prometheus/promql/value.go

536 lines
15 KiB
Go

// Copyright 2017 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 promql
import (
"encoding/json"
"errors"
"fmt"
"math"
"strconv"
"strings"
"github.com/prometheus/prometheus/model/histogram"
"github.com/prometheus/prometheus/model/labels"
"github.com/prometheus/prometheus/promql/parser"
"github.com/prometheus/prometheus/tsdb/chunkenc"
"github.com/prometheus/prometheus/util/annotations"
)
func (Matrix) Type() parser.ValueType { return parser.ValueTypeMatrix }
func (Vector) Type() parser.ValueType { return parser.ValueTypeVector }
func (Scalar) Type() parser.ValueType { return parser.ValueTypeScalar }
func (String) Type() parser.ValueType { return parser.ValueTypeString }
// String represents a string value.
type String struct {
T int64
V string
}
func (s String) String() string {
return s.V
}
func (s String) MarshalJSON() ([]byte, error) {
return json.Marshal([...]interface{}{float64(s.T) / 1000, s.V})
}
// Scalar is a data point that's explicitly not associated with a metric.
type Scalar struct {
T int64
V float64
}
func (s Scalar) String() string {
v := strconv.FormatFloat(s.V, 'f', -1, 64)
return fmt.Sprintf("scalar: %v @[%v]", v, s.T)
}
func (s Scalar) MarshalJSON() ([]byte, error) {
v := strconv.FormatFloat(s.V, 'f', -1, 64)
return json.Marshal([...]interface{}{float64(s.T) / 1000, v})
}
// Series is a stream of data points belonging to a metric.
type Series struct {
Metric labels.Labels `json:"metric"`
Floats []FPoint `json:"values,omitempty"`
Histograms []HPoint `json:"histograms,omitempty"`
// DropName is used to indicate whether the __name__ label should be dropped
// as part of the query evaluation.
DropName bool `json:"-"`
}
func (s Series) String() string {
// TODO(beorn7): This currently renders floats first and then
// histograms, each sorted by timestamp. Maybe, in mixed series, that's
// fine. Maybe, however, primary sorting by timestamp is preferred, in
// which case this has to be changed.
vals := make([]string, 0, len(s.Floats)+len(s.Histograms))
for _, f := range s.Floats {
vals = append(vals, f.String())
}
for _, h := range s.Histograms {
vals = append(vals, h.String())
}
return fmt.Sprintf("%s =>\n%s", s.Metric, strings.Join(vals, "\n"))
}
// FPoint represents a single float data point for a given timestamp.
type FPoint struct {
T int64
F float64
}
func (p FPoint) String() string {
s := strconv.FormatFloat(p.F, 'f', -1, 64)
return fmt.Sprintf("%s @[%v]", s, p.T)
}
// MarshalJSON implements json.Marshaler.
//
// JSON marshaling is only needed for the HTTP API. Since FPoint is such a
// frequently marshaled type, it gets an optimized treatment directly in
// web/api/v1/api.go. Therefore, this method is unused within Prometheus. It is
// still provided here as convenience for debugging and for other users of this
// code. Also note that the different marshaling implementations might lead to
// slightly different results in terms of formatting and rounding of the
// timestamp.
func (p FPoint) MarshalJSON() ([]byte, error) {
v := strconv.FormatFloat(p.F, 'f', -1, 64)
return json.Marshal([...]interface{}{float64(p.T) / 1000, v})
}
// HPoint represents a single histogram data point for a given timestamp.
// H must never be nil.
type HPoint struct {
T int64
H *histogram.FloatHistogram
}
func (p HPoint) String() string {
return fmt.Sprintf("%s @[%v]", p.H.String(), p.T)
}
// MarshalJSON implements json.Marshaler.
