[jira] [Closed] (TINKERPOP-2197) gremlin javascript - Error: read ECONNRESET at TLSWrap.onStreamRead - websocket error

["stephen mallette (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/TINKERPOP-2197?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

stephen mallette closed TINKERPOP-2197.
---------------------------------------
    Resolution: Cannot Reproduce

Since no additional information has been provided on this for the past few months, I'm going to close this for now. Should it be possible to provide the information requested in the future, please fee free to re-open this.

> gremlin javascript - Error: read ECONNRESET  at TLSWrap.onStreamRead - websocket error
> --------------------------------------------------------------------------------------
>
>                 Key: TINKERPOP-2197
>                 URL: https://issues.apache.org/jira/browse/TINKERPOP-2197
>             Project: TinkerPop
>          Issue Type: Bug
>          Components: javascript
>    Affects Versions: 3.4.0
>         Environment: windows 10 ent, 10.016299
> nodejs 11.10.1
> gemlin javascript 3.4.0
> express 4.16.4
>            Reporter: Thomas Mahringer
>            Priority: Major
>         Attachments: gremlin-ws-error.png
>
>
> *Environment*
>  
> I'm running a nodejs express app and connect to MSFT azure gremlin through the js driver:
>  
> {code:java}
> connect() {
>  this.authenticator = new     
>   Gremlin.driver.auth.PlainTextSaslAuthenticator(
>   `/dbs/${this.config.database}/colls/${this.config.collection}`,  
>    this.config.primaryKey)
>    this.client = new Gremlin.driver.Client(
>      this.config.endpoint,
>      { 
>        authenticator: this.authenticator, 
>        traversalsource: "g", 
>        rejectUnauthorized: true, 
>        mimeType: "application/vnd.gremlin-v2.0+json" 
>     }
> }
> );
> {code}
>  
>  
> The app calls various gremlin commands through the string + "query parameter" syntax, e.g. 
> {code:java}
> await this.client.submit("g.V().hasLabel(label)", {label: "Person"});{code}
>  
> All the queries work fine but when the app is idling for about 5-10 minutes, the nodejs process exits with the above error. None of my error handlers are hit. 
> So I debugged the gremlin js code and found out where the error is thrown: 
> It's the error handler in gremlin/lib/driver/connection.js, which gets installed in "open"
> {code:java}
> open() {
>   if (this.isOpen) {
>     return Promise.resolve();
>   }
>   if (this._openPromise) {
>     return this._openPromise;
>   }
>   this.emit('log', `ws open`);
>   this._ws = new WebSocket(this.url, {
>     headers: this.options.headers,
>     ca: this.options.ca,
>     cert: this.options.cert,
>     pfx: this.options.pfx,
>     rejectUnauthorized: this.options.rejectUnauthorized
>   });
>   this._ws.on('message', (data) => this._handleMessage(data));
>   // ******* Install error handler
>   this._ws.on('error', (err) => this._handleError(err));
> ...
> }
> _handleError(err) {
>  this.emit('log', `ws error ${err}`);
>  console.error("***************** Added log to improve debug ****************")
>  this._cleanupWebsocket();
>  this.emit('error', err); // Error ist thrown here
> }{code}
>  
> In the debugger I can see that the error is caused in *stream_base_commons.js:*
> {code:java}
> function onStreamRead(arrayBuffer) {
>  const nread = streamBaseState[kReadBytesOrError];
>  const handle = this;
>  const stream = this[owner_symbol];
>  stream[kUpdateTimer]();
>  if (nread > 0 && !stream.destroyed) {
>    const offset = streamBaseState[kArrayBufferOffset];
>    const buf = new FastBuffer(arrayBuffer, offset, nread);
>    if (!stream.push(buf)) {
>      handle.reading = false;
>      if (!stream.destroyed) {
>        const err = handle.readStop();
>        if (err)
>          stream.destroy(errnoException(err, 'read'));
>      }
>    }
>    return;
>  }
>  if (nread === 0) {
>    return;
>  }
>  if (nread !== UV_EOF) {
>    /*Happens here >>>> */ return stream.destroy(errnoException(nread, 'read'));
>  }
> ...
> }
> {code}
>  
> So my questions are:
>  * Why is the error thrown in the first place. (After app idles for 5-10 minutes)
>  ** What happens in "this.emit('error', err);" in "Connection._handleError".
>  * What is the right place to catch the error? I've of course wrapped the "submit" code above in try/catch (in case of async/await) or as "then(...).catch()..." (in case of using the promise directly). Since the error causes nodejs to exit, it's quite bad.:) 
>  ** As it all happens asynchronously, I would need something like an "onError" handler. But the web socket and its handler (this._ws.on('error')...) are within the  "Connection" class.
> The attached image shows the stack trace in Visual Studio Code Debugger.
> Any help is appreciated!
> Thanks
> Thomas 



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