properly handle stdout, stderr, and null (#1029)

* properly handle stdout, stderr, and null

* update snapshots

* fix test

Author: Cerebrovinny

cmd/root.go

@@ -101,14 +101,25 @@ func setupLogger(atmosConfig *schema.AtmosConfiguration) {
 		log.SetLevel(log.InfoLevel)
 	}
 
-	if atmosConfig.Logs.File != "/dev/stderr" {
+	var output io.Writer
+
+	switch atmosConfig.Logs.File {
+	case "/dev/stderr":
+		output = os.Stderr
+	case "/dev/stdout":
+		output = os.Stdout
+	case "/dev/null":
+		output = io.Discard // More efficient than opening os.DevNull
+	default:
 		logFile, err := os.OpenFile(atmosConfig.Logs.File, os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0o666)
 		if err != nil {
 			log.Fatal("Failed to open log file:", err)
 		}
 		defer logFile.Close()
-		log.SetOutput(logFile)
+		output = logFile
 	}
+
+	log.SetOutput(output)
 }
 
 // Execute adds all child commands to the root command and sets flags appropriately.
@@ -183,7 +194,7 @@ func init() {
 		"Errors can be redirected to any file or any standard file descriptor (including '/dev/null'): atmos <command> --redirect-stderr /dev/stdout")
 
 	RootCmd.PersistentFlags().String("logs-level", "Info", "Logs level. Supported log levels are Trace, Debug, Info, Warning, Off. If the log level is set to Off, Atmos will not log any messages")
-	RootCmd.PersistentFlags().String("logs-file", "/dev/stdout", "The file to write Atmos logs to. Logs can be written to any file or any standard file descriptor, including '/dev/stdout', '/dev/stderr' and '/dev/null'")
+	RootCmd.PersistentFlags().String("logs-file", "/dev/stderr", "The file to write Atmos logs to. Logs can be written to any file or any standard file descriptor, including '/dev/stdout', '/dev/stderr' and '/dev/null'")
 
 	// Set custom usage template
 	err := templates.SetCustomUsageFunc(RootCmd)

pkg/config/config.go

@@ -75,7 +75,7 @@ var (
 			BasePath: "stacks/workflows",
 		},
 		Logs: schema.Logs{
-			File:  "/dev/stdout",
+			File:  "/dev/stderr",
 			Level: "Info",
 		},
 		Schemas: schema.Schemas{

tests/fixtures/scenarios/valid-log-level/atmos.yaml

@@ -1,8 +1,8 @@
 logs:
   level: Trace
-  file: /dev/stdout
+  file: /dev/stderr
 
 stacks:
   base_path: stacks
   included_paths:
-    - "**/*" 
+    - "**/*"

tests/snapshots/TestCLICommands_Valid_Log_Level_in_Config_File.stderr.golden

@@ -54,7 +54,8 @@ tests:
       stdout:
         - '^\n👽 Atmos (\d+\.\d+\.\d+|test) on [a-z]+/[a-z0-9_]+\n\n$'
       stderr:
-        - "^$"
+        # This is actually an invalid debug statement, we are not passing the log level in the command line
+        - "DEBU Using command line argument"
       exit_code: 0
 
   - name: "Valid Log Level in Environment Variable"