{"record":{"id":"54daa7354af8cd69","repo":"vitessio/vitess","slug":"no-dialer-registered-for-vtgate-protocol-s","errorCode":null,"errorMessage":"no dialer registered for VTGate protocol %s","messagePattern":"no dialer registered for VTGate protocol (.+?)","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"error","filePath":"go/vt/vtgate/vtgateconn/vtgateconn.go","lineNumber":270,"sourceCode":"// DeregisterDialer removes the named DialerFunc from the registered list of\n// dialers. If the named DialerFunc does not exist, it is a noop.\n//\n// This is useful to avoid unbounded memory use if many different dialer\n// implementations are used throughout the lifetime of a program.\nfunc DeregisterDialer(name string) {\n\tdialersM.Lock()\n\tdefer dialersM.Unlock()\n\tdelete(dialers, name)\n}\n\n// DialProtocol dials a specific protocol, and returns the *VTGateConn\nfunc DialProtocol(ctx context.Context, protocol string, address string) (*VTGateConn, error) {\n\tdialersM.Lock()\n\tdialer, ok := dialers[protocol]\n\tdialersM.Unlock()\n\n\tif !ok {\n\t\treturn nil, fmt.Errorf(\"no dialer registered for VTGate protocol %s\", protocol)\n\t}\n\timpl, err := dialer(ctx, address)\n\tif err != nil {\n\t\treturn nil, err\n\t}\n\treturn &VTGateConn{\n\t\timpl: impl,\n\t}, nil\n}\n\n// Dial dials using the command-line specified protocol, and returns\n// the *VTGateConn.\nfunc Dial(ctx context.Context, address string) (*VTGateConn, error) {\n\treturn DialProtocol(ctx, vtgateProtocol, address)\n}\n\n// DialCustom creates a new VTGateConn with the given DialerFunc.\nfunc DialCustom(ctx context.Context, dialer DialerFunc, address string) (*VTGateConn, error) {","sourceCodeStart":252,"sourceCodeEnd":288,"githubUrl":"https://github.com/vitessio/vitess/blob/01a25a7d176f94613b8d59d799f438380a8760e4/go/vt/vtgate/vtgateconn/vtgateconn.go#L252-L288","documentation":"vtgateconn.DialProtocol looks up a client dialer in a registry keyed by protocol name (e.g. 'grpc'). If no dialer has been registered for the given protocol string, dialing cannot proceed and this error is returned. It is a pure client-side configuration/naming error.","triggerScenarios":"Calling vtgateconn.DialProtocol(ctx, protocol, address) with a protocol string that was never registered via RegisterDialer, e.g. typo 'grpcs', or a build/tag that excludes the grpc dialer registration.","commonSituations":"Typos in the protocol part of a vtgate address ('grpc' vs 'grpc+' prefix confusion), using a custom binary that does not import the grpc dialer package, or tests/tools built without the expected dialer registration.","solutions":["Use the exact registered protocol name, typically \"grpc\": vtgateconn.DialProtocol(ctx, \"grpc\", address)","Verify your binary imports the dialer package (e.g. _ \"vitess.io/vitess/go/vt/vtgate/grpcvtgateconn\") so its init registers the dialer","Print registered keys or check code: dialers map keys in vtgateconn","If using a smart client (DialVTGate / go/vt/discovery), confirm the vtgate address scheme matches a supported protocol"],"exampleFix":"// before\nconn, err := vtgateconn.DialProtocol(ctx, \"grpcs\", \"localhost:15991\")\n// after\nimport _ \"vitess.io/vitess/go/vt/vtgate/grpcvtgateconn\"\nconn, err := vtgateconn.DialProtocol(ctx, \"grpc\", \"localhost:15991\")","handlingStrategy":"validation","validationCode":"// Go: verify the grpc dialer is registered before dialing\nimport _ \"vitess.io/vitess/go/vt/vtgate/grpcvtgateconn\"\n\nfunc protocolSupported(p string) bool {\n    return p == \"grpc\" // dialers registry keys; check vtgateconn source for others\n}","typeGuard":null,"tryCatchPattern":"conn, err := vtgateconn.DialProtocol(ctx, \"grpc\", addr)\nif err != nil {\n    if strings.Contains(err.Error(), \"no dialer registered\") {\n        return nil, fmt.Errorf(\"protocol %q unavailable: ensure grpcvtgateconn is imported\", addr)\n    }\n    return nil, err\n}","preventionTips":["Always use the literal protocol name \"grpc\" unless you registered a custom dialer","Blank-import the dialer package (grpcvtgateconn) in any binary that dials vtgate","Centralize dialing in one helper so the protocol string appears once","Write a smoke test that dials vtgate at startup to fail fast on registry issues"],"tags":["vtgate","client","protocol","configuration"],"backgroundTag":"no-dialer-registered","analyzedSha":"01a25a7d176f94613b8d59d799f438380a8760e4","analyzedAt":"2026-09-01T17:28:30.605Z","contentChangedAt":null,"schemaVersion":2},"datasetVersion":"2026-09-08T10:18:20.063Z"}