Documentation
¶
Index ¶
- func Chain(mw ...endpoint.Middleware) func(endpoint.Endpoint) endpoint.Endpoint
- func Combine(mw ...endpoint.Middleware) func(endpoint.Endpoint) endpoint.Endpoint
- func FailerMiddleware(errorMatcher ErrorMatcher) endpoint.Middleware
- func OperationName(ctx context.Context) (string, bool)
- func OperationNameMiddleware(name string) endpoint.Middleware
- type ErrorMatcher
- type Factory
- type MiddlewareFactory
Examples ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func Chain ¶ added in v0.2.0
Chain composes a single middleware from a list. Compared to endpoint.Chain, this function accepts a variadic list. Deprecated: use Combine instead.
Example ¶
annotate := func(pos string) endpoint.Middleware {
return func(e endpoint.Endpoint) endpoint.Endpoint {
return func(ctx context.Context, req interface{}) (response interface{}, err error) {
fmt.Println(pos + " pre")
response, err = e(ctx, req)
fmt.Println(pos + " post")
return
}
}
}
e := Chain(
annotate("first"),
annotate("second"),
annotate("third"),
)(
func(context.Context, interface{}) (interface{}, error) {
fmt.Println("endpoint")
return nil, nil
},
)
if _, err := e(ctx, req); err != nil {
panic(err)
}
Output: first pre second pre third pre endpoint third post second post first post
func Combine ¶ added in v0.10.0
Combine composes a single middleware from a list. Compared to endpoint.Chain, this function accepts a variadic list.
Example ¶
annotate := func(pos string) endpoint.Middleware {
return func(e endpoint.Endpoint) endpoint.Endpoint {
return func(ctx context.Context, req interface{}) (response interface{}, err error) {
fmt.Println(pos + " pre")
response, err = e(ctx, req)
fmt.Println(pos + " post")
return
}
}
}
e := Combine(
annotate("first"),
annotate("second"),
annotate("third"),
)(
func(context.Context, interface{}) (interface{}, error) {
fmt.Println("endpoint")
return nil, nil
},
)
if _, err := e(ctx, req); err != nil {
panic(err)
}
Output: first pre second pre third pre endpoint third post second post first post
func FailerMiddleware ¶ added in v0.4.0
func FailerMiddleware(errorMatcher ErrorMatcher) endpoint.Middleware
FailerMiddleware checks if a returned error matches a predicate and wraps it in a failer response if it does.
func OperationName ¶ added in v0.10.0
OperationName fetches the endpoint operation name from the context (if any). If an endpoint name is not found or it isn't string, the second return argument is false.
func OperationNameMiddleware ¶ added in v0.10.0
func OperationNameMiddleware(name string) endpoint.Middleware
OperationNameMiddleware populates the context with a common name for the endpoint. It can be used in subsequent endpoints in the chain to identify the operation.
Types ¶
type ErrorMatcher ¶ added in v0.4.0
ErrorMatcher is a predicate for errors. It can be used in middleware to decide whether to take action or not.
type Factory ¶
type Factory interface {
// NewEndpoint returns an endpoint wrapped with preconfigured middleware.
// It also accepts an operation name for per operation middleware (eg. logging or tracing middleware).
NewEndpoint(name string, e endpoint.Endpoint) endpoint.Endpoint
}
Factory returns an endpoint wrapped with preconfigured middleware.
func NewFactory ¶
func NewFactory(middlewareFactories ...MiddlewareFactory) Factory
NewFactory returns a new Factory.
type MiddlewareFactory ¶
type MiddlewareFactory func(name string) endpoint.Middleware
MiddlewareFactory creates a middleware per operation.
func Middleware ¶
func Middleware(middleware endpoint.Middleware) MiddlewareFactory
Middleware wraps singleton middleware and wraps them in a MiddlewareFactory.
Source Files