[pkg/ottl] Add negation to the grammar (open-telemetry#16553)

* Add negation to the grammar

* changelog

* Reword

.chloggen/ottl-not.yaml

@@ -0,0 +1,16 @@
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: enhancement
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: pkg/ottl
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Add ability to negate conditions with the `not` keyword
+
+# One or more tracking issues related to the change
+issues: [16553]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:

pkg/ottl/README.md

@@ -136,7 +136,8 @@ Boolean Expressions allow a decision to be made about whether an Invocation shou
 
 Boolean Expressions consist of the literal string `where` followed by one or more Booleans (see below).
 Booleans can be joined with the literal strings `and` and `or`.
-Note that `and` Boolean Expressions have higher precedence than `or`.
+Booleans can be negated with the literal string `not`.
+Note that `not` has the highest precedence and `and` Boolean Expressions have higher precedence than `or`.
 Boolean Expressions can be grouped with parentheses to override evaluation precedence.
 
 ### Booleans
@@ -156,6 +157,11 @@ The valid operators are:
 - Less Than or Equal To (`<=`). Tests if left is less than or equal to right.
 - Greater Than or Equal to (`>=`). Tests if left is greater than or equal to right.
 
+Booleans can be negated with the `not` keyword such as
+- `not true`
+- `not name == "foo"`   
+  `not (IsMatch(name, "http_.*") == true and kind > 0)`
+
 ### Comparison Rules
 
 The table below describes what happens when two Values are compared. Value types are provided by the user of OTTL. All of the value types supported by OTTL are listed in this table.

pkg/ottl/boolean_value.go

@@ -30,6 +30,13 @@ func (e BoolExpr[K]) Eval(ctx context.Context, tCtx K) (bool, error) {
 	return e.boolExpressionEvaluator(ctx, tCtx)
 }
 
+func not[K any](original BoolExpr[K]) (BoolExpr[K], error) {
+	return BoolExpr[K]{func(ctx context.Context, tCtx K) (bool, error) {
+		result, err := original.Eval(ctx, tCtx)
+		return !result, err
+	}}, nil
+}
+
 func alwaysTrue[K any](context.Context, K) (bool, error) {
 	return true, nil
 }
@@ -144,21 +151,32 @@ func (p *Parser[K]) newBooleanValueEvaluator(value *booleanValue) (BoolExpr[K],
 	if value == nil {
 		return BoolExpr[K]{alwaysTrue[K]}, nil
 	}
+
+	var boolExpr BoolExpr[K]
+	var err error
 	switch {
 	case value.Comparison != nil:
-		comparison, err := p.newComparisonEvaluator(value.Comparison)
+		boolExpr, err = p.newComparisonEvaluator(value.Comparison)
 		if err != nil {
 			return BoolExpr[K]{}, err
 		}
-		return comparison, nil
 	case value.ConstExpr != nil:
 		if *value.ConstExpr {
-			return BoolExpr[K]{alwaysTrue[K]}, nil
+			boolExpr = BoolExpr[K]{alwaysTrue[K]}
+		} else {
+			boolExpr = BoolExpr[K]{alwaysFalse[K]}
 		}
-		return BoolExpr[K]{alwaysFalse[K]}, nil
 	case value.SubExpr != nil:
-		return p.newBoolExpr(value.SubExpr)
+		boolExpr, err = p.newBoolExpr(value.SubExpr)
+		if err != nil {
+			return BoolExpr[K]{}, err
+		}
+	default:
+		return BoolExpr[K]{}, fmt.Errorf("unhandled boolean operation %v", value)
 	}
 
-	return BoolExpr[K]{}, fmt.Errorf("unhandled boolean operation %v", value)
+	if value.Negation != nil {
+		return not(boolExpr)
+	}
+	return boolExpr, nil
 }

