prometheus/promql/parser/functions.go
beorn7 9eafed0f79 promql: Add histogram_count and histogram_sum
This follow a simple function-based approach to access the count and
sum fields of a native Histogram. It might be more elegant to
implement “accessors” via the dot operator, as considered in the
brainstorming doc [1]. However, that would require the introduction of
a whole new concept in PromQL. For the PoC, we should be fine with the
function-based approch. Even the obvious inefficiencies (rate'ing a
whole histogram twice when we only want to rate each the count and the
sum once) could be optimized behind the scenes.

Note that the function-based approach elegantly solves the problem of
detecting counter resets in the sum of observations in the case of
negative observations. (Since the whole native Histogram is rate'd,
the counter reset is detected for the Histogram as a whole.)

We will decide later if an “accessor” approach is really needed. It
would change the example expression for average duration in
functions.md from

      histogram_sum(rate(http_request_duration_seconds[10m]))
	/
      histogram_count(rate(http_request_duration_seconds[10m]))

to

      rate(http_request_duration_seconds.sum[10m])
	/
      rate(http_request_duration_seconds.count[10m])

[1]: https://docs.google.com/document/d/1ch6ru8GKg03N02jRjYriurt-CZqUVY09evPg6yKTA1s/edit

Signed-off-by: beorn7 <beorn@grafana.com>
2022-06-28 18:16:48 +02:00

394 lines
9.7 KiB
Go

// Copyright 2015 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 parser
// Function represents a function of the expression language and is
// used by function nodes.
type Function struct {
Name string
ArgTypes []ValueType
Variadic int
ReturnType ValueType
}
// Functions is a list of all functions supported by PromQL, including their types.
var Functions = map[string]*Function{
"abs": {
Name: "abs",
ArgTypes: []ValueType{ValueTypeVector},
ReturnType: ValueTypeVector,
},
"absent": {
Name: "absent",
ArgTypes: []ValueType{ValueTypeVector},
ReturnType: ValueTypeVector,
},
"absent_over_time": {
Name: "absent_over_time",
ArgTypes: []ValueType{ValueTypeMatrix},
ReturnType: ValueTypeVector,
},
"acos": {
Name: "acos",
ArgTypes: []ValueType{ValueTypeVector},
ReturnType: ValueTypeVector,
},
"acosh": {
Name: "acosh",
ArgTypes: []ValueType{ValueTypeVector},
ReturnType: ValueTypeVector,
},
"asin": {
Name: "asin",
ArgTypes: []ValueType{ValueTypeVector},
ReturnType: ValueTypeVector,
},
"asinh": {
Name: "asinh",
ArgTypes: []ValueType{ValueTypeVector},
ReturnType: ValueTypeVector,
},
"atan": {
Name: "atan",
ArgTypes: []ValueType{ValueTypeVector},
ReturnType: ValueTypeVector,
},
"atanh": {
Name: "atanh",
ArgTypes: []ValueType{ValueTypeVector},
ReturnType: ValueTypeVector,
},
"avg_over_time": {
Name: "avg_over_time",
ArgTypes: []ValueType{ValueTypeMatrix},
ReturnType: ValueTypeVector,
},
"ceil": {
Name: "ceil",
ArgTypes: []ValueType{ValueTypeVector},
ReturnType: ValueTypeVector,
},
"changes": {
Name: "changes",
ArgTypes: []ValueType{ValueTypeMatrix},
ReturnType: ValueTypeVector,
},
"clamp": {
Name: "clamp",
ArgTypes: []ValueType{ValueTypeVector, ValueTypeScalar, ValueTypeScalar},
ReturnType: ValueTypeVector,
},
"clamp_max": {
Name: "clamp_max",
