fix: [alerts] [ch-query] added aliases in metric query result (#1760)

* fix: [alerts] [ch-query] added aliases in metric query result

* fix: added more column type support for target in ch query

* fix: added error handling when data type is unexpected in metric result

Co-authored-by: Pranay Prateek <pranay@signoz.io>

ee/query-service/app/db/metrics.go

@@ -12,6 +12,7 @@ import (
 	"time"
 
 	"go.signoz.io/signoz/ee/query-service/model"
+	baseconst "go.signoz.io/signoz/pkg/query-service/constants"
 	basemodel "go.signoz.io/signoz/pkg/query-service/model"
 	"go.signoz.io/signoz/pkg/query-service/utils"
 	"go.uber.org/zap"
@@ -91,6 +92,32 @@ func (r *ClickhouseReader) GetMetricResultEE(ctx context.Context, query string)
 				metricPoint.Timestamp = v.UnixMilli()
 			case *float64:
 				metricPoint.Value = *v
+			case **float64:
+				// ch seems to return this type when column is derived from
+				// SELECT count(*)/ SELECT count(*)
+				floatVal := *v
+				if floatVal != nil {
+					metricPoint.Value = *floatVal
+				}
+			case *float32:
+				float32Val := float32(*v)
+				metricPoint.Value = float64(float32Val)
+			case *uint8, *uint64, *uint16, *uint32:
+				if _, ok := baseconst.ReservedColumnTargetAliases[colName]; ok {
+					metricPoint.Value = float64(reflect.ValueOf(v).Elem().Uint())
+				} else {
+					groupBy = append(groupBy, fmt.Sprintf("%v", reflect.ValueOf(v).Elem().Uint()))
+					groupAttributes[colName] = fmt.Sprintf("%v", reflect.ValueOf(v).Elem().Uint())
+				}
+			case *int8, *int16, *int32, *int64:
+				if _, ok := baseconst.ReservedColumnTargetAliases[colName]; ok {
+					metricPoint.Value = float64(reflect.ValueOf(v).Elem().Int())
+				} else {
+					groupBy = append(groupBy, fmt.Sprintf("%v", reflect.ValueOf(v).Elem().Int()))
+					groupAttributes[colName] = fmt.Sprintf("%v", reflect.ValueOf(v).Elem().Int())
+				}
+			default:
+				zap.S().Errorf("invalid var found in metric builder query result", v, colName)
 			}
 		}
 		sort.Strings(groupBy)

pkg/query-service/app/clickhouseReader/reader.go

@@ -2916,6 +2916,32 @@ func (r *ClickHouseReader) GetMetricResult(ctx context.Context, query string) ([
 				metricPoint.Timestamp = v.UnixMilli()
 			case *float64:
 				metricPoint.Value = *v
+			case **float64:
+				// ch seems to return this type when column is derived from
+				// SELECT count(*)/ SELECT count(*)
+				floatVal := *v
+				if floatVal != nil {
+					metricPoint.Value = *floatVal
+				}
+			case *float32:
+				float32Val := float32(*v)
+				metricPoint.Value = float64(float32Val)
+			case *uint8, *uint64, *uint16, *uint32:
+				if _, ok := constants.ReservedColumnTargetAliases[colName]; ok {
+					metricPoint.Value = float64(reflect.ValueOf(v).Elem().Uint())
+				} else {
+					groupBy = append(groupBy, fmt.Sprintf("%v", reflect.ValueOf(v).Elem().Uint()))
+					groupAttributes[colName] = fmt.Sprintf("%v", reflect.ValueOf(v).Elem().Uint())
+				}
+			case *int8, *int16, *int32, *int64:
+				if _, ok := constants.ReservedColumnTargetAliases[colName]; ok {
+					metricPoint.Value = float64(reflect.ValueOf(v).Elem().Int())
+				} else {
+					groupBy = append(groupBy, fmt.Sprintf("%v", reflect.ValueOf(v).Elem().Int()))
+					groupAttributes[colName] = fmt.Sprintf("%v", reflect.ValueOf(v).Elem().Int())
+				}
+			default:
+				zap.S().Errorf("invalid var found in metric builder query result", v, colName)
 			}
 		}
 		sort.Strings(groupBy)

pkg/query-service/constants/constants.go

@@ -190,3 +190,8 @@ const (
 		"CAST((attributes_float64_key, attributes_float64_value), 'Map(String, Float64)') as  attributes_float64," +
 		"CAST((resources_string_key, resources_string_value), 'Map(String, String)') as resources_string "
 )
+
+// ReservedColumnTargetAliases identifies result value from a user
+// written clickhouse query. The column alias indcate which value is
+// to be considered as final result (or target)
+var ReservedColumnTargetAliases = map[string]bool{"result": true, "res": true, "value": true}

pkg/query-service/rules/thresholdRule.go

@@ -422,25 +422,40 @@ func (r *ThresholdRule) runChQuery(ctx context.Context, db clickhouse.Conn, quer
 				}
 
 			case *float64:
-				if colName == "res" || colName == "value" {
+				if _, ok := constants.ReservedColumnTargetAliases[colName]; ok {
 					sample.Point.V = *v
-
 				} else {
 					lbls.Set(colName, fmt.Sprintf("%f", *v))
 				}
-			case *uint64:
+			case **float64:
-				intv := *v
+				// ch seems to return this type when column is derived from
-				if colName == "res" || colName == "value" {
+				// SELECT count(*)/ SELECT count(*)
-					sample.Point.V = float64(intv)
+				floatVal := *v
-				} else {
+				if floatVal != nil {
-					lbls.Set(colName, fmt.Sprintf("%d", intv))
+					if _, ok := constants.ReservedColumnTargetAliases[colName]; ok {
+						sample.Point.V = *floatVal
+					} else {
+						lbls.Set(colName, fmt.Sprintf("%f", *floatVal))
+					}
 				}
-			case *uint8:
+			case *float32:
-				intv := *v
+				float32Val := float32(*v)
-				if colName == "res" || colName == "value" {
+				if _, ok := constants.ReservedColumnTargetAliases[colName]; ok {
-					sample.Point.V = float64(intv)
+					sample.Point.V = float64(float32Val)
 				} else {
-					lbls.Set(colName, fmt.Sprintf("%d", intv))
+					lbls.Set(colName, fmt.Sprintf("%f", float32Val))
+				}
+			case *uint8, *uint64, *uint16, *uint32:
+				if _, ok := constants.ReservedColumnTargetAliases[colName]; ok {
+					sample.Point.V = float64(reflect.ValueOf(v).Elem().Uint())
+				} else {
+					lbls.Set(colName, fmt.Sprintf("%v", reflect.ValueOf(v).Elem().Uint()))
+				}
+			case *int8, *int16, *int32, *int64:
+				if _, ok := constants.ReservedColumnTargetAliases[colName]; ok {
+					sample.Point.V = float64(reflect.ValueOf(v).Elem().Int())
+				} else {
+					lbls.Set(colName, fmt.Sprintf("%v", reflect.ValueOf(v).Elem().Int()))
 				}
 			default:
 				zap.S().Errorf("ruleId:", r.ID(), "\t error: invalid var found in query result", v, columnNames[i])