96 lines
3.9 KiB
Go
96 lines
3.9 KiB
Go
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// Copyright 2017 The Prometheus Authors
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package promhttp
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import (
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"net/http"
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"time"
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"github.com/prometheus/client_golang/prometheus"
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)
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// The RoundTripperFunc type is an adapter to allow the use of ordinary
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// functions as RoundTrippers. If f is a function with the appropriate
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// signature, RountTripperFunc(f) is a RoundTripper that calls f.
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type RoundTripperFunc func(req *http.Request) (*http.Response, error)
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// RoundTrip implements the RoundTripper interface.
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func (rt RoundTripperFunc) RoundTrip(r *http.Request) (*http.Response, error) {
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return rt(r)
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}
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// InstrumentRoundTripperInFlight is a middleware that wraps the provided
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// http.RoundTripper. It sets the provided prometheus.Gauge to the number of
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// requests currently handled by the wrapped http.RoundTripper.
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//
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// See the example for ExampleInstrumentRoundTripperDuration for example usage.
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func InstrumentRoundTripperInFlight(gauge prometheus.Gauge, next http.RoundTripper) RoundTripperFunc {
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return RoundTripperFunc(func(r *http.Request) (*http.Response, error) {
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gauge.Inc()
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defer gauge.Dec()
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return next.RoundTrip(r)
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})
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}
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// InstrumentRoundTripperCounter is a middleware that wraps the provided
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// http.RoundTripper to observe the request result with the provided CounterVec.
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// The CounterVec must have zero, one, or two labels. The only allowed label
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// names are "code" and "method". The function panics if any other instance
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// labels are provided. Partitioning of the CounterVec happens by HTTP status
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// code and/or HTTP method if the respective instance label names are present
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// in the CounterVec. For unpartitioned counting, use a CounterVec with
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// zero labels.
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//
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// If the wrapped RoundTripper panics or returns a non-nil error, the Counter
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// is not incremented.
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//
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// See the example for ExampleInstrumentRoundTripperDuration for example usage.
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func InstrumentRoundTripperCounter(counter *prometheus.CounterVec, next http.RoundTripper) RoundTripperFunc {
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code, method := checkLabels(counter)
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return RoundTripperFunc(func(r *http.Request) (*http.Response, error) {
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resp, err := next.RoundTrip(r)
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if err == nil {
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counter.With(labels(code, method, r.Method, resp.StatusCode)).Inc()
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}
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return resp, err
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})
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}
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// InstrumentRoundTripperDuration is a middleware that wraps the provided
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// http.RoundTripper to observe the request duration with the provided ObserverVec.
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// The ObserverVec must have zero, one, or two labels. The only allowed label
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// names are "code" and "method". The function panics if any other instance
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// labels are provided. The Observe method of the Observer in the ObserverVec
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// is called with the request duration in seconds. Partitioning happens by HTTP
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// status code and/or HTTP method if the respective instance label names are
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// present in the ObserverVec. For unpartitioned observations, use an
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// ObserverVec with zero labels. Note that partitioning of Histograms is
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// expensive and should be used judiciously.
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//
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// If the wrapped RoundTripper panics or returns a non-nil error, no values are
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// reported.
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func InstrumentRoundTripperDuration(obs prometheus.ObserverVec, next http.RoundTripper) RoundTripperFunc {
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code, method := checkLabels(obs)
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return RoundTripperFunc(func(r *http.Request) (*http.Response, error) {
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start := time.Now()
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resp, err := next.RoundTrip(r)
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if err == nil {
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obs.With(labels(code, method, r.Method, resp.StatusCode)).Observe(time.Since(start).Seconds())
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}
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return resp, err
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})
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}
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