Replace godep with dep

This commit is contained in:
Manuel de Brito Fontes 2017-10-06 17:26:14 -03:00
parent 1e7489927c
commit bf5616c65b
14883 changed files with 3937406 additions and 361781 deletions

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@ -1,38 +0,0 @@
// Copyright 2017 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.
// +build !go1.8
package promhttp
import (
"io"
"net/http"
)
func newDelegator(w http.ResponseWriter, observeWriteHeaderFunc func(int)) delegator {
d := &responseWriterDelegator{
ResponseWriter: w,
observeWriteHeader: observeWriteHeaderFunc,
}
_, cn := w.(http.CloseNotifier)
_, fl := w.(http.Flusher)
_, hj := w.(http.Hijacker)
_, rf := w.(io.ReaderFrom)
if cn && fl && hj && rf {
return &fancyDelegator{d}
}
return d
}

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@ -1,73 +0,0 @@
// Copyright 2017 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.
// +build go1.8
package promhttp
import (
"io"
"net/http"
)
// newDelegator handles the four different methods of upgrading a
// http.ResponseWriter to delegator.
func newDelegator(w http.ResponseWriter, observeWriteHeaderFunc func(int)) delegator {
d := &responseWriterDelegator{
ResponseWriter: w,
observeWriteHeader: observeWriteHeaderFunc,
}
_, cn := w.(http.CloseNotifier)
_, fl := w.(http.Flusher)
_, hj := w.(http.Hijacker)
_, ps := w.(http.Pusher)
_, rf := w.(io.ReaderFrom)
// Check for the four most common combination of interfaces a
// http.ResponseWriter might implement.
switch {
case cn && fl && hj && rf && ps:
// All interfaces.
return &fancyPushDelegator{
fancyDelegator: &fancyDelegator{d},
p: &pushDelegator{d},
}
case cn && fl && hj && rf:
// All interfaces, except http.Pusher.
return &fancyDelegator{d}
case ps:
// Just http.Pusher.
return &pushDelegator{d}
}
return d
}
type fancyPushDelegator struct {
p *pushDelegator
*fancyDelegator
}
func (f *fancyPushDelegator) Push(target string, opts *http.PushOptions) error {
return f.p.Push(target, opts)
}
type pushDelegator struct {
*responseWriterDelegator
}
func (f *pushDelegator) Push(target string, opts *http.PushOptions) error {
return f.ResponseWriter.(http.Pusher).Push(target, opts)
}

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@ -11,24 +11,21 @@
// See the License for the specific language governing permissions and
// limitations under the License.
// Package promhttp provides tooling around HTTP servers and clients.
// Copyright (c) 2013, The Prometheus Authors
// All rights reserved.
//
// 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.
// Use of this source code is governed by a BSD-style license that can be found
// in the LICENSE file.
// Package promhttp contains functions to create http.Handler instances to
// expose Prometheus metrics via HTTP. In later versions of this package, it
// will also contain tooling to instrument instances of http.Handler and
// http.RoundTripper.
//
// 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.
// 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 to create handlers that act
// differently on errors or allow to log errors.
package promhttp
import (

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// 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.
// Copyright (c) 2013, The Prometheus Authors
// All rights reserved.
//
// Use of this source code is governed by a BSD-style license that can be found
// in the LICENSE file.
package promhttp
import (
"bytes"
"errors"
"log"
"net/http"
"net/http/httptest"
"testing"
"github.com/prometheus/client_golang/prometheus"
)
type errorCollector struct{}
func (e errorCollector) Describe(ch chan<- *prometheus.Desc) {
ch <- prometheus.NewDesc("invalid_metric", "not helpful", nil, nil)
}
func (e errorCollector) Collect(ch chan<- prometheus.Metric) {
ch <- prometheus.NewInvalidMetric(
prometheus.NewDesc("invalid_metric", "not helpful", nil, nil),
errors.New("collect error"),
)
}
func TestHandlerErrorHandling(t *testing.T) {
// Create a registry that collects a MetricFamily with two elements,
// another with one, and reports an error.
