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Plugins

Plugins are implementations of Go Micro interfaces which can be used to replace the built in defaults.

Overview

At a high level plugins provide the opportunity to swap out underlying infrastructure and dependencies. This means a microservice can be written in one way and run locally with zero dependencies but then equally run as a highly resilient system in the cloud when using distributed systems to underpin its usage.

A full comprehensive list of plugins can be found at github.com/micro/go-plugins.

Directory Description
Broker PubSub messaging; NATS, NSQ, RabbitMQ, Kafka
Client RPC Clients; gRPC, HTTP
Codec Message Encoding; BSON, Mercury
Micro Micro Runtime 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 plugins.go file

package main

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

Create your service and ensure you call service.Init

package main

import (
	"github.com/micro/go-micro/v2"
)

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

	// Parse CLI flags
	service.Init()
}

Build your service

go build -o service ./main.go ./plugins.go

Env

Use environment variables to set the

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

Flags

Or use command line flags to enable them

./service --broker=rabbitmq --registry=kubernetes --transport=nats

Options

Import and set as options when creating a new service

import (
	"github.com/micro/go-micro/v2"
	"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

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