micro/server/server.go
2019-02-15 16:14:41 +00:00

207 lines
5.1 KiB
Go

// Package server is an interface for a micro server
package server
import (
"context"
"os"
"os/signal"
"syscall"
"github.com/google/uuid"
"github.com/micro/go-log"
"github.com/micro/go-micro/codec"
"github.com/micro/go-micro/registry"
)
// Server is a simple micro server abstraction
type Server interface {
Options() Options
Init(...Option) error
Handle(Handler) error
NewHandler(interface{}, ...HandlerOption) Handler
NewSubscriber(string, interface{}, ...SubscriberOption) Subscriber
Subscribe(Subscriber) error
Start() error
Stop() error
String() string
}
// Router handle serving messages
type Router interface {
// ServeRequest processes a request to completion
ServeRequest(context.Context, Request, Response) error
}
// Message is an async message interface
type Message interface {
Topic() string
Payload() interface{}
ContentType() string
}
// Request is a synchronous request interface
type Request interface {
// Service name requested
Service() string
// The action requested
Method() string
// Endpoint name requested
Endpoint() string
// Content type provided
ContentType() string
// Header of the request
Header() map[string]string
// Body is the initial decoded value
Body() interface{}
// Read the undecoded request body
Read() ([]byte, error)
// The encoded message stream
Codec() codec.Reader
// Indicates whether its a stream
Stream() bool
}
// Response is the response writer for unencoded messages
type Response interface {
// Encoded writer
Codec() codec.Writer
// Write the header
WriteHeader(map[string]string)
// write a response directly to the client
Write([]byte) error
}
// Stream represents a stream established with a client.
// A stream can be bidirectional which is indicated by the request.
// The last error will be left in Error().
// EOF indicates end of the stream.
type Stream interface {
Context() context.Context
Request() Request
Send(interface{}) error
Recv(interface{}) error
Error() error
Close() error
}
// Handler interface represents a request handler. It's generated
// by passing any type of public concrete object with endpoints into server.NewHandler.
// Most will pass in a struct.
//
// Example:
//
// type Greeter struct {}
//
// func (g *Greeter) Hello(context, request, response) error {
// return nil
// }
//
type Handler interface {
Name() string
Handler() interface{}
Endpoints() []*registry.Endpoint
Options() HandlerOptions
}
// Subscriber interface represents a subscription to a given topic using
// a specific subscriber function or object with endpoints.
type Subscriber interface {
Topic() string
Subscriber() interface{}
Endpoints() []*registry.Endpoint
Options() SubscriberOptions
}
type Option func(*Options)
var (
DefaultAddress = ":0"
DefaultName = "server"
DefaultVersion = "latest"
DefaultId = uuid.New().String()
DefaultServer Server = newRpcServer()
DefaultRouter = newRpcRouter()
)
// DefaultOptions returns config options for the default service
func DefaultOptions() Options {
return DefaultServer.Options()
}
// Init initialises the default server with options passed in
func Init(opt ...Option) {
if DefaultServer == nil {
DefaultServer = newRpcServer(opt...)
}
DefaultServer.Init(opt...)
}
// NewServer returns a new server with options passed in
func NewServer(opt ...Option) Server {
return newRpcServer(opt...)
}
// NewSubscriber creates a new subscriber interface with the given topic
// and handler using the default server
func NewSubscriber(topic string, h interface{}, opts ...SubscriberOption) Subscriber {
return DefaultServer.NewSubscriber(topic, h, opts...)
}
// NewHandler creates a new handler interface using the default server
// Handlers are required to be a public object with public
// endpoints. Call to a service endpoint such as Foo.Bar expects
// the type:
//
// type Foo struct {}
// func (f *Foo) Bar(ctx, req, rsp) error {
// return nil
// }
//
func NewHandler(h interface{}, opts ...HandlerOption) Handler {
return DefaultServer.NewHandler(h, opts...)
}
// Handle registers a handler interface with the default server to
// handle inbound requests
func Handle(h Handler) error {
return DefaultServer.Handle(h)
}
// Subscribe registers a subscriber interface with the default server
// which subscribes to specified topic with the broker
func Subscribe(s Subscriber) error {
return DefaultServer.Subscribe(s)
}
// Run starts the default server and waits for a kill
// signal before exiting. Also registers/deregisters the server
func Run() error {
if err := Start(); err != nil {
return err
}
ch := make(chan os.Signal, 1)
signal.Notify(ch, syscall.SIGTERM, syscall.SIGINT, syscall.SIGKILL)
log.Logf("Received signal %s", <-ch)
return Stop()
}
// Start starts the default server
func Start() error {
config := DefaultServer.Options()
log.Logf("Starting server %s id %s", config.Name, config.Id)
return DefaultServer.Start()
}
// Stop stops the default server
func Stop() error {
log.Logf("Stopping server")
return DefaultServer.Stop()
}
// String returns name of Server implementation
func String() string {
return DefaultServer.String()
}