server

Documentation

Overview

Package server is an interface for a micro server

Index

• Variables
• func Handle(h Handler) error
• func Init(opt ...Option)
• func NewContext(ctx context.Context, s Server) context.Context
• func Run() error
• func Start() error
• func Stop() error
• func String() string
• func Subscribe(s Subscriber) error
• type Debug
• type Handler
  • func NewHandler(h interface{}, opts ...HandlerOption) Handler
• type HandlerFunc
• type HandlerOption
  • func EndpointMetadata(name string, md map[string]string) HandlerOption
  • func InternalHandler(b bool) HandlerOption
• type HandlerOptions
• type HandlerWrapper
• type Message
• type Option
  • func Address(a string) Option
  • func Advertise(a string) Option
  • func Broker(b broker.Broker) Option
  • func Codec(contentType string, c codec.NewCodec) Option
  • func DebugHandler(d debug.DebugHandler) Option
  • func Id(id string) Option
  • func Metadata(md map[string]string) Option
  • func Name(n string) Option
  • func RegisterCheck(fn func(context.Context) error) Option
  • func RegisterInterval(t time.Duration) Option
  • func RegisterTTL(t time.Duration) Option
  • func Registry(r registry.Registry) Option
  • func Transport(t transport.Transport) Option
  • func Version(v string) Option
  • func Wait(wg *sync.WaitGroup) Option
  • func WithRouter(r Router) Option
  • func WrapHandler(w HandlerWrapper) Option
  • func WrapSubscriber(w SubscriberWrapper) Option
• type Options
  • func DefaultOptions() Options
• type Request
• type Response
• type Router
• type Server
  • func FromContext(ctx context.Context) (Server, bool)
  • func NewServer(opt ...Option) Server
• type Stream
• type StreamWrapper
• type Subscriber
  • func NewSubscriber(topic string, h interface{}, opts ...SubscriberOption) Subscriber
• type SubscriberFunc
• type SubscriberOption
  • func DisableAutoAck() SubscriberOption
  • func InternalSubscriber(b bool) SubscriberOption
  • func SubscriberContext(ctx context.Context) SubscriberOption
  • func SubscriberQueue(n string) SubscriberOption
• type SubscriberOptions
  • func NewSubscriberOptions(opts ...SubscriberOption) SubscriberOptions
• type SubscriberWrapper

Variables

var (
	DefaultContentType = "application/protobuf"

	DefaultCodecs = map[string]codec.NewCodec{
		"application/grpc":         grpc.NewCodec,
		"application/grpc+json":    grpc.NewCodec,
		"application/grpc+proto":   grpc.NewCodec,
		"application/json":         json.NewCodec,
		"application/json-rpc":     jsonrpc.NewCodec,
		"application/protobuf":     proto.NewCodec,
		"application/proto-rpc":    protorpc.NewCodec,
		"application/octet-stream": raw.NewCodec,
	}
)

var (
	DefaultAddress              = ":0"
	DefaultName                 = "server"
	DefaultVersion              = "latest"
	DefaultId                   = uuid.New().String()
	DefaultServer        Server = newRpcServer()
	DefaultRouter               = newRpcRouter()
	DefaultRegisterCheck        = func(context.Context) error { return nil }
)

Functions

func Handle

func Handle(h Handler) error

Handle registers a handler interface with the default server to handle inbound requests

func Init

func Init(opt ...Option)

Init initialises the default server with options passed in

func NewContext

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

func Run

func Run() error

Run starts the default server and waits for a kill signal before exiting. Also registers/deregisters the server

func Start

func Start() error

Start starts the default server

func Stop

func Stop() error

Stop stops the default server

func String

func String() string

String returns name of Server implementation

func Subscribe

func Subscribe(s Subscriber) error

Subscribe registers a subscriber interface with the default server which subscribes to specified topic with the broker

Types

type Debug

type Debug struct {
	debug.DebugHandler
}

We use this to wrap any debug handlers so we preserve the signature Debug.{Method}

type Handler

type Handler interface {
	Name() string
	Handler() interface{}
	Endpoints() []*registry.Endpoint
	Options() HandlerOptions
}

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
}

func NewHandler

func NewHandler(h interface{}, opts ...HandlerOption) Handler

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
}

type HandlerFunc

type HandlerFunc func(ctx context.Context, req Request, rsp interface{}) error

HandlerFunc represents a single method of a handler. It's used primarily for the wrappers. What's handed to the actual method is the concrete request and response types.

type HandlerOption

type HandlerOption func(*HandlerOptions)

func EndpointMetadata

func EndpointMetadata(name string, md map[string]string) HandlerOption

EndpointMetadata is a Handler option that allows metadata to be added to individual endpoints.

func InternalHandler

func InternalHandler(b bool) HandlerOption

Internal Handler options specifies that a handler is not advertised to the discovery system. In the future this may also limit request to the internal network or authorised user.

type HandlerOptions

type HandlerOptions struct {
	Internal bool
	Metadata map[string]map[string]string
}

type HandlerWrapper

type HandlerWrapper func(HandlerFunc) HandlerFunc

HandlerWrapper wraps the HandlerFunc and returns the equivalent

type Message

type Message interface {
	Topic() string
	Payload() interface{}
	ContentType() string
}

