Function extractOpts

scripts/metricsdocgen/scanner/scanner.go:465–510

extractOpts extracts fields from a prometheus.*Opts composite literal.

(expr ast.Expr, decls declarations)

// extractOpts extracts fields from a prometheus.*Opts composite literal.
func extractOpts(expr ast.Expr, decls declarations) (metricOpts, bool) {
	// Handle both direct composite literals and calls that return opts.
	var lit *ast.CompositeLit

	switch e := expr.(type) {
	case *ast.CompositeLit:
		lit = e
	case *ast.UnaryExpr:
		// Handle &prometheus.GaugeOpts{...}
		if l, ok := e.X.(*ast.CompositeLit); ok {
			lit = l
		}
	}

	if lit == nil {
		return metricOpts{}, false
	}

	var opts metricOpts
	for _, elt := range lit.Elts {
		kv, ok := elt.(*ast.KeyValueExpr)
		if !ok {
			continue
		}

		key, ok := kv.Key.(*ast.Ident)
		if !ok {
			continue
		}

		value := resolveStringExpr(kv.Value, decls)

		switch key.Name {
		case "Namespace":
			opts.Namespace = value
		case "Subsystem":
			opts.Subsystem = value
		case "Name":
			opts.Name = value
		case "Help":
			opts.Help = value
		}
	}

	return opts, opts.Name != ""
}

// buildMetricName constructs the full metric name from namespace, subsystem, and name.
func buildMetricName(namespace, subsystem, name string) string {