Live: array for Processor, Outputter and Subscriber in channel rule top level (#39677)

pkg/services/live/pipeline/frame_output_threshold.go

@@ -0,0 +1,156 @@
+package pipeline
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	"github.com/grafana/grafana-plugin-sdk-go/data"
+)
+
+type ThresholdOutputConfig struct {
+	FieldName string `json:"fieldName"`
+	Channel   string `json:"channel"`
+}
+
+//go:generate mockgen -destination=frame_output_threshold_mock.go -package=pipeline github.com/grafana/grafana/pkg/services/live/pipeline FrameGetSetter
+
+type FrameGetSetter interface {
+	Get(orgID int64, channel string) (*data.Frame, bool, error)
+	Set(orgID int64, channel string, frame *data.Frame) error
+}
+
+// ThresholdOutput can monitor threshold transitions of the specified field and output
+// special state frame to the configured channel.
+type ThresholdOutput struct {
+	frameStorage FrameGetSetter
+	config       ThresholdOutputConfig
+}
+
+func NewThresholdOutput(frameStorage FrameGetSetter, config ThresholdOutputConfig) *ThresholdOutput {
+	return &ThresholdOutput{frameStorage: frameStorage, config: config}
+}
+
+const FrameOutputTypeThreshold = "threshold"
+
+func (out *ThresholdOutput) Type() string {
+	return FrameOutputTypeThreshold
+}
+
+func (out *ThresholdOutput) OutputFrame(_ context.Context, vars Vars, frame *data.Frame) ([]*ChannelFrame, error) {
+	if frame == nil {
+		return nil, nil
+	}
+	previousFrame, previousFrameOk, err := out.frameStorage.Get(vars.OrgID, out.config.Channel)
+	if err != nil {
+		return nil, err
+	}
+	fieldName := out.config.FieldName
+
+	currentFrameFieldIndex := -1
+	for i, f := range frame.Fields {
+		if f.Name == fieldName {
+			currentFrameFieldIndex = i
+		}
+	}
+	if currentFrameFieldIndex < 0 {
+		return nil, nil
+	}
+	if frame.Fields[currentFrameFieldIndex].Config == nil {
+		return nil, nil
+	}
+	if frame.Fields[currentFrameFieldIndex].Config.Thresholds == nil {
+		return nil, nil
+	}
+
+	mode := frame.Fields[currentFrameFieldIndex].Config.Thresholds.Mode
+	if mode != data.ThresholdsModeAbsolute {
+		return nil, fmt.Errorf("unsupported threshold mode: %s", mode)
+	}
+
+	if len(frame.Fields[currentFrameFieldIndex].Config.Thresholds.Steps) == 0 {
+		return nil, nil
+	}
+
+	previousFrameFieldIndex := -1
+	if previousFrameOk {
+		for i, f := range previousFrame.Fields {
+			if f.Name == fieldName {
+				previousFrameFieldIndex = i
+			}
+		}
+	}
+
+	var previousState *string
+	if previousFrameOk && previousFrameFieldIndex >= 0 {
+		var previousThreshold data.Threshold
+		value, ok := previousFrame.Fields[previousFrameFieldIndex].At(previousFrame.Fields[0].Len() - 1).(*float64)
+		if !ok {
+			return nil, nil
+		}
+		if value == nil {
+			// TODO: what should we do here?
+			return nil, nil
+		}
+		emptyState := ""
+		previousState = &emptyState
+		for _, threshold := range frame.Fields[currentFrameFieldIndex].Config.Thresholds.Steps {
+			if *value >= float64(threshold.Value) {
+				previousThreshold = threshold
+				previousState = &previousThreshold.State
+				continue
+			}
+			break
+		}
+	}
+
+	fTime := data.NewFieldFromFieldType(data.FieldTypeTime, 0)
+	fTime.Name = "time"
+	f1 := data.NewFieldFromFieldType(data.FieldTypeFloat64, 0)
+	f1.Name = "value"
+	f2 := data.NewFieldFromFieldType(data.FieldTypeString, 0)
+	f2.Name = "state"
+	f3 := data.NewFieldFromFieldType(data.FieldTypeString, 0)
+	f3.Name = "color"
+
+	for i := 0; i < frame.Fields[currentFrameFieldIndex].Len(); i++ {
+		// TODO: support other numeric types.
+		value, ok := frame.Fields[currentFrameFieldIndex].At(i).(*float64)
+		if !ok {
+			return nil, nil
+		}
+		if value == nil {
+			// TODO: what should we do here?
+			return nil, nil
+		}
+		var currentThreshold data.Threshold
+		for _, threshold := range frame.Fields[currentFrameFieldIndex].Config.Thresholds.Steps {
+			if *value >= float64(threshold.Value) {
+				currentThreshold = threshold
+				continue
+			}
+			break
+		}
+		if previousState == nil || currentThreshold.State != *previousState {
+			fTime.Append(time.Now())
+			f1.Append(*value)
+			f2.Append(currentThreshold.State)
+			f3.Append(currentThreshold.Color)
+			previousState = &currentThreshold.State
+		}
+	}
+
+	if fTime.Len() > 0 {
+		stateFrame := data.NewFrame("state", fTime, f1, f2, f3)
+		err := out.frameStorage.Set(vars.OrgID, out.config.Channel, frame)
+		if err != nil {
+			return nil, err
+		}
+		return []*ChannelFrame{{
+			Channel: out.config.Channel,
+			Frame:   stateFrame,
+		}}, nil
+	}
+
+	return nil, out.frameStorage.Set(vars.OrgID, out.config.Channel, frame)
+}