Package client is an interface for an RPC client



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    View Source
    var (
    	// DefaultClient is a default client to use out of the box
    	DefaultClient Client = newRpcClient()
    	// DefaultBackoff is the default backoff function for retries
    	DefaultBackoff = exponentialBackoff
    	// DefaultRetry is the default check-for-retry function for retries
    	DefaultRetry = RetryOnError
    	// DefaultRetries is the default number of times a request is tried
    	DefaultRetries = 1
    	// DefaultRequestTimeout is the default request timeout
    	DefaultRequestTimeout = time.Second * 5
    	// DefaultPoolSize sets the connection pool size
    	DefaultPoolSize = 100
    	// DefaultPoolTTL sets the connection pool ttl
    	DefaultPoolTTL = time.Minute
    	// NewClient returns a new client
    	NewClient func(...Option) Client = newRpcClient
    View Source
    var (
    	DefaultContentType = "application/protobuf"
    	DefaultCodecs = map[string]codec.NewCodec{
    		"application/grpc":         grpc.NewCodec,
    		"application/grpc+json":    grpc.NewCodec,
    		"application/grpc+proto":   grpc.NewCodec,
    		"application/protobuf":     proto.NewCodec,
    		"application/json":         json.NewCodec,
    		"application/json-rpc":     jsonrpc.NewCodec,
    		"application/proto-rpc":    protorpc.NewCodec,
    		"application/octet-stream": raw.NewCodec,


    func Call

    func Call(ctx context.Context, request Request, response interface{}, opts ...CallOption) error

      Makes a synchronous call to a service using the default client

      func NewContext

      func NewContext(ctx context.Context, c Client) context.Context

      func Publish

      func Publish(ctx context.Context, msg Message, opts ...PublishOption) error

        Publishes a publication using the default client. Using the underlying broker set within the options.

        func RetryAlways

        func RetryAlways(ctx context.Context, req Request, retryCount int, err error) (bool, error)

          RetryAlways always retry on error

          func RetryOnError

          func RetryOnError(ctx context.Context, req Request, retryCount int, err error) (bool, error)

            RetryOnError retries a request on a 500 or timeout error

            func String

            func String() string


            type BackoffFunc

            type BackoffFunc func(ctx context.Context, req Request, attempts int) (time.Duration, error)

            type Cache

            type Cache struct {
            	// contains filtered or unexported fields

              Cache for responses

              func NewCache

              func NewCache() *Cache

                NewCache returns an initialised cache.

                func (*Cache) Get

                func (c *Cache) Get(ctx context.Context, req *Request) (interface{}, bool)

                  Get a response from the cache

                  func (*Cache) List

                  func (c *Cache) List() map[string]string

                    List the key value pairs in the cache

                    func (*Cache) Set

                    func (c *Cache) Set(ctx context.Context, req *Request, rsp interface{}, expiry time.Duration)

                      Set a response in the cache

                      type CallFunc

                      type CallFunc func(ctx context.Context, node *registry.Node, req Request, rsp interface{}, opts CallOptions) error

                        CallFunc represents the individual call func

                        type CallOption

                        type CallOption func(*CallOptions)

                          CallOption used by Call or Stream

                          func WithAddress

                          func WithAddress(a ...string) CallOption

                            WithAddress sets the remote addresses to use rather than using service discovery

                            func WithBackoff

                            func WithBackoff(fn BackoffFunc) CallOption

                              WithBackoff is a CallOption which overrides that which set in Options.CallOptions

                              func WithCache

                              func WithCache(c time.Duration) CallOption

                                WithCache is a CallOption which sets the duration the response shoull be cached for

                                func WithCallWrapper

                                func WithCallWrapper(cw ...CallWrapper) CallOption

                                  WithCallWrapper is a CallOption which adds to the existing CallFunc wrappers

                                  func WithDialTimeout

                                  func WithDialTimeout(d time.Duration) CallOption

                                    WithDialTimeout is a CallOption which overrides that which set in Options.CallOptions

                                    func WithRequestTimeout

                                    func WithRequestTimeout(d time.Duration) CallOption

                                      WithRequestTimeout is a CallOption which overrides that which set in Options.CallOptions

                                      func WithRetries

                                      func WithRetries(i int) CallOption

                                        WithRetries is a CallOption which overrides that which set in Options.CallOptions

                                        func WithRetry

                                        func WithRetry(fn RetryFunc) CallOption

                                          WithRetry is a CallOption which overrides that which set in Options.CallOptions

                                          func WithSelectOption

                                          func WithSelectOption(so ...selector.SelectOption) CallOption

                                          func WithServiceToken

                                          func WithServiceToken() CallOption

                                            WithServiceToken is a CallOption which overrides the authorization header with the services own auth token