pkg/ottl/boolean_value_test.go

@@ -351,6 +351,108 @@ func Test_newBooleanExpressionEvaluator(t *testing.T) {
 				},
 			},
 		},
+		{"i", true,
+			&booleanExpression{
+				Left: &term{
+					Left: &booleanValue{
+						Negation:  ottltest.Strp("not"),
+						ConstExpr: booleanp(false),
+					},
+				},
+			},
+		},
+		{"j", false,
+			&booleanExpression{
+				Left: &term{
+					Left: &booleanValue{
+						Negation:  ottltest.Strp("not"),
+						ConstExpr: booleanp(true),
+					},
+				},
+			},
+		},
+		{"k", true,
+			&booleanExpression{
+				Left: &term{
+					Left: &booleanValue{
+						Negation: ottltest.Strp("not"),
+						Comparison: &comparison{
+							Left: value{
+								String: ottltest.Strp("test"),
+							},
+							Op: EQ,
+							Right: value{
+								String: ottltest.Strp("not test"),
+							},
+						},
+					},
+				},
+			},
+		},
+		{"l", false,
+			&booleanExpression{
+				Left: &term{
+					Left: &booleanValue{
+						ConstExpr: booleanp(true),
+					},
+					Right: []*opAndBooleanValue{
+						{
+							Operator: "and",
+							Value: &booleanValue{
+								Negation: ottltest.Strp("not"),
+								SubExpr: &booleanExpression{
+									Left: &term{
+										Left: &booleanValue{
+											ConstExpr: booleanp(true),
+										},
+									},
+									Right: []*opOrTerm{
+										{
+											Operator: "or",
+											Term: &term{
+												Left: &booleanValue{
+													ConstExpr: booleanp(false),
+												},
+											},
+										},
+									},
+								},
+							},
+						},
+					},
+				},
+			},
+		},
+		{"m", false,
+			&booleanExpression{
+				Left: &term{
+					Left: &booleanValue{
+						Negation:  ottltest.Strp("not"),
+						ConstExpr: booleanp(true),
+					},
+					Right: []*opAndBooleanValue{
+						{
+							Operator: "and",
+							Value: &booleanValue{
+								Negation:  ottltest.Strp("not"),
+								ConstExpr: booleanp(false),
+							},
+						},
+					},
+				},
+				Right: []*opOrTerm{
+					{
+						Operator: "or",
+						Term: &term{
+							Left: &booleanValue{
+								Negation:  ottltest.Strp("not"),
+								ConstExpr: booleanp(true),
+							},
+						},
+					},
+				},
+			},
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {

pkg/ottl/grammar.go

@@ -30,6 +30,7 @@ type parsedStatement struct {
 // either an equality or inequality, explicit true or false, or
 // a parenthesized subexpression.
 type booleanValue struct {
+	Negation   *string            `parser:"@OpNot?"`
 	Comparison *comparison        `parser:"( @@"`
 	ConstExpr  *boolean           `parser:"| @Boolean"`
 	SubExpr    *booleanExpression `parser:"| '(' @@ ')' )"`
@@ -266,6 +267,7 @@ func buildLexer() *lexer.StatefulDefinition {
 		{Name: `Float`, Pattern: `[-+]?\d*\.\d+([eE][-+]?\d+)?`},
 		{Name: `Int`, Pattern: `[-+]?\d+`},
 		{Name: `String`, Pattern: `"(\\"|[^"])*"`},
+		{Name: `OpNot`, Pattern: `\b(not)\b`},
 		{Name: `OpOr`, Pattern: `\b(or)\b`},
 		{Name: `OpAnd`, Pattern: `\b(and)\b`},
 		{Name: `OpComparison`, Pattern: `==|!=|>=|<=|>|<`},

pkg/ottl/lexer_test.go

@@ -83,6 +83,12 @@ func Test_lexer(t *testing.T) {
 			{"OpOr", "or"},
 			{"Lowercase", "but"},
 		}},
+		{"not", "true and not false", false, []result{
+			{"Boolean", "true"},
+			{"OpAnd", "and"},
+			{"OpNot", "not"},
+			{"Boolean", "false"},
+		}},
 		{"nothing_recognizable", "{}", true, []result{
 			{"", ""},
 		}},

pkg/ottl/parser_test.go

@@ -1116,6 +1116,79 @@ func Test_parseWhere(t *testing.T) {
 				},
 			}),
 		},
+		{
+			statement: `true and not false`,
+			expected: setNameTest(&booleanExpression{
+				Left: &term{
+					Left: &booleanValue{
+						ConstExpr: booleanp(true),
+					},
+					Right: []*opAndBooleanValue{
+						{
+							Operator: "and",
+							Value: &booleanValue{
+								Negation:  ottltest.Strp("not"),
+								ConstExpr: booleanp(false),
+							},
+						},
+					},
+				},
+			}),
+		},
+		{
+			statement: `not name == "bar"`,
+			expected: setNameTest(&booleanExpression{
+				Left: &term{
+					Left: &booleanValue{
+						Negation: ottltest.Strp("not"),
+						Comparison: &comparison{
+							Left: value{
+								Literal: &mathExprLiteral{
+									Path: &Path{
+										Fields: []Field{
+											{
+												Name: "name",
+											},
+										},
+									},
+								},
+							},
+							Op: EQ,
+							Right: value{
+								String: ottltest.Strp("bar"),
+							},
+						},
+					},
+				},
+			}),
+		},
+		{
+			statement: `not (true or false)`,
+			expected: setNameTest(&booleanExpression{
+				Left: &term{
+					Left: &booleanValue{
+						Negation: ottltest.Strp("not"),
+						SubExpr: &booleanExpression{
+							Left: &term{
+								Left: &booleanValue{
+									ConstExpr: booleanp(true),
+								},
+							},
+							Right: []*opOrTerm{
+								{
+									Operator: "or",
+									Term: &term{
+										Left: &booleanValue{
+											ConstExpr: booleanp(false),
+										},
+									},
+								},
+							},
+						},
+					},
+				},
+			}),
+		},
 	}
 
 	// create a test name that doesn't confuse vscode so we can rerun tests with one click