### Development Tools
- Visual Studio Code
- Goland
- Cursor

### Install gRPC
```shell
$ go install google.golang.org/protobuf/cmd/protoc-gen-go@v1.28
$ go install google.golang.org/grpc/cmd/protoc-gen-go-grpc@v1.2
```

### Install gRPC-Gateway
```shell
$ go install github.com/grpc-ecosystem/grpc-gateway/v2/protoc-gen-grpc-gateway@latest
$ go install google.golang.org/protobuf/cmd/protoc-gen-go@latest
$ go install google.golang.org/grpc/cmd/protoc-gen-go-grpc@latest
```

### Project Setup
- Create a Go project, e.g., `MyPlugin`
- Create a `pkg` directory for exportable code
- Create a `pb` directory for gRPC proto files
- Create an `example` directory for testing the plugin

> You can also create a directory `xxx` directly in the monibuca project's plugin folder to store your plugin code

## 2. Create a Plugin

```go
package plugin_myplugin
import (
    "m7s.live/v5"
)

var _ = m7s.InstallPlugin[MyPlugin]()

type MyPlugin struct {
    m7s.Plugin
    Foo string
}
```
- `MyPlugin` struct is the plugin definition, `Foo` is a plugin property that can be configured in the configuration file
- Must embed `m7s.Plugin` struct to provide basic plugin functionality
- `m7s.InstallPlugin[MyPlugin](...)` registers the plugin so it can be loaded by monibuca

### Provide Default Configuration
Example:
```go
const defaultConfig = m7s.DefaultYaml(`tcp:
  listenaddr: :5554`)

var _ = m7s.InstallPlugin[MyPlugin](defaultConfig)
```

## 3. Implement Event Callbacks (Optional)

### Initialization Callback
```go
func (config *MyPlugin) OnInit() (err error) {
    // Initialize things
    return
}
```
Used for plugin initialization after configuration is loaded. Return an error if initialization fails, and the plugin will be disabled.

### TCP Request Callback
```go
func (config *MyPlugin) OnTCPConnect(conn *net.TCPConn) task.ITask {
    
}
```
Called when receiving TCP connection requests if TCP listening port is configured.

### UDP Request Callback
```go
func (config *MyPlugin) OnUDPConnect(conn *net.UDPConn) task.ITask {

}
```
Called when receiving UDP connection requests if UDP listening port is configured.

### QUIC Request Callback
```go
func (config *MyPlugin) OnQUICConnect(quic.Connection) task.ITask {

}
```
Called when receiving QUIC connection requests if QUIC listening port is configured.

## 4. HTTP Interface Callbacks

### Legacy v4 Callback Style
```go
func (config *MyPlugin) API_test1(rw http.ResponseWriter, r *http.Request) {
    // do something
}
```
Accessible via `http://ip:port/myplugin/api/test1`

### Route Mapping Configuration
This method supports parameterized routing:
```go
func (config *MyPlugin) RegisterHandler() map[string]http.HandlerFunc {
    return map[string]http.HandlerFunc{
        "/test1/{streamPath...}": config.test1,
    }
}
func (config *MyPlugin) test1(rw http.ResponseWriter, r *http.Request) {
    streamPath := r.PathValue("streamPath")
    // do something
}
```

## 5. Implement Push/Pull Clients

### Implement Push Client
Push client needs to implement IPusher interface and pass the creation method to InstallPlugin.
```go
type Pusher struct {
    pullCtx m7s.PullJob
}

func (c *Pusher) GetPullJob() *m7s.PullJob {
    return &c.pullCtx
}

func NewPusher(_ config.Push) m7s.IPusher {
    return &Pusher{}
}
var _ = m7s.InstallPlugin[MyPlugin](NewPusher)
```

### Implement Pull Client
Pull client needs to implement IPuller interface and pass the creation method to InstallPlugin.
The following Puller inherits from m7s.HTTPFilePuller for basic file and HTTP pulling:
```go
type Puller struct {
    m7s.HTTPFilePuller
}

func NewPuller(_ config.Pull) m7s.IPuller {
    return &Puller{}
}
var _ = m7s.InstallPlugin[MyPlugin](NewPuller)
```

## 6. Implement gRPC Service

### Create `myplugin.proto` in `pb` Directory
```proto
syntax = "proto3";
import "google/api/annotations.proto";
import "google/protobuf/empty.proto";
package myplugin;
option go_package="m7s.live/v5/plugin/myplugin/pb";

service api {
    rpc MyMethod (MyRequest) returns (MyResponse) {
        option (google.api.http) = {
            post: "/myplugin/api/bar"
            body: "foo"
        };
    }
}
message MyRequest {
    string foo = 1;
}
message MyResponse {
    string bar = 1;
}
```