                                            func WithStreamTimeout

                                            func WithStreamTimeout(d time.Duration) CallOption

                                              WithStreamTimeout sets the stream timeout

                                              type CallOptions

                                              type CallOptions struct {
                                              	SelectOptions []selector.SelectOption
                                              	// Address of remote hosts
                                              	Address []string
                                              	// Backoff func
                                              	Backoff BackoffFunc
                                              	// Check if retriable func
                                              	Retry RetryFunc
                                              	// Transport Dial Timeout
                                              	DialTimeout time.Duration
                                              	// Number of Call attempts
                                              	Retries int
                                              	// Request/Response timeout
                                              	RequestTimeout time.Duration
                                              	// Stream timeout for the stream
                                              	StreamTimeout time.Duration
                                              	// Use the services own auth token
                                              	ServiceToken bool
                                              	// Duration to cache the response for
                                              	CacheExpiry time.Duration
                                              	// Middleware for low level call func
                                              	CallWrappers []CallWrapper
                                              	// Other options for implementations of the interface
                                              	// can be stored in a context
                                              	Context context.Context

                                              type CallWrapper

                                              type CallWrapper func(CallFunc) CallFunc

                                                CallWrapper is a low level wrapper for the CallFunc

                                                type Client

                                                type Client interface {
                                                	Init(...Option) error
                                                	Options() Options
                                                	NewMessage(topic string, msg interface{}, opts ...MessageOption) Message
                                                	NewRequest(service, endpoint string, req interface{}, reqOpts ...RequestOption) Request
                                                	Call(ctx context.Context, req Request, rsp interface{}, opts ...CallOption) error
                                                	Stream(ctx context.Context, req Request, opts ...CallOption) (Stream, error)
                                                	Publish(ctx context.Context, msg Message, opts ...PublishOption) error
                                                	String() string

                                                  Client is the interface used to make requests to services. It supports Request/Response via Transport and Publishing via the Broker. It also supports bidirectional streaming of requests.

                                                  func FromContext

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

                                                  type Message

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

                                                    Message is the interface for publishing asynchronously

                                                    func NewMessage

                                                    func NewMessage(topic string, payload interface{}, opts ...MessageOption) Message

                                                      Creates a new message using the default client

                                                      type MessageOption

                                                      type MessageOption func(*MessageOptions)

                                                        MessageOption used by NewMessage

                                                        func WithMessageContentType

                                                        func WithMessageContentType(ct string) MessageOption

                                                        type MessageOptions

                                                        type MessageOptions struct {
                                                        	ContentType string

                                                        type Option

                                                        type Option func(*Options)

                                                          Option used by the Client

                                                          func Backoff

                                                          func Backoff(fn BackoffFunc) Option

                                                            Backoff is used to set the backoff function used when retrying Calls

                                                            func Broker

                                                            func Broker(b broker.Broker) Option

                                                              Broker to be used for pub/sub

                                                              func Codec

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

                                                                Codec to be used to encode/decode requests for a given content type

                                                                func ContentType

                                                                func ContentType(ct string) Option

                                                                  Default content type of the client

                                                                  func DialTimeout

                                                                  func DialTimeout(d time.Duration) Option

                                                                    Transport dial timeout

                                                                    func PoolSize

                                                                    func PoolSize(d int) Option

                                                                      PoolSize sets the connection pool size

                                                                      func PoolTTL

                                                                      func PoolTTL(d time.Duration) Option

                                                                        PoolTTL sets the connection pool ttl

                                                                        func Registry

                                                                        func Registry(r registry.Registry) Option

                                                                          Registry to find nodes for a given service

                                                                          func RequestTimeout

                                                                          func RequestTimeout(d time.Duration) Option

                                                                            The request timeout. Should this be a Call Option?

                                                                            func Retries

                                                                            func Retries(i int) Option

                                                                              Number of retries when making the request. Should this be a Call Option?

                                                                              func Retry

                                                                              func Retry(fn RetryFunc) Option

                                                                                Retry sets the retry function to be used when re-trying.

                                                                                func Selector

                                                                                func Selector(s selector.Selector) Option

                                                                                  Select is used to select a node to route a request to

                                                                                  func StreamTimeout

                                                                                  func StreamTimeout(d time.Duration) Option

                                                                                    StreamTimeout sets the stream timeout

                                                                                    func Transport

                                                                                    func Transport(t transport.Transport) Option

                                                                                      Transport to use for communication e.g http, rabbitmq, etc

                                                                                      func WithRouter

                                                                                      func WithRouter(r Router) Option

                                                                                        WithRouter sets the client router

                                                                                        func Wrap

                                                                                        func Wrap(w Wrapper) Option

                                                                                          Adds a Wrapper to a list of options passed into the client

                                                                                          func WrapCall

                                                                                          func WrapCall(cw ...CallWrapper) Option

                                                                                            Adds a Wrapper to the list of CallFunc wrappers

                                                                                            type Options

                                                                                            type Options struct {
                                                                                            	// Used to select codec
                                                                                            	ContentType string
                                                                                            	// Plugged interfaces
                                                                                            	Broker    broker.Broker
                                                                                            	Codecs    map[string]codec.NewCodec
                                                                                            	Registry  registry.Registry
                                                                                            	Selector  selector.Selector
                                                                                            	Transport transport.Transport
                                                                                            	// Router sets the router
                                                                                            	Router Router
                                                                                            	// Connection Pool
                                                                                            	PoolSize int
                                                                                            	PoolTTL  time.Duration
                                                                                            	// Response cache
                                                                                            	Cache *Cache
                                                                                            	// Middleware for client
                                                                                            	Wrappers []Wrapper
                                                                                            	// Default Call Options
                                                                                            	CallOptions CallOptions
                                                                                            	// Other options for implementations of the interface
                                                                                            	// can be stored in a context
                                                                                            	Context context.Context