reg := prometheus.NewRegistry()
cnt := prometheus.NewCounter(prometheus.CounterOpts{
Name: "the_count",
Help: "Ah-ah-ah! Thunder and lightning!",
})
reg.MustRegister(cnt)
cntVec := prometheus.NewCounterVec(
prometheus.CounterOpts{
Name: "name",
Help: "docstring",
ConstLabels: prometheus.Labels{"constname": "constvalue"},
},
[]string{"labelname"},
)
cntVec.WithLabelValues("val1").Inc()
cntVec.WithLabelValues("val2").Inc()
reg.MustRegister(cntVec)
reg.MustRegister(errorCollector{})
logBuf := &bytes.Buffer{}
logger := log.New(logBuf, "", 0)
writer := httptest.NewRecorder()
request, _ := http.NewRequest("GET", "/", nil)
request.Header.Add("Accept", "test/plain")
errorHandler := HandlerFor(reg, HandlerOpts{
ErrorLog: logger,
ErrorHandling: HTTPErrorOnError,
})
continueHandler := HandlerFor(reg, HandlerOpts{
ErrorLog: logger,
ErrorHandling: ContinueOnError,
})
panicHandler := HandlerFor(reg, HandlerOpts{
ErrorLog: logger,
ErrorHandling: PanicOnError,
})
wantMsg := `error gathering metrics: error collecting metric Desc{fqName: "invalid_metric", help: "not helpful", constLabels: {}, variableLabels: []}: collect error
`
wantErrorBody := `An error has occurred during metrics gathering:
error collecting metric Desc{fqName: "invalid_metric", help: "not helpful", constLabels: {}, variableLabels: []}: collect error
`
wantOKBody := `# HELP name docstring
# TYPE name counter
name{constname="constvalue",labelname="val1"} 1
name{constname="constvalue",labelname="val2"} 1
# HELP the_count Ah-ah-ah! Thunder and lightning!
# TYPE the_count counter
the_count 0
`
errorHandler.ServeHTTP(writer, request)
if got, want := writer.Code, http.StatusInternalServerError; got != want {
t.Errorf("got HTTP status code %d, want %d", got, want)
}
if got := logBuf.String(); got != wantMsg {
t.Errorf("got log message:\n%s\nwant log mesage:\n%s\n", got, wantMsg)
}
if got := writer.Body.String(); got != wantErrorBody {
t.Errorf("got body:\n%s\nwant body:\n%s\n", got, wantErrorBody)
}
logBuf.Reset()
writer.Body.Reset()
writer.Code = http.StatusOK
continueHandler.ServeHTTP(writer, request)
if got, want := writer.Code, http.StatusOK; got != want {
t.Errorf("got HTTP status code %d, want %d", got, want)
}
if got := logBuf.String(); got != wantMsg {
t.Errorf("got log message %q, want %q", got, wantMsg)
}
if got := writer.Body.String(); got != wantOKBody {
t.Errorf("got body %q, want %q", got, wantOKBody)
}
defer func() {
if err := recover(); err == nil {
t.Error("expected panic from panicHandler")
}
}()
panicHandler.ServeHTTP(writer, request)
}

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// Copyright 2017 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
import (
"net/http"
"time"
"github.com/prometheus/client_golang/prometheus"
)
// The RoundTripperFunc type is an adapter to allow the use of ordinary
// functions as RoundTrippers. If f is a function with the appropriate
// signature, RountTripperFunc(f) is a RoundTripper that calls f.
type RoundTripperFunc func(req *http.Request) (*http.Response, error)
// RoundTrip implements the RoundTripper interface.
func (rt RoundTripperFunc) RoundTrip(r *http.Request) (*http.Response, error) {
return rt(r)
}
// InstrumentRoundTripperInFlight is a middleware that wraps the provided
// http.RoundTripper. It sets the provided prometheus.Gauge to the number of
// requests currently handled by the wrapped http.RoundTripper.
