Merge pull request 'Page the next person when nobody answers' (#16) from escalation into main

Reviewed-on: #16

README.md

@@ -377,6 +377,50 @@ exhausts its retries. Written from the result rather than at enqueue, so the
 timeline says what actually happened — and a page that never landed is visible
 instead of looking the same as one that did.
 
+### Escalation
+
+Without a ladder, an unacknowledged incident re-pages the same topic every
+`notify_repeat` forever. That is a louder version of the same silence: if the
+person on call is asleep, out of signal, or has left, nothing else happens.
+
+A team can configure an ordered ladder instead. Each level has a timeout and a
+set of targets, and a target is either a named person or **whoever the team's
+rota says is on call today** — the target that keeps working when the rota
+changes and nobody remembers to edit the policy.
+
+```
+level 1   5m    oncall            the rota gets first refusal
+level 2   5m    user:bob          then a named second
+                                  then repeat_count more rounds
+                                  then the team's fallback topic, once
+```
+
+When a level's timeout passes with the incident still `triggered`, the next
+level is paged. Off the end of the ladder the whole thing runs again
+`repeat_count` times, and after that the team's `fallback_topic` is paged once
+as the end of the line. The incident stays open throughout: running out of
+people to wake is not the same as somebody answering.
+
+**Acknowledging or resolving stops it**, which is the point — continuing to wake
+people after somebody has said "I have this" is how a tool teaches people to
+mute it. **Snoozing pauses it**: a deliberate "not now" holds the ladder where
+it is, and it resumes when the snooze runs out.
+
+Every step is on the incident's timeline with the level and the names it woke,
+so somebody reading it afterwards can tell why their phone rang at 04:00. A
+level whose targets are all unreachable — no ntfy topic, a disabled account, an
+empty rota — is recorded as `nobody reachable` and the ladder moves on rather
+than stalling on a rung that cannot ring.
+
+**Reminders and escalation never both run.** A team with a ladder gets
+escalation; a team without keeps the reminder behaviour exactly as it was. Two
+pages for one silence is the surest way to get a tool muted.
+
+The ladder's `fallback_topic` is per team, unlike `TERDUT_NTFY_FALLBACK_TOPIC`,
+which is the install-wide topic used when an incident opens with nobody on call.
+They answer different questions: one is "nobody was scheduled", the other is
+"everybody scheduled has been tried".
+
 ### Stale alert expiry
 
 A resolved webhook is the only signal that an alert has stopped firing, so a
@@ -578,6 +622,8 @@ and was removed in v0.13.0 once senders had moved onto keys.
 | `GET` | `/api/teams/{teamID}/integrations` | member | List integrations. Never returns keys |
 | `POST` | `/api/teams/{teamID}/integrations` | **owner** | Mint an integration `{"name","kind"}` — key and URL shown once |
 | `DELETE` | `/api/teams/{teamID}/integrations/{integrationID}` | **owner** | Revoke an integration |
+| `GET` | `/api/teams/{teamID}/escalation` | member | The team's [escalation ladder](#escalation) `{repeat_count, fallback_topic, levels[]}`. Empty levels means the team has none |
+| `PUT` | `/api/teams/{teamID}/escalation` | **owner** | Replace it wholesale. `400` for a level with no targets or no timeout — a rung that pages nobody is a silence with a number on it |
 | `GET` | `/api/teams/{teamID}/deadman` | member | The team's [dead man's switch](#dead-mans-switch) configuration `{matchers, timeout_seconds, severity}` |
 | `PUT` | `/api/teams/{teamID}/deadman` | **owner** | Replace it. `400` when no matcher names an `alertname`, because a switch that silently watches nothing is the failure this feature exists to prevent |
 

internal/api/alertmanager.go

@@ -403,12 +403,18 @@ func openIncident(ctx context.Context, q querier, notify NotifyConfig, teamID in
 		}
 	}
 
-	// Queue the page, but do not send it here: this runs inside a transaction on
+	// Queue the page, but do not send it here: this runs inside the webhook's
-	// a single-connection pool, so an HTTP call would hold up every other
+	// transaction, and an HTTP call would hold a connection open across a
-	// request. The notifier picks the row up within a tick.
+	// network round trip. The notifier picks the row up within a tick.
 	if err := enqueueOpened(ctx, q, notify, id, onCall); err != nil {
 		return 0, err
 	}
+
+	// And start the escalation clock, if the team keeps one. In the same
+	// transaction, so an incident is never briefly open with nobody counting.
+	if err := startEscalation(ctx, q, id, teamID); err != nil {
+		return 0, err
+	}
 	return id, nil
 }
 

