availability implementation (preview)

internal/api/routes.go

@@ -17,6 +17,7 @@ func (a *API) InitRoutes() {
 		v1Api.POST("component_status", v1.PostComponentStatusHandler(a.db, a.log))
 
 		v1Api.GET("incidents", v1.GetIncidentsHandler(a.db, a.log))
+
 	}
 
 	// setup v2 group routing

internal/api/v1/v1.go

@@ -120,9 +120,10 @@ func GetIncidentsHandler(db *db.DB, logger *zap.Logger) gin.HandlerFunc {
 
 type Component struct {
 	ComponentID
-	Attrs     []*ComponentAttribute `json:"attributes"`
-	Name      string                `json:"name"`
-	Incidents []*Incident           `json:"incidents"`
+	Attrs        []*ComponentAttribute `json:"attributes"`
+	Name         string                `json:"name"`
+	Incidents    []*Incident           `json:"incidents"`
+	Availability []*AvailabilityData   `json:"availability"`
 }
 
 type ComponentID struct {
@@ -134,6 +135,15 @@ type ComponentAttribute struct {
 	Value string `json:"value"`
 }
 
+type AvailabilityData struct {
+	MonthlyAvailability []MonthlyAvailability `json:"monthly_availability"`
+}
+
+type MonthlyAvailability struct {
+	Month      string  `json:"month"`      // Name of the month, "2023-01"
+	Percentage float64 `json:"percentage"` // Percent (0.0 - 100.0)
+}
+
 func GetComponentsStatusHandler(db *db.DB, logger *zap.Logger) gin.HandlerFunc {
 	return func(c *gin.Context) {
 		logger.Debug("retrieve components with incidents")
@@ -145,8 +155,28 @@ func GetComponentsStatusHandler(db *db.DB, logger *zap.Logger) gin.HandlerFunc {
 
 		// We can't change this logic, because of date representation.
 		// Will be changed in the V2.
-		components := make([]*Component, len(r))
-		for index, component := range r {
+
+		// needs to uncomment after debugging:
+		//components := make([]*Component, len(r))
+		//for index, component := range r {
+		//	attrs := make([]*ComponentAttribute, len(component.Attrs))
+		//	for i, attr := range component.Attrs {
+		//		attrs[i] = &ComponentAttribute{
+		//			Name:  attr.Name,
+		//			Value: attr.Value,
+		//		}
+		//	}
+		// needs to uncomment after debugging <-
+
+		// needs to remove after debugging:
+		var components []*Component
+		for _, component := range r {
+			// Name checking
+			if component.Name != "Auto Scaling" {
+				continue // Skip
+			}
+			// needs to remove after debugging <-
+
 			attrs := make([]*ComponentAttribute, len(component.Attrs))
 			for i, attr := range component.Attrs {
 				attrs[i] = &ComponentAttribute{
@@ -188,18 +218,114 @@ func GetComponentsStatusHandler(db *db.DB, logger *zap.Logger) gin.HandlerFunc {
 				incidents[i] = newInc
 			}
 
-			components[index] = &Component{
-				ComponentID: ComponentID{int(component.ID)},
-				Attrs:       attrs,
-				Name:        component.Name,
-				Incidents:   incidents,
-			}
+			availability, _ := calculateAvailability(&component)
+
+			components = append(components, &Component{
+				ComponentID:  ComponentID{int(component.ID)},
+				Attrs:        attrs,
+				Name:         component.Name,
+				Incidents:    incidents,
+				Availability: []*AvailabilityData{{MonthlyAvailability: availability}},
+			})
+			// needs to uncomment after debugging:
+			//components[index] = &Component{
+			//	ComponentID:  ComponentID{int(component.ID)},
+			//	Attrs:        attrs,
+			//	Name:         component.Name,
+			//	Incidents:    incidents,
+			//	Availability: []*AvailabilityData{{MonthlyAvailability: availability}},
+			//}
+			// needs to uncomment after debugging <-
 		}
 
 		c.JSON(http.StatusOK, components)
 	}
 }
 
+// Function calculates the availability of a component over the last
+// year based only on completed incidents and an impact of 3
+func calculateAvailability(component *db.Component) ([]MonthlyAvailability, error) {
+	// Get the current date and starting point (12 months ago)
+	currentDate := time.Now()
+	startDate := currentDate.AddDate(0, -11, 0) // a year ago, including current the month
+	monthlyDowntime := make(map[string]float64)
+	for d := startDate; !d.After(currentDate); d = d.AddDate(0, 1, 0) {
+		month := d.Format("2006-01")
+		monthlyDowntime[month] = 0
+	}
+
+	for _, inc := range component.Incidents {
+		if inc.EndDate == nil || inc.Impact == nil || *inc.Impact != 3 {
+			continue
+		}
+
+		incidentStart := time.Time(*inc.StartDate)
+		incidentEnd := time.Time(*inc.EndDate)
+
+		if incidentEnd.Before(startDate) || incidentStart.After(currentDate) {
+			continue
+		}
+
+		if incidentStart.Before(startDate) {
+			incidentStart = startDate
+		}
+		if incidentEnd.After(currentDate) {
+			incidentEnd = currentDate
+		}
+
+		for d := incidentStart; d.Before(incidentEnd); d = d.AddDate(0, 1, 0) {
+			month := d.Format("2006-01")
+			monthStart := time.Date(d.Year(), d.Month(), 1, 0, 0, 0, 0, d.Location())
+			monthEnd := monthStart.AddDate(0, 1, 0)
+
+			downtimeStart := maxTime(incidentStart, monthStart)
+			downtimeEnd := minTime(incidentEnd, monthEnd)
+			downtime := downtimeEnd.Sub(downtimeStart).Hours()
+
+			monthlyDowntime[month] += downtime
+		}
+	}
+
+	monthlyAvailability := make([]MonthlyAvailability, 0, len(monthlyDowntime))
+	for month, downtime := range monthlyDowntime {
+		totalHours := hoursInMonth(month)
+		availability := 100 - (downtime / totalHours * 100)
+		// rounding the availability value to the nearest hundredth
+		availability = float64(int(availability*100+0.5)) / 100
+		monthlyAvailability = append(monthlyAvailability, MonthlyAvailability{
+			Month:      month,
+			Percentage: availability,
+		})
+	}
+
+	return monthlyAvailability, nil
+}
+
+func minTime(start, end time.Time) time.Time {
+	if start.Before(end) {
+		return start
+	}
+	return end
+}
+
+func maxTime(start, end time.Time) time.Time {
+	if start.After(end) {
+		return start
+	}
+	return end
+}
+
+func hoursInMonth(month string) float64 {
+	parsedTime, err := time.Parse("2006-01", month)
+	if err != nil {
+		return 0
+	}
+	firstDay := time.Date(parsedTime.Year(), parsedTime.Month(), 1, 0, 0, 0, 0, parsedTime.Location())
+	nextMonth := firstDay.AddDate(0, 1, 0)
+
+	return float64(nextMonth.Sub(firstDay).Hours())
+}
+
 type ComponentStatusPost struct {
 	Name       string                `json:"name" binding:"required"`
 	Impact     int                   `json:"impact" binding:"required,gte=1,lte=3"`