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 | package promhttp |
| 15 | |
| 16 | import ( |
| 17 | "net/http" |
| 18 | "time" |
| 19 | |
| 20 | "github.com/prometheus/client_golang/prometheus" |
| 21 | ) |
| 22 | |
| 23 | // The RoundTripperFunc type is an adapter to allow the use of ordinary |
| 24 | // functions as RoundTrippers. If f is a function with the appropriate |
| 25 | // signature, RountTripperFunc(f) is a RoundTripper that calls f. |
| 26 | type RoundTripperFunc func(req *http.Request) (*http.Response, error) |
| 27 | |
| 28 | // RoundTrip implements the RoundTripper interface. |
| 29 | func (rt RoundTripperFunc) RoundTrip(r *http.Request) (*http.Response, error) { |
| 30 | return rt(r) |
| 31 | } |
| 32 | |
| 33 | // InstrumentRoundTripperInFlight is a middleware that wraps the provided |
| 34 | // http.RoundTripper. It sets the provided prometheus.Gauge to the number of |
| 35 | // requests currently handled by the wrapped http.RoundTripper. |
| 36 | // |
| 37 | // See the example for ExampleInstrumentRoundTripperDuration for example usage. |
| 38 | func InstrumentRoundTripperInFlight(gauge prometheus.Gauge, next http.RoundTripper) RoundTripperFunc { |
| 39 | return RoundTripperFunc(func(r *http.Request) (*http.Response, error) { |
| 40 | gauge.Inc() |
| 41 | defer gauge.Dec() |
| 42 | return next.RoundTrip(r) |
| 43 | }) |
| 44 | } |
| 45 | |
| 46 | // InstrumentRoundTripperCounter is a middleware that wraps the provided |
| 47 | // http.RoundTripper to observe the request result with the provided CounterVec. |
| 48 | // The CounterVec must have zero, one, or two non-const non-curried labels. For |
| 49 | // those, the only allowed label names are "code" and "method". The function |
| 50 | // panics otherwise. Partitioning of the CounterVec happens by HTTP status code |
| 51 | // and/or HTTP method if the respective instance label names are present in the |
| 52 | // CounterVec. For unpartitioned counting, use a CounterVec with zero labels. |
| 53 | // |
| 54 | // If the wrapped RoundTripper panics or returns a non-nil error, the Counter |
| 55 | // is not incremented. |
| 56 | // |
| 57 | // See the example for ExampleInstrumentRoundTripperDuration for example usage. |
| 58 | func InstrumentRoundTripperCounter(counter *prometheus.CounterVec, next http.RoundTripper) RoundTripperFunc { |
| 59 | code, method := checkLabels(counter) |
| 60 | |
| 61 | return RoundTripperFunc(func(r *http.Request) (*http.Response, error) { |
| 62 | resp, err := next.RoundTrip(r) |
| 63 | if err == nil { |
| 64 | counter.With(labels(code, method, r.Method, resp.StatusCode)).Inc() |
| 65 | } |
| 66 | return resp, err |
| 67 | }) |
| 68 | } |
| 69 | |
| 70 | // InstrumentRoundTripperDuration is a middleware that wraps the provided |
| 71 | // http.RoundTripper to observe the request duration with the provided |
| 72 | // ObserverVec. The ObserverVec must have zero, one, or two non-const |
| 73 | // non-curried labels. For those, the only allowed label names are "code" and |
| 74 | // "method". The function panics otherwise. The Observe method of the Observer |
| 75 | // in the ObserverVec is called with the request duration in |
| 76 | // seconds. Partitioning happens by HTTP status code and/or HTTP method if the |
| 77 | // respective instance label names are present in the ObserverVec. For |
| 78 | // unpartitioned observations, use an ObserverVec with zero labels. Note that |
| 79 | // partitioning of Histograms is expensive and should be used judiciously. |
| 80 | // |
| 81 | // If the wrapped RoundTripper panics or returns a non-nil error, no values are |
| 82 | // reported. |
| 83 | // |
| 84 | // Note that this method is only guaranteed to never observe negative durations |
| 85 | // if used with Go1.9+. |
| 86 | func InstrumentRoundTripperDuration(obs prometheus.ObserverVec, next http.RoundTripper) RoundTripperFunc { |
| 87 | code, method := checkLabels(obs) |
| 88 | |
| 89 | return RoundTripperFunc(func(r *http.Request) (*http.Response, error) { |
| 90 | start := time.Now() |
| 91 | resp, err := next.RoundTrip(r) |
| 92 | if err == nil { |
| 93 | obs.With(labels(code, method, r.Method, resp.StatusCode)).Observe(time.Since(start).Seconds()) |
| 94 | } |
| 95 | return resp, err |
| 96 | }) |
| 97 | } |