                                                                                            func NewOptions

                                                                                            func NewOptions(options ...Option) Options

                                                                                            type PublishOption

                                                                                            type PublishOption func(*PublishOptions)

                                                                                              PublishOption used by Publish

                                                                                              func PublishContext

                                                                                              func PublishContext(ctx context.Context) PublishOption

                                                                                                PublishContext sets the context in publish options

                                                                                                func WithExchange

                                                                                                func WithExchange(e string) PublishOption

                                                                                                  WithExchange sets the exchange to route a message through

                                                                                                  type PublishOptions

                                                                                                  type PublishOptions struct {
                                                                                                  	// Exchange is the routing exchange for the message
                                                                                                  	Exchange string
                                                                                                  	// Other options for implementations of the interface
                                                                                                  	// can be stored in a context
                                                                                                  	Context context.Context

                                                                                                  type Request

                                                                                                  type Request interface {
                                                                                                  	// The service to call
                                                                                                  	Service() string
                                                                                                  	// The action to take
                                                                                                  	Method() string
                                                                                                  	// The endpoint to invoke
                                                                                                  	Endpoint() string
                                                                                                  	// The content type
                                                                                                  	ContentType() string
                                                                                                  	// The unencoded request body
                                                                                                  	Body() interface{}
                                                                                                  	// Write to the encoded request writer. This is nil before a call is made
                                                                                                  	Codec() codec.Writer
                                                                                                  	// indicates whether the request will be a streaming one rather than unary
                                                                                                  	Stream() bool

                                                                                                    Request is the interface for a synchronous request used by Call or Stream

                                                                                                    func NewRequest

                                                                                                    func NewRequest(service, endpoint string, request interface{}, reqOpts ...RequestOption) Request

                                                                                                      Creates a new request using the default client. Content Type will be set to the default within options and use the appropriate codec

                                                                                                      type RequestOption

                                                                                                      type RequestOption func(*RequestOptions)

                                                                                                        RequestOption used by NewRequest

                                                                                                        func StreamingRequest

                                                                                                        func StreamingRequest() RequestOption

                                                                                                        func WithContentType

                                                                                                        func WithContentType(ct string) RequestOption

                                                                                                        type RequestOptions

                                                                                                        type RequestOptions struct {
                                                                                                        	ContentType string
                                                                                                        	Stream      bool
                                                                                                        	// Other options for implementations of the interface
                                                                                                        	// can be stored in a context
                                                                                                        	Context context.Context

                                                                                                        type Response

                                                                                                        type Response interface {
                                                                                                        	// Read the response
                                                                                                        	Codec() codec.Reader
                                                                                                        	// read the header
                                                                                                        	Header() map[string]string
                                                                                                        	// Read the undecoded response
                                                                                                        	Read() ([]byte, error)

                                                                                                          Response is the response received from a service

                                                                                                          type RetryFunc

                                                                                                          type RetryFunc func(ctx context.Context, req Request, retryCount int, err error) (bool, error)

                                                                                                            note that returning either false or a non-nil error will result in the call not being retried

                                                                                                            type Router

                                                                                                            type Router interface {
                                                                                                            	SendRequest(context.Context, Request) (Response, error)

                                                                                                              Router manages request routing

                                                                                                              type Stream

                                                                                                              type Stream interface {
                                                                                                              	// Context for the stream
                                                                                                              	Context() context.Context
                                                                                                              	// The request made
                                                                                                              	Request() Request
                                                                                                              	// The response read
                                                                                                              	Response() Response
                                                                                                              	// Send will encode and send a request
                                                                                                              	Send(interface{}) error
                                                                                                              	// Recv will decode and read a response
                                                                                                              	Recv(interface{}) error
                                                                                                              	// Error returns the stream error
                                                                                                              	Error() error
                                                                                                              	// Close closes the stream
                                                                                                              	Close() error

                                                                                                                Stream is the inteface for a bidirectional synchronous stream

                                                                                                                func NewStream

                                                                                                                func NewStream(ctx context.Context, request Request, opts ...CallOption) (Stream, error)

                                                                                                                  Creates a streaming connection with a service and returns responses on the channel passed in. It's up to the user to close the streamer.

                                                                                                                  type StreamWrapper

                                                                                                                  type StreamWrapper func(Stream) Stream

                                                                                                                    StreamWrapper wraps a Stream and returns the equivalent

                                                                                                                    type Wrapper

                                                                                                                    type Wrapper func(Client) Client

                                                                                                                      Wrapper wraps a client and returns a client