ArgTypes: []ValueType{ValueTypeVector, ValueTypeScalar},
ReturnType: ValueTypeVector,
},
"clamp_min": {
Name: "clamp_min",
ArgTypes: []ValueType{ValueTypeVector, ValueTypeScalar},
ReturnType: ValueTypeVector,
},
"cos": {
Name: "cos",
ArgTypes: []ValueType{ValueTypeVector},
ReturnType: ValueTypeVector,
},
"cosh": {
Name: "cosh",
ArgTypes: []ValueType{ValueTypeVector},
ReturnType: ValueTypeVector,
},
"count_over_time": {
Name: "count_over_time",
ArgTypes: []ValueType{ValueTypeMatrix},
ReturnType: ValueTypeVector,
},
"days_in_month": {
Name: "days_in_month",
ArgTypes: []ValueType{ValueTypeVector},
Variadic: 1,
ReturnType: ValueTypeVector,
},
"day_of_month": {
Name: "day_of_month",
ArgTypes: []ValueType{ValueTypeVector},
Variadic: 1,
ReturnType: ValueTypeVector,
},
"day_of_week": {
Name: "day_of_week",
ArgTypes: []ValueType{ValueTypeVector},
Variadic: 1,
ReturnType: ValueTypeVector,
},
"day_of_year": {
Name: "day_of_year",
ArgTypes: []ValueType{ValueTypeVector},
Variadic: 1,
ReturnType: ValueTypeVector,
},
"deg": {
Name: "deg",
ArgTypes: []ValueType{ValueTypeVector},
ReturnType: ValueTypeVector,
},
"delta": {
Name: "delta",
ArgTypes: []ValueType{ValueTypeMatrix},
ReturnType: ValueTypeVector,
},
"deriv": {
Name: "deriv",
ArgTypes: []ValueType{ValueTypeMatrix},
ReturnType: ValueTypeVector,
},
"exp": {
Name: "exp",
ArgTypes: []ValueType{ValueTypeVector},
ReturnType: ValueTypeVector,
},
"floor": {
Name: "floor",
ArgTypes: []ValueType{ValueTypeVector},
ReturnType: ValueTypeVector,
},
"histogram_count": {
Name: "histogram_count",
ArgTypes: []ValueType{ValueTypeVector},
ReturnType: ValueTypeVector,
},
"histogram_sum": {
Name: "histogram_sum",
ArgTypes: []ValueType{ValueTypeVector},
ReturnType: ValueTypeVector,
},
"histogram_fraction": {
Name: "histogram_fraction",
ArgTypes: []ValueType{ValueTypeScalar, ValueTypeScalar, ValueTypeVector},
ReturnType: ValueTypeVector,
},
"histogram_quantile": {
Name: "histogram_quantile",
ArgTypes: []ValueType{ValueTypeScalar, ValueTypeVector},
ReturnType: ValueTypeVector,
},
"holt_winters": {
Name: "holt_winters",
ArgTypes: []ValueType{ValueTypeMatrix, ValueTypeScalar, ValueTypeScalar},
ReturnType: ValueTypeVector,
},
"hour": {
Name: "hour",
ArgTypes: []ValueType{ValueTypeVector},
Variadic: 1,
ReturnType: ValueTypeVector,
},
"idelta": {
Name: "idelta",
ArgTypes: []ValueType{ValueTypeMatrix},
ReturnType: ValueTypeVector,
},
"increase": {
Name: "increase",
ArgTypes: []ValueType{ValueTypeMatrix},
ReturnType: ValueTypeVector,
},
"irate": {
Name: "irate",
ArgTypes: []ValueType{ValueTypeMatrix},
ReturnType: ValueTypeVector,
},
"label_replace": {
Name: "label_replace",
ArgTypes: []ValueType{ValueTypeVector, ValueTypeString, ValueTypeString, ValueTypeString, ValueTypeString},
ReturnType: ValueTypeVector,
},
"label_join": {
Name: "label_join",
ArgTypes: []ValueType{ValueTypeVector, ValueTypeString, ValueTypeString, ValueTypeString},
Variadic: -1,
ReturnType: ValueTypeVector,
},
"last_over_time": {
Name: "last_over_time",
ArgTypes: []ValueType{ValueTypeMatrix},
ReturnType: ValueTypeVector,
},
"ln": {
Name: "ln",
ArgTypes: []ValueType{ValueTypeVector},
ReturnType: ValueTypeVector,
},
"log10": {
Name: "log10",
ArgTypes: []ValueType{ValueTypeVector},
ReturnType: ValueTypeVector,
},
