benbjohnson/litestream · error

cannot expand home directory for sse-customer-key-path: %w

Error message

cannot expand home directory for sse-customer-key-path: %w

What it means

Wraps os.UserHomeDir() failure while expanding a leading '~' in the s3 sse-customer-key-path config option. Fires when the path starts with '~' but the user's home directory cannot be determined (e.g. HOME not set in the environment); the SSE-C key file cannot be located.

Source

Thrown at cmd/litestream/main.go:1696

	if c.Concurrency != nil {
		client.Concurrency = *c.Concurrency
	}

	// Apply SSE-C configuration if specified.
	if c.SSECustomerKey != "" || c.SSECustomerKeyPath != "" {
		client.SSECustomerAlgorithm = c.SSECustomerAlgorithm
		if client.SSECustomerAlgorithm == "" {
			client.SSECustomerAlgorithm = "AES256"
		}

		// Read key from file if path is specified, otherwise use direct value.
		if c.SSECustomerKeyPath != "" {
			keyPath := c.SSECustomerKeyPath
			// Expand ~ to home directory
			if strings.HasPrefix(keyPath, "~") {
				home, err := os.UserHomeDir()
				if err != nil {
					return nil, fmt.Errorf("cannot expand home directory for sse-customer-key-path: %w", err)
				}
				keyPath = home + keyPath[1:]
			}
			keyData, err := os.ReadFile(keyPath)
			if err != nil {
				return nil, fmt.Errorf("cannot read sse-customer-key-path %q: %w", c.SSECustomerKeyPath, err)
			}
			client.SSECustomerKey = strings.TrimSpace(string(keyData))
		} else {
			client.SSECustomerKey = c.SSECustomerKey
		}
	}

	// Apply SSE-KMS configuration if specified.
	if c.SSEKMSKeyID != "" {
		client.SSEKMSKeyID = c.SSEKMSKeyID
	}

View on GitHub (pinned to 4ed7a308f6)

Solutions

1. Set HOME (or USERPROFILE on Windows) in the service environment
2. Use an absolute path for sse-customer-key-path instead of '~'

When it happens

Trigger: Thrown at cmd/litestream/main.go:1696 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of benbjohnson/litestream@4ed7a308f6 (2026-09-06). Data as JSON: /api/errors/be87b5e44cfd671f. Report an issue: GitHub.