feat: Add resiliency data and functions in resiliency package

Signed-off-by: Abhinav Sharma <abhinavs1920bpl@gmail.com>

Author: abhinavs1920

pkg/resiliency/resiliency.go

@@ -0,0 +1,191 @@
+package resiliency
+
+// Package resiliency centralises all logic related to parsing and aggregating
+// resiliency reports that are emitted by the krkn engine.  A report is printed
+// on a single log line prefixed by the token `KRKN_RESILIENCY_REPORT_JSON:`
+// and contains a JSON payload describing the outcome of one(for krknctl) or more chaos
+// scenarios executed by the engine.
+//
+// The goal of this package is to provide:
+//   1.  A small set of structs mirroring the JSON schema.
+//   2.  A parser capable of extracting and unmarshalling the payload from a
+//       raw block of log text.
+//   3.  Helper utilities to merge many individual reports into a single final
+//       summary which is later persisted to `resiliency-report.json` by the
+//       CLI.
+
+import (
+    "encoding/json"
+    "errors"
+    "fmt"
+    "os"
+    "regexp"
+)
+
+// ----------------------------------------------------------------------------
+//  Data structures
+// ----------------------------------------------------------------------------
+
+type OverallResiliencyReport struct {
+    Scenarios       map[string]float64 `json:"scenarios"`
+    ResiliencyScore float64            `json:"resiliency_score"`
+    PassedSlos      int               `json:"passed_slos"`
+    TotalSlos       int               `json:"total_slos"`
+}
+
+
+// ----------------------------------------------------------------------------
+
+
+type DetailedScenarioReport struct {
+    OverallReport OverallResiliencyReport
+}
+
+// ----------------------------------------------------------------------------
+
+type FinalReport struct {
+    Scenarios       map[string]float64 `json:"scenarios"`
+    ResiliencyScore float64            `json:"resiliency_score"`
+    PassedSlos      int               `json:"passed_slos"`
+    TotalSlos       int               `json:"total_slos"`
+}
+
+// ----------------------------------------------------------------------------
+//  Parser & Aggregator
+// ----------------------------------------------------------------------------
+
+var reportRegex = regexp.MustCompile(`KRKN_RESILIENCY_REPORT_JSON:\s*(\{.*)`)
+
+// ParseResiliencyReport searches the supplied log bytes for a line prefixed by
+// the special token and, if found, attempts to unmarshal the trailing JSON into
+// a DetailedScenarioReport.
+func ParseResiliencyReport(logContent []byte) (*DetailedScenarioReport, error) {
+    match := reportRegex.FindSubmatch(logContent)
+    if len(match) < 2 {
+        return nil, errors.New("resiliency report marker not found in logs")
+    }
+
+    raw := match[1]
+
+    var rep DetailedScenarioReport
+
+    // 1. Direct overall_resiliency_report at root.
+    type root1 struct {
+        Overall OverallResiliencyReport `json:"overall_resiliency_report"`
+    }
+    var r1 root1
+    if err := json.Unmarshal(raw, &r1); err == nil && r1.Overall.ResiliencyScore != 0 {
+        rep.OverallReport = r1.Overall
+        return &rep, nil
+    }
+
+    // 2. Nested under telemetry.overall_resiliency_report.
+    type root2 struct {
+        Telemetry struct {
+            Overall OverallResiliencyReport `json:"overall_resiliency_report"`
+        } `json:"telemetry"`
+    }
+    var r2 root2
+    if err := json.Unmarshal(raw, &r2); err == nil && r2.Telemetry.Overall.ResiliencyScore != 0 {
+        rep.OverallReport = r2.Telemetry.Overall
+        return &rep, nil
+    }
+
+    // 3. As a map of scenario scores at root with optional aggregate values.
+    type root3 struct {
+        Scenarios        map[string]float64 `json:"scenarios"`
+        ResiliencyScore  float64           `json:"resiliency_score"`
+        PassedSlos       int               `json:"passed_slos"`
+        TotalSlos        int               `json:"total_slos"`
+    }
+    var r3 root3
+    if err := json.Unmarshal(raw, &r3); err == nil && len(r3.Scenarios) > 0 {
+        rep.OverallReport = OverallResiliencyReport{
+            Scenarios:       r3.Scenarios,
+            ResiliencyScore: r3.ResiliencyScore,
+            PassedSlos:      r3.PassedSlos,
+            TotalSlos:       r3.TotalSlos,
+        }
+        return &rep, nil
+    }
+
+    // 4. scenarios as an array of objects with name+score.
+    type scenarioItem struct {
+        Name  string  `json:"name"`
+        Score float64 `json:"score"`
+        Breakdown struct {
+            Passed int `json:"passed"`
+            Failed int `json:"failed"`
+        } `json:"breakdown"`
+    }
+    type root4 struct {
+        Scenarios []scenarioItem `json:"scenarios"`
+    }
+    var r4 root4
+    if err := json.Unmarshal(raw, &r4); err == nil && len(r4.Scenarios) > 0 {
+        m := make(map[string]float64)
+        var total float64
+        var passed, totalSLOs int
+        for _, it := range r4.Scenarios {
+            m[it.Name] = it.Score
+            total += it.Score
+            passed += it.Breakdown.Passed
+            totalSLOs += it.Breakdown.Passed + it.Breakdown.Failed
+        }
+        avg := total / float64(len(r4.Scenarios))
+        rep.OverallReport = OverallResiliencyReport{
+            Scenarios:       m,
+            ResiliencyScore: avg,
+            PassedSlos:      passed,
+            TotalSlos:       totalSLOs,
+        }
+        return &rep, nil
+    }
+
+    return nil, errors.New("unrecognised resiliency report JSON structure")
+}
+
+/// TODO: @abhinavs1920 (Implement weighted average of scores) 
+func AggregateReports(reports []DetailedScenarioReport) FinalReport {
+    final := FinalReport{
+        Scenarios: make(map[string]float64),
+    }
+
+    var scoreSum float64
+    var scoreCount int
+
+    for _, rep := range reports {
+        // Merge per-scenario scores.
+        for name, score := range rep.OverallReport.Scenarios {
+            final.Scenarios[name] = score
+            scoreSum += score
+            scoreCount++
+        }
+        // Aggregate SLO counters.
+        final.PassedSlos += rep.OverallReport.PassedSlos
+        final.TotalSlos += rep.OverallReport.TotalSlos
+    }
+
+    if scoreCount > 0 {
+        final.ResiliencyScore = scoreSum / float64(scoreCount)
+    } else {
+        // No data -> perfect score.
+        final.ResiliencyScore = 100.0
+    }
+
+    return final
+}
+
+func WriteFinalReport(report FinalReport, filename string) error {
+    data, err := json.MarshalIndent(report, "", "  ")
+    if err != nil {
+        return err
+    }
+    return os.WriteFile(filename, data, 0o644)
+}
+
+func PrintHumanSummary(report FinalReport) {
+    if data, err := json.MarshalIndent(report, "", "  "); err == nil {
+        fmt.Printf("Overall Resiliency Report Summary:\n%s\n", string(data))
+    }
+}