Function varsToStruct

tools/dpgen/generate.go:47–154

varsToStruct generates a Go struct from the configuration variables in the CollectionSpec.

(spec *ebpf.CollectionSpec, name, kind, comment string, embeds []string)

// varsToStruct generates a Go struct from the configuration variables in the
// CollectionSpec.
func varsToStruct(spec *ebpf.CollectionSpec, name, kind, comment string, embeds []string) (string, error) {
	type field struct {
		comment  string
		goName   string
		cName    string
		typ      string
		defValue string
	}

	kind = "kind:" + kind

	fields := make([]field, 0, len(spec.Variables))

	for n, v := range spec.Variables {
		// Only consider variables in a specific config section to avoid interfering
		// with unrelated objects.
		if v.SectionName != config.Section {
			continue
		}

		// DECLARE_CONFIG prefixes the variable name with a well-known prefix to
		// avoid collisions with other variables with common names.
		n = strings.TrimPrefix(n, config.ConstantPrefix)

		if v.Type == nil {
			return "", fmt.Errorf("variable %s has no type information, was the ELF built without BTF?", n)
		}

		// Skip variables that don't have the requested kind.
		tags := v.Type.Tags
		if !slices.Contains(tags, kind) {
			continue
		}

		// Pop the kind tag from the list of tags, we don't want to render it out
		// to the config struct.
		tags = slices.DeleteFunc(tags, func(s string) bool { return s == kind })

		if len(tags) == 0 || tags[0] == "" {
			return "", fmt.Errorf("variable %s has no doc comment", n)
		}

		typ, err := btfVarGoType(v.Type)
		if err != nil {
			return "", fmt.Errorf("variable %s: getting Go type: %w", n, err)
		}

		comment, err := tagsToComment(tags)
		if err != nil {
			return "", fmt.Errorf("variable %s: converting tags to comments: %w", n, err)
		}

		defValue, err := varGoValue(v)
		if err != nil {
			return "", fmt.Errorf("variable %s: getting default Go value: %w", n, err)
		}

		fields = append(fields, field{comment, camelCase(n), n, typ, goValueLiteral(defValue)})