//
// See the example for ExampleInstrumentRoundTripperDuration for example usage.
func InstrumentRoundTripperInFlight(gauge prometheus.Gauge, next http.RoundTripper) RoundTripperFunc {
return RoundTripperFunc(func(r *http.Request) (*http.Response, error) {
gauge.Inc()
defer gauge.Dec()
return next.RoundTrip(r)
})
}
// InstrumentRoundTripperCounter is a middleware that wraps the provided
// http.RoundTripper to observe the request result with the provided CounterVec.
// The CounterVec must have zero, one, or two labels. The only allowed label
// names are "code" and "method". The function panics if any other instance
// labels are provided. Partitioning of the CounterVec happens by HTTP status
// code and/or HTTP method if the respective instance label names are present
// in the CounterVec. For unpartitioned counting, use a CounterVec with
// zero labels.
//
// If the wrapped RoundTripper panics or returns a non-nil error, the Counter
// is not incremented.
//
// See the example for ExampleInstrumentRoundTripperDuration for example usage.
func InstrumentRoundTripperCounter(counter *prometheus.CounterVec, next http.RoundTripper) RoundTripperFunc {
code, method := checkLabels(counter)
return RoundTripperFunc(func(r *http.Request) (*http.Response, error) {
resp, err := next.RoundTrip(r)
if err == nil {
counter.With(labels(code, method, r.Method, resp.StatusCode)).Inc()
}
return resp, err
})
}
// InstrumentRoundTripperDuration is a middleware that wraps the provided
// http.RoundTripper to observe the request duration with the provided ObserverVec.
// The ObserverVec must have zero, one, or two labels. The only allowed label
// names are "code" and "method". The function panics if any other instance
// labels are provided. The Observe method of the Observer in the ObserverVec
// is called with the request duration in seconds. Partitioning happens by HTTP
// status code and/or HTTP method if the respective instance label names are
// present in the ObserverVec. For unpartitioned observations, use an
// ObserverVec with zero labels. Note that partitioning of Histograms is
// expensive and should be used judiciously.
//
// If the wrapped RoundTripper panics or returns a non-nil error, no values are
// reported.
func InstrumentRoundTripperDuration(obs prometheus.ObserverVec, next http.RoundTripper) RoundTripperFunc {
code, method := checkLabels(obs)
return RoundTripperFunc(func(r *http.Request) (*http.Response, error) {
start := time.Now()
resp, err := next.RoundTrip(r)
if err == nil {
obs.With(labels(code, method, r.Method, resp.StatusCode)).Observe(time.Since(start).Seconds())
}
return resp, err
})
}

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// Copyright 2017 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.
// +build go1.8
package promhttp
import (
"context"
"crypto/tls"
"net/http"
"net/http/httptrace"
"time"
)
// InstrumentTrace is used to offer flexibility in instrumenting the available
// httptrace.ClientTrace hook functions. Each function is passed a float64
// representing the time in seconds since the start of the http request. A user
// may choose to use separately buckets Histograms, or implement custom
// instance labels on a per function basis.
type InstrumentTrace struct {
GotConn func(float64)
PutIdleConn func(float64)
GotFirstResponseByte func(float64)
Got100Continue func(float64)
DNSStart func(float64)
DNSDone func(float64)
ConnectStart func(float64)
ConnectDone func(float64)
TLSHandshakeStart func(float64)
TLSHandshakeDone func(float64)
WroteHeaders func(float64)
Wait100Continue func(float64)
WroteRequest func(float64)
}
// InstrumentRoundTripperTrace is a middleware that wraps the provided
// RoundTripper and reports times to hook functions provided in the
// InstrumentTrace struct. Hook functions that are not present in the provided
// InstrumentTrace struct are ignored. Times reported to the hook functions are
// time since the start of the request. Note that partitioning of Histograms
// is expensive and should be used judiciously.
