micro

README

Go Micro

Go Micro is a framework for micro service development.

Overview

Go Micro provides the core requirements for distributed systems development including RPC and Event driven communication. The micro philosophy is sane defaults with a pluggable architecture. We provide defaults to get you started quickly but everything can be easily swapped out.

Plugins are available at github.com/micro/go-plugins.

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Features

Go Micro abstracts away the details of distributed systems. Here are the main features.

• Service Discovery - Automatic service registration and name resolution. Service discovery is at the core of micro service development. When service A needs to speak to service B it needs the location of that service. The default discovery mechanism is multicast DNS (mdns), a zeroconf system. You can optionally set gossip using the SWIM protocol for p2p networks or consul for a resilient cloud-native setup.

• Load Balancing - Client side load balancing built on service discovery. Once we have the addresses of any number of instances of a service we now need a way to decide which node to route to. We use random hashed load balancing to provide even distribution across the services and retry a different node if there's a problem.

• Message Encoding - Dynamic message encoding based on content-type. The client and server will use codecs along with content-type to seamlessly encode and decode Go types for you. Any variety of messages could be encoded and sent from different clients. The client and server handle this by default. This includes protobuf and json by default.

• Sync Streaming - RPC based request/response with support for bidirectional streaming. We provide an abstraction for synchronous communication. A request made to a service will be automatically resolved, load balanced, dialled and streamed. The default transport is http/1.1 or http2 when tls is enabled.

• Async Messaging - PubSub is built in as a first class citizen for asynchronous communication and event driven architectures. Event notifications are a core pattern in micro service development. The default messaging is point-to-point http/1.1 or http2 when tls is enabled.

• Pluggable Interfaces - Go Micro makes use of Go interfaces for each distributed system abstraction. Because of this these interfaces are pluggable and allows Go Micro to be runtime agnostic. You can plugin any underlying technology. Find plugins in github.com/micro/go-plugins.

Getting Started

See the docs for detailed information on the architecture, installation and use of go-micro.

Sponsors

Sixt is an Enterprise Sponsor of Micro

Become a sponsor by backing micro on Patreon

Documentation

Overview

Package micro is a pluggable framework for microservices

Index

• Variables
• func NewContext(ctx context.Context, s Service) context.Context
• func RegisterHandler(s server.Server, h interface{}, opts ...server.HandlerOption) error
• func RegisterSubscriber(topic string, s server.Server, h interface{}, opts ...server.SubscriberOption) error
• type Function
  • func NewFunction(opts ...Option) Function
• type Option
  • func Action(a func(*cli.Context)) Option
  • func AfterStart(fn func() error) Option
  • func AfterStop(fn func() error) Option
  • func BeforeStart(fn func() error) Option
  • func BeforeStop(fn func() error) Option
  • func Broker(b broker.Broker) Option
  • func Client(c client.Client) Option
  • func Cmd(c cmd.Cmd) Option
  • func Context(ctx context.Context) Option
  • func Flags(flags ...cli.Flag) Option
  • func Metadata(md map[string]string) Option
  • func Name(n string) Option
  • func RegisterInterval(t time.Duration) Option
  • func RegisterTTL(t time.Duration) Option
  • func Registry(r registry.Registry) Option
  • func Selector(s selector.Selector) Option
  • func Server(s server.Server) Option
  • func Transport(t transport.Transport) Option
  • func Version(v string) Option
  • func WrapCall(w ...client.CallWrapper) Option
  • func WrapClient(w ...client.Wrapper) Option
  • func WrapHandler(w ...server.HandlerWrapper) Option
  • func WrapSubscriber(w ...server.SubscriberWrapper) Option
• type Options
• type Publisher
  • func NewPublisher(topic string, c client.Client) Publisher
• type Service
  • func FromContext(ctx context.Context) (Service, bool)
  • func NewService(opts ...Option) Service

Variables

var (
	HeaderPrefix = "Micro-"
)

Functions

func NewContext

func NewContext(ctx context.Context, s Service) context.Context

NewContext returns a new Context with the Service embedded within it.