//
// JSON marshaling is only needed for the HTTP API. Since HPoint is such a
// frequently marshaled type, it gets an optimized treatment directly in
// web/api/v1/api.go. Therefore, this method is unused within Prometheus. It is
// still provided here as convenience for debugging and for other users of this
// code. Also note that the different marshaling implementations might lead to
// slightly different results in terms of formatting and rounding of the
// timestamp.
func (p HPoint) MarshalJSON() ([]byte, error) {
h := struct {
Count string `json:"count"`
Sum string `json:"sum"`
Buckets [][]interface{} `json:"buckets,omitempty"`
}{
Count: strconv.FormatFloat(p.H.Count, 'f', -1, 64),
Sum: strconv.FormatFloat(p.H.Sum, 'f', -1, 64),
}
it := p.H.AllBucketIterator()
for it.Next() {
bucket := it.At()
if bucket.Count == 0 {
continue // No need to expose empty buckets in JSON.
}
boundaries := 2 // Exclusive on both sides AKA open interval.
if bucket.LowerInclusive {
if bucket.UpperInclusive {
boundaries = 3 // Inclusive on both sides AKA closed interval.
} else {
boundaries = 1 // Inclusive only on lower end AKA right open.
}
} else {
if bucket.UpperInclusive {
boundaries = 0 // Inclusive only on upper end AKA left open.
}
}
bucketToMarshal := []interface{}{
boundaries,
strconv.FormatFloat(bucket.Lower, 'f', -1, 64),
strconv.FormatFloat(bucket.Upper, 'f', -1, 64),
strconv.FormatFloat(bucket.Count, 'f', -1, 64),
}
h.Buckets = append(h.Buckets, bucketToMarshal)
}
return json.Marshal([...]interface{}{float64(p.T) / 1000, h})
}
// size returns the size of the HPoint compared to the size of an FPoint.
// The total size is calculated considering the histogram timestamp (p.T - 8 bytes),
// and then a number of bytes in the histogram.
// This sum is divided by 16, as samples are 16 bytes.
func (p HPoint) size() int {
return (p.H.Size() + 8) / 16
}
// totalHPointSize returns the total number of samples in the given slice of HPoints.
func totalHPointSize(histograms []HPoint) int {
var total int
for _, h := range histograms {
total += h.size()
}
return total
}
// Sample is a single sample belonging to a metric. It represents either a float
// sample or a histogram sample. If H is nil, it is a float sample. Otherwise,
// it is a histogram sample.
type Sample struct {
T int64
F float64
H *histogram.FloatHistogram
Metric labels.Labels
// DropName is used to indicate whether the __name__ label should be dropped
// as part of the query evaluation.
DropName bool
}
func (s Sample) String() string {
var str string
if s.H == nil {
p := FPoint{T: s.T, F: s.F}
str = p.String()
} else {
p := HPoint{T: s.T, H: s.H}
str = p.String()
}
return fmt.Sprintf("%s => %s", s.Metric, str)
}
// MarshalJSON is mirrored in web/api/v1/api.go with jsoniter because FPoint and
// HPoint wouldn't be marshaled with jsoniter otherwise.
func (s Sample) MarshalJSON() ([]byte, error) {
if s.H == nil {
f := struct {
M labels.Labels `json:"metric"`
F FPoint `json:"value"`
}{
M: s.Metric,
F: FPoint{T: s.T, F: s.F},
}
return json.Marshal(f)
}
h := struct {
M labels.Labels `json:"metric"`
H HPoint `json:"histogram"`
}{
M: s.Metric,
H: HPoint{T: s.T, H: s.H},
}
return json.Marshal(h)
}
// Vector is basically only an alias for []Sample, but the contract is that
// in a Vector, all Samples have the same timestamp.
type Vector []Sample
func (vec Vector) String() string {
entries := make([]string, len(vec))
for i, s := range vec {
entries[i] = s.String()
}
return strings.Join(entries, "\n")
}
// TotalSamples returns the total number of samples in the series within a vector.