//
// For hook functions that receive an error as an argument, no observations are
// made in the event of a non-nil error value.
//
// See the example for ExampleInstrumentRoundTripperDuration for example usage.
func InstrumentRoundTripperTrace(it *InstrumentTrace, next http.RoundTripper) RoundTripperFunc {
return RoundTripperFunc(func(r *http.Request) (*http.Response, error) {
start := time.Now()
trace := &httptrace.ClientTrace{
GotConn: func(_ httptrace.GotConnInfo) {
if it.GotConn != nil {
it.GotConn(time.Since(start).Seconds())
}
},
PutIdleConn: func(err error) {
if err != nil {
return
}
if it.PutIdleConn != nil {
it.PutIdleConn(time.Since(start).Seconds())
}
},
DNSStart: func(_ httptrace.DNSStartInfo) {
if it.DNSStart != nil {
it.DNSStart(time.Since(start).Seconds())
}
},
DNSDone: func(_ httptrace.DNSDoneInfo) {
if it.DNSStart != nil {
it.DNSStart(time.Since(start).Seconds())
}
},
ConnectStart: func(_, _ string) {
if it.ConnectStart != nil {
it.ConnectStart(time.Since(start).Seconds())
}
},
ConnectDone: func(_, _ string, err error) {
if err != nil {
return
}
if it.ConnectDone != nil {
it.ConnectDone(time.Since(start).Seconds())
}
},
GotFirstResponseByte: func() {
if it.GotFirstResponseByte != nil {
it.GotFirstResponseByte(time.Since(start).Seconds())
}
},
Got100Continue: func() {
if it.Got100Continue != nil {
it.Got100Continue(time.Since(start).Seconds())
}
},
TLSHandshakeStart: func() {
if it.TLSHandshakeStart != nil {
it.TLSHandshakeStart(time.Since(start).Seconds())
}
},
TLSHandshakeDone: func(_ tls.ConnectionState, err error) {
if err != nil {
return
}
if it.TLSHandshakeDone != nil {
it.TLSHandshakeDone(time.Since(start).Seconds())
}
},
WroteHeaders: func() {
if it.WroteHeaders != nil {
it.WroteHeaders(time.Since(start).Seconds())
}
},
Wait100Continue: func() {
if it.Wait100Continue != nil {
it.Wait100Continue(time.Since(start).Seconds())
}
},
WroteRequest: func(_ httptrace.WroteRequestInfo) {
if it.WroteRequest != nil {
it.WroteRequest(time.Since(start).Seconds())
}
},
}
r = r.WithContext(httptrace.WithClientTrace(context.Background(), trace))
return next.RoundTrip(r)
})
}

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// Copyright 2017 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
import (
"bufio"
"io"
"net"
"net/http"
"strconv"
"strings"
"time"
dto "github.com/prometheus/client_model/go"
"github.com/prometheus/client_golang/prometheus"
)
// magicString is used for the hacky label test in checkLabels. Remove once fixed.
const magicString = "zZgWfBxLqvG8kc8IMv3POi2Bb0tZI3vAnBx+gBaFi9FyPzB/CzKUer1yufDa"
// InstrumentHandlerInFlight is a middleware that wraps the provided
// http.Handler. It sets the provided prometheus.Gauge to the number of
// requests currently handled by the wrapped http.Handler.
//
// See the example for InstrumentHandlerDuration for example usage.
func InstrumentHandlerInFlight(g prometheus.Gauge, next http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
g.Inc()
defer g.Dec()
next.ServeHTTP(w, r)
})
}
// InstrumentHandlerDuration is a middleware that wraps the provided
// http.Handler to observe the request duration with the provided ObserverVec.
