khenaidoo | ab1f7bd | 2019-11-14 14:00:27 -0500 | [diff] [blame] | 1 | // Copyright 2017 The Prometheus Authors |
| 2 | // Licensed under the Apache License, Version 2.0 (the "License"); |
| 3 | // you may not use this file except in compliance with the License. |
| 4 | // You may obtain a copy of the License at |
| 5 | // |
| 6 | // http://www.apache.org/licenses/LICENSE-2.0 |
| 7 | // |
| 8 | // Unless required by applicable law or agreed to in writing, software |
| 9 | // distributed under the License is distributed on an "AS IS" BASIS, |
| 10 | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 11 | // See the License for the specific language governing permissions and |
| 12 | // limitations under the License. |
| 13 | |
| 14 | package promhttp |
| 15 | |
| 16 | import ( |
| 17 | "crypto/tls" |
| 18 | "net/http" |
| 19 | "net/http/httptrace" |
| 20 | "time" |
| 21 | |
| 22 | "github.com/prometheus/client_golang/prometheus" |
| 23 | ) |
| 24 | |
| 25 | // The RoundTripperFunc type is an adapter to allow the use of ordinary |
| 26 | // functions as RoundTrippers. If f is a function with the appropriate |
| 27 | // signature, RountTripperFunc(f) is a RoundTripper that calls f. |
| 28 | type RoundTripperFunc func(req *http.Request) (*http.Response, error) |
| 29 | |
| 30 | // RoundTrip implements the RoundTripper interface. |
| 31 | func (rt RoundTripperFunc) RoundTrip(r *http.Request) (*http.Response, error) { |
| 32 | return rt(r) |
| 33 | } |
| 34 | |
| 35 | // InstrumentRoundTripperInFlight is a middleware that wraps the provided |
| 36 | // http.RoundTripper. It sets the provided prometheus.Gauge to the number of |
| 37 | // requests currently handled by the wrapped http.RoundTripper. |
| 38 | // |
| 39 | // See the example for ExampleInstrumentRoundTripperDuration for example usage. |
| 40 | func InstrumentRoundTripperInFlight(gauge prometheus.Gauge, next http.RoundTripper) RoundTripperFunc { |
| 41 | return RoundTripperFunc(func(r *http.Request) (*http.Response, error) { |
| 42 | gauge.Inc() |
| 43 | defer gauge.Dec() |
| 44 | return next.RoundTrip(r) |
| 45 | }) |
| 46 | } |
| 47 | |
| 48 | // InstrumentRoundTripperCounter is a middleware that wraps the provided |
| 49 | // http.RoundTripper to observe the request result with the provided CounterVec. |
| 50 | // The CounterVec must have zero, one, or two non-const non-curried labels. For |
| 51 | // those, the only allowed label names are "code" and "method". The function |
| 52 | // panics otherwise. Partitioning of the CounterVec happens by HTTP status code |
| 53 | // and/or HTTP method if the respective instance label names are present in the |
| 54 | // CounterVec. For unpartitioned counting, use a CounterVec with zero labels. |
| 55 | // |
| 56 | // If the wrapped RoundTripper panics or returns a non-nil error, the Counter |
| 57 | // is not incremented. |
| 58 | // |
| 59 | // See the example for ExampleInstrumentRoundTripperDuration for example usage. |
| 60 | func InstrumentRoundTripperCounter(counter *prometheus.CounterVec, next http.RoundTripper) RoundTripperFunc { |
| 61 | code, method := checkLabels(counter) |
| 62 | |
| 63 | return RoundTripperFunc(func(r *http.Request) (*http.Response, error) { |
| 64 | resp, err := next.RoundTrip(r) |
| 65 | if err == nil { |
| 66 | counter.With(labels(code, method, r.Method, resp.StatusCode)).Inc() |
| 67 | } |
| 68 | return resp, err |
| 69 | }) |
| 70 | } |
| 71 | |
| 72 | // InstrumentRoundTripperDuration is a middleware that wraps the provided |
| 73 | // http.RoundTripper to observe the request duration with the provided |
| 74 | // ObserverVec. The ObserverVec must have zero, one, or two non-const |
| 75 | // non-curried labels. For those, the only allowed label names are "code" and |
| 76 | // "method". The function panics otherwise. The Observe method of the Observer |
| 77 | // in the ObserverVec is called with the request duration in |
| 78 | // seconds. Partitioning happens by HTTP status code and/or HTTP method if the |
| 79 | // respective instance label names are present in the ObserverVec. For |
| 80 | // unpartitioned observations, use an ObserverVec with zero labels. Note that |
| 81 | // partitioning of Histograms is expensive and should be used judiciously. |
| 82 | // |
| 83 | // If the wrapped RoundTripper panics or returns a non-nil error, no values are |
| 84 | // reported. |
| 85 | // |
| 86 | // Note that this method is only guaranteed to never observe negative durations |
| 87 | // if used with Go1.9+. |
| 88 | func InstrumentRoundTripperDuration(obs prometheus.ObserverVec, next http.RoundTripper) RoundTripperFunc { |
| 89 | code, method := checkLabels(obs) |
| 90 | |
| 91 | return RoundTripperFunc(func(r *http.Request) (*http.Response, error) { |
| 92 | start := time.Now() |
