feat: Allow Environment Variables to override config.json (#125)

* add envvar override of config.json

* use viper

* Revert "use viper"

This reverts commit 18cb752.

* bump patch in version

* adds log to match monorepo pr

---------

Co-authored-by: colinlyguo <colinlyguo@scroll.io>

internal/config/config.go

@@ -2,10 +2,15 @@ package config
 
 import (
 	"encoding/json"
+	"fmt"
 	"os"
 	"path/filepath"
+	"reflect"
+	"strconv"
+	"strings"
 
 	"github.com/scroll-tech/go-ethereum/common"
+	"github.com/scroll-tech/go-ethereum/log"
 	"github.com/scroll-tech/go-ethereum/rpc"
 
 	"github.com/scroll-tech/chain-monitor/internal/utils/database"
@@ -88,5 +93,98 @@ func NewConfig(file string) (*Config, error) {
 	if err != nil {
 		return nil, err
 	}
+
+	// Override config with environment variables
+	err = overrideConfigWithEnv(&cfg, "SCROLL_CHAIN_MONITOR")
+	if err != nil {
+		return nil, err
+	}
+
 	return &cfg, nil
 }
+
+// overrideConfigWithEnv recursively overrides config values with environment variables
+func overrideConfigWithEnv(cfg interface{}, prefix string) error {
+	v := reflect.ValueOf(cfg)
+	if v.Kind() != reflect.Ptr || v.IsNil() {
+		return nil
+	}
+	v = v.Elem()
+
+	t := v.Type()
+	for i := 0; i < t.NumField(); i++ {
+		field := t.Field(i)
+		fieldValue := v.Field(i)
+
+		if !fieldValue.CanSet() {
+			continue
+		}
+
+		tag := field.Tag.Get("json")
+		if tag == "" {
+			tag = strings.ToLower(field.Name)
+		}
+
+		envKey := prefix + "_" + strings.ToUpper(tag)
+
+		switch fieldValue.Kind() {
+		case reflect.Ptr:
+			if !fieldValue.IsNil() {
+				err := overrideConfigWithEnv(fieldValue.Interface(), envKey)
+				if err != nil {
+					return err
+				}
+			}
+		case reflect.Struct:
+			err := overrideConfigWithEnv(fieldValue.Addr().Interface(), envKey)
+			if err != nil {
+				return err
+			}
+		default:
+			if envValue, exists := os.LookupEnv(envKey); exists {
+				err := setField(fieldValue, envValue)
+				log.Info("Overriding config with env var", "key", envKey)
+				if err != nil {
+					return err
+				}
+			}
+		}
+	}
+
+	return nil
+}
+
+// setField sets the value of a field based on the environment variable value
+func setField(field reflect.Value, value string) error {
+	switch field.Kind() {
+	case reflect.String:
+		field.SetString(value)
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		intValue, err := strconv.ParseInt(value, 10, 64)
+		if err != nil {
+			return err
+		}
+		field.SetInt(intValue)
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
+		uintValue, err := strconv.ParseUint(value, 10, 64)
+		if err != nil {
+			return err
+		}
+		field.SetUint(uintValue)
+	case reflect.Float32, reflect.Float64:
+		floatValue, err := strconv.ParseFloat(value, 64)
+		if err != nil {
+			return err
+		}
+		field.SetFloat(floatValue)
+	case reflect.Bool:
+		boolValue, err := strconv.ParseBool(value)
+		if err != nil {
+			return err
+		}
+		field.SetBool(boolValue)
+	default:
+		return fmt.Errorf("unsupported type: %v", field.Kind())
+	}
+	return nil
+}

internal/utils/version.go

@@ -5,7 +5,7 @@ import (
 	"runtime/debug"
 )
 
-var tag = "v1.1.27"
+var tag = "v1.1.28"
 
 var commit = func() string {
 	if info, ok := debug.ReadBuildInfo(); ok {