feat(template): set zap loglevel via environment var (#92)

* Set ZAP loglevel via environment var

Signed-off-by: Steffen Exler <Steffen.Exler@mail.schwarz>

* Update _template/cmd/{{.Base.appName}}/main.go

Co-authored-by: Tobias Brumhard <tobias.brumhard@mail.schwarz>

* Put logger logic into internal folder

Signed-off-by: Steffen Exler <Steffen.Exler@mail.schwarz>

* Rename logger.GetLogger to logger.NewAtLevel

Signed-off-by: Tobias Brumhard <tobias.brumhard@mail.schwarz>

Co-authored-by: Tobias Brumhard <tobias.brumhard@mail.schwarz>

_template/cmd/{{.Base.appName}}/main.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"os"
 
+	"{{.Base.moduleName}}/internal/logger"
 	"go.uber.org/zap"
 
 	// This controls the maxprocs environment variable in container runtimes.
@@ -19,7 +20,7 @@ func main() {
 }
 
 func run() error {
-	logger, err := zap.NewProduction()
+	logger, err := logger.NewAtLevel(os.Getenv("LOG_LEVEL"))
 	if err != nil {
 		return err
 	}

_template/internal/logger/logger.go

@@ -0,0 +1,27 @@
+package logger
+
+import (
+	"go.uber.org/zap"
+	"go.uber.org/zap/zapcore"
+)
+
+func NewAtLevel(levelStr string) (*zap.Logger, error) {
+	logLevel := zapcore.InfoLevel
+	if levelStr != "" {
+		var err error
+		logLevel, err = zapcore.ParseLevel(levelStr)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	logConf := zap.NewProductionConfig()
+	logConf.Level = zap.NewAtomicLevelAt(logLevel)
+
+	logger, err := logConf.Build()
+	if err != nil {
+		return nil, err
+	}
+
+	return logger, nil
+}