What causes "invalid sync_interval: %w" in benbjohnson/litestream?

Use a valid Go duration string with a unit suffix, e.g. sync_interval=10s

invalid sync_interval: %w

Error message

invalid sync_interval: %w

What it means

VFSConfig.Set validates URI/config parameters. The sync_interval value must parse as a Go time.ParseDuration string (e.g. "10s", "1m"). This error wraps the underlying parse failure when the value is not a valid duration.

Source

Thrown at vfs_config.go:69

}

func DeleteVFSConfig(dbName string) {
	vfsConfigsMu.Lock()
	defer vfsConfigsMu.Unlock()
	delete(vfsConfigs, dbName)
}

func (cfg *VFSConfig) Set(key, value string) error {
	switch key {
	case "replica_url":
		cfg.ReplicaURL = value
	case "write_enabled":
		b := strings.ToLower(value) == "true" || value == "1"
		cfg.WriteEnabled = &b
	case "sync_interval":
		d, err := time.ParseDuration(value)
		if err != nil {
			return fmt.Errorf("invalid sync_interval: %w", err)
		}
		cfg.SyncInterval = &d
	case "buffer_path":
		cfg.BufferPath = value
	case "hydration_enabled":
		b := strings.ToLower(value) == "true" || value == "1"
		cfg.HydrationEnabled = &b
	case "hydration_path":
		cfg.HydrationPath = value
	case "poll_interval":
		d, err := time.ParseDuration(value)
		if err != nil {
			return fmt.Errorf("invalid poll_interval: %w", err)
		}
		cfg.PollInterval = &d
	case "cache_size":
		n, err := strconv.Atoi(value)
		if err != nil {

View on GitHub (pinned to 4ed7a308f6)

Solutions

Use a valid Go duration string with a unit suffix, e.g. sync_interval=10s
Fix the URI/config value: examples 1s, 500ms, 1m30s
If building values programmatically, use time.Duration.String() to render the value

Example fix

// before
litestream://file:///db?sync_interval=10
// after
litestream://file:///db?sync_interval=10s

Defensive patterns

Strategy: validation

Validate before calling

d, err := time.ParseDuration(v)
if err != nil { return fmt.Errorf("sync_interval must be a Go duration like 10s: %w", err) }
_ = d

Try / catch

if err := cfg.Set("sync_interval", v); err != nil {
    if strings.Contains(err.Error(), "invalid sync_interval") {
        // surface the wrapped time.ParseDuration message to the operator
    }
}

Prevention

Always include a unit suffix in duration config values (s, m, h)
Test URI config parsing in CI before deploying
Generate duration strings via time.Duration.String()

When it happens

Trigger: Calling Set("sync_interval", <value>) — directly or via ParseVFSURIConfig from a VFS URI like litestream://...?sync_interval=xyz — where the value fails time.ParseDuration (e.g. "10", "abc", "10sec").

Common situations: Writing sync_interval=10 without a unit in the VFS URI or config file; using unit spellings Go does not accept (sec, mins); copy/paste from non-Go documentation.

Understand the failure class

Background: "invalid duration" / "failed to parse duration": why your timeout, interval, or TTL string is rejected and which formats each library accepts — this error's family across 32 libraries.

Related errors

AI-assisted analysis of benbjohnson/litestream@4ed7a308f6 (2026-09-06). Data as JSON: /api/errors/de33ed0f731b3d90. Report an issue: GitHub.