metrics: add worker error metrics

This commit introduces the collection of error
metrics since it is now possible to differentiate
between internal errors and user input errors.
Additionally, the error status is reported for
job duration metrics.

internal/worker/clienterrors/errors.go

@@ -34,6 +34,40 @@ type Error struct {
 	Details interface{}     `json:"details"`
 }
 
+const (
+	JobStatusSuccess        = "2xx"
+	JobStatusUserInputError = "4xx"
+	JobStatusInternalError  = "5xx"
+)
+
+type StatusCode string
+
+func (s *StatusCode) ToString() string {
+	return string(*s)
+}
+
+func GetStatusCode(err *Error) StatusCode {
+	if err == nil {
+		return JobStatusSuccess
+	}
+	switch err.ID {
+	case ErrorDNFDepsolveError:
+		return JobStatusInternalError
+	case ErrorDNFMarkingError:
+		return JobStatusInternalError
+	case ErrorNoDynamicArgs:
+		return JobStatusUserInputError
+	case ErrorInvalidTargetConfig:
+		return JobStatusUserInputError
+	case ErrorSharingTarget:
+		return JobStatusUserInputError
+	case ErrorInvalidTarget:
+		return JobStatusUserInputError
+	default:
+		return JobStatusInternalError
+	}
+}
+
 func WorkerClientError(code ClientErrorCode, reason string, details ...interface{}) *Error {
 	return &Error{
 		ID:      code,