func RegisterHandler

func RegisterHandler(s server.Server, h interface{}, opts ...server.HandlerOption) error

RegisterHandler is syntactic sugar for registering a handler

func RegisterSubscriber

func RegisterSubscriber(topic string, s server.Server, h interface{}, opts ...server.SubscriberOption) error

RegisterSubscriber is syntactic sugar for registering a subscriber

Types

type Function

type Function interface {
	// Inherits Service interface
	Service
	// Done signals to complete execution
	Done() error
	// Handle registers an RPC handler
	Handle(v interface{}) error
	// Subscribe registers a subscriber
	Subscribe(topic string, v interface{}) error
}

Function is a one time executing Service

func NewFunction

func NewFunction(opts ...Option) Function

NewFunction returns a new Function for a one time executing Service

type Option

type Option func(*Options)

func Action

func Action(a func(*cli.Context)) Option

func AfterStart

func AfterStart(fn func() error) Option

func AfterStop

func AfterStop(fn func() error) Option

func BeforeStart

func BeforeStart(fn func() error) Option

func BeforeStop

func BeforeStop(fn func() error) Option

func Broker

func Broker(b broker.Broker) Option

func Client

func Client(c client.Client) Option

func Cmd

func Cmd(c cmd.Cmd) Option

func Context

func Context(ctx context.Context) Option

Context specifies a context for the service. Can be used to signal shutdown of the service. Can be used for extra option values.

func Flags

func Flags(flags ...cli.Flag) Option

func Metadata

func Metadata(md map[string]string) Option

Metadata associated with the service

func Name

func Name(n string) Option

Name of the service

func RegisterInterval

func RegisterInterval(t time.Duration) Option

RegisterInterval specifies the interval on which to re-register

func RegisterTTL

func RegisterTTL(t time.Duration) Option

RegisterTTL specifies the TTL to use when registering the service

func Registry

func Registry(r registry.Registry) Option

Registry sets the registry for the service and the underlying components

func Selector

func Selector(s selector.Selector) Option

Selector sets the selector for the service client

func Server

func Server(s server.Server) Option

func Transport

func Transport(t transport.Transport) Option

Transport sets the transport for the service and the underlying components

func Version

func Version(v string) Option

Version of the service

func WrapCall

func WrapCall(w ...client.CallWrapper) Option

WrapCall is a convenience method for wrapping a Client CallFunc

func WrapClient

func WrapClient(w ...client.Wrapper) Option

WrapClient is a convenience method for wrapping a Client with some middleware component. A list of wrappers can be provided. Wrappers are applied in reverse order so the last is executed first.

func WrapHandler

func WrapHandler(w ...server.HandlerWrapper) Option

WrapHandler adds a handler Wrapper to a list of options passed into the server

func WrapSubscriber

func WrapSubscriber(w ...server.SubscriberWrapper) Option

WrapSubscriber adds a subscriber Wrapper to a list of options passed into the server

type Options

type Options struct {
	Broker    broker.Broker
	Cmd       cmd.Cmd
	Client    client.Client
	Server    server.Server
	Registry  registry.Registry
	Transport transport.Transport

	// Before and After funcs
	BeforeStart []func() error
	BeforeStop  []func() error
	AfterStart  []func() error
	AfterStop   []func() error

	// Other options for implementations of the interface
	// can be stored in a context
	Context context.Context
}

type Publisher

type Publisher interface {
	Publish(ctx context.Context, msg interface{}, opts ...client.PublishOption) error
}

Publisher is syntactic sugar for publishing

func NewPublisher

func NewPublisher(topic string, c client.Client) Publisher

NewPublisher returns a new Publisher

type Service

type Service interface {
	Init(...Option)
	Options() Options
	Client() client.Client
	Server() server.Server
	Run() error
	String() string
}

Service is an interface that wraps the lower level libraries within go-micro. Its a convenience method for building and initialising services.

func FromContext

func FromContext(ctx context.Context) (Service, bool)

FromContext retrieves a Service from the Context.

func NewService

func NewService(opts ...Option) Service

NewService creates and returns a new Service based on the packages within.