diff options
Diffstat (limited to 'vendor/github.com/prometheus/client_golang/prometheus/vec.go')
| -rw-r--r-- | vendor/github.com/prometheus/client_golang/prometheus/vec.go | 491 |
1 files changed, 213 insertions, 278 deletions
diff --git a/vendor/github.com/prometheus/client_golang/prometheus/vec.go b/vendor/github.com/prometheus/client_golang/prometheus/vec.go index cea158249..7f3eef9a4 100644 --- a/vendor/github.com/prometheus/client_golang/prometheus/vec.go +++ b/vendor/github.com/prometheus/client_golang/prometheus/vec.go @@ -20,253 +20,200 @@ import ( "github.com/prometheus/common/model" ) -// metricVec is a Collector to bundle metrics of the same name that differ in -// their label values. metricVec is not used directly (and therefore -// unexported). It is used as a building block for implementations of vectors of -// a given metric type, like GaugeVec, CounterVec, SummaryVec, and HistogramVec. -// It also handles label currying. It uses basicMetricVec internally. -type metricVec struct { - *metricMap - - curry []curriedLabelValue - - // hashAdd and hashAddByte can be replaced for testing collision handling. - hashAdd func(h uint64, s string) uint64 +// 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. -func newMetricVec(desc *Desc, newMetric func(lvs ...string) Metric) *metricVec { - return &metricVec{ - metricMap: &metricMap{ - metrics: map[uint64][]metricWithLabelValues{}, - desc: desc, - newMetric: newMetric, - }, +// 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, } } -// 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 { - h, err := m.hashLabelValues(lvs) - if err != nil { - return false - } - - return m.metricMap.deleteByHashWithLabelValues(h, lvs, m.curry) +// metricWithLabelValues provides the metric and its label values for +// disambiguation on hash collision. +type metricWithLabelValues struct { + values []string + metric Metric } -// 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 Desc. 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 { - h, err := m.hashLabels(labels) - if err != nil { - return false - } - - return m.metricMap.deleteByHashWithLabels(h, labels, m.curry) +// Describe implements Collector. The length of the returned slice +// is always one. +func (m *MetricVec) Describe(ch chan<- *Desc) { + ch <- m.desc } -func (m *metricVec) curryWith(labels Labels) (*metricVec, error) { - var ( - newCurry []curriedLabelValue - oldCurry = m.curry - iCurry int - ) - for i, label := range m.desc.variableLabels { - val, ok := labels[label] - if iCurry < len(oldCurry) && oldCurry[iCurry].index == i { - if ok { - return nil, fmt.Errorf("label name %q is already curried", label) - } - newCurry = append(newCurry, oldCurry[iCurry]) - iCurry++ - } else { - if !ok { - continue // Label stays uncurried. - } - newCurry = append(newCurry, curriedLabelValue{i, val}) +// 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 } } - if l := len(oldCurry) + len(labels) - len(newCurry); l > 0 { - return nil, fmt.Errorf("%d unknown label(s) found during currying", l) - } - - return &metricVec{ - metricMap: m.metricMap, - curry: newCurry, - hashAdd: m.hashAdd, - hashAddByte: m.hashAddByte, - }, nil } -func (m *metricVec) getMetricWithLabelValues(lvs ...string) (Metric, error) { +// 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.metricMap.getOrCreateMetricWithLabelValues(h, lvs, m.curry), nil + return m.getOrCreateMetricWithLabelValues(h, lvs), nil } -func (m *metricVec) getMetricWith(labels Labels) (Metric, error) { +// 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.metricMap.getOrCreateMetricWithLabels(h, labels, m.curry), nil + return m.getOrCreateMetricWithLabels(h, labels), nil } -func (m *metricVec) hashLabelValues(vals []string) (uint64, error) { - if err := validateLabelValues(vals, len(m.desc.variableLabels)-len(m.curry)); err != nil { - return 0, err - } - - var ( - h = hashNew() - curry = m.curry - iVals, iCurry int - ) - for i := 0; i < len(m.desc.variableLabels); i++ { - if iCurry < len(curry) && curry[iCurry].index == i { - h = m.hashAdd(h, curry[iCurry].value) - iCurry++ - } else { - h = m.hashAdd(h, vals[iVals]) - iVals++ - } - h = m.hashAddByte(h, model.SeparatorByte) +// 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 h, nil + return metric } -func (m *metricVec) hashLabels(labels Labels) (uint64, error) { - if err := validateValuesInLabels(labels, len(m.desc.variableLabels)-len(m.curry)); err != nil { - return 0, err - } - - var ( - h = hashNew() - curry = m.curry - iCurry int - ) - for i, label := range m.desc.variableLabels { - val, ok := labels[label] - if iCurry < len(curry) && curry[iCurry].index == i { - if ok { - return 0, fmt.Errorf("label name %q is already curried", label) - } - h = m.hashAdd(h, curry[iCurry].value) - iCurry++ - } else { - 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) +// 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 h, nil -} - -// metricWithLabelValues provides the metric and its label values for -// disambiguation on hash collision. -type metricWithLabelValues struct { - values []string - metric Metric -} - -// curriedLabelValue sets the curried value for a label at the given index. -type curriedLabelValue struct { - index int - value string -} - -// metricMap is a helper for metricVec and shared between differently curried -// metricVecs. -type metricMap struct { - mtx sync.RWMutex // Protects metrics. - metrics map[uint64][]metricWithLabelValues - desc *Desc - newMetric func(labelValues ...string) Metric -} - -// Describe implements Collector. It will send exactly one Desc to the provided -// channel. -func (m *metricMap) Describe(ch chan<- *Desc) { - ch <- m.desc + return metric } -// Collect implements Collector. -func (m *metricMap) Collect(ch chan<- Metric) { - m.mtx.RLock() - defer m.mtx.RUnlock() +// 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() - for _, metrics := range m.metrics { - for _, metric := range metrics { - ch <- metric.metric - } + h, err := m.hashLabelValues(lvs) + if err != nil { + return false } + return m.deleteByHashWithLabelValues(h, lvs) } -// Reset deletes all metrics in this vector. -func (m *metricMap) Reset() { +// 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() - for h := range m.metrics { - delete(m.metrics, h) + 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 *metricMap) deleteByHashWithLabelValues( - h uint64, lvs []string, curry []curriedLabelValue, -) bool { - m.mtx.Lock() - defer m.mtx.Unlock() - - metrics, ok := m.metrics[h] +func (m *MetricVec) deleteByHashWithLabelValues(h uint64, lvs []string) bool { + metrics, ok := m.children[h] if !ok { return false } - i := findMetricWithLabelValues(metrics, lvs, curry) + i := m.findMetricWithLabelValues(metrics, lvs) if i >= len(metrics) { return false } if len(metrics) > 1 { - m.metrics[h] = append(metrics[:i], metrics[i+1:]...) + m.children[h] = append(metrics[:i], metrics[i+1:]...) } else { - delete(m.metrics, h) + delete(m.children, h) } return true } @@ -274,35 +221,69 @@ func (m *metricMap) deleteByHashWithLabelValues( // 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 *metricMap) deleteByHashWithLabels( - h uint64, labels Labels, curry []curriedLabelValue, -) bool { - metrics, ok := m.metrics[h] +func (m *MetricVec) deleteByHashWithLabels(h uint64, labels Labels) bool { + metrics, ok := m.children[h] if !ok { return false } - i := findMetricWithLabels(m.desc, metrics, labels, curry) + i := m.findMetricWithLabels(metrics, labels) if i >= len(metrics) { return false } if len(metrics) > 1 { - m.metrics[h] = append(metrics[:i], metrics[i+1:]...) + m.children[h] = append(metrics[:i], metrics[i+1:]...) } else { - delete(m.metrics, h) + 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 *metricMap) getOrCreateMetricWithLabelValues( - hash uint64, lvs []string, curry []curriedLabelValue, -) Metric { +func (m *MetricVec) getOrCreateMetricWithLabelValues(hash uint64, lvs []string) Metric { m.mtx.RLock() - metric, ok := m.getMetricWithHashAndLabelValues(hash, lvs, curry) + metric, ok := m.getMetricWithLabelValues(hash, lvs) m.mtx.RUnlock() if ok { return metric @@ -310,11 +291,13 @@ func (m *metricMap) getOrCreateMetricWithLabelValues( m.mtx.Lock() defer m.mtx.Unlock() - metric, ok = m.getMetricWithHashAndLabelValues(hash, lvs, curry) + metric, ok = m.getMetricWithLabelValues(hash, lvs) if !ok { - inlinedLVs := inlineLabelValues(lvs, curry) - metric = m.newMetric(inlinedLVs...) - m.metrics[hash] = append(m.metrics[hash], metricWithLabelValues{values: inlinedLVs, metric: metric}) + // 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 } @@ -323,11 +306,9 @@ func (m *metricMap) getOrCreateMetricWithLabelValues( // or creates it and returns the new one. // // This function holds the mutex. -func (m *metricMap) getOrCreateMetricWithLabels( - hash uint64, labels Labels, curry []curriedLabelValue, -) Metric { +func (m *MetricVec) getOrCreateMetricWithLabels(hash uint64, labels Labels) Metric { m.mtx.RLock() - metric, ok := m.getMetricWithHashAndLabels(hash, labels, curry) + metric, ok := m.getMetricWithLabels(hash, labels) m.mtx.RUnlock() if ok { return metric @@ -335,37 +316,33 @@ func (m *metricMap) getOrCreateMetricWithLabels( m.mtx.Lock() defer m.mtx.Unlock() - metric, ok = m.getMetricWithHashAndLabels(hash, labels, curry) + metric, ok = m.getMetricWithLabels(hash, labels) if !ok { - lvs := extractLabelValues(m.desc, labels, curry) + lvs := m.extractLabelValues(labels) metric = m.newMetric(lvs...) - m.metrics[hash] = append(m.metrics[hash], metricWithLabelValues{values: lvs, metric: metric}) + m.children[hash] = append(m.children[hash], metricWithLabelValues{values: lvs, metric: metric}) } return metric } -// getMetricWithHashAndLabelValues gets a metric while handling possible -// collisions in the hash space. Must be called while holding the read mutex. -func (m *metricMap) getMetricWithHashAndLabelValues( - h uint64, lvs []string, curry []curriedLabelValue, -) (Metric, bool) { - metrics, ok := m.metrics[h] +// 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 := findMetricWithLabelValues(metrics, lvs, curry); i < len(metrics) { + if i := m.findMetricWithLabelValues(metrics, lvs); i < len(metrics) { return metrics[i].metric, true } } return nil, false } -// getMetricWithHashAndLabels gets a metric while handling possible collisions in +// getMetricWithLabels gets a metric while handling possible collisions in // the hash space. Must be called while holding read mutex. -func (m *metricMap) getMetricWithHashAndLabels( - h uint64, labels Labels, curry []curriedLabelValue, -) (Metric, bool) { - metrics, ok := m.metrics[h] +func (m *MetricVec) getMetricWithLabels(h uint64, labels Labels) (Metric, bool) { + metrics, ok := m.children[h] if ok { - if i := findMetricWithLabels(m.desc, metrics, labels, curry); i < len(metrics) { + if i := m.findMetricWithLabels(metrics, labels); i < len(metrics) { return metrics[i].metric, true } } @@ -374,11 +351,9 @@ func (m *metricMap) getMetricWithHashAndLabels( // findMetricWithLabelValues returns the index of the matching metric or // len(metrics) if not found. -func findMetricWithLabelValues( - metrics []metricWithLabelValues, lvs []string, curry []curriedLabelValue, -) int { +func (m *MetricVec) findMetricWithLabelValues(metrics []metricWithLabelValues, lvs []string) int { for i, metric := range metrics { - if matchLabelValues(metric.values, lvs, curry) { + if m.matchLabelValues(metric.values, lvs) { return i } } @@ -387,51 +362,32 @@ func findMetricWithLabelValues( // findMetricWithLabels returns the index of the matching metric or len(metrics) // if not found. -func findMetricWithLabels( - desc *Desc, metrics []metricWithLabelValues, labels Labels, curry []curriedLabelValue, -) int { +func (m *MetricVec) findMetricWithLabels(metrics []metricWithLabelValues, labels Labels) int { for i, metric := range metrics { - if matchLabels(desc, metric.values, labels, curry) { + if m.matchLabels(metric.values, labels) { return i } } return len(metrics) } -func matchLabelValues(values []string, lvs []string, curry []curriedLabelValue) bool { - if len(values) != len(lvs)+len(curry) { +func (m *MetricVec) matchLabelValues(values []string, lvs []string) bool { + if len(values) != len(lvs) { return false } - var iLVs, iCurry int for i, v := range values { - if iCurry < len(curry) && curry[iCurry].index == i { - if v != curry[iCurry].value { - return false - } - iCurry++ - continue - } - if v != lvs[iLVs] { + if v != lvs[i] { return false } - iLVs++ } return true } -func matchLabels(desc *Desc, values []string, labels Labels, curry []curriedLabelValue) bool { - if len(values) != len(labels)+len(curry) { +func (m *MetricVec) matchLabels(values []string, labels Labels) bool { + if len(labels) != len(values) { return false } - iCurry := 0 - for i, k := range desc.variableLabels { - if iCurry < len(curry) && curry[iCurry].index == i { - if values[i] != curry[iCurry].value { - return false - } - iCurry++ - continue - } + for i, k := range m.desc.variableLabels { if values[i] != labels[k] { return false } @@ -439,31 +395,10 @@ func matchLabels(desc *Desc, values []string, labels Labels, curry []curriedLabe return true } -func extractLabelValues(desc *Desc, labels Labels, curry []curriedLabelValue) []string { - labelValues := make([]string, len(labels)+len(curry)) - iCurry := 0 - for i, k := range desc.variableLabels { - if iCurry < len(curry) && curry[iCurry].index == i { - labelValues[i] = curry[iCurry].value - iCurry++ - continue - } +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 } - -func inlineLabelValues(lvs []string, curry []curriedLabelValue) []string { - labelValues := make([]string, len(lvs)+len(curry)) - var iCurry, iLVs int - for i := range labelValues { - if iCurry < len(curry) && curry[iCurry].index == i { - labelValues[i] = curry[iCurry].value - iCurry++ - continue - } - labelValues[i] = lvs[iLVs] - iLVs++ - } - return labelValues -} |