Merge pull request #9248 from LeviHarrison/atan2-binary-op

PromQL: Add `atan2` binary operator

docs/querying/operators.md

@@ -40,6 +40,16 @@ grouping labels becoming the output label set. The metric name is dropped. Entri
 for which no matching entry in the right-hand vector can be found are not part of
 the result.
 
+### Trigonometric binary operators
+
+The following trigonometric binary operators, which work in radians, exist in Prometheus:
+
+* `atan2` (based on https://pkg.go.dev/math#Atan2)
+
+Trigonometric operators allow trigonometric functions to be executed on two vectors using
+vector matching, which isn't available with normal functions. They act in the same manner
+as arithmetic operators.
+
 ### Comparison binary operators
 
 The following binary comparison operators exist in Prometheus:
@@ -264,7 +274,7 @@ The following list shows the precedence of binary operators in Prometheus, from
 highest to lowest.
 
 1. `^`
-2. `*`, `/`, `%`
+2. `*`, `/`, `%`, `atan2`
 3. `+`, `-`
 4. `==`, `!=`, `<=`, `<`, `>=`, `>`
 5. `and`, `unless`

promql/engine.go

@@ -2116,6 +2116,8 @@ func vectorElemBinop(op parser.ItemType, lhs, rhs float64) (float64, bool) {
 		return lhs, lhs >= rhs
 	case parser.LTE:
 		return lhs, lhs <= rhs
+	case parser.ATAN2:
+		return math.Atan2(lhs, rhs), true
 	}
 	panic(errors.Errorf("operator %q not allowed for operations between Vectors", op))
 }

promql/parser/generated_parser.y

@@ -84,6 +84,7 @@ NEQ_REGEX
 POW
 SUB
 AT
+ATAN2
 %token	operatorsEnd
 
 // Aggregators.
@@ -156,7 +157,7 @@ START_METRIC_SELECTOR
 %left LAND LUNLESS
 %left EQLC GTE GTR LSS LTE NEQ
 %left ADD SUB
-%left MUL DIV MOD
+%left MUL DIV MOD ATAN2
 %right POW
 
 // Offset modifiers do not have associativity.
@@ -237,6 +238,7 @@ aggregate_modifier:
 
 // Operator precedence only works if each of those is listed separately.
 binary_expr     : expr ADD     bin_modifier expr { $$ = yylex.(*parser).newBinaryExpression($1, $2, $3, $4) }
+                | expr ATAN2   bin_modifier expr { $$ = yylex.(*parser).newBinaryExpression($1, $2, $3, $4) }
                 | expr DIV     bin_modifier expr { $$ = yylex.(*parser).newBinaryExpression($1, $2, $3, $4) }
                 | expr EQLC    bin_modifier expr { $$ = yylex.(*parser).newBinaryExpression($1, $2, $3, $4) }
                 | expr GTE     bin_modifier expr { $$ = yylex.(*parser).newBinaryExpression($1, $2, $3, $4) }
@@ -674,7 +676,7 @@ series_value    : IDENTIFIER
 aggregate_op    : AVG | BOTTOMK | COUNT | COUNT_VALUES | GROUP | MAX | MIN | QUANTILE | STDDEV | STDVAR | SUM | TOPK ;
 
 // inside of grouping options label names can be recognized as keywords by the lexer. This is a list of keywords that could also be a label name.
-maybe_label     : AVG | BOOL | BOTTOMK | BY | COUNT | COUNT_VALUES | GROUP | GROUP_LEFT | GROUP_RIGHT | IDENTIFIER | IGNORING | LAND | LOR | LUNLESS | MAX | METRIC_IDENTIFIER | MIN | OFFSET | ON | QUANTILE | STDDEV | STDVAR | SUM | TOPK | START | END;
+maybe_label     : AVG | BOOL | BOTTOMK | BY | COUNT | COUNT_VALUES | GROUP | GROUP_LEFT | GROUP_RIGHT | IDENTIFIER | IGNORING | LAND | LOR | LUNLESS | MAX | METRIC_IDENTIFIER | MIN | OFFSET | ON | QUANTILE | STDDEV | STDVAR | SUM | TOPK | START | END | ATAN2;
 
 unary_op        : ADD | SUB;
 

promql/parser/lex.go

@@ -97,6 +97,7 @@ var key = map[string]ItemType{
 	"and":    LAND,
 	"or":     LOR,
 	"unless": LUNLESS,
+	"atan2":  ATAN2,
 