internal/api/escalation.go

@@ -0,0 +1,506 @@
+package api
+
+import (
+	"context"
+	"database/sql"
+	"log"
+	"net/http"
+	"strconv"
+	"strings"
+	"time"
+)
+
+// evEscalated records a rung of the ladder on the incident's timeline: which
+// level, and who it woke.
+const evEscalated = "escalated"
+
+// escalationPolicy is a team's ladder, loaded whole. It is small — a handful of
+// levels with a few targets each — and every use needs all of it, so there is
+// no point reading it a level at a time.
+type escalationPolicy struct {
+	teamID        int64
+	repeatCount   int64
+	fallbackTopic string
+	levels        []escalationLevel
+}
+
+type escalationLevel struct {
+	id       int64
+	position int64
+	timeout  time.Duration
+	targets  []escalationTarget
+}
+
+type escalationTarget struct {
+	kind   string // "user" or "oncall"
+	userID *int64
+}
+
+// configured reports whether this team has anything to escalate through. A
+// policy row with no levels is the same as no policy: the team gets the
+// pre-escalation behaviour, which is reminders on the assignee's topic.
+func (p *escalationPolicy) configured() bool { return p != nil && len(p.levels) > 0 }
+
+// level returns the level at a 1-based position.
+func (p *escalationPolicy) level(pos int64) (escalationLevel, bool) {
+	for _, l := range p.levels {
+		if l.position == pos {
+			return l, true
+		}
+	}
+	return escalationLevel{}, false
+}
+
+// loadEscalationPolicy reads one team's ladder. A team with no policy row
+// returns nil, which every caller treats as "not configured" rather than as an
+// error: most teams will never set one up.
+func loadEscalationPolicy(ctx context.Context, q querier, teamID int64) (*escalationPolicy, error) {
+	p := &escalationPolicy{teamID: teamID}
+	err := q.QueryRowContext(ctx,
+		"SELECT repeat_count, fallback_topic FROM escalation_policies WHERE team_id = $1",
+		teamID).Scan(&p.repeatCount, &p.fallbackTopic)
+	if err == sql.ErrNoRows {
+		return nil, nil
+	}
+	if err != nil {
+		return nil, err
+	}
+
+	rows, err := q.QueryContext(ctx, `
+		SELECT l.id, l.position, l.timeout_seconds, t.kind, t.user_id
+		FROM   escalation_levels l
+		LEFT   JOIN escalation_targets t ON t.level_id = l.id
+		WHERE  l.team_id = $1
+		ORDER  BY l.position, t.id`, teamID)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	byPosition := map[int64]int{} // position -> index in p.levels
+	for rows.Next() {
+		var id, position, timeout int64
+		var kind *string
+		var userID *int64
+		if err := rows.Scan(&id, &position, &timeout, &kind, &userID); err != nil {
+			return nil, err
+		}
+		idx, seen := byPosition[position]
+		if !seen {
+			p.levels = append(p.levels, escalationLevel{
+				id:       id,
+				position: position,
+				timeout:  time.Duration(timeout) * time.Second,
+			})
+			idx = len(p.levels) - 1
+			byPosition[position] = idx
+		}
+		// LEFT JOIN: a level with no targets yet still produces a row, with a
+		// NULL kind. It is a rung that pages nobody, which the API refuses to
+		// store but an older row could still hold.
+		if kind != nil {
+			p.levels[idx].targets = append(p.levels[idx].targets,
+				escalationTarget{kind: *kind, userID: userID})
+		}
+	}
+	return p, rows.Err()
+}
+
+// escalate advances every incident whose current level has run out of time.
+//
+// Runs on the notifier's tick, beside the reminder pass, because it is the same
+// question asked differently: reminders ask "has this been ignored long
+// enough to say it again", escalation asks "long enough to say it to somebody
+// else". Sharing the tick means one query cadence and one outbox.
+func escalate(ctx context.Context, db *sql.DB, cfg NotifyConfig) {
+	rows, err := db.QueryContext(ctx, `
+		SELECT i.id, i.team_id, i.escalation_level, i.escalation_level_at, i.escalation_round
+		FROM   incidents i
+		JOIN   escalation_policies p ON p.team_id = i.team_id
+		WHERE  i.resolved_at IS NULL
+		  AND  i.archived_at IS NULL
+		  AND  i.status = 'triggered'
+		  AND  (i.snoozed_until IS NULL OR i.snoozed_until <= $1)
+		  AND  i.escalation_level > 0`, time.Now().Unix())
+	if err != nil {
+		log.Printf("escalation: find due: %v", err)
+		return
+	}
+
+	type pending struct {
+		incidentID, teamID, level, round int64
+		levelAt                          int64
+	}
+	var due []pending
+	for rows.Next() {
+		var p pending
+		var levelAt *int64
+		if err := rows.Scan(&p.incidentID, &p.teamID, &p.level, &levelAt, &p.round); err != nil {
+			rows.Close()
+			log.Printf("escalation: scan: %v", err)
+			return
+		}
+		if levelAt == nil {
+			continue
+		}
+		p.levelAt = *levelAt
+		due = append(due, p)
+	}
+	rows.Close()
+	if err := rows.Err(); err != nil {
+		log.Printf("escalation: iterate: %v", err)
+		return
+	}
+
+	now := time.Now()
+	for _, d := range due {
+		policy, err := loadEscalationPolicy(ctx, db, d.teamID)
+		if err != nil {
+			log.Printf("escalation: load policy for team %d: %v", d.teamID, err)
+			continue
+		}
+		if !policy.configured() {
+			continue
+		}
+		current, ok := policy.level(d.level)
+		if !ok {
+			continue
+		}
+		if now.Sub(time.Unix(d.levelAt, 0)) < current.timeout {
+			continue
+		}
+		if err := advanceEscalation(ctx, db, cfg, policy, d.incidentID, d.level, d.round, now); err != nil {
+			log.Printf("escalation: advance incident %d: %v", d.incidentID, err)
+		}
+	}
+}
+
+// advanceEscalation moves one incident to its next rung, or off the end of the
+// ladder.
+//
+// The whole move is one transaction: the level, the page and the timeline entry
