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/vec.go | 404 +++++++++++++++++++++ 1 file changed, 404 insertions(+) create mode 100644 vendor/github.com/prometheus/client_golang/prometheus/vec.go (limited to 'vendor/github.com/prometheus/client_golang/prometheus/vec.go') diff --git a/vendor/github.com/prometheus/client_golang/prometheus/vec.go b/vendor/github.com/prometheus/client_golang/prometheus/vec.go new file mode 100644 index 0000000..7f3eef9 --- /dev/null +++ b/vendor/github.com/prometheus/client_golang/prometheus/vec.go @@ -0,0 +1,404 @@ +// 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 ( + "fmt" + "sync" + + "github.com/prometheus/common/model" +) + +// MetricVec is a Collector to bundle metrics of the same name that +// differ in their label values. MetricVec is usually not used directly but as a +// building block for implementations of vectors of a given metric +// type. GaugeVec, CounterVec, SummaryVec, and UntypedVec are examples already +// provided in this package. +type MetricVec struct { + mtx sync.RWMutex // Protects the children. + children map[uint64][]metricWithLabelValues + desc *Desc + + newMetric func(labelValues ...string) Metric + hashAdd func(h uint64, s string) uint64 // replace hash function for testing collision handling + hashAddByte func(h uint64, b byte) uint64 +} + +// newMetricVec returns an initialized MetricVec. The concrete value is +// returned for embedding into another struct. +func newMetricVec(desc *Desc, newMetric func(lvs ...string) Metric) *MetricVec { + return &MetricVec{ + children: map[uint64][]metricWithLabelValues{}, + desc: desc, + newMetric: newMetric, + hashAdd: hashAdd, + hashAddByte: hashAddByte, + } +} + +// metricWithLabelValues provides the metric and its label values for +// disambiguation on hash collision. +type metricWithLabelValues struct { + values []string + metric Metric +} + +// Describe implements Collector. The length of the returned slice +// is always one. +func (m *MetricVec) Describe(ch chan<- *Desc) { + ch <- m.desc +} + +// Collect implements Collector. +func (m *MetricVec) Collect(ch chan<- Metric) { + m.mtx.RLock() + defer m.mtx.RUnlock() + + for _, metrics := range m.children { + for _, metric := range metrics { + ch <- metric.metric + } + } +} + +// GetMetricWithLabelValues returns the Metric for the given slice of label +// values (same order as the VariableLabels in Desc). If that combination of +// label values is accessed for the first time, a new Metric is created. +// +// It is possible to call this method without using the returned Metric to only +// create the new Metric but leave it at its start value (e.g. a Summary or +// Histogram without any observations). See also the SummaryVec example. +// +// Keeping the Metric for later use is possible (and should be considered if +// performance is critical), but keep in mind that Reset, DeleteLabelValues and +// Delete can be used to delete the Metric from the MetricVec. In that case, the +// Metric will still exist, but it will not be exported anymore, even if a +// Metric with the same label values is created later. See also the CounterVec +// example. +// +// An error is returned if the number of label values is not the same as the +// number of VariableLabels in Desc. +// +// Note that for more than one label value, this method is prone to mistakes +// caused by an incorrect order of arguments. Consider GetMetricWith(Labels) as +// an alternative to avoid that type of mistake. For higher label numbers, the +// latter has a much more readable (albeit more verbose) syntax, but it comes +// with a performance overhead (for creating and processing the Labels map). +// See also the GaugeVec example. +func (m *MetricVec) GetMetricWithLabelValues(lvs ...string) (Metric, error) { + h, err := m.hashLabelValues(lvs) + if err != nil { + return nil, err + } + + return m.getOrCreateMetricWithLabelValues(h, lvs), nil +} + +// GetMetricWith returns the Metric for the given Labels map (the label names +// must match those of the VariableLabels in Desc). If that label map is +// accessed for the first time, a new Metric is created. Implications of +// creating a Metric without using it and keeping the Metric for later use are +// the same as for GetMetricWithLabelValues. +// +// An