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 prometheus |
| 15 | |
| 16 | // Observer is the interface that wraps the Observe method, which is used by |
| 17 | // Histogram and Summary to add observations. |
| 18 | type Observer interface { |
| 19 | Observe(float64) |
| 20 | } |
| 21 | |
| 22 | // The ObserverFunc type is an adapter to allow the use of ordinary |
| 23 | // functions as Observers. If f is a function with the appropriate |
| 24 | // signature, ObserverFunc(f) is an Observer that calls f. |
| 25 | // |
| 26 | // This adapter is usually used in connection with the Timer type, and there are |
| 27 | // two general use cases: |
| 28 | // |
| 29 | // The most common one is to use a Gauge as the Observer for a Timer. |
| 30 | // See the "Gauge" Timer example. |
| 31 | // |
| 32 | // The more advanced use case is to create a function that dynamically decides |
| 33 | // which Observer to use for observing the duration. See the "Complex" Timer |
| 34 | // example. |
| 35 | type ObserverFunc func(float64) |
| 36 | |
| 37 | // Observe calls f(value). It implements Observer. |
| 38 | func (f ObserverFunc) Observe(value float64) { |
| 39 | f(value) |
| 40 | } |
| 41 | |
| 42 | // ObserverVec is an interface implemented by `HistogramVec` and `SummaryVec`. |
| 43 | type ObserverVec interface { |
| 44 | GetMetricWith(Labels) (Observer, error) |
| 45 | GetMetricWithLabelValues(lvs ...string) (Observer, error) |
| 46 | With(Labels) Observer |
| 47 | WithLabelValues(...string) Observer |
| 48 | CurryWith(Labels) (ObserverVec, error) |
| 49 | MustCurryWith(Labels) ObserverVec |
| 50 | |
| 51 | Collector |
| 52 | } |
khenaidoo | d948f77 | 2021-08-11 17:49:24 -0400 | [diff] [blame^] | 53 | |
| 54 | // ExemplarObserver is implemented by Observers that offer the option of |
| 55 | // observing a value together with an exemplar. Its ObserveWithExemplar method |
| 56 | // works like the Observe method of an Observer but also replaces the currently |
| 57 | // saved exemplar (if any) with a new one, created from the provided value, the |
| 58 | // current time as timestamp, and the provided Labels. Empty Labels will lead to |
| 59 | // a valid (label-less) exemplar. But if Labels is nil, the current exemplar is |
| 60 | // left in place. ObserveWithExemplar panics if any of the provided labels are |
| 61 | // invalid or if the provided labels contain more than 64 runes in total. |
| 62 | type ExemplarObserver interface { |
| 63 | ObserveWithExemplar(value float64, exemplar Labels) |
| 64 | } |