+// are one event, and an incident recorded as being at level 3 that nobody at
+// level 3 was told about is the worst of the possible half-states.
+func advanceEscalation(ctx context.Context, db *sql.DB, cfg NotifyConfig, policy *escalationPolicy, incidentID, level, round int64, now time.Time) error {
+	tx, err := db.BeginTx(ctx, nil)
+	if err != nil {
+		return err
+	}
+	defer tx.Rollback() //nolint:errcheck
+
+	next := level + 1
+	nextRound := round
+	if _, ok := policy.level(next); !ok {
+		// Off the end. Either start the chain again, or make the last call.
+		if round < policy.repeatCount {
+			next, nextRound = 1, round+1
+		} else {
+			if err := escalationExhausted(ctx, tx, policy, incidentID, now); err != nil {
+				return err
+			}
+			return tx.Commit()
+		}
+	}
+
+	target, ok := policy.level(next)
+	if !ok {
+		return nil
+	}
+	paged, err := pageLevel(ctx, tx, cfg, policy, incidentID, target)
+	if err != nil {
+		return err
+	}
+
+	if _, err := tx.ExecContext(ctx, `
+		UPDATE incidents
+		   SET escalation_level = $1, escalation_level_at = $2, escalation_round = $3
+		 WHERE id = $4`, next, now.Unix(), nextRound, incidentID); err != nil {
+		return err
+	}
+
+	detail := "level " + strconv.FormatInt(next, 10)
+	if nextRound > round {
+		detail += " (round " + strconv.FormatInt(nextRound+1, 10) + ")"
+	}
+	if len(paged) > 0 {
+		detail += ": " + strings.Join(paged, ", ")
+	} else {
+		// Worth recording loudly: the rung exists, its turn came, and it woke
+		// nobody. That is a policy that looks configured and is not.
+		detail += ": nobody reachable"
+	}
+	if err := logEvent(ctx, tx, incidentID, evEscalated, nil, nil, &detail); err != nil {
+		return err
+	}
+	return tx.Commit()
+}
+
+// escalationExhausted is the end of the line: the fallback topic, once, and a
+// timeline entry saying the ladder is finished. The incident stays triggered —
+// escalation running out is not the same as somebody answering.
+func escalationExhausted(ctx context.Context, tx *sql.Tx, policy *escalationPolicy, incidentID int64, now time.Time) error {
+	detail := "escalation exhausted"
+	if policy.fallbackTopic != "" {
+		if err := enqueueNotification(ctx, tx, incidentID, nil, policy.fallbackTopic, notifyEscalated); err != nil {
+			return err
+		}
+		detail += ": paged " + policy.fallbackTopic
+	} else {
+		detail += ": no fallback topic configured"
+	}
+
+	// Level 0 again, so the sweep stops considering it. The round counter is
+	// left where it is, as the record of how far it got.
+	if _, err := tx.ExecContext(ctx,
+		"UPDATE incidents SET escalation_level = 0, escalation_level_at = NULL WHERE id = $1",
+		incidentID); err != nil {
+		return err
+	}
+	return logEvent(ctx, tx, incidentID, evEscalated, nil, nil, &detail)
+}
+
+// pageLevel notifies every target of one level and reports who was woken.
+//
+// Each target gets its own outbox row, so each gets its own Acknowledge token:
+// the button in a notification must acknowledge as the person holding the
+// phone, not as whoever was paged first.
+func pageLevel(ctx context.Context, tx *sql.Tx, cfg NotifyConfig, policy *escalationPolicy, incidentID int64, level escalationLevel) ([]string, error) {
+	var paged []string
+	seen := map[int64]bool{}
+
+	for _, t := range level.targets {
+		userID := t.userID
+		if t.kind == "oncall" {
+			onCall, err := currentOnCall(ctx, tx, policy.teamID)
+			if err != nil {
+				return nil, err
+			}
+			if onCall == nil {
+				continue
+			}
+			userID = onCall
+		}
+		if userID == nil || seen[*userID] {
+			continue
+		}
+		seen[*userID] = true
+
+		var topic *string
+		var username string
+		if err := tx.QueryRowContext(ctx,
+			"SELECT ntfy_topic, username FROM users WHERE id = $1 AND disabled_at IS NULL",
+			*userID).Scan(&topic, &username); err != nil {
+			// A disabled or deleted account is not an error in the middle of an
+			// escalation: it is a target that cannot be woken, and the next
+			// level is the answer to that.
+			continue
+		}
+		if topic == nil || *topic == "" {
+			continue
+		}
+		if err := enqueueNotification(ctx, tx, incidentID, userID, *topic, notifyEscalated); err != nil {
+			return nil, err
+		}
+		paged = append(paged, username)
+	}
+	return paged, nil
+}
+
+// startEscalation puts a newly opened incident on the first rung, when its team
+// has a ladder. Called from openIncident, inside the same transaction, so an
+// incident is never briefly open with no escalation clock running.
+func startEscalation(ctx context.Context, q querier, incidentID, teamID int64) error {
+	policy, err := loadEscalationPolicy(ctx, q, teamID)
+	if err != nil || !policy.configured() {
+		return err
+	}
+	_, err = q.ExecContext(ctx,
+		"UPDATE incidents SET escalation_level = 1, escalation_level_at = $1 WHERE id = $2",
+		time.Now().Unix(), incidentID)
+	return err
+}
+
+// stopEscalation takes an incident off the ladder. Acknowledging or resolving
+// is somebody saying "I have this", and continuing to wake people after that is
+// the behaviour that teaches people to ignore the tool.
+func stopEscalation(ctx context.Context, q querier, incidentID int64) error {
+	_, err := q.ExecContext(ctx,
+		"UPDATE incidents SET escalation_level = 0, escalation_level_at = NULL WHERE id = $1",
+		incidentID)
+	return err
+}
+
+// handleGetEscalation returns a team's ladder.
+func handleGetEscalation(db *sql.DB) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		teamID, ok := teamParam(w, r)
+		if !ok {
