channeldb: add migration for payment statuses for completed payments

channeldb/migrations.go

@@ -2,6 +2,7 @@ package channeldb
 
 import (
 	"bytes"
+	"crypto/sha256"
 	"fmt"
 
 	"github.com/coreos/bbolt"
@@ -373,3 +374,46 @@ func migrateEdgePolicies(tx *bolt.Tx) error {
 
 	return nil
 }
+
+// paymentStatusesMigration is a database migration intended for adding payment
+// statuses for each existing payment entity in bucket to be able control
+// transitions of statuses and prevent cases such as double payment
+func paymentStatusesMigration(tx *bolt.Tx) error {
+	// Get the bucket dedicated to storing payments
+	bucket := tx.Bucket(paymentBucket)
+	if bucket == nil {
+		return nil
+	}
+
+	// Get the bucket dedicated to storing statuses of payments,
+	// where a key is payment hash, value is payment status
+	paymentStatuses, err := tx.CreateBucketIfNotExists(paymentStatusBucket)
+	if err != nil {
+		return err
+	}
+
+	log.Infof("Migration database adds to all existing payments " +
+		"statuses as Completed")
+
+	// For each payment in the bucket, fetch all data.
+	return bucket.ForEach(func(k, v []byte) error {
+		// Ignores if it is sub-bucket.
+		if v == nil {
+			return nil
+		}
+
+		r := bytes.NewReader(v)
+		payment, err := deserializeOutgoingPayment(r)
+		if err != nil {
+			return err
+		}
+
+		// Calculate payment hash for current payment.
+		paymentHash := sha256.Sum256(payment.PaymentPreimage[:])
+
+		// Tries to update status for current payment to completed
+		// if it fails - migration abort transaction and return payment bucket
+		// to previous state.
+		return paymentStatuses.Put(paymentHash[:], StatusCompleted.Bytes())
+	})
+}