| 93 | resp, err := next.RoundTrip(r) |
| 94 | if err == nil { |
| 95 | obs.With(labels(code, method, r.Method, resp.StatusCode)).Observe(time.Since(start).Seconds()) |
| 96 | } |
| 97 | return resp, err |
| 98 | }) |
| 99 | } |
| 100 | |
| 101 | // InstrumentTrace is used to offer flexibility in instrumenting the available |
| 102 | // httptrace.ClientTrace hook functions. Each function is passed a float64 |
| 103 | // representing the time in seconds since the start of the http request. A user |
| 104 | // may choose to use separately buckets Histograms, or implement custom |
| 105 | // instance labels on a per function basis. |
| 106 | type InstrumentTrace struct { |
| 107 | GotConn func(float64) |
| 108 | PutIdleConn func(float64) |
| 109 | GotFirstResponseByte func(float64) |
| 110 | Got100Continue func(float64) |
| 111 | DNSStart func(float64) |
| 112 | DNSDone func(float64) |
| 113 | ConnectStart func(float64) |
| 114 | ConnectDone func(float64) |
| 115 | TLSHandshakeStart func(float64) |
| 116 | TLSHandshakeDone func(float64) |
| 117 | WroteHeaders func(float64) |
| 118 | Wait100Continue func(float64) |
| 119 | WroteRequest func(float64) |
| 120 | } |
| 121 | |
| 122 | // InstrumentRoundTripperTrace is a middleware that wraps the provided |
| 123 | // RoundTripper and reports times to hook functions provided in the |
| 124 | // InstrumentTrace struct. Hook functions that are not present in the provided |
| 125 | // InstrumentTrace struct are ignored. Times reported to the hook functions are |
| 126 | // time since the start of the request. Only with Go1.9+, those times are |
| 127 | // guaranteed to never be negative. (Earlier Go versions are not using a |
| 128 | // monotonic clock.) Note that partitioning of Histograms is expensive and |
| 129 | // should be used judiciously. |
| 130 | // |
| 131 | // For hook functions that receive an error as an argument, no observations are |
| 132 | // made in the event of a non-nil error value. |
| 133 | // |
| 134 | // See the example for ExampleInstrumentRoundTripperDuration for example usage. |
| 135 | func InstrumentRoundTripperTrace(it *InstrumentTrace, next http.RoundTripper) RoundTripperFunc { |
| 136 | return RoundTripperFunc(func(r *http.Request) (*http.Response, error) { |
| 137 | start := time.Now() |
| 138 | |
| 139 | trace := &httptrace.ClientTrace{ |
| 140 | GotConn: func(_ httptrace.GotConnInfo) { |
| 141 | if it.GotConn != nil { |
| 142 | it.GotConn(time.Since(start).Seconds()) |
| 143 | } |
| 144 | }, |
| 145 | PutIdleConn: func(err error) { |
| 146 | if err != nil { |
| 147 | return |
| 148 | } |
| 149 | if it.PutIdleConn != nil { |
| 150 | it.PutIdleConn(time.Since(start).Seconds()) |
| 151 | } |
| 152 | }, |
| 153 | DNSStart: func(_ httptrace.DNSStartInfo) { |
| 154 | if it.DNSStart != nil { |
| 155 | it.DNSStart(time.Since(start).Seconds()) |
| 156 | } |
| 157 | }, |
| 158 | DNSDone: func(_ httptrace.DNSDoneInfo) { |
| 159 | if it.DNSDone != nil { |
| 160 | it.DNSDone(time.Since(start).Seconds()) |
| 161 | } |
| 162 | }, |
| 163 | ConnectStart: func(_, _ string) { |
| 164 | if it.ConnectStart != nil { |
| 165 | it.ConnectStart(time.Since(start).Seconds()) |
| 166 | } |
| 167 | }, |
| 168 | ConnectDone: func(_, _ string, err error) { |
| 169 | if err != nil { |
| 170 | return |
| 171 | } |
| 172 | if it.ConnectDone != nil { |
| 173 | it.ConnectDone(time.Since(start).Seconds()) |
| 174 | } |
| 175 | }, |
| 176 | GotFirstResponseByte: func() { |
| 177 | if it.GotFirstResponseByte != nil { |
| 178 | it.GotFirstResponseByte(time.Since(start).Seconds()) |
| 179 | } |
| 180 | }, |
| 181 | Got100Continue: func() { |
| 182 | if it.Got100Continue != nil { |
| 183 | it.Got100Continue(time.Since(start).Seconds()) |
| 184 | } |
| 185 | }, |
| 186 | TLSHandshakeStart: func() { |
| 187 | if it.TLSHandshakeStart != nil { |
| 188 | it.TLSHandshakeStart(time.Since(start).Seconds()) |
| 189 | } |
| 190 | }, |
| 191 | TLSHandshakeDone: func(_ tls.ConnectionState, err error) { |
| 192 | if err != nil { |
| 193 | return |
| 194 | } |
| 195 | if it.TLSHandshakeDone != nil { |
| 196 | it.TLSHandshakeDone(time.Since(start).Seconds()) |
| 197 | } |
| 198 | }, |
| 199 | WroteHeaders: func() { |
| 200 | if it.WroteHeaders != nil { |
| 201 | it.WroteHeaders(time.Since(start).Seconds()) |
| 202 | } |
| 203 | }, |
| 204 | Wait100Continue: func() { |
| 205 | if it.Wait100Continue != nil { |
| 206 | it.Wait100Continue(time.Since(start).Seconds()) |
| 207 | } |
| 208 | }, |
| 209 | WroteRequest: func(_ httptrace.WroteRequestInfo) { |
| 210 | if it.WroteRequest != nil { |
| 211 | it.WroteRequest(time.Since(start).Seconds()) |
| 212 | } |
| 213 | }, |
| 214 | } |
| 215 | r = r.WithContext(httptrace.WithClientTrace(r.Context(), trace)) |
| 216 | |
| 217 | return next.RoundTrip(r) |
| 218 | }) |
| 219 | } |