common config loader added to tools

tools/conf_loader.go

@@ -0,0 +1,53 @@
+package tools
+
+import (
+	"strings"
+
+	"cloud.o-forge.io/core/oc-lib/logs"
+	"github.com/goraz/onion"
+)
+
+// GetConfLoader
+// Get the configuration loader for the application
+// Parameters:
+// - AppName: string : the name of the application
+// Returns:
+// - *onion.Onion : the configuration loader
+//  The configuration loader will load the configuration from the following sources:
+//  - the environment variables with the prefix APPNAME_
+//  - the file /etc/oc/appname.json
+//  - the file ./appname.json
+//  The configuration loader will merge the configuration from the different sources
+//  The configuration loader will give priority to the environment variables
+//  The configuration loader will give priority to the local file over the default file
+
+func GetConfLoader(AppName string) *onion.Onion {
+	logger := logs.GetLogger()
+	EnvPrefix := strings.ToUpper(AppName[0:2]+AppName[3:]) + "_"
+	defaultConfigFile := "/etc/oc/" + AppName[0:2] + ".json"
+	localConfigFile := "./" + AppName[0:2] + ".json"
+	var configFile string
+	var o *onion.Onion
+	l3 := onion.NewEnvLayerPrefix("_", EnvPrefix)
+	l2, err := onion.NewFileLayer(localConfigFile, nil)
+	if err == nil {
+		logger.Info().Msg("Local config file found " + localConfigFile + ", overriding default file")
+		configFile = localConfigFile
+	}
+	l1, err := onion.NewFileLayer(defaultConfigFile, nil)
+	if err == nil {
+		logger.Info().Msg("Config file found : " + defaultConfigFile)
+		configFile = defaultConfigFile
+	}
+	if configFile == "" {
+		logger.Info().Msg("No config file found, using env")
+		o = onion.New(l3)
+	} else if l1 != nil && l2 != nil {
+		o = onion.New(l1, l2, l3)
+	} else if l1 == nil {
+		o = onion.New(l2, l3)
+	} else if l2 == nil {
+		o = onion.New(l1, l3)
+	}
+	return o
+}