<commit_before>// Copyright 2016 The Prometheus Authors
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

// Package promhttp provides tooling around HTTP servers and clients.
//
// First, the package allows the creation of http.Handler instances to expose
// Prometheus metrics via HTTP. promhttp.Handler acts on the
// prometheus.DefaultGatherer. With HandlerFor, you can create a handler for a
// custom registry or anything that implements the Gatherer interface. It also
// allows the creation of handlers that act differently on errors or allow to
// log errors.
//
// Second, the package provides tooling to instrument instances of http.Handler
// via middleware. Middleware wrappers follow the naming scheme
// InstrumentHandlerX, where X describes the intended use of the middleware.
// See each function's doc comment for specific details.
//
// Finally, the package allows for an http.RoundTripper to be instrumented via
// middleware. Middleware wrappers follow the naming scheme
// InstrumentRoundTripperX, where X describes the intended use of the
// middleware. See each function's doc comment for specific details.
package promhttp

import (
	"compress/gzip"
	"fmt"
	"io"
	"net/http"
	"strings"
	"sync"
	"time"

	"github.com/prometheus/common/expfmt"

	"github.com/prometheus/client_golang/prometheus"
)

const (
	contentTypeHeader     = "Content-Type"
	contentEncodingHeader = "Content-Encoding"
	acceptEncodingHeader  = "Accept-Encoding"
)

var gzipPool = sync.Pool{
	New: func() interface{} {
		return gzip.NewWriter(nil)
	},
}

// 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 {
	return InstrumentMetricHandler(
		prometheus.DefaultRegisterer, HandlerFor(prometheus.DefaultGatherer, HandlerOpts{}),
	)
}

// 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 {
	var (
		inFlightSem chan struct{}
		errCnt      = prometheus.NewCounterVec(
			prometheus.CounterOpts{
				Name: "promhttp_metric_handler_errors_total",
				Help: "Total number of internal errors encountered by the promhttp metric handler.",
			},
			[]string{"cause"},
		)
	)

	if opts.MaxRequestsInFlight > 0 {
		inFlightSem = make(chan struct{}, opts.MaxRequestsInFlight)
	}
	if opts.Registry != nil {
		// Initialize all possibilites that can occur below.
		errCnt.WithLabelValues("gathering")
		errCnt.WithLabelValues("encoding")<commit_msg>Correct spelling: possibilites -> possibilities<commit_after>// Copyright 2016 The Prometheus Authors
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

// Package promhttp provides tooling around HTTP servers and clients.
//
// First, the package allows the creation of http.Handler instances to expose
// Prometheus metrics via HTTP. promhttp.Handler acts on the
// prometheus.DefaultGatherer. With HandlerFor, you can create a handler for a
// custom registry or anything that implements the Gatherer interface. It also
// allows the creation of handlers that act differently on errors or allow to
// log errors.
//
// Second, the package provides tooling to instrument instances of http.Handler
// via middleware. Middleware wrappers follow the naming scheme
// InstrumentHandlerX, where X describes the intended use of the middleware.
// See each function's doc comment for specific details.
//
// Finally, the package allows for an http.RoundTripper to be instrumented via
// middleware. Middleware wrappers follow the naming scheme
// InstrumentRoundTripperX, where X describes the intended use of the
// middleware. See each function's doc comment for specific details.
package promhttp

import (
	"compress/gzip"
	"fmt"
	"io"
	"net/http"
	"strings"
	"sync"
	"time"

	"github.com/prometheus/common/expfmt"

	"github.com/prometheus/client_golang/prometheus"
)

const (
	contentTypeHeader     = "Content-Type"
	contentEncodingHeader = "Content-Encoding"
	acceptEncodingHeader  = "Accept-Encoding"
)

var gzipPool = sync.Pool{
	New: func() interface{} {
		return gzip.NewWriter(nil)
	},
}

// 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 {
	return InstrumentMetricHandler(
		prometheus.DefaultRegisterer, HandlerFor(prometheus.DefaultGatherer, HandlerOpts{}),
	)
}

// 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 {
	var (
		inFlightSem chan struct{}
		errCnt      = prometheus.NewCounterVec(
			prometheus.CounterOpts{
				Name: "promhttp_metric_handler_errors_total",
				Help: "Total number of internal errors encountered by the promhttp metric handler.",
			},
			[]string{"cause"},
		)
	)

	if opts.MaxRequestsInFlight > 0 {
		inFlightSem = make(chan struct{}, opts.MaxRequestsInFlight)
	}
	if opts.Registry != nil {
		// Initialize all possibilities that can occur below.
		errCnt.WithLabelValues("gathering")
		errCnt.WithLabelValues("encoding")
{'fraction_non_alphanumeric': 0.07968465736810187, 'fraction_numerical': 0.002183141297756216, 'mean_word_length': 4.1090458488228006, 'pattern_counts': {'":': 0, '<': 3, '<?xml version=': 0, '>': 6, 'https://': 0, 'lorem ipsum': 0, 'www.': 2, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
{'dir': 'git-commits-cleaned', 'id': '5496158', 'n_tokens_mistral': 2288, 'n_tokens_neox': 2161, 'n_words': 946}