// Float samples have a weight of 1 in this number, while histogram samples have a higher
// weight according to their size compared with the size of a float sample.
// See HPoint.size for details.
func (vec Vector) TotalSamples() int {
numSamples := 0
for _, sample := range vec {
numSamples++
if sample.H != nil {
numSamples += sample.H.Size() / 16
}
}
return numSamples
}
// ContainsSameLabelset checks if a vector has samples with the same labelset
// Such a behavior is semantically undefined
// https://github.com/prometheus/prometheus/issues/4562
func (vec Vector) ContainsSameLabelset() bool {
switch len(vec) {
case 0, 1:
return false
case 2:
return vec[0].Metric.Hash() == vec[1].Metric.Hash()
default:
l := make(map[uint64]struct{}, len(vec))
for _, ss := range vec {
hash := ss.Metric.Hash()
if _, ok := l[hash]; ok {
return true
}
l[hash] = struct{}{}
}
return false
}
}
// Matrix is a slice of Series that implements sort.Interface and
// has a String method.
type Matrix []Series
func (m Matrix) String() string {
// TODO(fabxc): sort, or can we rely on order from the querier?
strs := make([]string, len(m))
for i, ss := range m {
strs[i] = ss.String()
}
return strings.Join(strs, "\n")
}
// TotalSamples returns the total number of samples in the series within a matrix.
// Float samples have a weight of 1 in this number, while histogram samples have a higher
// weight according to their size compared with the size of a float sample.
// See HPoint.size for details.
func (m Matrix) TotalSamples() int {
numSamples := 0
for _, series := range m {
numSamples += len(series.Floats) + totalHPointSize(series.Histograms)
}
return numSamples
}
func (m Matrix) Len() int { return len(m) }
func (m Matrix) Less(i, j int) bool { return labels.Compare(m[i].Metric, m[j].Metric) < 0 }
func (m Matrix) Swap(i, j int) { m[i], m[j] = m[j], m[i] }
// ContainsSameLabelset checks if a matrix has samples with the same labelset.
// Such a behavior is semantically undefined.
// https://github.com/prometheus/prometheus/issues/4562
func (m Matrix) ContainsSameLabelset() bool {
switch len(m) {
case 0, 1:
return false
case 2:
return m[0].Metric.Hash() == m[1].Metric.Hash()
default:
l := make(map[uint64]struct{}, len(m))
for _, ss := range m {
hash := ss.Metric.Hash()
if _, ok := l[hash]; ok {
return true
}
l[hash] = struct{}{}
}
return false
}
}
// Result holds the resulting value of an execution or an error
// if any occurred.
type Result struct {
Err error
Value parser.Value
Warnings annotations.Annotations
}
// Vector returns a Vector if the result value is one. An error is returned if
// the result was an error or the result value is not a Vector.
func (r *Result) Vector() (Vector, error) {
if r.Err != nil {
return nil, r.Err
}
v, ok := r.Value.(Vector)
if !ok {
return nil, errors.New("query result is not a Vector")
}
return v, nil
}
// Matrix returns a Matrix. An error is returned if
// the result was an error or the result value is not a Matrix.
func (r *Result) Matrix() (Matrix, error) {
if r.Err != nil {
return nil, r.Err
}
v, ok := r.Value.(Matrix)
if !ok {
return nil, errors.New("query result is not a range Vector")
}
return v, nil
}
// Scalar returns a Scalar value. An error is returned if
// the result was an error or the result value is not a Scalar.
func (r *Result) Scalar() (Scalar, error) {
if r.Err != nil {
return Scalar{}, r.Err
}
v, ok := r.Value.(Scalar)
if !ok {
return Scalar{}, errors.New("query result is not a Scalar")
}
return v, nil
}
func (r *Result) String() string {
if r.Err != nil {
return r.Err.Error()
}
if r.Value == nil {
return ""
}
return r.Value.String()
}
// StorageSeries simulates promql.Series as storage.Series.
