client

package
v4.7.1 Latest Latest
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 Go to latest Published: Feb 23, 2023 License: Apache-2.0 Imports: 29 Imported by: 24

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 = 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/json"

	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 

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

Types

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 Closer 

type Closer interface {
	// CloseSend closes the send direction of the stream.
	CloseSend() error
}

Closer handle client close

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 {
	Closer
	// 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

Source Files

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