// The ObserverVec must have zero, one, or two labels. The only allowed label
// names are "code" and "method". The function panics if any other instance
// labels are provided. The Observe method of the Observer in the ObserverVec
// is called with the request duration in seconds. Partitioning happens by HTTP
// status code and/or HTTP method if the respective instance label names are
// present in the ObserverVec. For unpartitioned observations, use an
// ObserverVec with zero labels. Note that partitioning of Histograms is
// expensive and should be used judiciously.
//
// If the wrapped Handler does not set a status code, a status code of 200 is assumed.
//
// If the wrapped Handler panics, no values are reported.
func InstrumentHandlerDuration(obs prometheus.ObserverVec, next http.Handler) http.HandlerFunc {
code, method := checkLabels(obs)
if code {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
now := time.Now()
d := newDelegator(w, nil)
next.ServeHTTP(d, r)
obs.With(labels(code, method, r.Method, d.Status())).Observe(time.Since(now).Seconds())
})
}
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
now := time.Now()
next.ServeHTTP(w, r)
obs.With(labels(code, method, r.Method, 0)).Observe(time.Since(now).Seconds())
})
}
// InstrumentHandlerCounter is a middleware that wraps the provided
// http.Handler to observe the request result with the provided CounterVec.
// The CounterVec must have zero, one, or two labels. The only allowed label
// names are "code" and "method". The function panics if any other instance
// labels are provided. Partitioning of the CounterVec happens by HTTP status
// code and/or HTTP method if the respective instance label names are present
// in the CounterVec. For unpartitioned counting, use a CounterVec with
// zero labels.
//
// If the wrapped Handler does not set a status code, a status code of 200 is assumed.
//
// If the wrapped Handler panics, the Counter is not incremented.
//
// See the example for InstrumentHandlerDuration for example usage.
func InstrumentHandlerCounter(counter *prometheus.CounterVec, next http.Handler) http.HandlerFunc {
code, method := checkLabels(counter)
if code {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
d := newDelegator(w, nil)
next.ServeHTTP(d, r)
counter.With(labels(code, method, r.Method, d.Status())).Inc()
})
}
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
next.ServeHTTP(w, r)
counter.With(labels(code, method, r.Method, 0)).Inc()
})
}
// InstrumentHandlerTimeToWriteHeader is a middleware that wraps the provided
// http.Handler to observe with the provided ObserverVec the request duration
// until the response headers are written. The ObserverVec must have zero, one,
// or two labels. The only allowed label names are "code" and "method". The
// function panics if any other instance labels are provided. The Observe
// method of the Observer in the ObserverVec is called with the request
// duration in seconds. Partitioning happens by HTTP status code and/or HTTP
// method if the respective instance label names are present in the
// ObserverVec. For unpartitioned observations, use an ObserverVec with zero
// labels. Note that partitioning of Histograms is expensive and should be used
// judiciously.
//
// If the wrapped Handler panics before calling WriteHeader, no value is
// reported.
//
// See the example for InstrumentHandlerDuration for example usage.
func InstrumentHandlerTimeToWriteHeader(obs prometheus.ObserverVec, next http.Handler) http.HandlerFunc {
code, method := checkLabels(obs)
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
now := time.Now()
d := newDelegator(w, func(status int) {
obs.With(labels(code, method, r.Method, status)).Observe(time.Since(now).Seconds())
})
next.ServeHTTP(d, r)
})
}
// InstrumentHandlerRequestSize is a middleware that wraps the provided
// http.Handler to observe the request size with the provided ObserverVec.
// The ObserverVec must have zero, one, or two labels. The only allowed label
// names are "code" and "method". The function panics if any other instance
// labels are provided. The Observe method of the Observer in the ObserverVec
// is called with the request size in bytes. Partitioning happens by HTTP
// status code and/or HTTP method if the respective instance label names are
// present in the ObserverVec. For unpartitioned observations, use an
// ObserverVec with zero labels. Note that partitioning of Histograms is
// expensive and should be used judiciously.
//
// If the wrapped Handler does not set a status code, a status code of 200 is assumed.