type StorageSeries struct {
series Series
}
// NewStorageSeries returns a StorageSeries from a Series.
func NewStorageSeries(series Series) *StorageSeries {
return &StorageSeries{
series: series,
}
}
func (ss *StorageSeries) Labels() labels.Labels {
return ss.series.Metric
}
// Iterator returns a new iterator of the data of the series. In case of
// multiple samples with the same timestamp, it returns the float samples first.
func (ss *StorageSeries) Iterator(it chunkenc.Iterator) chunkenc.Iterator {
if ssi, ok := it.(*storageSeriesIterator); ok {
ssi.reset(ss.series)
return ssi
}
return newStorageSeriesIterator(ss.series)
}
type storageSeriesIterator struct {
floats []FPoint
histograms []HPoint
iFloats, iHistograms int
currT int64
currF float64
currH *histogram.FloatHistogram
}
func newStorageSeriesIterator(series Series) *storageSeriesIterator {
return &storageSeriesIterator{
floats: series.Floats,
histograms: series.Histograms,
iFloats: -1,
iHistograms: 0,
currT: math.MinInt64,
}
}
func (ssi *storageSeriesIterator) reset(series Series) {
ssi.floats = series.Floats
ssi.histograms = series.Histograms
ssi.iFloats = -1
ssi.iHistograms = 0
ssi.currT = math.MinInt64
ssi.currF = 0
ssi.currH = nil
}
func (ssi *storageSeriesIterator) Seek(t int64) chunkenc.ValueType {
if ssi.iFloats >= len(ssi.floats) && ssi.iHistograms >= len(ssi.histograms) {
return chunkenc.ValNone
}
for ssi.currT < t {
if ssi.Next() == chunkenc.ValNone {
return chunkenc.ValNone
}
}
if ssi.currH != nil {
return chunkenc.ValFloatHistogram
}
return chunkenc.ValFloat
}
func (ssi *storageSeriesIterator) At() (t int64, v float64) {
return ssi.currT, ssi.currF
}
func (ssi *storageSeriesIterator) AtHistogram(*histogram.Histogram) (int64, *histogram.Histogram) {
panic(errors.New("storageSeriesIterator: AtHistogram not supported"))
}
func (ssi *storageSeriesIterator) AtFloatHistogram(*histogram.FloatHistogram) (int64, *histogram.FloatHistogram) {
return ssi.currT, ssi.currH
}
func (ssi *storageSeriesIterator) AtT() int64 {
return ssi.currT
}
func (ssi *storageSeriesIterator) Next() chunkenc.ValueType {
if ssi.currH != nil {
ssi.iHistograms++
} else {
ssi.iFloats++
}
var (
pickH, pickF = false, false
floatsExhausted = ssi.iFloats >= len(ssi.floats)
histogramsExhausted = ssi.iHistograms >= len(ssi.histograms)
)
switch {
case floatsExhausted:
if histogramsExhausted { // Both exhausted!
return chunkenc.ValNone
}
pickH = true
case histogramsExhausted: // and floats not exhausted.
pickF = true
// From here on, we have to look at timestamps.
case ssi.histograms[ssi.iHistograms].T < ssi.floats[ssi.iFloats].T:
// Next histogram comes before next float.
pickH = true
default:
// In all other cases, we pick float so that we first iterate
// through floats if the timestamp is the same.
pickF = true
}
switch {
case pickF:
p := ssi.floats[ssi.iFloats]
ssi.currT = p.T
ssi.currF = p.F
ssi.currH = nil
return chunkenc.ValFloat
case pickH:
p := ssi.histograms[ssi.iHistograms]
ssi.currT = p.T
ssi.currF = 0
ssi.currH = p.H
return chunkenc.ValFloatHistogram
default:
panic("storageSeriesIterater.Next failed to pick value type")
}
}
func (ssi *storageSeriesIterator) Err() error {
return nil
}