middleware

Documentation

Index

• Constants
• func LogRequest() goa.Middleware
• func LogResponse() goa.Middleware
• func Recover() goa.Middleware
• func RequestID() goa.Middleware
• func RequireHeader(pathPattern *regexp.Regexp, requiredHeaderName string, ...) goa.Middleware
• func Timeout(timeout time.Duration) goa.Middleware

Constants

const ReqIDKey middlewareKey = 1

ReqIDKey is the context key used by the RequestID middleware to store the request ID value.

const RequestIDHeader = "X-Request-Id"

RequestIDHeader is the name of the header used to transmit the request ID.

Functions

func LogRequest

func LogRequest() goa.Middleware

LogRequest creates a request logger middleware. This middleware is aware of the RequestID middleware and if registered after it leverages the request ID for logging.

func LogResponse

func LogResponse() goa.Middleware

LogResponse creates a response logger middleware. Only Logs the raw response data without accumulating any statistics.

func Recover

func Recover() goa.Middleware

Recover is a middleware that recovers panics and returns an internal error response.

func RequestID

func RequestID() goa.Middleware

RequestID is a middleware that injects a request ID into the context of each request. Retrieve it using ctx.Value(ReqIDKey). If the incoming request has a RequestIDHeader header then that value is used else a random value is generated.

func RequireHeader

func RequireHeader(
	pathPattern *regexp.Regexp,
	requiredHeaderName string,
	requiredHeaderValue *regexp.Regexp,
	failureStatus int) goa.Middleware

RequireHeader requires a request header to match a value pattern. If the header is missing or does not match then the failureStatus is the response (e.g. http.StatusUnauthorized). If pathPattern is nil then any path is included. If requiredHeaderValue is nil then any value is accepted so long as the header is non-empty.

func Timeout

func Timeout(timeout time.Duration) goa.Middleware

Timeout sets a global timeout for all controller actions. The timeout notification is made through the context, it is the responsability of the request handler to handle it. For example:

func (ctrl *Controller) DoLongRunningAction(ctx *DoLongRunningActionContext) error {
	action := NewLongRunning()      // setup long running action
	c := make(chan error, 1)        // create return channel
	go func() { c <- action.Run() } // Launch long running action goroutine
	select {
	case <- ctx.Done():             // timeout triggered
		action.Cancel()         // cancel long running action
		<-c                     // wait for Run to return.
		return ctx.Err()        // retrieve cancel reason
	case err := <-c:   		// action finished on time
		return err  		// forward its return value
	}
}

Package golang.org/x/net/context/ctxhttp contains an implementation of an HTTP client which is context-aware:

func (ctrl *Controller) HttpAction(ctx *HttpActionContext) error {
	req, err := http.NewRequest("GET", "http://iamaslowservice.com", nil)
	// ...
	resp, err := ctxhttp.Do(ctx, nil, req) // returns if timeout triggers
	// ...
}

Controller actions can check if a timeout is set by calling the context Deadline method.