server

package
v3.2.14 Latest Latest
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 Go to latest Published: Feb 18, 2021 License: Apache-2.0 Imports: 26 Imported by: 0

Documentation

Overview

Package server is an interface for a micro server

Index

Constants

This section is empty.

Variables

View Source 
var (
	// DefaultRegisterFunc uses backoff to register service
	DefaultRegisterFunc = func(svc *register.Service, config Options) error {
		var err error

		opts := []register.RegisterOption{
			register.RegisterTTL(config.RegisterTTL),
			register.RegisterDomain(config.Namespace),
		}

		for i := 0; i <= config.RegisterAttempts; i++ {
			err = config.Register.Register(config.Context, svc, opts...)
			if err == nil {
				break
			}

			time.Sleep(backoff.Do(i + 1))
			continue
		}
		return err
	}
	// DefaultDeregisterFunc uses backoff to deregister service
	DefaultDeregisterFunc = func(svc *register.Service, config Options) error {
		var err error

		opts := []register.DeregisterOption{
			register.DeregisterDomain(config.Namespace),
		}

		for i := 0; i <= config.DeregisterAttempts; i++ {
			err = config.Register.Deregister(config.Context, svc, opts...)
			if err == nil {
				break
			}

			time.Sleep(backoff.Do(i + 1))
			continue
		}
		return err
	}
)
View Source 
var (
	// DefaultAddress will be used if no address passed
	DefaultAddress = ":0"
	// DefaultName will be used if no name passed
	DefaultName = "server"
	// DefaultVersion will be used if no version passed
	DefaultVersion = "latest"
	// DefaultId will be used if no id passed
	DefaultId = uuid.New().String()
	// DefaultRegisterCheck holds func that run before register server
	DefaultRegisterCheck = func(context.Context) error { return nil }
	// DefaultRegisterInterval holds interval for register
	DefaultRegisterInterval = time.Second * 30
	// DefaultRegisterTTL holds register record ttl, must be multiple of DefaultRegisterInterval
	DefaultRegisterTTL = time.Second * 90
	// DefaultNamespace will be used if no namespace passed
	DefaultNamespace = "micro"
	// DefaultMaxMsgSize holds default max msg ssize
	DefaultMaxMsgSize = 1024 * 1024 * 4 // 4Mb
	// DefaultMaxMsgRecvSize holds default max recv size
	DefaultMaxMsgRecvSize = 1024 * 1024 * 4 // 4Mb
	// DefaultMaxMsgSendSize holds default max send size
	DefaultMaxMsgSendSize = 1024 * 1024 * 4 // 4Mb
)
View Source 
var (
	// DefaultCodecs will be used to encode/decode
	DefaultCodecs = map[string]codec.Codec{

		"application/octet-stream": codec.NewCodec(),
	}
)

Functions

func NewContext 

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

NewContext stores Server to context

func NewRegisterService added in v3.2.0 

func NewRegisterService(s Server) (*register.Service, error)

NewRegisterService returns *register.Service from Server

func ValidateSubscriber 

func ValidateSubscriber(sub Subscriber) error

ValidateSubscriber func

Types

type Handler 

type Handler interface {
	Name() string
	Handler() interface{}
	Endpoints() []*register.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
}

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)

HandlerOption func

func EndpointMetadata 

func EndpointMetadata(name string, md metadata.Metadata) HandlerOption

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

func InternalHandler 

func InternalHandler(b bool) HandlerOption

InternalHandler 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]metadata.Metadata
	Context  context.Context
}

HandlerOptions struct

func NewHandlerOptions 

func NewHandlerOptions(opts ...HandlerOption) HandlerOptions

NewHandlerOptions creates new HandlerOptions

type HandlerWrapper 

type HandlerWrapper func(HandlerFunc) HandlerFunc

HandlerWrapper wraps the HandlerFunc and returns the equivalent

type Message 

type Message interface {
	// Topic of the message
	Topic() string
	// The decoded payload value
	Payload() interface{}
	// The content type of the payload
	ContentType() string
	// The raw headers of the message
	Header() metadata.Metadata
	// The raw body of the message
	Body() []byte
	// Codec used to decode the message
	Codec() codec.Codec
}

Message is an async message interface

type Option 

type Option func(*Options)

