Add send-log retention days to panel Settings.

Global administrators can set delivery journal retention (7-365 days) in SQLite;
SEND_LOG_RETENTION_DAYS seeds the initial default and the log-tailer re-reads
the value every prune cycle without a restart.

Co-authored-by: Cursor <cursoragent@cursor.com>

internal/logtail/logtail.go

@@ -39,17 +39,15 @@ type StatusStore interface {
 // is a var so tests can shorten it.
 var pollInterval = time.Second
 
+// retentionInterval is how often the retention sweep runs (also once at
+// startup). It is a var so tests can shorten it.
+var retentionInterval = 6 * time.Hour
+
 // queueIDs lists the messages Postfix currently holds, for the reconcile sweep.
 // It is a var so tests can answer without a running Postfix.
 var queueIDs = postfix.QueueIDs
 
 const (
-	// retentionInterval is how often the retention sweep runs (also once at
-	// startup). The window itself is configurable; the cadence need not be.
-	retentionInterval = 6 * time.Hour
-	// defaultRetentionDays applies when the configured value is unset/invalid
-	// (guide § Environment variables: SEND_LOG_RETENTION_DAYS).
-	defaultRetentionDays = 90
 	// reconcileInterval is how often the sweep compares stuck rows against the
 	// Postfix queue, and reconcileGrace how long a row is left alone first.
 	// The grace covers the ordinary lag between the milter writing the row and
@@ -59,6 +57,10 @@ const (
 	reconcileGrace    = 2 * time.Minute
 )
 
+// RetentionDays returns the send-log retention window in days. The log-tailer
+// calls it on every prune cycle so a panel change takes effect without restart.
+type RetentionDays func() int
+
 // deliveryRe matches a Postfix delivery line and captures queue-id, recipient
 // and status, e.g.
 //
@@ -98,11 +100,11 @@ func parseDelivery(line string) (queueID, recipient, status string, ok bool) {
 }
 
 // Run follows path and updates send-log statuses until ctx is cancelled, while
-// a background sweep prunes rows older than retentionDays. Reading resumes at
+// a background sweep prunes rows older than retention(). Reading resumes at
 // the offset the previous run persisted, so a restart parses the delivery lines
 // written while the panel was down. It returns nil on a clean shutdown.
-func Run(ctx context.Context, path string, st StatusStore, retentionDays int) error {
-	go retentionLoop(ctx, st, retentionDays)
+func Run(ctx context.Context, path string, st StatusStore, retention RetentionDays) error {
+	go retentionLoop(ctx, st, retention)
 
 	// The reconcile sweep must not run against a backlog the tailer has not
 	// read yet: on a restart the log holds the very lines that resolve the rows
@@ -192,11 +194,12 @@ func reconcile(st StatusStore, cutoff time.Time) {
 }
 
 // retentionLoop prunes expired send-log rows immediately and then periodically.
-func retentionLoop(ctx context.Context, st StatusStore, retentionDays int) {
-	if retentionDays <= 0 {
-		retentionDays = defaultRetentionDays
-	}
+func retentionLoop(ctx context.Context, st StatusStore, retention RetentionDays) {
 	prune := func() {
+		retentionDays := retention()
+		if retentionDays <= 0 {
+			retentionDays = store.SendLogRetentionDaysDefault
+		}
 		cutoff := time.Now().UTC().AddDate(0, 0, -retentionDays)
 		n, err := st.DeleteSendLogBefore(cutoff)
 		if err != nil {

internal/logtail/logtail_test.go

@@ -212,7 +212,7 @@ func TestFollowTailsAndRotates(t *testing.T) {
 	cs := &captureStore{}
 	ctx, cancel := context.WithCancel(context.Background())
 	done := make(chan error, 1)
-	go func() { done <- Run(ctx, path, cs, 90) }()
+	go func() { done <- Run(ctx, path, cs, func() int { return 90 }) }()
 
 	// Give follow() time to open at EOF (it seeks to end immediately on start,
 	// so the seed line above is ignored), then append a delivery line.
@@ -295,7 +295,7 @@ func startRun(t *testing.T, path string, cs *captureStore) func() {
 	t.Helper()
 	ctx, cancel := context.WithCancel(context.Background())
 	done := make(chan error, 1)
-	go func() { done <- Run(ctx, path, cs, 90) }()
+	go func() { done <- Run(ctx, path, cs, func() int { return 90 }) }()
 	// follow() opens and seeks on start; give it a moment before the caller
 	// appends, so the append is not raced by the initial open.
 	time.Sleep(50 * time.Millisecond)

internal/logtail/retention_test.go

@@ -0,0 +1,83 @@
+package logtail
+
+import (
+	"context"
+	"sync"
+	"sync/atomic"
+	"testing"
+	"time"
+
+	"github.com/mixeme/selfpost/internal/store"
+)
+
+type retentionProbeStore struct {
+	mu     sync.Mutex
+	cutoff time.Time
+}
+
+func (s *retentionProbeStore) UpdateStatus(string, string, string) (int64, error) {
+	return 0, nil
+}
+
+func (s *retentionProbeStore) ListQueuedOlderThan(time.Time) ([]store.QueuedDelivery, error) {
+	return nil, nil
+}
+
+func (s *retentionProbeStore) DeleteSendLogBefore(cutoff time.Time) (int64, error) {
+	s.mu.Lock()
+	s.cutoff = cutoff
+	s.mu.Unlock()
+	return 0, nil
+}
+
+func (s *retentionProbeStore) LogtailState(string) (store.LogtailState, bool, error) {
+	return store.LogtailState{}, false, nil
+}
+
+func (s *retentionProbeStore) SaveLogtailState(string, store.LogtailState) error {
+	return nil
+}
+
+func (s *retentionProbeStore) lastCutoff() time.Time {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	return s.cutoff
+}
+
+// retentionLoop must re-read the configured window every cycle so a panel
+// change takes effect without restarting the process.
+func TestRetentionLoopUsesUpdatedValue(t *testing.T) {
+	old := retentionInterval
+	retentionInterval = 20 * time.Millisecond
+	t.Cleanup(func() { retentionInterval = old })
+
+	var days atomic.Int32
+	days.Store(30)
+
+	st := &retentionProbeStore{}
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+	go retentionLoop(ctx, st, func() int { return int(days.Load()) })
+
+	deadline := time.Now().Add(2 * time.Second)
+	for time.Now().Before(deadline) {
+		if age := time.Since(st.lastCutoff()); age < 31*24*time.Hour && age > 29*24*time.Hour {
+			break
+		}
+		time.Sleep(5 * time.Millisecond)
+	}
+	if age := time.Since(st.lastCutoff()); age < 29*24*time.Hour || age > 31*24*time.Hour {
+		t.Fatalf("first prune cutoff age %v, want about 30 days", age)
+	}
+
+	days.Store(7)
+	deadline = time.Now().Add(2 * time.Second)
+	for time.Now().Before(deadline) {
+		if age := time.Since(st.lastCutoff()); age < 8*24*time.Hour && age > 6*24*time.Hour {
+			return
+		}
+		time.Sleep(5 * time.Millisecond)
+	}
+	age := time.Since(st.lastCutoff())
+	t.Fatalf("second prune cutoff age %v, want about 7 days", age)
+}