+			return
+		}
+		if !requireTeamMember(w, r, teamID) {
+			return
+		}
+
+		policy, err := loadEscalationPolicy(r.Context(), db, teamID)
+		if err != nil {
+			respond(w, http.StatusInternalServerError, errResp("internal error"))
+			return
+		}
+		respond(w, http.StatusOK, escalationResponse(policy, teamID))
+	}
+}
+
+type escalationLevelJSON struct {
+	Position       int64                  `json:"position"`
+	TimeoutSeconds int64                  `json:"timeout_seconds"`
+	Targets        []escalationTargetJSON `json:"targets"`
+}
+
+type escalationTargetJSON struct {
+	Kind   string `json:"kind"`
+	UserID *int64 `json:"user_id,omitempty"`
+}
+
+type escalationJSON struct {
+	TeamID        int64                 `json:"team_id"`
+	RepeatCount   int64                 `json:"repeat_count"`
+	FallbackTopic string                `json:"fallback_topic"`
+	Levels        []escalationLevelJSON `json:"levels"`
+}
+
+func escalationResponse(p *escalationPolicy, teamID int64) escalationJSON {
+	out := escalationJSON{TeamID: teamID, Levels: []escalationLevelJSON{}}
+	if p == nil {
+		return out
+	}
+	out.RepeatCount = p.repeatCount
+	out.FallbackTopic = p.fallbackTopic
+	for _, l := range p.levels {
+		level := escalationLevelJSON{
+			Position:       l.position,
+			TimeoutSeconds: int64(l.timeout.Seconds()),
+			Targets:        []escalationTargetJSON{},
+		}
+		for _, t := range l.targets {
+			level.Targets = append(level.Targets, escalationTargetJSON{Kind: t.kind, UserID: t.userID})
+		}
+		out.Levels = append(out.Levels, level)
+	}
+	return out
+}
+
+// handleSetEscalation replaces a team's ladder wholesale.
+//
+// Replace rather than patch: the levels are an order, and an API that edits one
+// rung has to answer what happens to the numbering of the others. Sending the
+// whole ladder makes the order the client's to decide and the server's to
+// store, and makes an edit atomic — there is no moment where level 2 exists
+// twice.
+func handleSetEscalation(db *sql.DB) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		teamID, ok := teamParam(w, r)
+		if !ok {
+			return
+		}
+		if !requireTeamOwner(w, r, teamID) {
+			return
+		}
+
+		var req escalationJSON
+		if err := decodeJSON(r, &req); err != nil {
+			respond(w, http.StatusBadRequest, errResp("invalid request body"))
+			return
+		}
+		if req.RepeatCount < 0 || req.RepeatCount > 10 {
+			respond(w, http.StatusBadRequest, errResp("repeat_count must be between 0 and 10"))
+			return
+		}
+		for i, l := range req.Levels {
+			if l.TimeoutSeconds <= 0 {
+				respond(w, http.StatusBadRequest, errResp("every level needs a timeout"))
+				return
+			}
+			if len(l.Targets) == 0 {
+				// A rung that pages nobody is not a delay, it is a silence with
+				// a number on it.
+				respond(w, http.StatusBadRequest,
+					errResp("level "+strconv.FormatInt(int64(i+1), 10)+" has no targets"))
+				return
+			}
+			for _, t := range l.Targets {
+				switch t.Kind {
+				case "oncall":
+					if t.UserID != nil {
+						respond(w, http.StatusBadRequest, errResp("an oncall target takes no user_id"))
+						return
+					}
+				case "user":
+					if t.UserID == nil {
+						respond(w, http.StatusBadRequest, errResp("a user target needs a user_id"))
+						return
+					}
+				default:
+					respond(w, http.StatusBadRequest, errResp("target kind must be user or oncall"))
+					return
+				}
+			}
+		}
+
+		tx, err := db.BeginTx(r.Context(), nil)
+		if err != nil {
+			respond(w, http.StatusInternalServerError, errResp("internal error"))
+			return
+		}
+		defer tx.Rollback() //nolint:errcheck
+
+		if _, err := tx.ExecContext(r.Context(), `
+			INSERT INTO escalation_policies (team_id, repeat_count, fallback_topic, updated_at)
+			VALUES ($1, $2, $3, `+nowEpoch+`)
+			ON CONFLICT (team_id) DO UPDATE SET
+				repeat_count = excluded.repeat_count,
+				fallback_topic = excluded.fallback_topic,
+				updated_at = excluded.updated_at`,
+			teamID, req.RepeatCount, req.FallbackTopic); err != nil {
+			respond(w, http.StatusInternalServerError, errResp("internal error"))
+			return
+		}
+		// The levels are replaced, not merged; the cascade takes the targets.
+		if _, err := tx.ExecContext(r.Context(),
+			"DELETE FROM escalation_levels WHERE team_id = $1", teamID); err != nil {
+			respond(w, http.StatusInternalServerError, errResp("internal error"))
+			return
+		}
+
+		for i, l := range req.Levels {
+			var levelID int64
+			if err := tx.QueryRowContext(r.Context(), `
+				INSERT INTO escalation_levels (team_id, position, timeout_seconds)
+				VALUES ($1, $2, $3) RETURNING id`,
+				teamID, int64(i+1), l.TimeoutSeconds).Scan(&levelID); err != nil {
+				respond(w, http.StatusInternalServerError, errResp("internal error"))
+				return
+			}
+			for _, t := range l.Targets {
+				if _, err := tx.ExecContext(r.Context(), `
+					INSERT INTO escalation_targets (level_id, kind, user_id)
+					VALUES ($1, $2, $3)`, levelID, t.Kind, t.UserID); err != nil {
+					// The only foreign key here is the user.
+					respond(w, http.StatusBadRequest, errResp("unknown user in targets"))
+					return
+				}
+			}
+		}
+
+		if err := tx.Commit(); err != nil {
+			respond(w, http.StatusInternalServerError, errResp("internal error"))
+			return
+		}
+
+		policy, err := loadEscalationPolicy(r.Context(), db, teamID)
+		if err != nil {
+			respond(w, http.StatusInternalServerError, errResp("internal error"))
+			return
+		}
+		respond(w, http.StatusOK, escalationResponse(policy, teamID))
+	}
+}

