khenaidoo | ffe076b | 2019-01-15 16:08:08 -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 | // +build go1.8 |
| 15 | |
| 16 | package promhttp |
| 17 | |
| 18 | import ( |
| 19 | "context" |
| 20 | "crypto/tls" |
| 21 | "net/http" |
| 22 | "net/http/httptrace" |
| 23 | "time" |
| 24 | ) |
| 25 | |
| 26 | // InstrumentTrace is used to offer flexibility in instrumenting the available |
| 27 | // httptrace.ClientTrace hook functions. Each function is passed a float64 |
| 28 | // representing the time in seconds since the start of the http request. A user |
| 29 | // may choose to use separately buckets Histograms, or implement custom |
| 30 | // instance labels on a per function basis. |
| 31 | type InstrumentTrace struct { |
| 32 | GotConn func(float64) |
| 33 | PutIdleConn func(float64) |
| 34 | GotFirstResponseByte func(float64) |
| 35 | Got100Continue func(float64) |
| 36 | DNSStart func(float64) |
| 37 | DNSDone func(float64) |
| 38 | ConnectStart func(float64) |
| 39 | ConnectDone func(float64) |
| 40 | TLSHandshakeStart func(float64) |
| 41 | TLSHandshakeDone func(float64) |
| 42 | WroteHeaders func(float64) |
| 43 | Wait100Continue func(float64) |
| 44 | WroteRequest func(float64) |
| 45 | } |
| 46 | |
| 47 | // InstrumentRoundTripperTrace is a middleware that wraps the provided |
| 48 | // RoundTripper and reports times to hook functions provided in the |
| 49 | // InstrumentTrace struct. Hook functions that are not present in the provided |
| 50 | // InstrumentTrace struct are ignored. Times reported to the hook functions are |
| 51 | // time since the start of the request. Only with Go1.9+, those times are |
| 52 | // guaranteed to never be negative. (Earlier Go versions are not using a |
| 53 | // monotonic clock.) Note that partitioning of Histograms is expensive and |
| 54 | // should be used judiciously. |
| 55 | // |
| 56 | // For hook functions that receive an error as an argument, no observations are |
| 57 | // made in the event of a non-nil error value. |
| 58 | // |
| 59 | // See the example for ExampleInstrumentRoundTripperDuration for example usage. |
| 60 | func InstrumentRoundTripperTrace(it *InstrumentTrace, next http.RoundTripper) RoundTripperFunc { |
| 61 | return RoundTripperFunc(func(r *http.Request) (*http.Response, error) { |
| 62 | start := time.Now() |
| 63 | |
| 64 | trace := &httptrace.ClientTrace{ |
| 65 | GotConn: func(_ httptrace.GotConnInfo) { |
| 66 | if it.GotConn != nil { |
| 67 | it.GotConn(time.Since(start).Seconds()) |
| 68 | } |
| 69 | }, |
| 70 | PutIdleConn: func(err error) { |
| 71 | if err != nil { |
| 72 | return |
| 73 | } |
| 74 | if it.PutIdleConn != nil { |
| 75 | it.PutIdleConn(time.Since(start).Seconds()) |
| 76 | } |
| 77 | }, |
| 78 | DNSStart: func(_ httptrace.DNSStartInfo) { |
| 79 | if it.DNSStart != nil { |
| 80 | it.DNSStart(time.Since(start).Seconds()) |
| 81 | } |
| 82 | }, |
| 83 | DNSDone: func(_ httptrace.DNSDoneInfo) { |
| 84 | if it.DNSDone != nil { |
| 85 | it.DNSDone(time.Since(start).Seconds()) |
| 86 | } |
| 87 | }, |
| 88 | ConnectStart: func(_, _ string) { |
| 89 | if it.ConnectStart != nil { |
| 90 | it.ConnectStart(time.Since(start).Seconds()) |
| 91 | } |
| 92 | }, |
| 93 | ConnectDone: func(_, _ string, err error) { |
| 94 | if err != nil { |
| 95 | return |
| 96 | } |
| 97 | if it.ConnectDone != nil { |
| 98 | it.ConnectDone(time.Since(start).Seconds()) |
| 99 | } |
| 100 | }, |
| 101 | GotFirstResponseByte: func() { |
| 102 | if it.GotFirstResponseByte != nil { |
| 103 | it.GotFirstResponseByte(time.Since(start).Seconds()) |
| 104 | } |
| 105 | }, |
| 106 | Got100Continue: func() { |
| 107 | if it.Got100Continue != nil { |
| 108 | it.Got100Continue(time.Since(start).Seconds()) |
| 109 | } |
| 110 | }, |
| 111 | TLSHandshakeStart: func() { |
| 112 | if it.TLSHandshakeStart != nil { |
| 113 | it.TLSHandshakeStart(time.Since(start).Seconds()) |
| 114 | } |
| 115 | }, |
| 116 | TLSHandshakeDone: func(_ tls.ConnectionState, err error) { |
| 117 | if err != nil { |
| 118 | return |
| 119 | } |
| 120 | if it.TLSHandshakeDone != nil { |
| 121 | it.TLSHandshakeDone(time.Since(start).Seconds()) |
| 122 | } |
| 123 | }, |
| 124 | WroteHeaders: func() { |
| 125 | if it.WroteHeaders != nil { |
| 126 | it.WroteHeaders(time.Since(start).Seconds()) |
| 127 | } |
| 128 | }, |
| 129 | Wait100Continue: func() { |
| 130 | if it.Wait100Continue != nil { |
| 131 | it.Wait100Continue(time.Since(start).Seconds()) |
| 132 | } |
| 133 | }, |
| 134 | WroteRequest: func(_ httptrace.WroteRequestInfo) { |
| 135 | if it.WroteRequest != nil { |
| 136 | it.WroteRequest(time.Since(start).Seconds()) |
| 137 | } |
| 138 | }, |
| 139 | } |
| 140 | r = r.WithContext(httptrace.WithClientTrace(context.Background(), trace)) |
| 141 | |
| 142 | return next.RoundTrip(r) |
| 143 | }) |
| 144 | } |