chore: add logger for push notifications

cmd/api/main.go

@@ -12,8 +12,39 @@ import (
 	"github.com/prabhupadasays/spsays-bff/internal/config"
 	"github.com/prabhupadasays/spsays-bff/internal/server"
 	"go.uber.org/zap"
+	"go.uber.org/zap/zapcore"
 )
 
+// newLogger builds the app logger, routing logs by level: Debug/Info/Warn go
+// to stdout and only Error/Fatal/Panic go to stderr. Hosting platforms tag
+// every stderr line as "error", so without this split a routine Debug/Info
+// line shows up with a misleading error badge. Production uses JSON at Info+;
+// development uses colored console at Debug+.
+func newLogger(production bool) *zap.Logger {
+	var encoder zapcore.Encoder
+	minLevel := zapcore.DebugLevel
+	if production {
+		encoder = zapcore.NewJSONEncoder(zap.NewProductionEncoderConfig())
+		minLevel = zapcore.InfoLevel
+	} else {
+		encCfg := zap.NewDevelopmentEncoderConfig()
+		encCfg.EncodeLevel = zapcore.CapitalColorLevelEncoder
+		encoder = zapcore.NewConsoleEncoder(encCfg)
+	}
+
+	low := zap.LevelEnablerFunc(func(l zapcore.Level) bool {
+		return l >= minLevel && l < zapcore.ErrorLevel
+	})
+	high := zap.LevelEnablerFunc(func(l zapcore.Level) bool {
+		return l >= zapcore.ErrorLevel
+	})
+	core := zapcore.NewTee(
+		zapcore.NewCore(encoder, zapcore.Lock(os.Stdout), low),
+		zapcore.NewCore(encoder, zapcore.Lock(os.Stderr), high),
+	)
+	return zap.New(core, zap.AddCaller(), zap.AddStacktrace(zapcore.ErrorLevel))
+}
+
 func main() {
 	// Load config
 	cfg, err := config.Load()
@@ -22,13 +53,8 @@ func main() {
 		os.Exit(1)
 	}
 
-	// Initialize logger
-	var logger *zap.Logger
-	if cfg.Env == "production" {
-		logger, _ = zap.NewProduction()
-	} else {
-		logger, _ = zap.NewDevelopment()
-	}
+	// Initialize logger — routes normal logs to stdout, errors to stderr.
+	logger := newLogger(cfg.Env == "production")
 	defer logger.Sync()
 
 	sugar := logger.Sugar()