Merge pull request #219 from xmidt-org/env-form

feat:Add an environ variable form for WRPs.

env.go

@@ -0,0 +1,225 @@
+// SPDX-FileCopyrightText: 2025 Comcast Cable Communications Management, LLC
+// SPDX-License-Identifier: Apache-2.0
+
+package wrp
+
+import (
+	"encoding/base64"
+	"fmt"
+	"reflect"
+	"regexp"
+	"strconv"
+	"strings"
+)
+
+func toEnvMap(msg any) map[string]string {
+	v := reflect.ValueOf(msg)
+	if v.Kind() != reflect.Ptr || v.Elem().Kind() != reflect.Struct {
+		return nil
+	}
+
+	v = v.Elem()
+	t := v.Type()
+	envVars := make(map[string]string)
+
+	for i := 0; i < t.NumField(); i++ {
+		field := t.Field(i)
+		value := v.Field(i)
+		tag := field.Tag.Get("env")
+		if tag == "" || tag == "-" {
+			continue
+		}
+
+		tagParts := strings.Split(tag, ",")
+		key := tagParts[0]
+		options := tagParts[1:]
+
+		if key == "" {
+			continue
+		}
+
+		if isEmptyValue(value) {
+			if contains(options, "omitempty") {
+				continue
+			}
+			envVars[key] = ""
+		}
+
+		switch value.Kind() {
+		case reflect.String:
+			envVars[key] = value.String()
+		case reflect.Ptr:
+			if value.Elem().Kind() == reflect.Int64 {
+				if !value.IsNil() {
+					envVars[key] = fmt.Sprintf("%d", value.Elem().Int())
+				}
+			}
+		case reflect.Slice:
+			if value.Type().Elem().Kind() == reflect.String {
+				if contains(options, "multiline") {
+					for i, s := range value.Interface().([]string) {
+						envVars[fmt.Sprintf("%s_%03d", key, i)] = s
+					}
+				} else {
+					envVars[key] = strings.Join(value.Interface().([]string), ",")
+				}
+			} else if value.Type().Elem().Kind() == reflect.Uint8 {
+				envVars[key] = base64.StdEncoding.EncodeToString(value.Interface().([]byte))
+			}
+		case reflect.Map:
+			if value.Type().Key().Kind() == reflect.String && value.Type().Elem().Kind() == reflect.String {
+				for k, v := range value.Interface().(map[string]string) {
+					safe := sanitizeEnvVarName(k)
+					envVars[fmt.Sprintf("%s_%s", key, safe)] = k + "=" + v
+				}
+			}
+		case reflect.Int, reflect.Int64:
+			envVars[key] = fmt.Sprintf("%d", value.Int())
+		}
+	}
+
+	return envVars
+}
+
+func fromEnvMap(envVars []string, msg any) error {
+	v := reflect.ValueOf(msg)
+	if v.Kind() != reflect.Ptr || v.Elem().Kind() != reflect.Struct {
+		return fmt.Errorf("msg must be a pointer to a struct")
+	}
+
+	v = v.Elem()
+	t := v.Type()
+	envMap := make(map[string]string)
+	for _, envVar := range envVars {
+		parts := strings.SplitN(envVar, "=", 2)
+		if len(parts) == 2 {
+			envMap[parts[0]] = parts[1]
+		}
+	}
+
+	for i := 0; i < t.NumField(); i++ {
+		field := t.Field(i)
+		value := v.Field(i)
+		tag := field.Tag.Get("env")
+		if tag == "" || tag == "-" {
+			continue
+		}
+
+		tagParts := strings.Split(tag, ",")
+		key := tagParts[0]
+		options := tagParts[1:]
+
+		if key == "" {
+			key = field.Name
+		}
+
+		switch value.Kind() {
+		case reflect.String:
+			value.SetString(envMap[key])
+		case reflect.Ptr:
+			if value.Type().Elem().Kind() == reflect.Int64 {
+				if v, exists := envMap[key]; !exists || v == "" {
+					continue
+				}
+				intVal, err := strconv.ParseInt(envMap[key], 10, 64)
+				if err != nil {
+					return err
+				}
+				value.Set(reflect.ValueOf(&intVal))
+			}
+		case reflect.Slice:
+			if value.Type().Elem().Kind() == reflect.String {
+				if contains(options, "multiline") {
+					var slice []string
+					for i := 0; ; i++ {
+						multiKey := fmt.Sprintf("%s_%03d", key, i)
+						if multiValue, ok := envMap[multiKey]; ok {
+							slice = append(slice, multiValue)
+						} else {
+							break
+						}
+					}
+					if len(slice) > 0 {
+						value.Set(reflect.ValueOf(slice))
+					}
+				} else {
+					if _, exists := envMap[key]; !exists {
+						continue
+					}
+					list := strings.Split(envMap[key], ",")
+					if len(list) > 0 && list[0] != "" {
+						value.Set(reflect.ValueOf(list))
+					}
+				}
+			} else if value.Type().Elem().Kind() == reflect.Uint8 {
+				if _, exists := envMap[key]; !exists {
+					continue
+				}
+				decoded, err := base64.StdEncoding.DecodeString(envMap[key])
+				if err != nil {
+					return err
+				}
+				if len(decoded) > 0 {
+					value.Set(reflect.ValueOf(decoded))
+				}
+			}
+		case reflect.Map:
+			if value.Type().Key().Kind() == reflect.String && value.Type().Elem().Kind() == reflect.String {
+				mapValue := make(map[string]string)
+				for k, v := range envMap {
+					if strings.HasPrefix(k, key) {
+						list := strings.SplitN(v, "=", 2)
+						for i := range list {
+							list[i] = strings.TrimSpace(list[i])
+						}
+						// If there is no value, append an empty string
+						list = append(list, "")
+						mapValue[list[0]] = list[1]
+					}
+				}
+				if len(mapValue) > 0 {
+					value.Set(reflect.ValueOf(mapValue))
+				}
+			}
+		case reflect.Int, reflect.Int64:
+			if v, exists := envMap[key]; !exists || v == "" {
+				continue
+			}
+			intVal, err := strconv.ParseInt(envMap[key], 10, 64)
+			if err != nil {
+				return err
+			}
+			value.SetInt(intVal)
+		}
+	}
+
+	return nil
+}
+
+func contains(slice []string, item string) bool {
+	for _, s := range slice {
+		if s == item {
+			return true
+		}
+	}
+	return false
+}
+
+func isEmptyValue(v reflect.Value) bool {
+	switch v.Kind() {
+	case reflect.String, reflect.Slice, reflect.Map:
+		return v.Len() == 0
+	case reflect.Ptr, reflect.Interface:
+		return v.IsNil()
+	}
+	return false
+}
+
+// Allowed environment variable characters.
+var envVarNameRegexp = regexp.MustCompile(`[^a-zA-Z0-9_]`)
+
+func sanitizeEnvVarName(name string) string {
+	name = envVarNameRegexp.ReplaceAllString(name, "_")
+	// Chomp off leading underscores.
+	return strings.TrimLeft(name, "_")
+}