//
// If the wrapped Handler panics, no values are reported.
//
// See the example for InstrumentHandlerDuration for example usage.
func InstrumentHandlerRequestSize(obs prometheus.ObserverVec, next http.Handler) http.HandlerFunc {
code, method := checkLabels(obs)
if code {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
d := newDelegator(w, nil)
next.ServeHTTP(d, r)
size := computeApproximateRequestSize(r)
obs.With(labels(code, method, r.Method, d.Status())).Observe(float64(size))
})
}
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
next.ServeHTTP(w, r)
size := computeApproximateRequestSize(r)
obs.With(labels(code, method, r.Method, 0)).Observe(float64(size))
})
}
// InstrumentHandlerResponseSize is a middleware that wraps the provided
// http.Handler to observe the response size with the provided ObserverVec.
// The ObserverVec must have zero, one, or two labels. The only allowed label
// names are "code" and "method". The function panics if any other instance
// labels are provided. The Observe method of the Observer in the ObserverVec
// is called with the response size in bytes. Partitioning happens by HTTP
// status code and/or HTTP method if the respective instance label names are
// present in the ObserverVec. For unpartitioned observations, use an
// ObserverVec with zero labels. Note that partitioning of Histograms is
// expensive and should be used judiciously.
//
// If the wrapped Handler does not set a status code, a status code of 200 is assumed.
//
// If the wrapped Handler panics, no values are reported.
//
// See the example for InstrumentHandlerDuration for example usage.
func InstrumentHandlerResponseSize(obs prometheus.ObserverVec, next http.Handler) http.Handler {
code, method := checkLabels(obs)
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
d := newDelegator(w, nil)
next.ServeHTTP(d, r)
obs.With(labels(code, method, r.Method, d.Status())).Observe(float64(d.Written()))
})
}
func checkLabels(c prometheus.Collector) (code bool, method bool) {
// TODO(beorn7): Remove this hacky way to check for instance labels
// once Descriptors can have their dimensionality queried.
var (
desc *prometheus.Desc
pm dto.Metric
)
descc := make(chan *prometheus.Desc, 1)
c.Describe(descc)
select {
case desc = <-descc:
default:
panic("no description provided by collector")
}
select {
case <-descc:
panic("more than one description provided by collector")
default:
}
close(descc)
if _, err := prometheus.NewConstMetric(desc, prometheus.UntypedValue, 0); err == nil {
return
}
if m, err := prometheus.NewConstMetric(desc, prometheus.UntypedValue, 0, magicString); err == nil {
if err := m.Write(&pm); err != nil {
panic("error checking metric for labels")
}
for _, label := range pm.Label {
name, value := label.GetName(), label.GetValue()
if value != magicString {
continue
}
switch name {
case "code":
code = true
case "method":
method = true
default:
panic("metric partitioned with non-supported labels")
}
return
}
panic("previously set label not found this must never happen")
}
if m, err := prometheus.NewConstMetric(desc, prometheus.UntypedValue, 0, magicString, magicString); err == nil {
if err := m.Write(&pm); err != nil {
panic("error checking metric for labels")
}
for _, label := range pm.Label {
name, value := label.GetName(), label.GetValue()
if value != magicString {
continue
}
if name == "code" || name == "method" {
continue
}
panic("metric partitioned with non-supported labels")
}
code = true
method = true
return
}
panic("metric partitioned with non-supported labels")
}
// emptyLabels is a one-time allocation for non-partitioned metrics to avoid
// unnecessary allocations on each request.
var emptyLabels = prometheus.Labels{}
func labels(code, method bool, reqMethod string, status int) prometheus.Labels {
if !(code || method) {
return emptyLabels
}
labels := prometheus.Labels{}
if code {
labels["code"] = sanitizeCode(status)
}
if method {
labels["method"] = sanitizeMethod(reqMethod)
}
return labels
}
func computeApproximateRequestSize(r *http.Request) int {
s := 0
if r.URL != nil {
s += len(r.URL.String())
}
s += len(r.Method)
s += len(r.Proto)
for name, values := range r.Header {
s += len(name)
for _, value := range values {
s += len(value)
}
}
s += len(r.Host)
// N.B. r.Form and r.MultipartForm are assumed to be included in r.URL.
