mirror of
https://github.com/prometheus/prometheus.git
synced 2024-11-10 15:44:05 -08:00
338 lines
9.9 KiB
Go
338 lines
9.9 KiB
Go
// Copyright 2013 Prometheus Team
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package ast
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import (
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"fmt"
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"math"
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"sort"
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"time"
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clientmodel "github.com/prometheus/client_golang/model"
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"github.com/prometheus/prometheus/utility"
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)
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// Function represents a function of the expression language and is
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// used by function nodes.
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type Function struct {
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name string
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argTypes []ExprType
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returnType ExprType
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callFn func(timestamp clientmodel.Timestamp, view *viewAdapter, args []Node) interface{}
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}
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// CheckArgTypes returns a non-nil error if the number or types of
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// passed in arg nodes do not match the function's expectations.
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func (function *Function) CheckArgTypes(args []Node) error {
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if len(function.argTypes) != len(args) {
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return fmt.Errorf(
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"wrong number of arguments to function %v(): %v expected, %v given",
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function.name, len(function.argTypes), len(args),
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)
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}
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for idx, argType := range function.argTypes {
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invalidType := false
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var expectedType string
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if _, ok := args[idx].(ScalarNode); argType == SCALAR && !ok {
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invalidType = true
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expectedType = "scalar"
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}
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if _, ok := args[idx].(VectorNode); argType == VECTOR && !ok {
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invalidType = true
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expectedType = "vector"
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}
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if _, ok := args[idx].(MatrixNode); argType == MATRIX && !ok {
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invalidType = true
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expectedType = "matrix"
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}
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if _, ok := args[idx].(StringNode); argType == STRING && !ok {
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invalidType = true
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expectedType = "string"
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}
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if invalidType {
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return fmt.Errorf(
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"wrong type for argument %v in function %v(), expected %v",
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idx, function.name, expectedType,
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)
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}
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}
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return nil
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}
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// === time() clientmodel.SampleValue ===
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func timeImpl(timestamp clientmodel.Timestamp, view *viewAdapter, args []Node) interface{} {
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return clientmodel.SampleValue(time.Now().Unix())
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}
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// === delta(matrix MatrixNode, isCounter ScalarNode) Vector ===
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func deltaImpl(timestamp clientmodel.Timestamp, view *viewAdapter, args []Node) interface{} {
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matrixNode := args[0].(MatrixNode)
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isCounter := args[1].(ScalarNode).Eval(timestamp, view) > 0
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resultVector := Vector{}
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// If we treat these metrics as counters, we need to fetch all values
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// in the interval to find breaks in the timeseries' monotonicity.
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// I.e. if a counter resets, we want to ignore that reset.
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var matrixValue Matrix
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if isCounter {
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matrixValue = matrixNode.Eval(timestamp, view)
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} else {
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matrixValue = matrixNode.EvalBoundaries(timestamp, view)
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}
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for _, samples := range matrixValue {
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// No sense in trying to compute a delta without at least two points. Drop
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// this vector element.
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if len(samples.Values) < 2 {
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continue
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}
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counterCorrection := clientmodel.SampleValue(0)
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lastValue := clientmodel.SampleValue(0)
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for _, sample := range samples.Values {
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currentValue := sample.Value
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if isCounter && currentValue < lastValue {
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counterCorrection += lastValue - currentValue
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}
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lastValue = currentValue
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}
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resultValue := lastValue - samples.Values[0].Value + counterCorrection
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targetInterval := args[0].(*MatrixSelector).interval
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sampledInterval := samples.Values[len(samples.Values)-1].Timestamp.Sub(samples.Values[0].Timestamp)
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if sampledInterval == 0 {
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// Only found one sample. Cannot compute a rate from this.
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continue
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}
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// Correct for differences in target vs. actual delta interval.
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//
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// Above, we didn't actually calculate the delta for the specified target
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// interval, but for an interval between the first and last found samples
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// under the target interval, which will usually have less time between
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// them. Depending on how many samples are found under a target interval,
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// the delta results are distorted and temporal aliasing occurs (ugly
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// bumps). This effect is corrected for below.
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intervalCorrection := clientmodel.SampleValue(targetInterval) / clientmodel.SampleValue(sampledInterval)
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resultValue *= intervalCorrection
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resultSample := &clientmodel.Sample{
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Metric: samples.Metric,
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Value: resultValue,
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Timestamp: timestamp,
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}
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resultVector = append(resultVector, resultSample)
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}
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return resultVector
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}
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// === rate(node *MatrixNode) Vector ===
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func rateImpl(timestamp clientmodel.Timestamp, view *viewAdapter, args []Node) interface{} {
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args = append(args, &ScalarLiteral{value: 1})
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vector := deltaImpl(timestamp, view, args).(Vector)
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// TODO: could be other type of MatrixNode in the future (right now, only
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// MatrixSelector exists). Find a better way of getting the duration of a
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// matrix, such as looking at the samples themselves.
