syz-cluster: use shorter report IDs

Since these may be included into email addresses, keep them short.

2 files changed, 37 insertions, 4 deletions

diff --git a/syz-cluster/pkg/db/report_repo.go b/syz-cluster/pkg/db/report_repo.go
index 4e039c4a7..c99e4a69d 100644
--- a/syz-cluster/pkg/db/report_repo.go
+++ b/syz-cluster/pkg/db/report_repo.go
@@ -5,9 +5,11 @@ package db
 
 import (
 	"context"
+	"crypto/rand"
+	"encoding/hex"
+	"fmt"
 
 	"cloud.google.com/go/spanner"
-	"github.com/google/uuid"
 )
 
 type ReportRepository struct {
@@ -27,10 +29,25 @@ func NewReportRepository(client *spanner.Client) *ReportRepository {
 }
 
 func (repo *ReportRepository) Insert(ctx context.Context, rep *SessionReport) error {
-	if rep.ID == "" {
-		rep.ID = uuid.NewString()
+	if rep.ID != "" {
+		return repo.genericEntityOps.Insert(ctx, rep)
 	}
-	return repo.genericEntityOps.Insert(ctx, rep)
+	const attempts = 3
+	for i := 0; i < attempts; i++ {
+		var err error
+		rep.ID, err = randomReportID()
+		if err != nil {
+			return err
+		}
+		err = repo.genericEntityOps.Insert(ctx, rep)
+		if err == errEntityExists {
+			continue
+		}
+		return err
+	}
+	// We shouldn't be getting here until we have sent out billions of reports.
+	// But let's return some error to still exit gracefully.
+	return fmt.Errorf("failed to pick a non-existing report ID")
 }
 
 func (repo *ReportRepository) ListNotReported(ctx context.Context, reporter string,
@@ -44,3 +61,13 @@ func (repo *ReportRepository) ListNotReported(ctx context.Context, reporter stri
 	addLimit(&stmt, limit)
 	return repo.readEntities(ctx, stmt)
 }
+
+// As report ID may be included in the email address, we'd prefer it to be shorter than a typical UUID.
+// A 16 byte hex ID should be good enough.
+func randomReportID() (string, error) {
+	data := make([]byte, 8)
+	if _, err := rand.Read(data); err != nil {
+		return "", err
+	}
+	return hex.EncodeToString(data), nil
+}
diff --git a/syz-cluster/pkg/db/spanner.go b/syz-cluster/pkg/db/spanner.go
index 1aee715f8..1c973ab46 100644
--- a/syz-cluster/pkg/db/spanner.go
+++ b/syz-cluster/pkg/db/spanner.go
@@ -28,6 +28,7 @@ import (
 	"github.com/golang-migrate/migrate/v4/source/iofs"
 	"google.golang.org/api/iterator"
 	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
 )
 
 type ParsedURI struct {
@@ -325,6 +326,8 @@ func (g *genericEntityOps[EntityType, KeyType]) Update(ctx context.Context, key
 	return err
 }
 
+var errEntityExists = errors.New("entity already exists")
+
 func (g *genericEntityOps[EntityType, KeyType]) Insert(ctx context.Context, obj *EntityType) error {
 	_, err := g.client.ReadWriteTransaction(ctx,
 		func(ctx context.Context, txn *spanner.ReadWriteTransaction) error {
@@ -334,6 +337,9 @@ func (g *genericEntityOps[EntityType, KeyType]) Insert(ctx context.Context, obj
 			}
 			return txn.BufferWrite([]*spanner.Mutation{insert})
 		})
+	if status.Code(err) == codes.AlreadyExists {
+		return errEntityExists
+	}
 	return err
 }