Storage implementations enforce minimum checkpoint intervals

storage/aws/aws.go

@@ -59,9 +59,10 @@ import (
 )
 
 const (
-	entryBundleSize = 256
-	logContType     = "application/octet-stream"
-	ckptContType    = "text/plain; charset=utf-8"
+	entryBundleSize       = 256
+	logContType           = "application/octet-stream"
+	ckptContType          = "text/plain; charset=utf-8"
+	minCheckpointInterval = 1 * time.Second
 
 	DefaultPushbackMaxOutstanding = 4096
 	DefaultIntegrationSizeLimit   = 5 * 4096
@@ -129,6 +130,9 @@ func New(ctx context.Context, cfg Config, opts ...func(*options.StorageOptions))
 	if opt.PushbackMaxOutstanding == 0 {
 		opt.PushbackMaxOutstanding = DefaultPushbackMaxOutstanding
 	}
+	if opt.CheckpointInterval < minCheckpointInterval {
+		return nil, fmt.Errorf("requested CheckpointInterval (%v) is less than minimum permitted %v", opt.CheckpointInterval, minCheckpointInterval)
+	}
 
 	sdkConfig, err := config.LoadDefaultConfig(ctx)
 	if err != nil {

storage/gcp/gcp.go

@@ -62,6 +62,11 @@ const (
 	entryBundleSize = 256
 	logContType     = "application/octet-stream"
 	ckptContType    = "text/plain; charset=utf-8"
+	// minCheckpointInterval is the shortest permitted interval between updating published checkpoints.
+	// GCS has a rate limit 1 update per second for individual objects, but we've observed that attempting
+	// to update at exactly that rate still results in the occasional refusal, so bake in a little wiggle
+	// room.
+	minCheckpointInterval = 1200 * time.Millisecond
 
 	DefaultPushbackMaxOutstanding = 4096
 	DefaultIntegrationSizeLimit   = 5 * 4096
@@ -121,6 +126,9 @@ func New(ctx context.Context, cfg Config, opts ...func(*options.StorageOptions))
 	if opt.PushbackMaxOutstanding == 0 {
 		opt.PushbackMaxOutstanding = DefaultPushbackMaxOutstanding
 	}
+	if opt.CheckpointInterval < minCheckpointInterval {
+		return nil, fmt.Errorf("requested CheckpointInterval (%v) is less than minimum permitted %v", opt.CheckpointInterval, minCheckpointInterval)
+	}
 
 	c, err := gcs.NewClient(ctx, gcs.WithJSONReads())
 	if err != nil {

storage/mysql/mysql.go

@@ -50,6 +50,8 @@ const (
 	checkpointID    = 0
 	treeStateID     = 0
 	entryBundleSize = 256
+
+	minCheckpointInterval = time.Second
 )
 
 // Storage is a MySQL-based storage implementation for Tessera.
@@ -66,6 +68,10 @@ type Storage struct {
 // Note that `tessera.WithCheckpointSigner()` is mandatory in the `opts` argument.
 func New(ctx context.Context, db *sql.DB, opts ...func(*options.StorageOptions)) (*Storage, error) {
 	opt := storage.ResolveStorageOptions(opts...)
+	if opt.CheckpointInterval < minCheckpointInterval {
+		return nil, fmt.Errorf("requested CheckpointInterval too low - %v < %v", opt.CheckpointInterval, minCheckpointInterval)
+	}
+
 	s := &Storage{
 		db:            db,
 		newCheckpoint: opt.NewCP,

storage/mysql/mysql_test.go

@@ -461,10 +461,10 @@ func newTestMySQLStorage(t *testing.T, ctx context.Context) *mysql.Storage {
 
 	s, err := mysql.New(ctx, testDB,
 		tessera.WithCheckpointSigner(noteSigner),
-		tessera.WithCheckpointInterval(200*time.Millisecond),
+		tessera.WithCheckpointInterval(time.Second),
 		tessera.WithBatching(128, 100*time.Millisecond))
 	if err != nil {
-		t.Errorf("Failed to create mysql.Storage: %v", err)
+		t.Fatalf("Failed to create mysql.Storage: %v", err)
 	}
 
 	return s

storage/posix/files.go

@@ -39,6 +39,8 @@ const (
 	dirPerm  = 0o755
 	filePerm = 0o644
 	stateDir = ".state"
+
+	minCheckpointInterval = time.Second
 )
 
 // Storage implements storage functions for a POSIX filesystem.
@@ -64,6 +66,9 @@ type NewTreeFunc func(size uint64, root []byte) error
 // - create must only be set when first creating the log, and will create the directory structure and an empty checkpoint
 func New(ctx context.Context, path string, create bool, opts ...func(*options.StorageOptions)) (*Storage, error) {
 	opt := storage.ResolveStorageOptions(opts...)
+	if opt.CheckpointInterval < minCheckpointInterval {
+		return nil, fmt.Errorf("requested CheckpointInterval (%v) is less than minimum permitted %v", opt.CheckpointInterval, minCheckpointInterval)
+	}
 
 	r := &Storage{
 		path:        path,