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interval := args[0].(*MatrixSelector).interval
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for i := range vector {
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vector[i].Value /= clientmodel.SampleValue(interval / time.Second)
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}
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return vector
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}
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type vectorByValueSorter struct {
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vector Vector
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}
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func (sorter vectorByValueSorter) Len() int {
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return len(sorter.vector)
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}
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func (sorter vectorByValueSorter) Less(i, j int) bool {
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return sorter.vector[i].Value < sorter.vector[j].Value
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}
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func (sorter vectorByValueSorter) Swap(i, j int) {
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sorter.vector[i], sorter.vector[j] = sorter.vector[j], sorter.vector[i]
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}
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// === sort(node *VectorNode) Vector ===
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func sortImpl(timestamp clientmodel.Timestamp, view *viewAdapter, args []Node) interface{} {
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byValueSorter := vectorByValueSorter{
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vector: args[0].(VectorNode).Eval(timestamp, view),
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}
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sort.Sort(byValueSorter)
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return byValueSorter.vector
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}
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// === sortDesc(node *VectorNode) Vector ===
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func sortDescImpl(timestamp clientmodel.Timestamp, view *viewAdapter, args []Node) interface{} {
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descByValueSorter := utility.ReverseSorter{
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Interface: vectorByValueSorter{
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vector: args[0].(VectorNode).Eval(timestamp, view),
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},
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}
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sort.Sort(descByValueSorter)
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return descByValueSorter.Interface.(vectorByValueSorter).vector
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}
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// === sampleVectorImpl() Vector ===
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func sampleVectorImpl(timestamp clientmodel.Timestamp, view *viewAdapter, args []Node) interface{} {
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return Vector{
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&clientmodel.Sample{
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Metric: clientmodel.Metric{
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clientmodel.MetricNameLabel: "http_requests",
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clientmodel.JobLabel: "api-server",
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"instance": "0",
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},
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Value: 10,
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Timestamp: timestamp,
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},
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&clientmodel.Sample{
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Metric: clientmodel.Metric{
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clientmodel.MetricNameLabel: "http_requests",
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clientmodel.JobLabel: "api-server",
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"instance": "1",
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},
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Value: 20,
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Timestamp: timestamp,
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},
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&clientmodel.Sample{
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Metric: clientmodel.Metric{
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clientmodel.MetricNameLabel: "http_requests",
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clientmodel.JobLabel: "api-server",
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"instance": "2",
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},
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Value: 30,
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Timestamp: timestamp,
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},
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&clientmodel.Sample{
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Metric: clientmodel.Metric{
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clientmodel.MetricNameLabel: "http_requests",
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clientmodel.JobLabel: "api-server",
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"instance": "3",
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"group": "canary",
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},
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Value: 40,
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Timestamp: timestamp,
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},
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&clientmodel.Sample{
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Metric: clientmodel.Metric{
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clientmodel.MetricNameLabel: "http_requests",
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clientmodel.JobLabel: "api-server",
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"instance": "2",
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"group": "canary",
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},
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Value: 40,
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Timestamp: timestamp,
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},
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&clientmodel.Sample{
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Metric: clientmodel.Metric{
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clientmodel.MetricNameLabel: "http_requests",
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clientmodel.JobLabel: "api-server",
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"instance": "3",
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"group": "mytest",
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},
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Value: 40,
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Timestamp: timestamp,
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},
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&clientmodel.Sample{
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Metric: clientmodel.Metric{
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clientmodel.MetricNameLabel: "http_requests",
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clientmodel.JobLabel: "api-server",
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"instance": "3",
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"group": "mytest",
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},
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Value: 40,
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Timestamp: timestamp,
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},
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}
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}
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// === scalar(node *VectorNode) Scalar ===
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func scalarImpl(timestamp clientmodel.Timestamp, view *viewAdapter, args []Node) interface{} {
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v := args[0].(VectorNode).Eval(timestamp, view)
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if len(v) != 1 {
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return clientmodel.SampleValue(math.NaN())
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}
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return clientmodel.SampleValue(v[0].Value)
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}
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// === count_scalar(vector VectorNode) model.SampleValue ===
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func countScalarImpl(timestamp clientmodel.Timestamp, view *viewAdapter, args []Node) interface{} {
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return clientmodel.SampleValue(len(args[0].(VectorNode).Eval(timestamp, view)))
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}
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var functions = map[string]*Function{
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"count_scalar": {
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name: "count_scalar",
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argTypes: []ExprType{VECTOR},
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returnType: SCALAR,
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callFn: countScalarImpl,
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},
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"delta": {
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name: "delta",
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argTypes: []ExprType{MATRIX, SCALAR},
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returnType: VECTOR,
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callFn: deltaImpl,
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},
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"rate": {
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name: "rate",
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argTypes: []ExprType{MATRIX},
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returnType: VECTOR,
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callFn: rateImpl,
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},
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"sampleVector": {
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name: "sampleVector",
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argTypes: []ExprType{},
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returnType: VECTOR,
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callFn: sampleVectorImpl,
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},
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"scalar": {
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name: "scalar",
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argTypes: []ExprType{VECTOR},
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returnType: SCALAR,
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callFn: scalarImpl,
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},
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"sort": {
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name: "sort",
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argTypes: []ExprType{VECTOR},
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returnType: VECTOR,
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callFn: sortImpl,
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},
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"sort_desc": {
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name: "sort_desc",
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argTypes: []ExprType{VECTOR},
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returnType: VECTOR,
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callFn: sortDescImpl,
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},
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"time": {
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name: "time",
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argTypes: []ExprType{},
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returnType: SCALAR,
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callFn: timeImpl,
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},
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}
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// GetFunction returns a predefined Function object for the given
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// name.
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func GetFunction(name string) (*Function, error) {
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function, ok := functions[name]
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if !ok {
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return nil, fmt.Errorf("couldn't find function %v()", name)
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}
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return function, nil
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}
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