plugin

README

Plugins

Go plugins is a place for community maintained plugins.

Overview

Micro tooling is built on a powerful pluggable architecture. Plugins can be swapped out with zero code changes. This repository contains plugins for all micro related tools. Read on for further info.

Check out the Micro on NATS blog post to learn more about plugins.

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Getting Started

• Contents
• Usage
• Build Pattern
• Contributions

Contents

Contents of this repository:

Directory	Description
Broker	PubSub messaging; NATS, NSQ, RabbitMQ, Kafka
Client	RPC Clients; gRPC, HTTP
Codec	Message Encoding; BSON, Mercury
Micro	Micro Toolkit Plugins
Registry	Service Discovery; Etcd, Gossip, NATS
Selector	Load balancing; Label, Cache, Static
Server	RPC Servers; gRPC, HTTP
Transport	Bidirectional Streaming; NATS, RabbitMQ
Wrapper	Middleware; Circuit Breakers, Rate Limiting, Tracing, Monitoring

Usage

Plugins can be added to go-micro in the following ways. By doing so they'll be available to set via command line args or environment variables.

Import the plugins in a Go program then call service.Init to parse the command line and environment variables.

import (
	"github.com/micro/go-micro"
	_ "github.com/micro/go-plugins/broker/rabbitmq"
	_ "github.com/micro/go-plugins/registry/kubernetes"
	_ "github.com/micro/go-plugins/transport/nats"
)

func main() {
	service := micro.NewService(
		// Set service name
		micro.Name("my.service"),
	)

	// Parse CLI flags
	service.Init()
}

Flags

Specify the plugins as flags

go run service.go --broker=rabbitmq --registry=kubernetes --transport=nats

Env

Use env vars to specify the plugins

MICRO_BROKER=rabbitmq \
MICRO_REGISTRY=kubernetes \ 
MICRO_TRANSPORT=nats \ 
go run service.go

Options

Import and set as options when creating a new service

import (
	"github.com/micro/go-micro"
	"github.com/micro/go-plugins/registry/kubernetes"
)

func main() {
	registry := kubernetes.NewRegistry() //a default to using env vars for master API

	service := micro.NewService(
		// Set service name
		micro.Name("my.service"),
		// Set service registry
		micro.Registry(registry),
	)
}

Build

An anti-pattern is modifying the main.go file to include plugins. Best practice recommendation is to include plugins in a separate file and rebuild with it included. This allows for automation of building plugins and clean separation of concerns.

Create file plugins.go

package main

import (
	_ "github.com/micro/go-plugins/broker/rabbitmq"
	_ "github.com/micro/go-plugins/registry/kubernetes"
	_ "github.com/micro/go-plugins/transport/nats"
)

Build with plugins.go

go build -o service main.go plugins.go

Run with plugins

MICRO_BROKER=rabbitmq \
MICRO_REGISTRY=kubernetes \
MICRO_TRANSPORT=nats \
service

Contributions

A few contributions by others

Feature	Description	Author
Registry/Kubernetes	Service discovery via the Kubernetes API	@nickjackson
Registry/Zookeeper	Service discovery using Zookeeper	@HeavyHorst

Documentation

Overview

Package plugin provides the ability to load plugins

Index

• func Build(path string, p *Plugin) error
• func Generate(path string, p *Plugin) error
• func Init(p *Plugin) error
• type Plugin
  • func Load(path string) (*Plugin, error)

Functions

func Build

func Build(path string, p *Plugin) error

Build generates a dso plugin using the go command `go build -buildmode=plugin`

func Generate

func Generate(path string, p *Plugin) error

Generate creates a go file at the specified path. You must use `go build -buildmode=plugin`to build it.

func Init

func Init(p *Plugin) error

Init sets up the plugin

Types

type Plugin

type Plugin struct {
	// Name of the plugin e.g rabbitmq
	Name string
	// Type of the plugin e.g broker
	Type string
	// Path specifies the import path
	Path string
	// NewFunc creates an instance of the plugin
	NewFunc interface{}
}

Plugin is a plugin loaded from a file

func Load

func Load(path string) (*Plugin, error)

Load loads a plugin created with `go build -buildmode=plugin`