set unit for CloudWatch GetMetricStatistics result

pkg/tsdb/cloudwatch/cloudwatch.go

@@ -362,6 +362,7 @@ func (e *CloudWatchExecutor) executeGetMetricDataQuery(ctx context.Context, regi
 		}
 
 		queryRes.Series = append(queryRes.Series, &series)
+		queryRes.Meta = simplejson.New()
 		queryResponses = append(queryResponses, queryRes)
 	}
 
@@ -565,6 +566,12 @@ func parseResponse(resp *cloudwatch.GetMetricStatisticsOutput, query *CloudWatch
 		}
 
 		queryRes.Series = append(queryRes.Series, &series)
+		queryRes.Meta = simplejson.New()
+		if len(resp.Datapoints) > 0 && resp.Datapoints[0].Unit != nil {
+			if unit, ok := cloudwatchUnitMappings[*resp.Datapoints[0].Unit]; ok {
+				queryRes.Meta.Set("unit", unit)
+			}
+		}
 	}
 
 	return queryRes, nil

pkg/tsdb/cloudwatch/constants.go

@@ -0,0 +1,30 @@
+package cloudwatch
+
+var cloudwatchUnitMappings = map[string]string{
+	"Seconds":      "s",
+	"Microseconds": "µs",
+	"Milliseconds": "ms",
+	"Bytes":        "bytes",
+	"Kilobytes":    "kbytes",
+	"Megabytes":    "mbytes",
+	"Gigabytes":    "gbytes",
+	//"Terabytes":        "",
+	"Bits": "bits",
+	//"Kilobits":         "",
+	//"Megabits":         "",
+	//"Gigabits":         "",
+	//"Terabits":         "",
+	"Percent": "percent",
+	//"Count":            "",
+	"Bytes/Second":     "Bps",
+	"Kilobytes/Second": "KBs",
+	"Megabytes/Second": "MBs",
+	"Gigabytes/Second": "GBs",
+	//"Terabytes/Second": "",
+	"Bits/Second":     "bps",
+	"Kilobits/Second": "Kbits",
+	"Megabits/Second": "Mbits",
+	"Gigabits/Second": "Gbits",
+	//"Terabits/Second":  "",
+	//"Count/Second":     "",
+}