package middleware

Import Path
	golang.org/x/pkgsite/internal/middleware (on go.dev)

Dependency Relation
	imports 34 packages, and imported by 8 packages


Involved Source Files

	      accept_requests.go
	      betaRedirect.go
	      caching.go
	      errorreporting.go
	      experiment.go
	      iapheader.go
	
		Package middleware implements a simple middleware pattern for http handlers,
		along with implementations for some common middlewares.

	      panic.go
	      quota.go
	      requestlog.go
	      secureheaders.go
	      stats.go
	      timeout.go


Package-Level Type Names (total 15, in which 8 are exported)


	/* sort exporteds by:  |  */
	
		An Experimenter contains information about active experiments from the
		experiment source.

		
			
		
			
				Experiments returns the experiments currently in use.

			
		
			func NewExperimenter(ctx context.Context, pollEvery time.Duration, getter ExperimentGetter, rep Reporter) (_ *Experimenter, err error)
			func golang.org/x/pkgsite/cmd/internal/cmdconfig.Experimenter(ctx context.Context, cfg *config.Config, getter ExperimentGetter, reportingClient *errorreporting.Client) *Experimenter
		
			func Experiment(e *Experimenter) Middleware


	
		ExperimentGetter is the signature of a function that gets experiments.

		
			func golang.org/x/pkgsite/cmd/internal/cmdconfig.ExperimentGetter(ctx context.Context, cfg *config.Config) ExperimentGetter
		
			func NewExperimenter(ctx context.Context, pollEvery time.Duration, getter ExperimentGetter, rep Reporter) (_ *Experimenter, err error)
			func golang.org/x/pkgsite/internal/queue.New(ctx context.Context, cfg *config.Config, queueName string, numWorkers int, expGetter ExperimentGetter, processFunc queue.inMemoryProcessFunc) (queue.Queue, error)
			func golang.org/x/pkgsite/cmd/internal/cmdconfig.Experimenter(ctx context.Context, cfg *config.Config, getter ExperimentGetter, reportingClient *errorreporting.Client) *Experimenter


	
		An Expirer computes the TTL that should be used when caching a page.

		
			func TTL(ttl time.Duration) Expirer
		
			func Cache(name string, client *redis.Client, expirer Expirer, authValues []string) Middleware


	
		LocalLogger is a logger that can be used when running locally (i.e.: not on
		GCP)

		
			
				Log implements the Logger interface via our internal log package.

		
			 T : Logger


	
		Logger is the interface used to write request logs to GCP.

		
			( T) Log(logging.Entry)
		
			 LocalLogger
			*cloud.google.com/go/logging.Logger
		
			func golang.org/x/pkgsite/cmd/internal/cmdconfig.Logger(ctx context.Context, cfg *config.Config, logName string) Logger
		
			func RequestLog(lg Logger) Middleware


	
		A Middleware is a func that wraps an http.Handler.

		
			func AcceptRequests(methods ...string) Middleware
			func BetaPkgGoDevRedirect() Middleware
			func Cache(name string, client *redis.Client, expirer Expirer, authValues []string) Middleware
			func Chain(middlewares ...Middleware) Middleware
			func ErrorReporting(report func(errorreporting.Entry)) Middleware
			func Experiment(e *Experimenter) Middleware
			func Identity() Middleware
			func Panic(panicHandler http.Handler) Middleware
			func Quota(settings config.QuotaSettings, client *redis.Client) Middleware
			func RequestLog(lg Logger) Middleware
			func SecureHeaders(enableCSP bool) Middleware
			func Stats() Middleware
			func Timeout(d time.Duration) Middleware
			func ValidateIAPHeader(audience string) Middleware
		
			func Chain(middlewares ...Middleware) Middleware


	

		
			
				// hash of page contents

			MillisToFirstByte int64
			MillisToLastByte int64
			Other map[string]interface{}
			
				// total size of data written

			
				// HTTP status



	
		A Reporter sends errors to the Error-Reporting service.

		
			( T) Report(errorreporting.Entry)
		
			*cloud.google.com/go/errorreporting.Client
		
			func NewExperimenter(ctx context.Context, pollEvery time.Duration, getter ExperimentGetter, rep Reporter) (_ *Experimenter, err error)


	


Package-Level Functions (total 32, in which 18 are exported)


	
		AcceptRequests serves 405 (Method Not Allowed) for any method not on the
		given list and 414 (Method Request URI Too Long) for any URI that exceeds
		the maxURILength.


	
		BetaPkgGoDevRedirect redirects requests from pkg.go.dev to beta.pkg.go.dev,
		based on whether a cookie is set for betapkggodev-redirect. The cookie
		can be turned on/off using a query param.


	
		Cache returns a new Middleware that caches every request.
		The name of the cache is used only for metrics.
		The expirer is a func that is used to map a new request to its TTL.
		authHeader is the header key used by the cache to know that a
		request should bypass the cache.
		authValues is the set of values that could be set on the authHeader in
		order to bypass the cache.


	
		Chain creates a new Middleware that applies a sequence of Middlewares, so
		that they execute in the given order when handling an http request.

		In other words, Chain(m1, m2)(handler) = m1(m2(handler))

		A similar pattern is used in e.g. github.com/justinas/alice:
		https://github.com/justinas/alice/blob/ce87934/chain.go#L45


	
		ElapsedStat records as a stat the elapsed time for a
		function execution. Invoke like so:
		  defer ElapsedStat(ctx, "FunctionName")()
		The resulting stat will be called "FunctionName ms" and will
		be the wall-clock execution time of the function in milliseconds.


	
		ErrorReporting returns a middleware that reports any server errors using the
		report func.


	
		Experiment returns a new Middleware that sets active experiments for each
		incoming request.


	
		Identity is a middleware that does nothing. It can be used as a helper when
		building middleware chains.


	
		NewExperimenter returns an Experimenter for use in the middleware. The
		experimenter regularly polls for updates to the snapshot in the background.


	
		Panic returns a middleware that executes panicHandler on any panic
		originating from the delegate handler.


	
		Quota implements a simple IP-based rate limiter. Each set of incoming IP
		addresses with the same low-order byte gets settings.QPS requests per second.

		Information is kept in a redis instance.

		If a request is disallowed, a 429 (TooManyRequests) will be served.


	
		RequestLog returns a middleware that logs each incoming requests using the
		given logger. This logger replaces the built-in appengine request logger,
		which logged PII when behind IAP, in such a way that was impossible to turn
		off.

		Logs may be viewed in Pantheon by selecting the log source corresponding to
		the AppEngine service name (e.g. 'dev-worker').


	
		SecureHeaders adds a content-security-policy and other security-related
		headers to all responses.


	
		SetStat sets a stat named key in the current context. If key already has a
		value, the old and new value are both stored in a slice.


	
		Stats returns a Middleware that, instead of serving the page,
		serves statistics about the page.


	
		Timeout returns a new Middleware that times out each request after the given
		duration.


	
		TTL returns an Expirer that expires all pages after the given TTL.


	
		ValidateIAPHeader checks that the request has a header that proves it arrived
		via the IAP.
		See https://cloud.google.com/iap/docs/signed-headers-howto#securing_iap_headers.


	


Package-Level Variables (total 15, in which 5 are exported)


	
		QuotaResultCount is a counter of quota results, by whether the request was blocked or not.


	
		To avoid test flakiness, when TestMode is true, cache writes are
		synchronous.


	


Package-Level Constants (total 7, none are exported)