if r.ContentLength != -1 {
s += int(r.ContentLength)
}
return s
}
func sanitizeMethod(m string) string {
switch m {
case "GET", "get":
return "get"
case "PUT", "put":
return "put"
case "HEAD", "head":
return "head"
case "POST", "post":
return "post"
case "DELETE", "delete":
return "delete"
case "CONNECT", "connect":
return "connect"
case "OPTIONS", "options":
return "options"
case "NOTIFY", "notify":
return "notify"
default:
return strings.ToLower(m)
}
}
// If the wrapped http.Handler has not set a status code, i.e. the value is
// currently 0, santizeCode will return 200, for consistency with behavior in
// the stdlib.
func sanitizeCode(s int) string {
switch s {
case 100:
return "100"
case 101:
return "101"
case 200, 0:
return "200"
case 201:
return "201"
case 202:
return "202"
case 203:
return "203"
case 204:
return "204"
case 205:
return "205"
case 206:
return "206"
case 300:
return "300"
case 301:
return "301"
case 302:
return "302"
case 304:
return "304"
case 305:
return "305"
case 307:
return "307"
case 400:
return "400"
case 401:
return "401"
case 402:
return "402"
case 403:
return "403"
case 404:
return "404"
case 405:
return "405"
case 406:
return "406"
case 407:
return "407"
case 408:
return "408"
case 409:
return "409"
case 410:
return "410"
case 411:
return "411"
case 412:
return "412"
case 413:
return "413"
case 414:
return "414"
case 415:
return "415"
case 416:
return "416"
case 417:
return "417"
case 418:
return "418"
case 500:
return "500"
case 501:
return "501"
case 502:
return "502"
case 503:
return "503"
case 504:
return "504"
case 505:
return "505"
case 428:
return "428"
case 429:
return "429"
case 431:
return "431"
case 511:
return "511"
default:
return strconv.Itoa(s)
}
}
type delegator interface {
Status() int
Written() int64
http.ResponseWriter
}
type responseWriterDelegator struct {
http.ResponseWriter
handler, method string
status int
written int64
wroteHeader bool
observeWriteHeader func(int)
}
func (r *responseWriterDelegator) Status() int {
return r.status
}
func (r *responseWriterDelegator) Written() int64 {
return r.written
}
func (r *responseWriterDelegator) WriteHeader(code int) {
r.status = code
r.wroteHeader = true
r.ResponseWriter.WriteHeader(code)
if r.observeWriteHeader != nil {
r.observeWriteHeader(code)
}
}
func (r *responseWriterDelegator) Write(b []byte) (int, error) {
if !r.wroteHeader {
r.WriteHeader(http.StatusOK)
}
n, err := r.ResponseWriter.Write(b)
r.written += int64(n)
return n, err
}
type fancyDelegator struct {
*responseWriterDelegator
}
func (r *fancyDelegator) CloseNotify() <-chan bool {
return r.ResponseWriter.(http.CloseNotifier).CloseNotify()
}
func (r *fancyDelegator) Hijack() (net.Conn, *bufio.ReadWriter, error) {
return r.ResponseWriter.(http.Hijacker).Hijack()
}
func (r *fancyDelegator) Flush() {
r.ResponseWriter.(http.Flusher).Flush()
}
func (r *fancyDelegator) ReadFrom(re io.Reader) (int64, error) {
if !r.wroteHeader {
r.WriteHeader(http.StatusOK)
}
n, err := r.ResponseWriter.(io.ReaderFrom).ReadFrom(re)
r.written += n
return n, err
}