 	// Aggregators.
 	"sum":          SUM,

promql/parser/lex_test.go

@@ -340,6 +340,10 @@ var tests = []struct {
 				input:    "bool",
 				expected: []Item{{BOOL, 0, "bool"}},
 			},
+			{
+				input:    "atan2",
+				expected: []Item{{ATAN2, 0, "atan2"}},
+			},
 		},
 	},
 	{

promql/testdata/operators.test

@@ -467,3 +467,17 @@ eval instant at 5m test_total < bool test_smaller
     {instance="localhost"} 0
 
 eval instant at 5m test_total < test_smaller
+
+clear
+
+# Testing atan2.
+load 5m
+    trigy{} 10
+    trigx{} 20
+    trigNaN{} NaN
+
+eval instant at 5m trigy atan2 trigx
+    trigy{} 0.4636476090008061
+
+eval instant at 5m trigy atan2 trigNaN
+    trigy{} NaN

web/ui/module/codemirror-promql/src/complete/promql.terms.ts

@@ -28,6 +28,7 @@ export const binOpTerms = [
   { label: '<' },
   { label: '<=' },
   { label: '!=' },
+  { label: 'atan2' },
   { label: 'and' },
   { label: 'or' },
   { label: 'unless' },

web/ui/module/codemirror-promql/src/grammar/promql.grammar

@@ -16,7 +16,7 @@
 
 @precedence {
   pow @right,
-  mul @left,
+  mul @left
   add @left,
   eql @left,
   and @left,
@@ -69,6 +69,7 @@ BinaryExpr {
   Expr !mul Mul    BinModifiers Expr |
   Expr !mul Div    BinModifiers Expr |
   Expr !mul Mod    BinModifiers Expr |
+  Expr !mul Atan2  BinModifiers Expr |
   Expr !add Add    BinModifiers Expr |
   Expr !add Sub    BinModifiers Expr |
   Expr !eql Eql    BinModifiers Expr |
@@ -333,6 +334,7 @@ NumberLiteral  {
 // Contextual keywords
 
 @external extend {Identifier} extendIdentifier from "./tokens" {
+  Atan2,
   Avg,
   Bottomk,
   Count,

web/ui/module/codemirror-promql/src/grammar/test/expression.txt

@@ -840,3 +840,10 @@ sum:my_metric_name:rate5m
 
 ==>
 MetricName(MetricIdentifier(Identifier))
+
+# Testing Atan2 inherited precedence level
+
+1 + foo atan2 bar
+
+==>
+PromQL(Expr(BinaryExpr(Expr(NumberLiteral),Add,BinModifiers,Expr(BinaryExpr(Expr(VectorSelector(MetricIdentifier(Identifier))),Atan2,BinModifiers,Expr(VectorSelector(MetricIdentifier(Identifier))))))))

web/ui/module/codemirror-promql/src/grammar/tokens.js

@@ -14,6 +14,7 @@
 import {
   And,
   Avg,
+  Atan2,
   Bool,
   Bottomk,
   By,
@@ -58,6 +59,7 @@ export const specializeIdentifier = (value, stack) => {
 
 const contextualKeywordTokens = {
   avg: Avg,
+  atan2: Atan2,
   bottomk: Bottomk,
   count: Count,
   count_values: CountValues,

web/ui/module/codemirror-promql/src/promql.ts

@@ -40,7 +40,7 @@ export function promQLLanguage(top: LanguageType): LRLanguage {
           'Avg Bottomk Count Count_values Group Max Min Quantile Stddev Stdvar Sum Topk': tags.operatorKeyword,
           'By Without Bool On Ignoring GroupLeft GroupRight Offset Start End': tags.modifier,
           'And Unless Or': tags.logicOperator,
-          'Sub Add Mul Mod Div Eql Neq Lte Lss Gte Gtr EqlRegex EqlSingle NeqRegex Pow At': tags.operator,
+          'Sub Add Mul Mod Div Atan2 Eql Neq Lte Lss Gte Gtr EqlRegex EqlSingle NeqRegex Pow At': tags.operator,
           UnaryOp: tags.arithmeticOperator,
           '( )': tags.paren,
           '[ ]': tags.squareBracket,