internal/api/escalation_test.go

@@ -0,0 +1,385 @@
+package api_test
+
+import (
+	"net/http"
+	"strings"
+	"testing"
+	"time"
+
+	"git.ryuvia.com/niklas/terdut-server/internal/api"
+)
+
+// teamUser creates a user in the default team with an ntfy topic, so they can
+// actually be paged.
+func teamUser(t *testing.T, s *ts, username, topic string) int64 {
+	t.Helper()
+	var user struct {
+		ID int64 `json:"id"`
+	}
+	decode(t, s.req(t, http.MethodPost, "/api/users",
+		map[string]string{"username": username, "email": username + "@test.com"}), &user)
+	resp := s.req(t, http.MethodPost, "/api/teams/"+defaultTeam+"/members",
+		map[string]any{"user_id": user.ID, "role": "member"})
+	resp.Body.Close()
+	setTopic(t, s, int(user.ID), topic)
+	return user.ID
+}
+
+// Escalation is all timeouts, and there is no fake clock in this package. The
+// tests back-date escalation_level_at instead, which is the same trick the dead
+// man's switch tests use on received_at: the sweeper reads a stored timestamp,
+// so moving the timestamp is moving the clock.
+
+// ladder configures the default team with two levels: the rota first, then a
+// named person, then the fallback topic.
+func ladder(t *testing.T, s *ts, secondUserID int64, repeat int64, fallback string) {
+	t.Helper()
+	resp := s.req(t, http.MethodPut, "/api/teams/"+defaultTeam+"/escalation", map[string]any{
+		"repeat_count":   repeat,
+		"fallback_topic": fallback,
+		"levels": []map[string]any{
+			{"timeout_seconds": 300, "targets": []map[string]any{{"kind": "oncall"}}},
+			{"timeout_seconds": 300, "targets": []map[string]any{{"kind": "user", "user_id": secondUserID}}},
+		},
+	})
+	defer resp.Body.Close()
+	if resp.StatusCode != http.StatusOK {
+		t.Fatalf("configure the ladder: %d", resp.StatusCode)
+	}
+}
+
+// overdue back-dates an incident's current level so its timeout has passed.
+func overdue(t *testing.T, s *ts, incidentID int64) {
+	t.Helper()
+	s.exec(t, "UPDATE incidents SET escalation_level_at = $1 WHERE id = $2",
+		time.Now().Add(-time.Hour).Unix(), incidentID)
+}
+
+func escalationLevel(t *testing.T, s *ts, incidentID int64) (level, round int64) {
+	t.Helper()
+	if err := s.db.QueryRow(
+		"SELECT escalation_level, escalation_round FROM incidents WHERE id = $1",
+		incidentID).Scan(&level, &round); err != nil {
+		t.Fatalf("read escalation state: %v", err)
+	}
+	return level, round
+}
+
+// The whole point: nobody answers, so somebody else is woken.
+func TestEscalation_PagesTheNextLevel(t *testing.T) {
+	s, f := notifyTS(t, api.NotifyConfig{PublicURL: "https://terdut.example.com", RepeatEvery: 15 * time.Minute})
+	second := teamUser(t, s, "second", "terdut-second")
+	ladder(t, s, second, 0, "terdut-fallback")
+
+	postWebhook(t, s, []map[string]any{
+		amAlert("fp-esc", "DiskFull", "firing", "2026-05-20T10:00:00Z", zeroTime, nil),
+	})
+	s.sweepNotify(t)
+
+	// Level 1 is the rota, so the first page went to the admin.
+	if level, _ := escalationLevel(t, s, 1); level != 1 {
+		t.Fatalf("a new incident should start at level 1, got %d", level)
+	}
+	if got := f.topicsSince(t); len(got) == 0 || got[0] != "terdut-admin" {
+		t.Fatalf("the first page should go to the on-call user, went to %v", got)
+	}
+
+	// Time passes with no acknowledgement.
+	f.forget()
+	overdue(t, s, 1)
+	s.sweepNotify(t)
+
+	if level, _ := escalationLevel(t, s, 1); level != 2 {
+		t.Errorf("expected level 2, got %d", level)
+	}
+	if got := f.topicsSince(t); len(got) != 1 || got[0] != "terdut-second" {
+		t.Errorf("level 2 should page the named user, paged %v", got)
+	}
+
+	// And the timeline says so, which is what somebody reads afterwards to
+	// understand why their phone rang at 04:00.
+	timeline := list(t, s.req(t, http.MethodGet, "/api/incidents/1/timeline", nil))
+	found := ""
+	for _, e := range timeline {
+		if e["type"] == "escalated" {
+			found, _ = e["detail"].(string)
+		}
+	}
+	if found == "" {
+		t.Error("the timeline should record the escalation")
+	} else if !strings.HasPrefix(found, "level 2") || !strings.Contains(found, "second") {
+		t.Errorf("the escalation entry should say which level and who: %q", found)
+	}
+}
+
+// Acknowledging is somebody saying "I have this". Nobody else should be woken.
+func TestEscalation_AcknowledgementStopsIt(t *testing.T) {
+	s, f := notifyTS(t, api.NotifyConfig{PublicURL: "https://terdut.example.com", RepeatEvery: 15 * time.Minute})
+	second := teamUser(t, s, "second", "terdut-second")
+	ladder(t, s, second, 0, "terdut-fallback")
+
+	postWebhook(t, s, []map[string]any{
+		amAlert("fp-ack", "DiskFull", "firing", "2026-05-20T10:00:00Z", zeroTime, nil),
+	})
+	s.sweepNotify(t)
+
+	s.req(t, http.MethodPost, "/api/incidents/1/acknowledge", nil).Body.Close()
+	if level, _ := escalationLevel(t, s, 1); level != 0 {
+		t.Errorf("acknowledging should take the incident off the ladder, level is %d", level)
+	}
+
+	f.forget()
+	overdue(t, s, 1) // no-op: level is 0, so there is nothing due
+	s.sweepNotify(t)
+	if got := f.topicsSince(t); len(got) != 0 {
+		t.Errorf("an acknowledged incident should page nobody, paged %v", got)
+	}
+}
+
+// Resolving stops it too, and by the same mechanism.
+func TestEscalation_ResolutionStopsIt(t *testing.T) {
+	s, f := notifyTS(t, api.NotifyConfig{PublicURL: "https://terdut.example.com", RepeatEvery: 15 * time.Minute})
+	second := teamUser(t, s, "second", "terdut-second")
+	ladder(t, s, second, 0, "terdut-fallback")
+
+	postWebhook(t, s, []map[string]any{
+		amAlert("fp-res", "DiskFull", "firing", "2026-05-20T10:00:00Z", zeroTime, nil),
+	})
+	s.sweepNotify(t)
+	s.req(t, http.MethodPost, "/api/incidents/1/resolve", nil).Body.Close()
+
+	f.forget()
+	overdue(t, s, 1)
+	s.sweepNotify(t)
+	if level, _ := escalationLevel(t, s, 1); level != 0 {
+		t.Errorf("a resolved incident should be off the ladder, level is %d", level)
+	}
+}
+
+// Snoozing is a deliberate "not now", so the ladder waits rather than carrying
+// on without the person who asked for quiet.
+func TestEscalation_SnoozePausesIt(t *testing.T) {
+	s, f := notifyTS(t, api.NotifyConfig{PublicURL: "https://terdut.example.com", RepeatEvery: 15 * time.Minute})
+	second := teamUser(t, s, "second", "terdut-second")
+	ladder(t, s, second, 0, "terdut-fallback")
+
+	postWebhook(t, s, []map[string]any{
+		amAlert("fp-snooze", "DiskFull", "firing", "2026-05-20T10:00:00Z", zeroTime, nil),
+	})
+	s.sweepNotify(t)
+
+	resp := s.req(t, http.MethodPost, "/api/incidents/1/snooze", map[string]any{"duration": "1h"})
+	resp.Body.Close()
+
+	f.forget()
+	overdue(t, s, 1)
+	s.sweepNotify(t)
+
+	if level, _ := escalationLevel(t, s, 1); level != 1 {
+		t.Errorf("a snoozed incident should stay where it is, level is %d", level)
+	}
+	if got := f.topicsSince(t); len(got) != 0 {
+		t.Errorf("a snoozed incident should page nobody, paged %v", got)
+	}
+
+	// When the snooze ends, the ladder picks up where it left off.
+	s.exec(t, "UPDATE incidents SET snoozed_until = $1 WHERE id = 1", time.Now().Add(-time.Minute).Unix())
+	s.sweepNotify(t)
+	if level, _ := escalationLevel(t, s, 1); level != 2 {
+		t.Errorf("after the snooze the ladder should resume, level is %d", level)
+	}
+}
+
+// Running out of ladder pages the team's fallback topic once, and says so.
+func TestEscalation_ExhaustionPagesTheFallback(t *testing.T) {
