From ed8bc523fd0d1a66acf3fa449c453508035efdfc Mon Sep 17 00:00:00 2001 From: Kevin Lyda Date: Sun, 12 Feb 2017 14:38:12 +0000 Subject: Initial pass at prometheus support. (#56) --- .../prometheus/client_golang/prometheus/value.go | 239 +++++++++++++++++++++ 1 file changed, 239 insertions(+) create mode 100644 vendor/github.com/prometheus/client_golang/prometheus/value.go (limited to 'vendor/github.com/prometheus/client_golang/prometheus/value.go') diff --git a/vendor/github.com/prometheus/client_golang/prometheus/value.go b/vendor/github.com/prometheus/client_golang/prometheus/value.go new file mode 100644 index 0000000..7d3e810 --- /dev/null +++ b/vendor/github.com/prometheus/client_golang/prometheus/value.go @@ -0,0 +1,239 @@ +// Copyright 2014 The Prometheus Authors +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package prometheus + +import ( + "errors" + "fmt" + "math" + "sort" + "sync/atomic" + "time" + + dto "github.com/prometheus/client_model/go" + + "github.com/golang/protobuf/proto" +) + +// ValueType is an enumeration of metric types that represent a simple value. +type ValueType int + +// Possible values for the ValueType enum. +const ( + _ ValueType = iota + CounterValue + GaugeValue + UntypedValue +) + +var errInconsistentCardinality = errors.New("inconsistent label cardinality") + +// value is a generic metric for simple values. It implements Metric, Collector, +// Counter, Gauge, and Untyped. Its effective type is determined by +// ValueType. This is a low-level building block used by the library to back the +// implementations of Counter, Gauge, and Untyped. +type value struct { + // valBits containst the bits of the represented float64 value. It has + // to go first in the struct to guarantee alignment for atomic + // operations. http://golang.org/pkg/sync/atomic/#pkg-note-BUG + valBits uint64 + + selfCollector + + desc *Desc + valType ValueType + labelPairs []*dto.LabelPair +} + +// newValue returns a newly allocated value with the given Desc, ValueType, +// sample value and label values. It panics if the number of label +// values is different from the number of variable labels in Desc. +func newValue(desc *Desc, valueType ValueType, val float64, labelValues ...string) *value { + if len(labelValues) != len(desc.variableLabels) { + panic(errInconsistentCardinality) + } + result := &value{ + desc: desc, + valType: valueType, + valBits: math.Float64bits(val), + labelPairs: makeLabelPairs(desc, labelValues), + } + result.init(result) + return result +} + +func (v *value) Desc() *Desc { + return v.desc +} + +func (v *value) Set(val float64) { + atomic.StoreUint64(&v.valBits, math.Float64bits(val)) +} + +func (v *value) SetToCurrentTime() { + v.Set(float64(time.Now().UnixNano()) / 1e9) +} + +func (v *value) Inc() { + v.Add(1) +} + +func (v *value) Dec() { + v.Add(-1) +} + +func (v *value) Add(val float64) { + for { + oldBits := atomic.LoadUint64(&v.valBits) + newBits := math.Float64bits(math.Float64frombits(oldBits) + val) + if atomic.CompareAndSwapUint64(&v.valBits, oldBits, newBits) { + return + } + } +} + +func (v *value) Sub(val float64) { + v.Add(val * -1) +} + +func (v *value) Write(out *dto.Metric) error { + val := math.Float64frombits(atomic.LoadUint64(&v.valBits)) + return populateMetric(v.valType, val, v.labelPairs, out) +} + +// valueFunc is a generic metric for simple values retrieved on collect time +// from a function. It implements Metric and Collector. Its effective type is +// determined by ValueType. This is a low-level building block used by the +// library to back the implementations of CounterFunc, GaugeFunc, and +// UntypedFunc. +type valueFunc struct { + selfCollector + + desc *Desc + valType ValueType + function func() float64 + labelPairs []*dto.LabelPair +} + +// newValueFunc returns a newly allocated valueFunc with the given Desc and +// ValueType. The value reported is determined by calling the given function +// from within the Write method. Take into account that metric collection may +// happen concurrently. If that results in concurrent calls to Write, like in +// the case where a valueFunc is directly registered with Prometheus, the +// provided function must be concurrency-safe. +func newValueFunc(desc *Desc, valueType ValueType, function func() float64) *valueFunc { + result := &valueFunc{ + desc: desc, + valType: valueType, + function: function, + labelPairs: makeLabelPairs(desc, nil), + } + result.init(result) + return result +} + +func (v *valueFunc) Desc() *Desc { + return v.desc +} + +func (v *valueFunc) Write(out *dto.Metric) error { + return populateMetric(v.valType, v.function(), v.labelPairs, out) +} + +// NewConstMetric returns a metric with one fixed value that cannot be +// changed. Users of this package will not have much use for it in regular +// operations. However, when implementing custom Collectors, it is useful as a +// throw-away metric that is generated on the fly to send it to Prometheus in +// the Collect method. NewConstMetric returns an error if the length of +// labelValues is not consistent with the variable labels in Desc. +func NewConstMetric(desc *Desc, valueType ValueType, value float64, labelValues ...string) (Metric, error) { + if len(desc.variableLabels) != len(labelValues) { + return nil, errInconsistentCardinality + } + return &constMetric{ + desc: desc, + valType: valueType, + val: value, + labelPairs: makeLabelPairs(desc, labelValues), + }, nil +} + +// MustNewConstMetric is a version of NewConstMetric that panics where +// NewConstMetric would have returned an error. +func MustNewConstMetric(desc *Desc, valueType ValueType, value float64, labelValues ...string) Metric { + m, err := NewConstMetric(desc, valueType, value, labelValues...) + if err != nil { + panic(err) + } + return m +} + +type constMetric struct { + desc *Desc + valType ValueType + val float64 + labelPairs []*dto.LabelPair +} + +func (m *constMetric) Desc() *Desc { + return m.desc +} + +func (m *constMetric) Write(out *dto.Metric) error { + return populateMetric(m.valType, m.val, m.labelPairs, out) +} + +func populateMetric( + t ValueType, + v float64, + labelPairs []*dto.LabelPair, + m *dto.Metric, +) error { + m.Label = labelPairs + switch t { + case CounterValue: + m.Counter = &dto.Counter{Value: proto.Float64(v)} + case GaugeValue: + m.Gauge = &dto.Gauge{Value: proto.Float64(v)} + case UntypedValue: + m.Untyped = &dto.Untyped{Value: proto.Float64(v)} + default: + return fmt.Errorf("encountered unknown type %v", t) + } + return nil +} + +func makeLabelPairs(desc *Desc, labelValues []string) []*dto.LabelPair { + totalLen := len(desc.variableLabels) + len(desc.constLabelPairs) + if totalLen == 0 { + // Super fast path. + return nil + } + if len(desc.variableLabels) == 0 { + // Moderately fast path. + return desc.constLabelPairs + } + labelPairs := make([]*dto.LabelPair, 0, totalLen) + for i, n := range desc.variableLabels { + labelPairs = append(labelPairs, &dto.LabelPair{ + Name: proto.String(n), + Value: proto.String(labelValues[i]), + }) + } + for _, lp := range desc.constLabelPairs { + labelPairs = append(labelPairs, lp) + } + sort.Sort(LabelPairSorter(labelPairs)) + return labelPairs +} -- cgit v1.2.3