Add alert archiving

Alerts can be manually archived (POST /api/alerts/{id}/archive) or
unarchived (DELETE /api/alerts/{id}/archive). A background goroutine
auto-archives resolved alerts older than TERDUT_ARCHIVE_AFTER (default 7d).
GET /api/alerts hides archived alerts by default; ?archived=true shows them.

internal/api/alerts.go

@@ -20,7 +20,8 @@ const alertSelectFrom = `
 	SELECT a.id, a.fingerprint, a.name, a.status,
 	       a.labels, a.annotations,
 	       a.starts_at, a.ends_at, a.generator_url, a.received_at,
-	       a.acknowledged_by, a.acknowledged_at, u.username
+	       a.acknowledged_by, a.acknowledged_at, u.username,
+	       a.archived_at
 	FROM   alerts a
 	LEFT   JOIN users u ON u.id = a.acknowledged_by`
 
@@ -39,6 +40,12 @@ func handleListAlerts(db *sql.DB) http.HandlerFunc {
 			where = append(where, "a.name = ?")
 			args = append(args, name)
 		}
+		if archived := q.Get("archived"); archived == "true" {
+			where = append(where, "a.archived_at IS NOT NULL")
+		} else {
+			where = append(where, "a.archived_at IS NULL")
+		}
+
 		if from := q.Get("from"); from != "" {
 			if t, err := time.Parse("2006-01-02", from); err == nil {
 				where = append(where, "a.received_at >= ?")
@@ -169,7 +176,7 @@ func scanAlert(s scanner) (models.Alert, error) {
 	var a models.Alert
 	var labelsJSON, annotationsJSON string
 	var startsAtUnix, receivedAtUnix int64
-	var endsAtUnix, ackAtUnix *int64
+	var endsAtUnix, ackAtUnix, archivedAtUnix *int64
 	var ackByID *int64
 	var ackByUser *string
 
@@ -179,6 +186,7 @@ func scanAlert(s scanner) (models.Alert, error) {
 		&startsAtUnix, &endsAtUnix,
 		&a.GeneratorURL, &receivedAtUnix,
 		&ackByID, &ackAtUnix, &ackByUser,
+		&archivedAtUnix,
 	); err != nil {
 		return a, err
 	}
@@ -197,5 +205,52 @@ func scanAlert(s scanner) (models.Alert, error) {
 		a.AcknowledgedByUser = ackByUser
 		a.AcknowledgedAt = &t
 	}
+	if archivedAtUnix != nil {
+		t := time.Unix(*archivedAtUnix, 0).UTC()
+		a.ArchivedAt = &t
+	}
 	return a, nil
 }
+
+func handleArchive(db *sql.DB) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		id, err := strconv.ParseInt(chi.URLParam(r, "id"), 10, 64)
+		if err != nil {
+			respond(w, http.StatusBadRequest, errResp("invalid alert id"))
+			return
+		}
+		res, err := db.ExecContext(r.Context(),
+			"UPDATE alerts SET archived_at = unixepoch() WHERE id = ?", id)
+		if err != nil {
+			respond(w, http.StatusInternalServerError, errResp("internal error"))
+			return
+		}
+		if n, _ := res.RowsAffected(); n == 0 {
+			respond(w, http.StatusNotFound, errResp("alert not found"))
+			return
+		}
+		a, _ := fetchAlert(r.Context(), db, id)
+		respond(w, http.StatusOK, a)
+	}
+}
+
+func handleUnarchive(db *sql.DB) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		id, err := strconv.ParseInt(chi.URLParam(r, "id"), 10, 64)
+		if err != nil {
+			respond(w, http.StatusBadRequest, errResp("invalid alert id"))
+			return
+		}
+		res, err := db.ExecContext(r.Context(),
+			"UPDATE alerts SET archived_at = NULL WHERE id = ?", id)
+		if err != nil {
+			respond(w, http.StatusInternalServerError, errResp("internal error"))
+			return
+		}
+		if n, _ := res.RowsAffected(); n == 0 {
+			respond(w, http.StatusNotFound, errResp("alert not found"))
+			return
+		}
+		w.WriteHeader(http.StatusNoContent)
+	}
+}