kubernetes/vendor/github.com/prometheus/client_golang/prometheus/promhttp/http.go

const contentTypeHeader …

const contentEncodingHeader …

const acceptEncodingHeader …

const processStartTimeHeader …

var gzipPool …

// Handler returns an http.Handler for the prometheus.DefaultGatherer, using
// default HandlerOpts, i.e. it reports the first error as an HTTP error, it has
// no error logging, and it applies compression if requested by the client.
//
// The returned http.Handler is already instrumented using the
// InstrumentMetricHandler function and the prometheus.DefaultRegisterer. If you
// create multiple http.Handlers by separate calls of the Handler function, the
// metrics used for instrumentation will be shared between them, providing
// global scrape counts.
//
// This function is meant to cover the bulk of basic use cases. If you are doing
// anything that requires more customization (including using a non-default
// Gatherer, different instrumentation, and non-default HandlerOpts), use the
// HandlerFor function. See there for details.
func Handler() http.Handler { … }

// HandlerFor returns an uninstrumented http.Handler for the provided
// Gatherer. The behavior of the Handler is defined by the provided
// HandlerOpts. Thus, HandlerFor is useful to create http.Handlers for custom
// Gatherers, with non-default HandlerOpts, and/or with custom (or no)
// instrumentation. Use the InstrumentMetricHandler function to apply the same
// kind of instrumentation as it is used by the Handler function.
func HandlerFor(reg prometheus.Gatherer, opts HandlerOpts) http.Handler { … }

// HandlerForTransactional is like HandlerFor, but it uses transactional gather, which
// can safely change in-place returned *dto.MetricFamily before call to `Gather` and after
// call to `done` of that `Gather`.
func HandlerForTransactional(reg prometheus.TransactionalGatherer, opts HandlerOpts) http.Handler { … }

// InstrumentMetricHandler is usually used with an http.Handler returned by the
// HandlerFor function. It instruments the provided http.Handler with two
// metrics: A counter vector "promhttp_metric_handler_requests_total" to count
// scrapes partitioned by HTTP status code, and a gauge
// "promhttp_metric_handler_requests_in_flight" to track the number of
// simultaneous scrapes. This function idempotently registers collectors for
// both metrics with the provided Registerer. It panics if the registration
// fails. The provided metrics are useful to see how many scrapes hit the
// monitored target (which could be from different Prometheus servers or other
// scrapers), and how often they overlap (which would result in more than one
// scrape in flight at the same time). Note that the scrapes-in-flight gauge
// will contain the scrape by which it is exposed, while the scrape counter will
// only get incremented after the scrape is complete (as only then the status
// code is known). For tracking scrape durations, use the
// "scrape_duration_seconds" gauge created by the Prometheus server upon each
// scrape.
func InstrumentMetricHandler(reg prometheus.Registerer, handler http.Handler) http.Handler { … }

type HandlerErrorHandling …

const HTTPErrorOnError …

const ContinueOnError …

const PanicOnError …

type Logger …

type HandlerOpts …

// gzipAccepted returns whether the client will accept gzip-encoded content.
func gzipAccepted(header http.Header) bool { … }

// httpError removes any content-encoding header and then calls http.Error with
// the provided error and http.StatusInternalServerError. Error contents is
// supposed to be uncompressed plain text. Same as with a plain http.Error, this
// must not be called if the header or any payload has already been sent.
func httpError(rsp http.ResponseWriter, err error) { … }