Stage 6: alert statistics endpoints

- GET /api/stats/alerts — total/firing/resolved counts - GET /api/stats/alerts/top — most frequent alert names (?limit, default 10) - GET /api/stats/alerts/by-hour — counts for all 24 hours (zeros filled in) - GET /api/stats/alerts/by-day — counts for all 7 days with names (zeros filled in) - All endpoints accept optional ?from/?to (YYYY-MM-DD) to filter by received_at
2026-05-20 22:31:18 +02:00
parent f8f209dcba
commit 923fc8bf9c
2 changed files with 186 additions and 0 deletions
@@ -0,0 +1,181 @@
+package api
+
+import (
+	"database/sql"
+	"fmt"
+	"net/http"
+	"net/url"
+	"strings"
+	"time"
+)
+
+func handleStatsAlerts(db *sql.DB) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		where, args := statsFilter(r.URL.Query())
+
+		var total, firing, resolved int64
+		err := db.QueryRowContext(r.Context(), fmt.Sprintf(`
+			SELECT COUNT(*),
+			       SUM(CASE WHEN status = 'firing'   THEN 1 ELSE 0 END),
+			       SUM(CASE WHEN status = 'resolved' THEN 1 ELSE 0 END)
+			FROM alerts WHERE %s`, where), args...,
+		).Scan(&total, &firing, &resolved)
+		if err != nil {
+			respond(w, http.StatusInternalServerError, errResp("internal error"))
+			return
+		}
+		respond(w, http.StatusOK, map[string]int64{
+			"total":    total,
+			"firing":   firing,
+			"resolved": resolved,
+		})
+	}
+}
+
+func handleStatsTop(db *sql.DB) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		where, args := statsFilter(r.URL.Query())
+
+		limit := 10
+		if l := r.URL.Query().Get("limit"); l != "" {
+			var n int
+			fmt.Sscanf(l, "%d", &n)
+			if n > 0 && n <= 100 {
+				limit = n
+			}
+		}
+		args = append(args, limit)
+
+		rows, err := db.QueryContext(r.Context(), fmt.Sprintf(`
+			SELECT name, COUNT(*) AS cnt
+			FROM   alerts
+			WHERE  %s
+			GROUP  BY name
+			ORDER  BY cnt DESC
+			LIMIT  ?`, where), args...)
+		if err != nil {
+			respond(w, http.StatusInternalServerError, errResp("internal error"))
+			return
+		}
+		defer rows.Close()
+
+		type entry struct {
+			Name  string `json:"name"`
+			Count int64  `json:"count"`
+		}
+		result := []entry{}
+		for rows.Next() {
+			var e entry
+			if err := rows.Scan(&e.Name, &e.Count); err != nil {
+				respond(w, http.StatusInternalServerError, errResp("internal error"))
+				return
+			}
+			result = append(result, e)
+		}
+		respond(w, http.StatusOK, result)
+	}
+}
+
+func handleStatsByHour(db *sql.DB) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		where, args := statsFilter(r.URL.Query())
+
+		rows, err := db.QueryContext(r.Context(), fmt.Sprintf(`
+			SELECT CAST(strftime('%%H', datetime(received_at, 'unixepoch')) AS INTEGER) AS hr,
+			       COUNT(*) AS cnt
+			FROM   alerts
+			WHERE  %s
+			GROUP  BY hr
+			ORDER  BY hr ASC`, where), args...)
+		if err != nil {
+			respond(w, http.StatusInternalServerError, errResp("internal error"))
+			return
+		}
+		defer rows.Close()
+
+		counts := make(map[int]int64, 24)
+		for rows.Next() {
+			var hr int
+			var cnt int64
+			if err := rows.Scan(&hr, &cnt); err != nil {
+				respond(w, http.StatusInternalServerError, errResp("internal error"))
+				return
+			}
+			counts[hr] = cnt
+		}
+
+		type entry struct {
+			Hour  int   `json:"hour"`
+			Count int64 `json:"count"`
+		}
+		result := make([]entry, 24)
+		for h := range result {
+			result[h] = entry{Hour: h, Count: counts[h]}
+		}
+		respond(w, http.StatusOK, result)
+	}
+}
+
+func handleStatsByDay(db *sql.DB) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		where, args := statsFilter(r.URL.Query())
+
+		// SQLite strftime('%w') → 0=Sunday … 6=Saturday
+		rows, err := db.QueryContext(r.Context(), fmt.Sprintf(`
+			SELECT CAST(strftime('%%w', datetime(received_at, 'unixepoch')) AS INTEGER) AS dow,
+			       COUNT(*) AS cnt
+			FROM   alerts
+			WHERE  %s
+			GROUP  BY dow
+			ORDER  BY dow ASC`, where), args...)
+		if err != nil {
+			respond(w, http.StatusInternalServerError, errResp("internal error"))
+			return
+		}
+		defer rows.Close()
+
+		counts := make(map[int]int64, 7)
+		for rows.Next() {
+			var dow int
+			var cnt int64
+			if err := rows.Scan(&dow, &cnt); err != nil {
+				respond(w, http.StatusInternalServerError, errResp("internal error"))
+				return
+			}
+			counts[dow] = cnt
+		}
+
+		dayNames := [7]string{"Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"}
+		type entry struct {
+			Day     int    `json:"day"`
+			DayName string `json:"day_name"`
+			Count   int64  `json:"count"`
+		}
+		result := make([]entry, 7)
+		for d := range result {
+			result[d] = entry{Day: d, DayName: dayNames[d], Count: counts[d]}
+		}
+		respond(w, http.StatusOK, result)
+	}
+}
+
+// statsFilter builds a WHERE clause and args from optional ?from and ?to query params.
+func statsFilter(q url.Values) (where string, args []any) {
+	clauses := []string{}
+	if from := q.Get("from"); from != "" {
+		if t, err := time.Parse("2006-01-02", from); err == nil {
+			clauses = append(clauses, "received_at >= ?")
+			args = append(args, t.UTC().Unix())
+		}
+	}
+	if to := q.Get("to"); to != "" {
+		if t, err := time.Parse("2006-01-02", to); err == nil {
+			clauses = append(clauses, "received_at < ?")
+			args = append(args, t.UTC().AddDate(0, 0, 1).Unix())
+		}
+	}
+	if len(clauses) == 0 {
+		return "1=1", args
+	}
+	return strings.Join(clauses, " AND "), args
+}