### Generate gRPC Code
Add to VSCode task.json:
```json
{
    "type": "shell",
    "label": "build pb myplugin",
    "command": "protoc",
    "args": [
        "-I.",
        "-I${workspaceRoot}/pb",
        "--go_out=.",
        "--go_opt=paths=source_relative",
        "--go-grpc_out=.",
        "--go-grpc_opt=paths=source_relative",
        "--grpc-gateway_out=.",
        "--grpc-gateway_opt=paths=source_relative",
        "myplugin.proto"
    ],
    "options": {
        "cwd": "${workspaceRoot}/plugin/myplugin/pb"
    }
}
```
Or run command in pb directory:
```shell
protoc -I. -I$ProjectFileDir$/pb --go_out=. --go_opt=paths=source_relative --go-grpc_out=. --go-grpc_opt=paths=source_relative --grpc-gateway_out=. --grpc-gateway_opt=paths=source_relative  myplugin.proto
```
Replace `$ProjectFileDir$` with the directory containing global pb files.

### Implement gRPC Service
Create api.go:
```go
package plugin_myplugin
import (
    "context"
    "m7s.live/m7s/v5"
    "m7s.live/m7s/v5/plugin/myplugin/pb"
)

func (config *MyPlugin) MyMethod(ctx context.Context, req *pb.MyRequest) (*pb.MyResponse, error) {
    return &pb.MyResponse{Bar: req.Foo}, nil
}
```

### Register gRPC Service
```go
package plugin_myplugin
import (
    "m7s.live/v5"
    "m7s.live/v5/plugin/myplugin/pb"
)

var _ = m7s.InstallPlugin[MyPlugin](&pb.Api_ServiceDesc, pb.RegisterApiHandler)

type MyPlugin struct {
    pb.UnimplementedApiServer
    m7s.Plugin
    Foo string
}
```

### Additional RESTful Endpoints
Same as v4:
```go
func (config *MyPlugin) API_test1(rw http.ResponseWriter, r *http.Request) {
    // do something
}
```
Accessible via GET request to `/myplugin/api/test1`

## 7. Publishing Streams

```go
publisher, err = p.Publish(streamPath, connectInfo)
```
The last two parameters are optional.

After obtaining the `publisher`, you can publish audio/video data using `publisher.WriteAudio` and `publisher.WriteVideo`.

### Define Audio/Video Data
If existing audio/video data formats don't meet your needs, you can define custom formats by implementing this interface:
```go
IAVFrame interface {
    GetAllocator() *util.ScalableMemoryAllocator
    SetAllocator(*util.ScalableMemoryAllocator)
    Parse(*AVTrack) error
    ConvertCtx(codec.ICodecCtx) (codec.ICodecCtx, IAVFrame, error)
    Demux(codec.ICodecCtx) (any, error)
    Mux(codec.ICodecCtx, *AVFrame)
    GetTimestamp() time.Duration
    GetCTS() time.Duration
    GetSize() int
    Recycle()
    String() string
    Dump(byte, io.Writer)
}
```
> Define separate types for audio and video

- GetAllocator/SetAllocator: Automatically implemented when embedding RecyclableMemory
- Parse: Identifies key frames, sequence frames, and other important information
- ConvertCtx: Called when protocol conversion is needed
- Demux: Called when audio/video data needs to be demuxed
- Mux: Called when audio/video data needs to be muxed
- Recycle: Automatically implemented when embedding RecyclableMemory
- String: Prints audio/video data information
- GetSize: Gets the size of audio/video data
- GetTimestamp: Gets the timestamp in nanoseconds
- GetCTS: Gets the Composition Time Stamp in nanoseconds (PTS = DTS+CTS)
- Dump: Prints binary audio/video data

## 8. Subscribing to Streams
```go
var suber *m7s.Subscriber
suber, err = p.Subscribe(ctx,streamPath)
go m7s.PlayBlock(suber, handleAudio, handleVideo)
```
Note that handleAudio and handleVideo are callback functions you need to implement. They take an audio/video format type as input and return an error. If the error is not nil, the subscription is terminated.

## 9. Prometheus Integration
Just implement the Collector interface, and the system will automatically collect metrics from all plugins:
```go
func (p *MyPlugin) Describe(ch chan<- *prometheus.Desc) {
  
}

func (p *MyPlugin) Collect(ch chan<- prometheus.Metric) {
  
}
```