client

package
v0.20.0 Latest Latest
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 Go to latest Published: Jan 13, 2019 License: Apache-2.0 Imports: 23 Imported by: 0

Documentation

Overview

Package client is an interface for an RPC client

Index

Constants

This section is empty.

Variables

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 = 1
	// DefaultPoolTTL sets the connection pool ttl
	DefaultPoolTTL = time.Minute
)
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,
	}
)

Functions

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 added in v0.10.0 

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

RetryAlways always retry on error

func RetryOnError added in v0.10.0 

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

Types

type BackoffFunc 

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

type CallFunc 

type CallFunc func(ctx context.Context, address string, 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 added in v0.8.0 

func WithAddress(a string) CallOption

WithAddress sets the remote address 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 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

type CallOptions 

type CallOptions struct {
	SelectOptions []selector.SelectOption

	// Address of remote host
	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

	// 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 bidiectional streaming of requests.

func FromContext 

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

func NewClient 

func NewClient(opt ...Option) Client

Creates a new client with the options passed in

type Message added in v0.8.0 

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

Message is the interface for publishing asynchronously

func NewMessage added in v0.8.0 

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

Creates a new message using the default client

type MessageOption added in v0.9.0 

type MessageOption func(*MessageOptions)

MessageOption used by NewMessage

type MessageOptions added in v0.9.0 

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

PoolSize sets the connection pool size

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 Transport 

func Transport(t transport.Transport) Option

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

func WithRouter added in v0.20.0 

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

	// 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
}

type PublishOption 

type PublishOption func(*PublishOptions)

PublishOption used by Publish

type PublishOptions 

type PublishOptions struct {
	// 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 endpoint to call
	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 added in v0.8.0 

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 added in v0.20.0 

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 added in v0.20.0 

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

Router manages request routing

type Stream 

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

Stream is the inteface for a bidirectional synchronous stream

func NewStream added in v0.8.0 

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

Source Files

View all Source files

Directories

Path Synopsis
Package mock provides a mock client for testing
 Package mock provides a mock client for testing
Package rpc provides an rpc client
 Package rpc provides an rpc client

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