How to connect to a Gremlin Websocket in Go?

Question

I'm trying to connect to Gremlin which should be running on port 8182 ([INFO] GremlinServer$1 - Channel started at port 8182)

When I'm connecting to: ws://127.0.0.1:8182 I'm getting the response:

2017/11/03 17:20:04 ERROR: database with the name 'gremlin' gave an error when connecting: websocket: bad handshake.

The Gremlin server responds with:

[WARN] HttpGremlinEndpointHandler - Invalid request - responding with 400 Bad Request and no gremlin script supplied

I'm using Gorilla Websocket in Go to connect:

gremlinGrpcAddress := fmt.Sprintf("ws://%s:%d/", f.config.Host, f.config.Port)

var dialer *websocket.Dialer

clientConn, _, err := dialer.Dial(gremlinGrpcAddress, nil)
if err != nil {
    return err
}

f.client = clientConn

UPDATE:
Connecting to echo.websocket.org works, so somehow it is something in the Gremlin server.

Have you looked at any of the available gremlin client libraries for Go, either to import or as an example of how to write a client? — Adrian, Nov 03 '17 at 16:30
Hi @Adrian, yes, I'm looking at https://github.com/go-gremlin/gremlin but because it's not being maintained I'm creating my own web socket connector. — Bob van Luijt, Nov 03 '17 at 16:37
There's also https://github.com/qasaur/gremgo which looks more complete. — Adrian, Nov 03 '17 at 16:38
Hmm, same error with Gremgo. It keeps returning a `bad handshake`... — Bob van Luijt, Nov 03 '17 at 16:44

score 2 · Accepted Answer · answered Nov 05 '17 at 14:42

2

The answer lies in the config YAML file.

What is needed is the correct channelizer.

GOOD:

channelizer: org.apache.tinkerpop.gremlin.server.channel.WebSocketChannelizer

answered Nov 05 '17 at 14:42

Bob van Luijt

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Jason's comment is relevant for 3.2.2 and above as well https://groups.google.com/forum/#!msg/gremlin-users/x4hiHsmTsHM/Xe4GcPtRCAAJ – Aaron Mar 23 '18 at 22:52

score 1 · Answer 2 · answered Nov 03 '17 at 18:55

1

Connect to ws://localhost:8182/gremlin instead of ws://localhost:8182. There are several references to it in the Apache TinkerPop documentation and the go-gremlin README.

answered Nov 03 '17 at 18:55

Jason Plurad

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How to connect to a Gremlin Websocket in Go?

2 Answers2