+	s, f := notifyTS(t, api.NotifyConfig{PublicURL: "https://terdut.example.com", RepeatEvery: 15 * time.Minute})
+	second := teamUser(t, s, "second", "terdut-second")
+	ladder(t, s, second, 0, "terdut-fallback")
+
+	postWebhook(t, s, []map[string]any{
+		amAlert("fp-end", "DiskFull", "firing", "2026-05-20T10:00:00Z", zeroTime, nil),
+	})
+	s.sweepNotify(t)
+
+	overdue(t, s, 1)
+	s.sweepNotify(t) // level 2
+	f.forget()
+	overdue(t, s, 1)
+	s.sweepNotify(t) // off the end
+
+	if got := f.topicsSince(t); len(got) != 1 || got[0] != "terdut-fallback" {
+		t.Errorf("exhaustion should page the fallback topic once, paged %v", got)
+	}
+	level, _ := escalationLevel(t, s, 1)
+	if level != 0 {
+		t.Errorf("an exhausted ladder should stop asking, level is %d", level)
+	}
+
+	// The incident is still open: running out of people is not an answer.
+	var status string
+	if err := s.db.QueryRow("SELECT status FROM incidents WHERE id = 1").Scan(&status); err != nil {
+		t.Fatal(err)
+	}
+	if status != "triggered" {
+		t.Errorf("exhaustion must not resolve the incident, status is %q", status)
+	}
+}
+
+// repeat_count walks the whole ladder again before giving up.
+func TestEscalation_RepeatsTheChain(t *testing.T) {
+	s, f := notifyTS(t, api.NotifyConfig{PublicURL: "https://terdut.example.com", RepeatEvery: 15 * time.Minute})
+	second := teamUser(t, s, "second", "terdut-second")
+	ladder(t, s, second, 1, "terdut-fallback") // one extra round
+
+	postWebhook(t, s, []map[string]any{
+		amAlert("fp-repeat", "DiskFull", "firing", "2026-05-20T10:00:00Z", zeroTime, nil),
+	})
+	s.sweepNotify(t)
+
+	overdue(t, s, 1)
+	s.sweepNotify(t) // level 2
+	f.forget()
+	overdue(t, s, 1)
+	s.sweepNotify(t) // back to level 1, round 2
+
+	level, round := escalationLevel(t, s, 1)
+	if level != 1 || round != 1 {
+		t.Errorf("expected level 1 round 1, got level %d round %d", level, round)
+	}
+	if got := f.topicsSince(t); len(got) != 1 || got[0] != "terdut-admin" {
+		t.Errorf("the second round should start at the top again, paged %v", got)
+	}
+}
+
+// A team without a ladder keeps exactly the behaviour it had, and never gets
+// both a reminder and an escalation for the same silence.
+func TestEscalation_WithoutAPolicyRemindersStillRun(t *testing.T) {
+	s, f := notifyTS(t, api.NotifyConfig{PublicURL: "https://terdut.example.com", RepeatEvery: 15 * time.Minute})
+	postWebhook(t, s, []map[string]any{
+		amAlert("fp-noesc", "DiskFull", "firing", "2026-05-20T10:00:00Z", zeroTime, nil),
+	})
+	s.sweepNotify(t)
+
+	// Age the first notification past the repeat interval.
+	f.forget()
+	s.exec(t, "UPDATE notifications SET created_at = $1, sent_at = $1",
+		time.Now().Add(-time.Hour).Unix())
+	s.sweepNotify(t)
+
+	if got := f.topicsSince(t); len(got) != 1 || got[0] != "terdut-admin" {
+		t.Errorf("without a ladder the reminder should still fire, paged %v", got)
+	}
+	if level, _ := escalationLevel(t, s, 1); level != 0 {
+		t.Errorf("an incident in a team with no ladder should not be on one, level is %d", level)
+	}
+}
+
+// With a ladder, reminders stop: two pages for one silence is how people learn
+// to mute the tool.
+func TestEscalation_WithAPolicyRemindersDoNotAlsoFire(t *testing.T) {
+	s, f := notifyTS(t, api.NotifyConfig{PublicURL: "https://terdut.example.com", RepeatEvery: 15 * time.Minute})
+	second := teamUser(t, s, "second", "terdut-second")
+	ladder(t, s, second, 0, "terdut-fallback")
+
+	postWebhook(t, s, []map[string]any{
+		amAlert("fp-both", "DiskFull", "firing", "2026-05-20T10:00:00Z", zeroTime, nil),
+	})
+	s.sweepNotify(t)
+
+	f.forget()
+	// Old enough for a reminder, but not yet due for escalation.
+	s.exec(t, "UPDATE notifications SET created_at = $1, sent_at = $1",
+		time.Now().Add(-time.Hour).Unix())
+	s.sweepNotify(t)
+
+	if got := f.topicsSince(t); len(got) != 0 {
+		t.Errorf("a team with a ladder should not also get reminders, paged %v", got)
+	}
+}
+
+// The API refuses a ladder that cannot page anybody.
+func TestEscalation_RejectsAnUnusablePolicy(t *testing.T) {
+	s := newTS(t)
+
+	for _, c := range []struct {
+		name string
+		body map[string]any
+	}{
+		{"a level with no targets", map[string]any{
+			"levels": []map[string]any{{"timeout_seconds": 300, "targets": []map[string]any{}}},
+		}},
+		{"a level with no timeout", map[string]any{
+			"levels": []map[string]any{{"timeout_seconds": 0, "targets": []map[string]any{{"kind": "oncall"}}}},
+		}},
+		{"a user target with no user", map[string]any{
+			"levels": []map[string]any{{"timeout_seconds": 300, "targets": []map[string]any{{"kind": "user"}}}},
+		}},
+		{"an unknown target kind", map[string]any{
+			"levels": []map[string]any{{"timeout_seconds": 300, "targets": []map[string]any{{"kind": "everybody"}}}},
+		}},
+		{"an absurd repeat count", map[string]any{
+			"repeat_count": 99,
+			"levels":       []map[string]any{{"timeout_seconds": 300, "targets": []map[string]any{{"kind": "oncall"}}}},
+		}},
+	} {
+		resp := s.req(t, http.MethodPut, "/api/teams/"+defaultTeam+"/escalation", c.body)
+		resp.Body.Close()
+		if resp.StatusCode != http.StatusBadRequest {
+			t.Errorf("%s: expected 400, got %d", c.name, resp.StatusCode)
+		}
+	}
+}
+
+// Editing the ladder is an owner's job; reading it is any member's.
+func TestEscalation_OwnerOnlyToEdit(t *testing.T) {
+	s := newTS(t)
+	_, call := member(t, s, "plain")
+
+	resp := call(http.MethodPut, "/api/teams/"+defaultTeam+"/escalation", map[string]any{
+		"levels": []map[string]any{{"timeout_seconds": 300, "targets": []map[string]any{{"kind": "oncall"}}}},
+	})
+	resp.Body.Close()
+	if resp.StatusCode != http.StatusForbidden {
+		t.Errorf("a member editing the ladder: expected 403, got %d", resp.StatusCode)
+	}
+
+	resp = call(http.MethodGet, "/api/teams/"+defaultTeam+"/escalation", nil)
+	resp.Body.Close()
+	if resp.StatusCode != http.StatusOK {
+		t.Errorf("a member reading the ladder: expected 200, got %d", resp.StatusCode)
+	}
+}
+
+// A target who cannot be woken is not a reason to stop: the next level is the
+// answer to an unreachable one.
+func TestEscalation_SkipsUnreachableTargets(t *testing.T) {
+	s, f := notifyTS(t, api.NotifyConfig{PublicURL: "https://terdut.example.com", RepeatEvery: 15 * time.Minute})
+	// Second user has no ntfy topic at all.
+	var user struct {
+		ID int64 `json:"id"`
+	}
+	decode(t, s.req(t, http.MethodPost, "/api/users",
+		map[string]string{"username": "silent", "email": "silent@test.com"}), &user)
+	s.req(t, http.MethodPost, "/api/teams/"+defaultTeam+"/members",
+		map[string]any{"user_id": user.ID, "role": "member"}).Body.Close()
+
+	ladder(t, s, user.ID, 0, "terdut-fallback")
+
+	postWebhook(t, s, []map[string]any{
+		amAlert("fp-silent", "DiskFull", "firing", "2026-05-20T10:00:00Z", zeroTime, nil),
+	})
+	s.sweepNotify(t)
+
+	f.forget()
+	overdue(t, s, 1)
+	s.sweepNotify(t)
+
+	// Level 2 was entered even though it woke nobody, so the ladder keeps
+	// moving toward the fallback rather than stalling on a silent rung.
+	if level, _ := escalationLevel(t, s, 1); level != 2 {
+		t.Errorf("expected the ladder to advance past an unreachable target, level is %d", level)
+	}
+	if got := f.topicsSince(t); len(got) != 0 {
+		t.Errorf("a target with no topic should page nothing, paged %v", got)
+	}
+}