"log2": {
Name: "log2",
ArgTypes: []ValueType{ValueTypeVector},
ReturnType: ValueTypeVector,
},
"max_over_time": {
Name: "max_over_time",
ArgTypes: []ValueType{ValueTypeMatrix},
ReturnType: ValueTypeVector,
},
"min_over_time": {
Name: "min_over_time",
ArgTypes: []ValueType{ValueTypeMatrix},
ReturnType: ValueTypeVector,
},
"minute": {
Name: "minute",
ArgTypes: []ValueType{ValueTypeVector},
Variadic: 1,
ReturnType: ValueTypeVector,
},
"month": {
Name: "month",
ArgTypes: []ValueType{ValueTypeVector},
Variadic: 1,
ReturnType: ValueTypeVector,
},
"pi": {
Name: "pi",
ArgTypes: []ValueType{},
ReturnType: ValueTypeScalar,
},
"predict_linear": {
Name: "predict_linear",
ArgTypes: []ValueType{ValueTypeMatrix, ValueTypeScalar},
ReturnType: ValueTypeVector,
},
"present_over_time": {
Name: "present_over_time",
ArgTypes: []ValueType{ValueTypeMatrix},
ReturnType: ValueTypeVector,
},
"quantile_over_time": {
Name: "quantile_over_time",
ArgTypes: []ValueType{ValueTypeScalar, ValueTypeMatrix},
ReturnType: ValueTypeVector,
},
"rad": {
Name: "rad",
ArgTypes: []ValueType{ValueTypeVector},
ReturnType: ValueTypeVector,
},
"rate": {
Name: "rate",
ArgTypes: []ValueType{ValueTypeMatrix},
ReturnType: ValueTypeVector,
},
"resets": {
Name: "resets",
ArgTypes: []ValueType{ValueTypeMatrix},
ReturnType: ValueTypeVector,
},
"round": {
Name: "round",
ArgTypes: []ValueType{ValueTypeVector, ValueTypeScalar},
Variadic: 1,
ReturnType: ValueTypeVector,
},
"scalar": {
Name: "scalar",
ArgTypes: []ValueType{ValueTypeVector},
ReturnType: ValueTypeScalar,
},
"sgn": {
Name: "sgn",
ArgTypes: []ValueType{ValueTypeVector},
ReturnType: ValueTypeVector,
},
"sin": {
Name: "sin",
ArgTypes: []ValueType{ValueTypeVector},
ReturnType: ValueTypeVector,
},
"sinh": {
Name: "sinh",
ArgTypes: []ValueType{ValueTypeVector},
ReturnType: ValueTypeVector,
},
"sort": {
Name: "sort",
ArgTypes: []ValueType{ValueTypeVector},
ReturnType: ValueTypeVector,
},
"sort_desc": {
Name: "sort_desc",
ArgTypes: []ValueType{ValueTypeVector},
ReturnType: ValueTypeVector,
},
"sqrt": {
Name: "sqrt",
ArgTypes: []ValueType{ValueTypeVector},
ReturnType: ValueTypeVector,
},
"stddev_over_time": {
Name: "stddev_over_time",
ArgTypes: []ValueType{ValueTypeMatrix},
ReturnType: ValueTypeVector,
},
"stdvar_over_time": {
Name: "stdvar_over_time",
ArgTypes: []ValueType{ValueTypeMatrix},
ReturnType: ValueTypeVector,
},
"sum_over_time": {
Name: "sum_over_time",
ArgTypes: []ValueType{ValueTypeMatrix},
ReturnType: ValueTypeVector,
},
"tan": {
Name: "tan",
ArgTypes: []ValueType{ValueTypeVector},
ReturnType: ValueTypeVector,
},
"tanh": {
Name: "tanh",
ArgTypes: []ValueType{ValueTypeVector},
ReturnType: ValueTypeVector,
},
"time": {
Name: "time",
ArgTypes: []ValueType{},
ReturnType: ValueTypeScalar,
},
"timestamp": {
Name: "timestamp",
ArgTypes: []ValueType{ValueTypeVector},
ReturnType: ValueTypeVector,
},
"vector": {
Name: "vector",
ArgTypes: []ValueType{ValueTypeScalar},
ReturnType: ValueTypeVector,
},
"year": {
Name: "year",
ArgTypes: []ValueType{ValueTypeVector},
Variadic: 1,
ReturnType: ValueTypeVector,
},
}
// getFunction returns a predefined Function object for the given name.
func getFunction(name string) (*Function, bool) {
function, ok := Functions[name]
return function, ok
}