[pkg/ottl] Support dynamic indexing

Signed-off-by: odubajDT <[email protected]>

pkg/ottl/contexts/internal/resource.go

@@ -71,6 +71,7 @@ func accessResourceAttributesKey[K ResourceContext](keys []ottl.Key[K]) ottl.Sta
 		Setter: func(ctx context.Context, tCtx K, val any) error {
 			return SetMapValue[K](ctx, tCtx, tCtx.GetResource().Attributes(), keys, val)
 		},
+		// TODO
 	}
 }
 

pkg/ottl/contexts/internal/scope.go

@@ -76,6 +76,7 @@ func accessInstrumentationScopeAttributesKey[K InstrumentationScopeContext](keys
 		Setter: func(ctx context.Context, tCtx K, val any) error {
 			return SetMapValue[K](ctx, tCtx, tCtx.GetInstrumentationScope().Attributes(), keys, val)
 		},
+		// TODO
 	}
 }
 

pkg/ottl/contexts/internal/span.go

@@ -465,6 +465,7 @@ func accessAttributesKey[K SpanContext](keys []ottl.Key[K]) ottl.StandardGetSett
 		Setter: func(ctx context.Context, tCtx K, val any) error {
 			return SetMapValue[K](ctx, tCtx, tCtx.GetSpan().Attributes(), keys, val)
 		},
+		// TODO
 	}
 }
 

pkg/ottl/contexts/ottldatapoint/datapoint.go

@@ -353,6 +353,7 @@ func accessAttributesKey(key []ottl.Key[TransformContext]) ottl.StandardGetSette
 			case pmetric.SummaryDataPoint:
 				return internal.SetMapValue[TransformContext](ctx, tCtx, tCtx.GetDataPoint().(pmetric.SummaryDataPoint).Attributes(), key, val)
 			}
+			// TODO
 			return nil
 		},
 	}

pkg/ottl/contexts/ottllog/log.go

@@ -448,6 +448,7 @@ func accessAttributesKey(key []ottl.Key[TransformContext]) ottl.StandardGetSette
 		Setter: func(ctx context.Context, tCtx TransformContext, val any) error {
 			return internal.SetMapValue[TransformContext](ctx, tCtx, tCtx.GetLogRecord().Attributes(), key, val)
 		},
+		// TODO
 	}
 }
 

pkg/ottl/contexts/ottlspanevent/span_events.go

@@ -272,6 +272,7 @@ func accessSpanEventAttributesKey(key []ottl.Key[TransformContext]) ottl.Standar
 		Setter: func(ctx context.Context, tCtx TransformContext, val any) error {
 			return internal.SetMapValue[TransformContext](ctx, tCtx, tCtx.GetSpanEvent().Attributes(), key, val)
 		},
+		// TODO
 	}
 }
 

pkg/ottl/grammar.go

@@ -234,6 +234,7 @@ func (a *argument) accept(v grammarVisitor) {
 // mathExpression, function call, or literal.
 type value struct {
 	IsNil          *isNil           `parser:"( @'nil'"`
+	ExpressionPath *path            `parser:"| '$''{' @@ '}'"`
 	Literal        *mathExprLiteral `parser:"| @@ (?! OpAddSub | OpMultDiv)"`
 	MathExpression *mathExpression  `parser:"| @@"`
 	Bytes          *byteSlice       `parser:"| @Bytes"`
@@ -260,6 +261,9 @@ func (v *value) accept(vis grammarVisitor) {
 			i.accept(vis)
 		}
 	}
+	if v.ExpressionPath != nil {
+		vis.visitPath(v.ExpressionPath)
+	}
 }
 
 // path represents a telemetry path mathExpression.
@@ -486,6 +490,7 @@ func buildLexer() *lexer.StatefulDefinition {
 		{Name: `LBrace`, Pattern: `\{`},
 		{Name: `RBrace`, Pattern: `\}`},
 		{Name: `Colon`, Pattern: `\:`},
+		{Name: `Dollar`, Pattern: `\$`},
 		{Name: `Punct`, Pattern: `[,.\[\]]`},
 		{Name: `Uppercase`, Pattern: `[A-Z][A-Z0-9_]*`},
 		{Name: `Lowercase`, Pattern: `[a-z][a-z0-9_]*`},

pkg/ottl/lexer_test.go

@@ -130,6 +130,15 @@ func Test_lexer(t *testing.T) {
 			{"String", `"bar"`},
 			{"RBrace", "}"},
 		}},
+		{"Expression path", `${foo["foo"]}`, false, []result{
+			{"Dollar", "$"},
+			{"LBrace", "{"},
+			{"Lowercase", "foo"},
+			{"Punct", "["},
+			{"String", `"foo"`},
+			{"Punct", "]"},
+			{"RBrace", "}"},
+		}},
 	}
 
 	for _, tt := range tests {