Message is an async message interface

type Option

type Option func(*Options)

func Address

func Address(a string) Option

Address to bind to - host:port

func Advertise

func Advertise(a string) Option

The address to advertise for discovery - host:port

func Broker

func Broker(b broker.Broker) Option

Broker to use for pub/sub

func Codec

func Codec(contentType string, c codec.NewCodec) Option

Codec to use to encode/decode requests for a given content type

func DebugHandler

func DebugHandler(d debug.DebugHandler) Option

DebugHandler for this server

func Id

func Id(id string) Option

Unique server id

func Metadata

func Metadata(md map[string]string) Option

Metadata associated with the server

func Name

func Name(n string) Option

Server name

func RegisterCheck

func RegisterCheck(fn func(context.Context) error) Option

RegisterCheck run func before registry service

func RegisterInterval

func RegisterInterval(t time.Duration) Option

Register the service with at interval

func RegisterTTL

func RegisterTTL(t time.Duration) Option

Register the service with a TTL

func Registry

func Registry(r registry.Registry) Option

Registry used for discovery

func Transport

func Transport(t transport.Transport) Option

Transport mechanism for communication e.g http, rabbitmq, etc

func Version

func Version(v string) Option

Version of the service

func Wait

func Wait(wg *sync.WaitGroup) Option

Wait tells the server to wait for requests to finish before exiting If `wg` is nil, server only wait for completion of rpc handler. For user need finer grained control, pass a concrete `wg` here, server will wait against it on stop.

func WithRouter

func WithRouter(r Router) Option

WithRouter sets the request router

func WrapHandler

func WrapHandler(w HandlerWrapper) Option

Adds a handler Wrapper to a list of options passed into the server

func WrapSubscriber

func WrapSubscriber(w SubscriberWrapper) Option

Adds a subscriber Wrapper to a list of options passed into the server

type Options

type Options struct {
	Codecs       map[string]codec.NewCodec
	Broker       broker.Broker
	Registry     registry.Registry
	Transport    transport.Transport
	Metadata     map[string]string
	Name         string
	Address      string
	Advertise    string
	Id           string
	Version      string
	HdlrWrappers []HandlerWrapper
	SubWrappers  []SubscriberWrapper

	// RegisterCheck runs a check function before registering the service
	RegisterCheck func(context.Context) error
	// The register expiry time
	RegisterTTL time.Duration
	// The interval on which to register
	RegisterInterval time.Duration

	// The router for requests
	Router Router

	// Debug Handler which can be set by a user
	DebugHandler debug.DebugHandler

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

func DefaultOptions

func DefaultOptions() Options

DefaultOptions returns config options for the default service

type Request

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
}

Request is a synchronous request interface

type Response

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
}

Response is the response writer for unencoded messages

type Router

type Router interface {
	// ServeRequest processes a request to completion
	ServeRequest(context.Context, Request, Response) error
}

Router handle serving messages

type Server

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
}

Server is a simple micro server abstraction

func FromContext

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

func NewServer

func NewServer(opt ...Option) Server

NewServer returns a new server with options passed in

type Stream

type Stream interface {
	Context() context.Context
	Request() Request
	Send(interface{}) error
	Recv(interface{}) error
	Error() error
	Close() 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 StreamWrapper

type StreamWrapper func(Stream) Stream

StreamWrapper wraps a Stream interface and returns the equivalent. Because streams exist for the lifetime of a method invocation this is a convenient way to wrap a Stream as its in use for trace, monitoring, metrics, etc.

type Subscriber

type Subscriber interface {
	Topic() string
	Subscriber() interface{}
	Endpoints() []*registry.Endpoint
	Options() SubscriberOptions
}

Subscriber interface represents a subscription to a given topic using a specific subscriber function or object with endpoints.

func NewSubscriber

func NewSubscriber(topic string, h interface{}, opts ...SubscriberOption) Subscriber

NewSubscriber creates a new subscriber interface with the given topic and handler using the default server

type SubscriberFunc

type SubscriberFunc func(ctx context.Context, msg Message) error

SubscriberFunc represents a single method of a subscriber. It's used primarily for the wrappers. What's handed to the actual method is the concrete publication message.

type SubscriberOption

type SubscriberOption func(*SubscriberOptions)

func DisableAutoAck

func DisableAutoAck() SubscriberOption

DisableAutoAck will disable auto acking of messages after they have been handled.

func InternalSubscriber

func InternalSubscriber(b bool) SubscriberOption

Internal Subscriber options specifies that a subscriber is not advertised to the discovery system.

func SubscriberContext

func SubscriberContext(ctx context.Context) SubscriberOption

SubscriberContext set context options to allow broker SubscriberOption passed

func SubscriberQueue

func SubscriberQueue(n string) SubscriberOption

Shared queue name distributed messages across subscribers

type SubscriberOptions

type SubscriberOptions struct {
	// AutoAck defaults to true. When a handler returns
	// with a nil error the message is acked.
	AutoAck  bool
	Queue    string
	Internal bool
	Context  context.Context
}

func NewSubscriberOptions

func NewSubscriberOptions(opts ...SubscriberOption) SubscriberOptions

type SubscriberWrapper

type SubscriberWrapper func(SubscriberFunc) SubscriberFunc

SubscriberWrapper wraps the SubscriberFunc and returns the equivalent