apache/seatunnel · error · CatalogException

Failed to open MongoDB Catalog: ${e.getMessage()}

Error message

Failed to open MongoDB Catalog: ${e.getMessage()}

What it means

MongodbCatalog.open creates the MongoDB client with MongoClients.create(baseUrl) and wraps any exception into a CatalogException 'Failed to open MongoDB Catalog: <message>'. This is the catalog's initialization step; failure usually means the connection string is malformed or the driver fails at client creation.

Source

Thrown at seatunnel-connectors-v2/connector-mongodb/src/main/java/org/apache/seatunnel/connectors/seatunnel/mongodb/catalog/MongodbCatalog.java:60

    private final String catalogName;
    private final String baseUrl;
    private transient MongoClient mongoClient;
    private final String defaultDatabase;

    public MongodbCatalog(String catalogName, String baseUrl, String defaultDatabase) {
        this.catalogName = catalogName;
        this.baseUrl = baseUrl;
        this.defaultDatabase = defaultDatabase;
    }

    @Override
    public void open() throws CatalogException {
        try {
            if (mongoClient == null) {
                mongoClient = MongoClients.create(baseUrl);
            }
        } catch (Exception e) {
            throw new CatalogException("Failed to open MongoDB Catalog: " + e.getMessage(), e);
        }
    }

    @Override
    public String name() {
        return catalogName;
    }

    @Override
    public String getDefaultDatabase() throws CatalogException {
        return defaultDatabase;
    }

    @Override
    public boolean databaseExists(String databaseName) throws CatalogException {
        try {
            return listDatabases().contains(databaseName);
        } catch (Exception e) {

View on GitHub (pinned to cf67b549a7)

Solutions

  1. Validate the MongoDB connection string format: mongodb://[user:pass@]host[:port][/db][?options] or mongodb+srv://.
  2. Check network/DNS resolution to the MongoDB hosts and that the SRV record exists for +srv URIs.
  3. Verify URI options (replicaSet, ssl, authSource) are supported by the driver version.
  4. Confirm username/password are URL-encoded if they contain special characters.

Example fix

// before
url = "mongodb+srv:/host:27017"; // malformed scheme
// after
url = "mongodb+srv://host.example.com:27017/?replicaSet=rs0";
Defensive patterns

Strategy: try-catch

Validate before calling

// validate the MongoDB URI before open()
if (baseUrl == null || !(baseUrl.startsWith("mongodb://") || baseUrl.startsWith("mongodb+srv://"))) {
    throw new IllegalArgumentException("Invalid MongoDB connection string: " + baseUrl);
}

Try / catch

try { catalog.open(); } catch (CatalogException e) { log.error("Mongo catalog open failed: {}", e.getMessage(), e.getCause()); throw e; }

Prevention

When it happens

Trigger: Calling catalog.open() when baseUrl is invalid/unparseable, or the driver throws during MongoClients.create (bad URI options, invalid SRV hostname, missing scheme).

Common situations: Typo in mongodb:// or mongodb+srv:// URI; unsupported URI options; DNS/seed discovery failures surfacing at client setup; empty or null baseUrl passed via catalog config.

Understand the failure class

Background: "Invalid URL" errors: why new URL(), URI.parse, and reqwest::Url reject your string — missing scheme, whitespace, and bad path format — this error's family across 39 libraries.

Related errors

AI-assisted analysis of apache/seatunnel@cf67b549a7 (2026-09-10). Data as JSON: /api/errors/b3c4a41f10786655. Report an issue: GitHub.