Option func

func Address 

func Address(a string) Option

Address to bind to - host:port 

func Advertise(a string) Option

Advertise the address to advertise for discovery - host:port

func Auth 

func Auth(a auth.Auth) Option

Auth mechanism for role based access control

func Broker 

func Broker(b broker.Broker) Option

Broker to use for pub/sub

func Codec 

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

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

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 Id 

func Id(id string) Option

Id unique server id

func Listener added in v3.1.0 

func Listener(l net.Listener) Option

Listener specifies the net.Listener to use instead of the default

func Logger 

func Logger(l logger.Logger) Option

Logger sets the logger option

func MaxConn added in v3.1.0 

func MaxConn(n int) Option

MaxConn specifies maximum number of max simultaneous connections to server

func Metadata 

func Metadata(md metadata.Metadata) Option

Metadata associated with the server

func Meter added in v3.1.6 

func Meter(m meter.Meter) Option

Meter sets the meter option

func Name 

func Name(n string) Option

Name sets the server name option

func Namespace 

func Namespace(n string) Option

Namespace to register handlers in

func Register added in v3.2.0 

func Register(r register.Register) Option

Register used for discovery

func RegisterCheck 

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

RegisterCheck run func before register service

func RegisterInterval 

func RegisterInterval(t time.Duration) Option

RegisterInterval registers service with at interval

func RegisterTTL 

func RegisterTTL(t time.Duration) Option

RegisterTTL registers service with a TTL

func SetOption 

func SetOption(k, v interface{}) Option

SetOption returns a function to setup a context with given value

func TLSConfig 

func TLSConfig(t *tls.Config) Option

TLSConfig specifies a *tls.Config

func Tracer 

func Tracer(t tracer.Tracer) Option

Tracer mechanism for distributed tracking

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

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

func WrapSubscriber 

func WrapSubscriber(w SubscriberWrapper) Option

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

type Options 

type Options struct {
	Codecs       map[string]codec.Codec
	Broker       broker.Broker
	Register     register.Register
	Tracer       tracer.Tracer
	Auth         auth.Auth
	Logger       logger.Logger
	Meter        meter.Meter
	Transport    transport.Transport
	Metadata     metadata.Metadata
	Name         string
	Address      string
	Advertise    string
	Id           string
	Namespace    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
	// RegisterAttempts specify how many times try to register
	RegisterAttempts int
	// DeegisterAttempts specify how many times try to deregister
	DeregisterAttempts int

	// The router for requests
	Router Router

	// TLSConfig specifies tls.Config for secure serving
	TLSConfig *tls.Config

	Wait *sync.WaitGroup

	// Listener may be passed if already created
	Listener net.Listener
	// MaxConn limit connections to server
	MaxConn int
	// Other options for implementations of the interface
	// can be stored in a context
	Context context.Context
}

Options server struct

func NewOptions 

func NewOptions(opts ...Option) Options

NewOptions returns new options struct with default or passed values

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() metadata.Metadata
	// Body is the initial decoded value
	Body() interface{}
	// Read the undecoded request body
	Read() ([]byte, error)
	// The encoded message stream
	Codec() codec.Codec
	// Indicates whether its a stream
	Stream() bool
}

Request is a synchronous request interface

type Response 

type Response interface {
	// Encoded writer
	Codec() codec.Codec
	// Write the header
	WriteHeader(md metadata.Metadata)
	// write a response directly to the client
	Write([]byte) error
}

Response is the response writer for unencoded messages

type Router 

type Router interface {
	// ProcessMessage processes a message
	ProcessMessage(ctx context.Context, msg Message) error
	// ServeRequest processes a request to completion
	ServeRequest(ctx context.Context, req Request, rsp Response) error
}

Router handle serving messages

type Server 

type Server interface {
	// Name returns server name
	Name() string
	// Initialise options
	Init(...Option) error
	// Retrieve the options
	Options() Options
	// Register a handler
	Handle(h Handler) error
	// Create a new handler
	NewHandler(h interface{}, opts ...HandlerOption) Handler
	// Create a new subscriber
	NewSubscriber(topic string, h interface{}, opts ...SubscriberOption) Subscriber
	// Register a subscriber
	Subscribe(s Subscriber) error
	// Start the server
	Start() error
	// Stop the server
	Stop() error
	// Server implementation
	String() string
}

Server is a simple micro server abstraction 

var (
	// DefaultServer default server
	DefaultServer Server = NewServer()
)

func FromContext 

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

FromContext returns Server from context

func NewServer 

func NewServer(opts ...Option) Server

NewServer returns new noop server

type Stream 

type Stream interface {
	Context() context.Context
	Request() Request
	Send(msg interface{}) error
	Recv(msg 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() []*register.Endpoint
	Options() SubscriberOptions
}

Subscriber interface represents a subscription to a given topic using a specific subscriber function or object with endpoints. It mirrors the handler in its behaviour.

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)

SubscriberOption func

func DisableAutoAck 

func DisableAutoAck() SubscriberOption

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

func InternalSubscriber 

func InternalSubscriber(b bool) SubscriberOption

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

func SetSubscriberOption 

func SetSubscriberOption(k, v interface{}) SubscriberOption

SetSubscriberOption returns a function to setup a context with given value

func SubscriberContext 

func SubscriberContext(ctx context.Context) SubscriberOption

SubscriberContext set context options to allow broker SubscriberOption passed

func SubscriberQueue 

func SubscriberQueue(n string) SubscriberOption

SubscriberQueue sets the 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
}

SubscriberOptions struct

func NewSubscriberOptions 

func NewSubscriberOptions(opts ...SubscriberOption) SubscriberOptions

NewSubscriberOptions create new SubscriberOptions

type SubscriberWrapper 

type SubscriberWrapper func(SubscriberFunc) SubscriberFunc

SubscriberWrapper wraps the SubscriberFunc and returns the equivalent

Source Files

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