internal/api/incident_store.go

@@ -235,6 +235,9 @@ func resolveIfSettled(ctx context.Context, q querier, incidentID int64) (bool, e
 	if n == 0 {
 		return false, nil
 	}
+	if err := stopEscalation(ctx, q, incidentID); err != nil {
+		return false, err
+	}
 	if err := logEvent(ctx, q, incidentID, evResolved, nil, nil, nil); err != nil {
 		return false, err
 	}
@@ -260,6 +263,10 @@ func acknowledgeIncident(ctx context.Context, q querier, incidentID, userID int6
 	if n, _ := res.RowsAffected(); n == 0 {
 		return false, nil
 	}
+	// Somebody has it: stop waking anybody else.
+	if err := stopEscalation(ctx, q, incidentID); err != nil {
+		return false, err
+	}
 	return true, logEvent(ctx, q, incidentID, evAcknowledged, &userID, nil, nil)
 }
 

internal/api/incidents.go

@@ -243,6 +243,11 @@ func handleIncidentResolve(db *sql.DB) http.HandlerFunc {
 			time.Now().Unix(), incidentResolutionManual, id) {
 			return
 		}
+		// A person closing an incident is the clearest possible "I have this".
+		if err := stopEscalation(r.Context(), db, id); err != nil {
+			respond(w, http.StatusInternalServerError, errResp("internal error"))
+			return
+		}
 		if err := logEvent(r.Context(), db, id, evResolved, &user.ID, nil, nil); err != nil {
 			respond(w, http.StatusInternalServerError, errResp("internal error"))
 			return

internal/api/notifier.go

@@ -43,6 +43,10 @@ const (
 	notifyTriggered = "triggered"
 	notifyReminder  = "reminder"
 	notifyResolved  = "resolved"
+
+	// notifyEscalated is a page that went out because nobody answered the last
+	// one. Told apart from a reminder because it goes to somebody else.
+	notifyEscalated = "escalated"
 )
 
 // Timeline event types the notifier writes, so an incident's history says who
@@ -120,6 +124,9 @@ func StartNotifier(ctx context.Context, db *sql.DB, cfg NotifyConfig) {
 // Exported so tests can drive a pass without waiting on the ticker.
 func NotifySweep(ctx context.Context, db *sql.DB, cfg NotifyConfig) {
 	enqueueReminders(ctx, db, cfg)
+	// Escalation before delivery, so a level that comes due on this tick is
+	// paged on this tick rather than waiting for the next one.
+	escalate(ctx, db, cfg)
 	deliverPending(ctx, db, cfg)
 }
 
@@ -159,7 +166,12 @@ func enqueueReminders(ctx context.Context, db *sql.DB, cfg NotifyConfig) {
 		  AND  i.resolved_at IS NULL
 		  AND  i.archived_at IS NULL
 		  AND  i.status = 'triggered'
-		  AND  (i.snoozed_until IS NULL OR i.snoozed_until <= $2)`,
+		  AND  (i.snoozed_until IS NULL OR i.snoozed_until <= $2)
+		  -- A team with an escalation ladder gets escalation instead. Both
+		  -- would mean two pages for one silence, which is how people learn to
+		  -- mute a tool.
+		  AND  NOT EXISTS (
+		           SELECT 1 FROM escalation_levels el WHERE el.team_id = i.team_id)`,
 		now.Add(-repeat).Unix(), now.Unix())
 	if err != nil {
 		log.Printf("notifier: find reminders: %v", err)

internal/api/notify_test.go

@@ -69,6 +69,27 @@ func (f *fakeNtfy) messages() []pushed {
 	return append([]pushed(nil), f.got...)
 }
 
