Bugfix: Logger config not being respected (#563)

Summary:
Pull Request resolved: #563

We currently make two calls to initialize the logger in this order:
- when the logger package is imported with a default configuration
- when we have initialized the configuration with the config we just initialized

However, currently we have wrapped the logger initialization in a do once.  This led to us always setting up a logger with default configurations and ignoring the second call with the configs we actually want.

I opted to remove the init function (which is called when the package is loaded) and instead have the call for the global logger create a new empty config logger if one does not exist yet.   In this case, this means we'll always yield to a provided config, but also that tests can just request and receive a standard logger without needing to create one manually in every test.

Reviewed By: ivnik

Differential Revision: D84361195

fbshipit-source-id: 022e201d7a514895a4b94e15fa1334d8d6010aad

Author: RoboticPrism

pkg/logging/logger.go

@@ -44,18 +44,17 @@ var (
 	indentLevel         int
 )
 
-func init() {
-	// default logger - will be used in tests
-	err := InitLog(Config{})
-	if err != nil {
-		// this should never fail - if it does
-		// something weird happened so we panic
-		panic(err)
-	}
-}
-
 // L returns the global logger for ttpforge
 func L() *zap.SugaredLogger {
+	// If the logger is not initialized at this point, initialize it with default settings.  Usually this should only happen in tests.
+	if logger == nil {
+		err := InitLog(Config{})
+		if err != nil {
+			// this should never fail - if it does
+			// something weird happened so we panic
+			panic(err)
+		}
+	}
 	return logger
 }