Add verbosity flag to all services (#244)

Signed-off-by: Daniel Weiße <dw@edgeless.systems>

internal/logger/cmdline.go

@@ -0,0 +1,24 @@
+package logger
+
+import (
+	"go.uber.org/zap"
+	"go.uber.org/zap/zapcore"
+)
+
+const CmdLineVerbosityDescription = "log verbosity in zap logging levels. Use -1 for debug information, 0 for info, 1 for warn, 2 for error"
+
+// VerbosityFromInt converts a verbosity level from an integer to a zapcore.Level.
+func VerbosityFromInt(verbosity int) zapcore.Level {
+	switch {
+	case verbosity <= -1:
+		return zap.DebugLevel
+	case verbosity == 0:
+		return zap.InfoLevel
+	case verbosity == 1:
+		return zap.WarnLevel
+	case verbosity >= 2:
+		return zap.ErrorLevel
+	default:
+		return zap.InfoLevel
+	}
+}