+// topicsSince lists the topics published to since the last forget, which is how
+// the escalation tests ask "who did this tick wake".
+func (f *fakeNtfy) topicsSince(t *testing.T) []string {
+	t.Helper()
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	out := make([]string, 0, len(f.got))
+	for _, m := range f.got {
+		out = append(out, m.Topic)
+	}
+	return out
+}
+
+// forget drops what has been published so far, so the next assertion is about
+// this tick rather than the whole test.
+func (f *fakeNtfy) forget() {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	f.got = nil
+}
+
 func (f *fakeNtfy) failWith(status int) {
 	f.mu.Lock()
 	defer f.mu.Unlock()

internal/api/router.go

@@ -109,6 +109,10 @@ func NewRouter(db *sql.DB, notify NotifyConfig, cfg config.Config) http.Handler
 		r.Post("/api/teams/{teamID}/members", handleAddTeamMember(db))
 		r.Delete("/api/teams/{teamID}/members/{userID}", handleRemoveTeamMember(db))
 
+		// A team's escalation ladder: who is paged when nobody answers.
+		r.Get("/api/teams/{teamID}/escalation", handleGetEscalation(db))
+		r.Put("/api/teams/{teamID}/escalation", handleSetEscalation(db))
+
 		// A team's own dead man's switches: which of its alerts are heartbeats,
 		// and how long a silence has to last before somebody is paged.
 		r.Get("/api/teams/{teamID}/deadman", handleGetTeamDeadman(db))

internal/db/migrations/006_escalation.sql

@@ -0,0 +1,95 @@
+-- Escalation: page somebody else when the first person does not answer.
+--
+-- This is the gap the whole multi-tenancy line of work was opened to close.
+-- Until now an unacknowledged incident re-paged the same topic every
+-- notify_repeat forever, which is a louder version of the same silence: if the
+-- person on call is asleep, has no signal, or has left, nothing else happens.
+--
+-- Shape: one policy per team, an ordered list of levels, each level with a
+-- timeout and a set of targets. When a level's timeout passes and the incident
+-- is still triggered, the next level is paged. When the last level passes, the
+-- chain repeats repeat_count times, and then the team's fallback topic is paged
+-- once as the end of the line.
+--
+-- A team WITHOUT a policy keeps exactly today's behaviour: page the assignee,
+-- then remind on the same topic. Escalation is opt-in per team, and the two
+-- never both run for one incident -- see enqueueReminders.
+CREATE TABLE escalation_policies (
+    -- One per team for now, hence the team as the key rather than an id with a
+    -- unique index: routing different alerts to different chains needs the
+    -- alert to carry something to route ON, which is a separate question.
+    team_id BIGINT PRIMARY KEY REFERENCES teams(id) ON DELETE CASCADE,
+
+    -- How many extra times to run the whole chain after it has been walked
+    -- once. 0 means walk it once and stop at the fallback.
+    repeat_count BIGINT NOT NULL DEFAULT 0 CHECK (repeat_count >= 0 AND repeat_count <= 10),
+
+    -- Where the last page goes when every level has been tried. Per team now:
+    -- TERDUT_NTFY_FALLBACK_TOPIC was one topic for the whole install, which in
+    -- a multi-team server pages the wrong people. Empty means the chain simply
+    -- ends.
+    fallback_topic TEXT NOT NULL DEFAULT '',
+
+    updated_at BIGINT NOT NULL DEFAULT FLOOR(EXTRACT(EPOCH FROM now()))::bigint
+);
+
+CREATE TABLE escalation_levels (
+    id              BIGINT GENERATED BY DEFAULT AS IDENTITY PRIMARY KEY,
+    team_id         BIGINT NOT NULL REFERENCES escalation_policies(team_id) ON DELETE CASCADE,
+    -- 1-based, dense. The API rewrites the whole ladder on every edit rather
+    -- than patching one rung, so there is no way to leave a gap.
+    position        BIGINT NOT NULL,
+    -- How long this level has to produce an acknowledgement before the next one
+    -- is paged. Seconds, like every other duration in this schema.
+    timeout_seconds BIGINT NOT NULL CHECK (timeout_seconds > 0),
+
+    UNIQUE (team_id, position)
+);
+
+-- Who a level pages. Either a named person, or whoever the team's rota says is
+-- on call today -- which is the target that keeps working when the rota
+-- changes and nobody remembers to edit the policy.
+CREATE TABLE escalation_targets (
+    id       BIGINT GENERATED BY DEFAULT AS IDENTITY PRIMARY KEY,
+    level_id BIGINT NOT NULL REFERENCES escalation_levels(id) ON DELETE CASCADE,
+    kind     TEXT   NOT NULL CHECK (kind IN ('user', 'oncall')),
+    -- Set for kind='user', NULL for kind='oncall'.
+    user_id  BIGINT REFERENCES users(id) ON DELETE CASCADE,
+
+    CHECK ((kind = 'user' AND user_id IS NOT NULL) OR (kind = 'oncall' AND user_id IS NULL))
+);
+
+CREATE INDEX escalation_targets_level_idx ON escalation_targets(level_id);
+
+-- ---------------------------------------------------------------------------
+-- Where an incident is in its chain.
+--
+-- On the incident rather than in a side table: it is read on every notifier
+-- tick alongside the incident's status, and one row per incident is exactly
+-- what the state is.
+-- ---------------------------------------------------------------------------
+
+-- 0 means no level has been paged yet, which is the state of every incident
+-- that existed before escalation and of every incident in a team with no
+-- policy. 1 is the first level.
+ALTER TABLE incidents ADD COLUMN escalation_level BIGINT NOT NULL DEFAULT 0;
+
+-- When the current level was entered, and therefore what its timeout is
+-- measured from. NULL while escalation_level is 0.
+ALTER TABLE incidents ADD COLUMN escalation_level_at BIGINT;
+
+-- How many times the chain has been walked in full. Compared against the
+-- policy's repeat_count.
+ALTER TABLE incidents ADD COLUMN escalation_round BIGINT NOT NULL DEFAULT 0;
+
+-- The notifier's escalation query: incidents still waiting, oldest level first.
+CREATE INDEX incidents_escalation_idx
+    ON incidents(escalation_level_at)
+ WHERE resolved_at IS NULL AND status = 'triggered';
+
+-- 'escalated' joins the outbox kinds: a page that went out because nobody
+-- answered the last one, which is worth telling apart from the first page and
+-- from a reminder when reading the timeline or debugging a delivery.
+ALTER TABLE notifications DROP CONSTRAINT notifications_kind_check;
+ALTER TABLE notifications ADD CONSTRAINT notifications_kind_check
+    CHECK (kind IN ('triggered', 'reminder', 'resolved', 'escalated'));