Publish ITWorx Pulse source

internal/freshness/evaluator.go

@@ -0,0 +1,54 @@
+package freshness
+
+import (
+	"errors"
+	"time"
+
+	"github.com/itworx/pulse/internal/datasource"
+)
+
+type Input struct {
+	SourceID string
+	Required bool
+	Health   datasource.SourceHealth
+	Previous datasource.HealthState
+	Now      time.Time
+}
+type Result struct {
+	State       datasource.HealthState
+	Age         *time.Duration
+	LastKnownAt time.Time
+	Recovery    bool
+	Event       string
+	Warning     string
+}
+
+func Evaluate(input Input) (Result, error) {
+	if input.SourceID == "" {
+		return Result{}, errors.New("source id is required")
+	}
+	now := input.Now
+	if now.IsZero() {
+		now = time.Now().UTC()
+	}
+	if err := input.Health.Validate(now); err != nil {
+		return Result{}, err
+	}
+	result := Result{State: input.Health.EffectiveState(now), LastKnownAt: input.Health.ObservedAt}
+	if !input.Health.ObservedAt.IsZero() {
+		age := now.Sub(input.Health.ObservedAt)
+		if age < 0 {
+			age = 0
+		}
+		result.Age = &age
+	}
+	if input.Required && result.State != datasource.HealthHealthy && result.State != datasource.HealthDegraded {
+		result.State = datasource.HealthUnknown
+		result.Warning = "REQUIRED_SOURCE_UNKNOWN"
+	}
+	if input.Previous == datasource.HealthUnknown && (result.State == datasource.HealthHealthy || result.State == datasource.HealthDegraded) {
+		result.Recovery = true
+		result.Event = "DATASOURCE_RECOVERED"
+	}
+	return result, nil
+}