Documentation
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Overview ¶
Package middleware implements a simple middleware pattern for http handlers, along with implementations for some common middlewares.
Index ¶
- Variables
- func ActiveRequests() []*internal.RequestInfo
- func NewCacher(client *redis.Client) *cacher
- func RequestForTraceID(id string) *internal.RequestInfo
- type ExperimentGetter
- type Experimenter
- type Expirer
- type LocalLogger
- type Logger
- type Middleware
- func AcceptRequests(methods ...string) Middleware
- func BetaPkgGoDevRedirect() Middleware
- func Chain(middlewares ...Middleware) Middleware
- func ErrorReporting(reporter derrors.Reporter) Middleware
- func Experiment(e *Experimenter) Middleware
- func GodocOrgRedirect() Middleware
- func Identity() Middleware
- func Panic(panicHandler http.Handler) Middleware
- func Quota(settings config.QuotaSettings, client *redis.Client) Middleware
- func RequestInfo() Middleware
- func RequestLog(lg Logger) Middleware
- func SecureHeaders(enableCSP bool) Middleware
- func ValidateIAPHeader(audience string) Middleware
Constants ¶
This section is empty.
Variables ¶
var ( CacheResultCount = &view.View{ Name: "go-discovery/cache/result_count", Measure: cacheResults, Aggregation: view.Count(), Description: "cache results, by cache name and whether it was a hit", TagKeys: []tag.Key{keyCacheName, keyCacheHit}, } CacheLatency = &view.View{ Name: "go-discovery/cache/result_latency", Measure: cacheLatency, Description: "cache result latency, by cache name and whether it was a hit", Aggregation: ochttp.DefaultLatencyDistribution, TagKeys: []tag.Key{keyCacheName, keyCacheHit}, } CacheErrorCount = &view.View{ Name: "go-discovery/cache/errors", Measure: cacheErrors, Aggregation: view.Count(), Description: "cache errors, by cache name", TagKeys: []tag.Key{keyCacheName, keyCacheOperation}, } // To avoid test flakiness, when TestMode is true, cache writes are // synchronous. TestMode = false )
var ( // QuotaResultCount is a counter of quota results, by whether the request was blocked or not. QuotaResultCount = &view.View{ Name: "go-discovery/quota/result_count", Measure: quotaResults, Aggregation: view.Count(), Description: "quota results, by blocked or allowed", TagKeys: []tag.Key{keyQuotaBlocked}, } )
Functions ¶
func ActiveRequests ¶
func ActiveRequests() []*internal.RequestInfo
ActiveRequests returns all requests that are currently being handled by the server, sorted by start time.
func NewCacher ¶
func NewCacher(client *redis.Client) *cacher
NewCacher returns a new Cacher, used for creating a middleware that caches each request.
func RequestForTraceID ¶
func RequestForTraceID(id string) *internal.RequestInfo
RequestForTraceID returns the active request with the given trace ID, or nil if there is no such request.
Types ¶
type ExperimentGetter ¶
type ExperimentGetter func(context.Context) ([]*internal.Experiment, error)
ExperimentGetter is the signature of a function that gets experiments.
type Experimenter ¶
type Experimenter struct {
// contains filtered or unexported fields
}
An Experimenter contains information about active experiments from the experiment source.
func NewExperimenter ¶
func NewExperimenter(ctx context.Context, pollEvery time.Duration, getter ExperimentGetter, rep derrors.Reporter) (_ *Experimenter, err error)
NewExperimenter returns an Experimenter for use in the middleware. The experimenter regularly polls for updates to the snapshot in the background.
func (*Experimenter) Experiments ¶
func (e *Experimenter) Experiments() []*internal.Experiment
Experiments returns the experiments currently in use.
type LocalLogger ¶
type LocalLogger struct{}
LocalLogger is a logger that can be used when running locally (i.e.: not on GCP)
func (LocalLogger) Log ¶
func (l LocalLogger) Log(entry logging.Entry)
Log implements the Logger interface via our internal log package.
type Middleware ¶
A Middleware is a func that wraps an http.Handler.
func AcceptRequests ¶
func AcceptRequests(methods ...string) Middleware
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.
func BetaPkgGoDevRedirect ¶
func BetaPkgGoDevRedirect() Middleware
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.
func Chain ¶
func Chain(middlewares ...Middleware) Middleware
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
func ErrorReporting ¶
func ErrorReporting(reporter derrors.Reporter) Middleware
ErrorReporting returns a middleware that reports any server errors using the report func.
func Experiment ¶
func Experiment(e *Experimenter) Middleware
Experiment returns a new Middleware that sets active experiments for each incoming request.
func GodocOrgRedirect ¶
func GodocOrgRedirect() Middleware
GodocOrgRedirect redirects requests from godoc.org to pkg.go.dev.
func Identity ¶
func Identity() Middleware
Identity is a middleware that does nothing. It can be used as a helper when building middleware chains.
func Panic ¶
func Panic(panicHandler http.Handler) Middleware
Panic returns a middleware that executes panicHandler on any panic originating from the delegate handler.
func Quota ¶
func Quota(settings config.QuotaSettings, client *redis.Client) Middleware
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.
func RequestInfo ¶
func RequestInfo() Middleware
RequestInfo adds information about the request to a context. It also stores it while the request is active. ActiveRequests retrieves all stored requests.
func RequestLog ¶
func RequestLog(lg Logger) Middleware
RequestLog returns a middleware that logs each incoming requests using the given logger.
Logs may be viewed in Pantheon by selecting the log source corresponding to the service name (e.g. 'dev-worker').
Install this middleware after RequestInfo to ensure that trace IDs appear in the log.
func SecureHeaders ¶
func SecureHeaders(enableCSP bool) Middleware
SecureHeaders adds a content-security-policy and other security-related headers to all responses.
func ValidateIAPHeader ¶
func ValidateIAPHeader(audience string) Middleware
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.
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