Implement the database archiving target (closes #43)

internal/delivery/target_database.go

@@ -2,21 +2,35 @@ package delivery
 
 import (
 	"context"
+	"fmt"
+	"path/filepath"
+	"sync"
 
 	"gorm.io/gorm"
 	"sneak.berlin/go/webhooker/internal/database"
 )
 
-// databaseTarget is a fire-and-forget target: the event is
-// already persisted in the per-webhook database by the time
-// delivery runs, so the target records a single successful
-// attempt. (Durable archiving to a separate store is tracked
-// as its own work.)
+// databaseTarget is a fire-and-forget target that archives the
+// full inbound event into a per-webhook archive SQLite file,
+// separate from the per-webhook event database. The event is
+// already persisted in the per-webhook event DB by the time
+// delivery runs; the database target additionally writes a
+// durable long-term copy into archive-{webhookID}.db and then
+// records a single successful attempt. See archiveWriter for
+// the close/reopen, auto-recreate, and expiry semantics.
 type databaseTarget struct {
 	eng *Engine
+
+	mu      sync.Mutex
+	writers map[string]*archiveWriter
 }
 
-// Deliver implements Target.
+// Deliver implements Target. It archives the event, then
+// records one successful attempt and marks the delivery
+// delivered. Archiving errors are logged but do not fail the
+// delivery: the event is already durably stored in the
+// per-webhook event database, so the target stays
+// fire-and-forget.
 func (t *databaseTarget) Deliver(
 	_ context.Context,
 	webhookDB *gorm.DB,
@@ -24,6 +38,16 @@ func (t *databaseTarget) Deliver(
 	_ *Task,
 	_ Scheduler,
 ) {
+	err := t.archive(d)
+	if err != nil {
+		t.eng.log.Error(
+			"failed to archive event to database target",
+			"delivery_id", d.ID,
+			"event_id", d.EventID,
+			"error", err,
+		)
+	}
+
 	t.eng.recordResult(
 		webhookDB, d, 1, true, 0, "", "", 0,
 	)
@@ -32,3 +56,68 @@ func (t *databaseTarget) Deliver(
 		webhookDB, d, database.DeliveryStatusDelivered,
 	)
 }
+
+// archive writes the full event as a row into the webhook's
+// archive database, honouring the optional per-target expiry
+// parsed from the target config JSON.
+func (t *databaseTarget) archive(d *database.Delivery) error {
+	webhookID := d.Event.WebhookID
+	if webhookID == "" {
+		return errArchiveMissingWebhookID
+	}
+
+	expiry, err := parseArchiveExpiry(d.Target.Config)
+	if err != nil {
+		return err
+	}
+
+	w, err := t.writerFor(webhookID)
+	if err != nil {
+		return err
+	}
+
+	row := archivedEvent{
+		EventID:      d.Event.ID,
+		WebhookID:    webhookID,
+		EntrypointID: d.Event.EntrypointID,
+		Method:       d.Event.Method,
+		Headers:      d.Event.Headers,
+		Body:         d.Event.Body,
+		ContentType:  d.Event.ContentType,
+	}
+
+	return w.write(row, expiry)
+}
+
+// writerFor returns the archiveWriter for a webhook, creating
+// and caching it on first use. Each webhook has one writer so
+// its close/reopen debounce state is shared across concurrent
+// deliveries. The archive file lives beside the per-webhook
+// event database in the data directory.
+func (t *databaseTarget) writerFor(
+	webhookID string,
+) (*archiveWriter, error) {
+	if t.eng.dbManager == nil {
+		return nil, errArchiveNoDataDir
+	}
+
+	dir := filepath.Dir(t.eng.dbManager.DBPath(webhookID))
+	path := filepath.Join(
+		dir, fmt.Sprintf("archive-%s.db", webhookID),
+	)
+
+	t.mu.Lock()
+	defer t.mu.Unlock()
+
+	if t.writers == nil {
+		t.writers = make(map[string]*archiveWriter)
+	}
+
+	w, ok := t.writers[webhookID]
+	if !ok {
+		w = newArchiveWriter(path, t.eng.log)
+		t.writers[webhookID] = w
+	}
+
+	return w, nil
+}