Empty response from prediction debug api interface

[zsnmwy]

Describe the bug

https://github.com/gocrane/crane/blob/be21d25057cf3b779e31956457d68664b375c136/pkg/server/router.go#L61-L64

apiVersion: prediction.crane.io/v1alpha1
kind: TimeSeriesPrediction
metadata:
  annotations:
    kubectl.kubernetes.io/last-applied-configuration: |
      {"apiVersion":"prediction.crane.io/v1alpha1","kind":"TimeSeriesPrediction","metadata":{"annotations":{},"name":"tsp-nodes-percent","namespace":"default"},"spec":{"predictionMetrics":[{"algorithm":{"algorithmType":"percentile","percentile":{"histogram":{"bucketSize":"10","bucketSizeGrowthRatio":"1.5","epsilon":"1e-10","firstBucketSize":"40","halfLife":"12h","maxValue":"10000.0"},"minSampleWeight":"1.0","sampleInterval":"1m"}},"expressionQuery":{"expression":"1-avg(rate(node_cpu_seconds_total{mode=\"idle\"}[1m])) by (instance)"},"resourceIdentifier":"nodes-cpu","type":"ExpressionQuery"},{"algorithm":{"algorithmType":"percentile","percentile":{"histogram":{"bucketSize":"10","bucketSizeGrowthRatio":"1.5","epsilon":"1e-10","firstBucketSize":"40","halfLife":"12h","maxValue":"1000000.0"},"minSampleWeight":"1.0","sampleInterval":"1m"}},"expressionQuery":{"expression":"sum(node_memory_MemTotal_bytes{} - node_memory_MemAvailable_bytes{}) by (instance)"},"resourceIdentifier":"nodes-mem","type":"ExpressionQuery"}],"predictionWindowSeconds":600,"targetRef":{"kind":"Node","name":"10.100.100.102"}}}
  creationTimestamp: "2022-07-21T14:55:02Z"
  generation: 1
  name: tsp-nodes-percent
  namespace: default
  resourceVersion: "1254800"
  uid: 318f5711-f363-4a48-888c-c118c1c6ba72
spec:
  predictionMetrics:
  - algorithm:
      algorithmType: percentile
      percentile:
        histogram:
          bucketSize: "10"
          bucketSizeGrowthRatio: "1.5"
          epsilon: "1e-10"
          firstBucketSize: "40"
          halfLife: 12h
          maxValue: "10000.0"
        minSampleWeight: "1.0"
        sampleInterval: 1m
    expressionQuery:
      expression: 1-avg(rate(node_cpu_seconds_total{mode="idle"}[1m])) by (instance)
    resourceIdentifier: nodes-cpu
    type: ExpressionQuery
  - algorithm:
      algorithmType: percentile
      percentile:
        histogram:
          bucketSize: "10"
          bucketSizeGrowthRatio: "1.5"
          epsilon: "1e-10"
          firstBucketSize: "40"
          halfLife: 12h
          maxValue: "1000000.0"
        minSampleWeight: "1.0"
        sampleInterval: 1m
    expressionQuery:
      expression: sum(node_memory_MemTotal_bytes{} - node_memory_MemAvailable_bytes{})
        by (instance)
    resourceIdentifier: nodes-mem
    type: ExpressionQuery
  predictionWindowSeconds: 600
  targetRef:
    kind: Node
    name: 10.100.100.102
status:
  conditions:
  - lastTransitionTime: "2022-07-21T15:17:02Z"
    message: ""
    reason: PredictSucceed
    status: "True"
    type: Ready
  predictionMetrics:
  - prediction:
    - samples:
      - timestamp: 1658416620
        value: "0.00000"
      - timestamp: 1658416680
        value: "0.00000"
      - timestamp: 1658416740
        value: "0.00000"
      - timestamp: 1658416800
        value: "0.00000"
      - timestamp: 1658416860
        value: "0.00000"
      - timestamp: 1658416920
        value: "0.00000"
      - timestamp: 1658416980
        value: "0.00000"
      - timestamp: 1658417040
        value: "0.00000"
      - timestamp: 1658417100
        value: "0.00000"
      - timestamp: 1658417160
        value: "0.00000"
      - timestamp: 1658417220
        value: "0.00000"
      - timestamp: 1658417280
        value: "0.00000"
      - timestamp: 1658417340
        value: "0.00000"
      - timestamp: 1658417400
        value: "0.00000"
      - timestamp: 1658417460
        value: "0.00000"
      - timestamp: 1658417520
        value: "0.00000"
      - timestamp: 1658417580
        value: "0.00000"
      - timestamp: 1658417640
        value: "0.00000"
      - timestamp: 1658417700
        value: "0.00000"
      - timestamp: 1658417760
        value: "0.00000"
      - timestamp: 1658417820
        value: "0.00000"
    ready: true
    resourceIdentifier: nodes-cpu
  - prediction:
    - samples:
      - timestamp: 1658416620
        value: "100.00000"
      - timestamp: 1658416680
        value: "100.00000"
      - timestamp: 1658416740
        value: "100.00000"
      - timestamp: 1658416800
        value: "100.00000"
      - timestamp: 1658416860
        value: "100.00000"
      - timestamp: 1658416920
        value: "100.00000"
      - timestamp: 1658416980
        value: "100.00000"
      - timestamp: 1658417040
        value: "100.00000"
      - timestamp: 1658417100
        value: "100.00000"
      - timestamp: 1658417160
        value: "100.00000"
      - timestamp: 1658417220
        value: "100.00000"
      - timestamp: 1658417280
        value: "100.00000"
      - timestamp: 1658417340
        value: "100.00000"
      - timestamp: 1658417400
        value: "100.00000"
      - timestamp: 1658417460
        value: "100.00000"
      - timestamp: 1658417520
        value: "100.00000"
      - timestamp: 1658417580
        value: "100.00000"
      - timestamp: 1658417640
        value: "100.00000"
      - timestamp: 1658417700
        value: "100.00000"
      - timestamp: 1658417760
        value: "100.00000"
      - timestamp: 1658417820
        value: "100.00000"
    ready: true
    resourceIdentifier: nodes-mem

Reproduce steps

• Use the latest images.

API Ref: https://www.postman.com/speeding-crater-505947/workspace/public/collection/14940923-8559deb0-9af9-4ace-bc64-14da3dd0c8f8?action=share&creator=14940923

Expected behavior

Should be return Prediction Metrics.

[zsnmwy]

@yufeiyu

[yufeiyu]

Thanks @zsnmwy for the issue. Looks like if there are more than ONE time series, this debug interface has some problems. I'll take a look at it.