error is returned if the number and names of the Labels are inconsistent +// with those of the VariableLabels in Desc. +// +// This method is used for the same purpose as +// GetMetricWithLabelValues(...string). See there for pros and cons of the two +// methods. +func (m *MetricVec) GetMetricWith(labels Labels) (Metric, error) { + h, err := m.hashLabels(labels) + if err != nil { + return nil, err + } + + return m.getOrCreateMetricWithLabels(h, labels), nil +} + +// WithLabelValues works as GetMetricWithLabelValues, but panics if an error +// occurs. The method allows neat syntax like: +// httpReqs.WithLabelValues("404", "POST").Inc() +func (m *MetricVec) WithLabelValues(lvs ...string) Metric { + metric, err := m.GetMetricWithLabelValues(lvs...) + if err != nil { + panic(err) + } + return metric +} + +// With works as GetMetricWith, but panics if an error occurs. The method allows +// neat syntax like: +// httpReqs.With(Labels{"status":"404", "method":"POST"}).Inc() +func (m *MetricVec) With(labels Labels) Metric { + metric, err := m.GetMetricWith(labels) + if err != nil { + panic(err) + } + return metric +} + +// DeleteLabelValues removes the metric where the variable labels are the same +// as those passed in as labels (same order as the VariableLabels in Desc). It +// returns true if a metric was deleted. +// +// It is not an error if the number of label values is not the same as the +// number of VariableLabels in Desc. However, such inconsistent label count can +// never match an actual Metric, so the method will always return false in that +// case. +// +// Note that for more than one label value, this method is prone to mistakes +// caused by an incorrect order of arguments. Consider Delete(Labels) as an +// alternative to avoid that type of mistake. For higher label numbers, the +// latter has a much more readable (albeit more verbose) syntax, but it comes +// with a performance overhead (for creating and processing the Labels map). +// See also the CounterVec example. +func (m *MetricVec) DeleteLabelValues(lvs ...string) bool { + m.mtx.Lock() + defer m.mtx.Unlock() + + h, err := m.hashLabelValues(lvs) + if err != nil { + return false + } + return m.deleteByHashWithLabelValues(h, lvs) +} + +// Delete deletes the metric where the variable labels are the same as those +// passed in as labels. It returns true if a metric was deleted. +// +// It is not an error if the number and names of the Labels are inconsistent +// with those of the VariableLabels in the Desc of the MetricVec. However, such +// inconsistent Labels can never match an actual Metric, so the method will +// always return false in that case. +// +// This method is used for the same purpose as DeleteLabelValues(...string). See +// there for pros and cons of the two methods. +func (m *MetricVec) Delete(labels Labels) bool { + m.mtx.Lock() + defer m.mtx.Unlock() + + h, err := m.hashLabels(labels) + if err != nil { + return false + } + + return m.deleteByHashWithLabels(h, labels) +} + +// deleteByHashWithLabelValues removes the metric from the hash bucket h. If +// there are multiple matches in the bucket, use lvs to select a metric and +// remove only that metric. +func (m *MetricVec) deleteByHashWithLabelValues(h uint64, lvs []string) bool { + metrics, ok := m.children[h] + if !ok { + return false + } + + i := m.findMetricWithLabelValues(metrics, lvs) + if i >= len(metrics) { + return false + } + + if len(metrics) > 1 { + m.children[h] = append(metrics[:i], metrics[i+1:]...) + } else { + delete(m.children, h) + } + return true +} + +// deleteByHashWithLabels removes the metric from the hash bucket h. If there +// are multiple matches in the bucket, use lvs to select a metric and remove +// only that metric. +func (m *MetricVec) deleteByHashWithLabels(h uint64, labels Labels) bool { + metrics, ok := m.children[h] + if !ok { + return false + } + i := m.findMetricWithLabels(metrics, labels) + if i >= len(metrics) { + return false + } + + if len(metrics) > 1 { + m.children[h] = append(metrics[:i], metrics[i+1:]...) + } else { + delete(m.children, h) + } + return true +} + +// Reset deletes all metrics in this vector. +func (m *MetricVec) Reset() { + m.mtx.Lock() + defer m.mtx.Unlock() + + for h := range m.children { + delete(m.children, h) + } +} + +func (m *MetricVec) hashLabelValues(vals []string) (uint64, error) { + if len(vals) != len(m.desc.variableLabels) { + return 0, errInconsistentCardinality + } + h := hashNew() + for _, val := range vals { + h = m.hashAdd(h, val) + h = m.hashAddByte(h, model.SeparatorByte) + } + return h, nil +} + +func (m *MetricVec) hashLabels(labels Labels) (uint64, error) { + if len(labels) != len(m.desc.variableLabels) { + return 0, errInconsistentCardinality + } + h := hashNew() + for _, label := range m.desc.variableLabels { + val, ok := labels[label] + if !ok { + return 0, fmt.Errorf("label name %q missing in label map", label) + } + h = m.hashAdd(h, val) + h = m.hashAddByte(h, model.SeparatorByte) + } + return h, nil +} + +// getOrCreateMetricWithLabelValues retrieves the metric by hash and label value +// or creates it and returns the new one. +// +// This function holds the mutex. +func (m *MetricVec) getOrCreateMetricWithLabelValues(hash uint64, lvs []string) Metric { + m.mtx.RLock() + metric, ok := m.getMetricWithLabelValues(hash, lvs) + m.mtx.RUnlock() + if ok { + return metric + } + + m.mtx.Lock() + defer m.mtx.Unlock() + metric, ok = m.getMetricWithLabelValues(hash, lvs) + if !ok { + // Copy to avoid allocation in case wo don't go down this code path. + copiedLVs := make([]string, len(lvs)) + copy(copiedLVs, lvs) + metric = m.newMetric(copiedLVs...) + m.children[hash] = append(m.children[hash], metricWithLabelValues{values: copiedLVs, metric: metric}) + } + return metric +} + +// getOrCreateMetricWithLabelValues retrieves the metric by hash and label value +// or creates it and returns the new one. +// +// This function holds the mutex. +func (m *MetricVec) getOrCreateMetricWithLabels(hash uint64, labels Labels) Metric { + m.mtx.RLock() + metric, ok := m.getMetricWithLabels(hash, labels) + m.mtx.RUnlock() + if ok { + return metric + } + + m.mtx.Lock() + defer m.mtx.Unlock() + metric, ok = m.getMetricWithLabels(hash, labels) + if !ok { + lvs := m.extractLabelValues(labels) + metric = m.newMetric(lvs...) + m.children[hash] = append(m.children[hash], metricWithLabelValues{values: lvs, metric: metric}) + } + return metric +} + +// getMetricWithLabelValues gets a metric while handling possible collisions in +// the hash space. Must be called while holding read mutex. +func (m *MetricVec) getMetricWithLabelValues(h uint64, lvs []string) (Metric, bool) { + metrics, ok := m.children[h] + if ok { + if i := m.findMetricWithLabelValues(metrics, lvs); i < len(metrics) { + return metrics[i].metric, true + } + } + return nil, false +} + +// getMetricWithLabels gets a metric while handling possible collisions in +// the hash space. Must be called while holding read mutex. +func (m *MetricVec) getMetricWithLabels(h uint64, labels Labels) (Metric, bool) { + metrics, ok := m.children[h] + if ok { + if i := m.findMetricWithLabels(metrics, labels); i < len(metrics) { + return metrics[i].metric, true + } + } + return nil, false +} + +// findMetricWithLabelValues returns the index of the matching metric or +// len(metrics) if not found. +func (m *MetricVec) findMetricWithLabelValues(metrics []metricWithLabelValues, lvs []string) int { + for i, metric := range metrics { + if m.matchLabelValues(metric.values, lvs) { + return i + } + } + return len(metrics) +} + +// findMetricWithLabels returns the index of the matching metric or len(metrics) +// if not found. +func (m *MetricVec) findMetricWithLabels(metrics []metricWithLabelValues, labels Labels) int { + for i, metric := range metrics { + if m.matchLabels(metric.values, labels) { + return i + } + } + return len(metrics) +} + +func (m *MetricVec) matchLabelValues(values []string, lvs []string) bool { + if len(values) != len(lvs) { + return false + } + for i, v := range values { + if v != lvs[i] { + return false + } + } + return true +} + +func (m *MetricVec) matchLabels(values []string, labels Labels) bool { + if len(labels) != len(values) { + return false + } + for i, k := range m.desc.variableLabels { + if values[i] != labels[k] { + return false + } + } + return true +} + +func (m *MetricVec) extractLabelValues(labels Labels) []string { + labelValues := make([]string, len(labels)) + for i, k := range m.desc.variableLabels { + labelValues[i] = labels[k] + } + return labelValues +} -- cgit v1.2.3