Gray-out in Firefox

[menne...@googlemail.com]

With Firefox (18.0.2) on Windows 7 and local Shiny (developer version from github), I experience frequent gray-outs: the browser window is covered by a gray screen, but comes back after a F5 or other refresh, so the server seems to work ok. This happens with all almost all sample programs I tried,  it is frequent (20% of the run), but not easily reproducible.

It seems to be some racing condition, when I generate heavy CPU load in the background, I can force it.

This NEVER happens with Chrome.

Just a report... I know there are more important things to do.

[Joe Cheng]

The grey shading indicates that the connection between the client and server is broken. Usually this is due to the server exiting (i.e. an unexpected error was raised). However if F5 is working then that seems not to be the case.

If you show the Firefox JavaScript console, do you see any error messages there?

Does this happen even with shiny::runExample("01_hello")?

--
You received this message because you are subscribed to the Google Groups "Shiny - Web Framework for R" group.
To unsubscribe from this group and stop receiving emails from it, send an email to shiny-discus...@googlegroups.com.
For more options, visit https://groups.google.com/groups/opt_out.
 
 

[menne...@googlemail.com]

Thanks, Joe,

>>If you show the Firefox JavaScript console, do you see any error messages there?

Will check next time.

Does this happen even with shiny::runExample("01_hello")?

I do not remember, but I admit I spend more time with trickier cases -.:) So do you probably. I do not believe it is a simple server error, because a) server is running; and more important, I can always start a separate Chrome window when this happens, and everything is fine.

Dieter

[Joe Cheng]

Oh wow, could it be related to this?

http://stackoverflow.com/questions/11816384/how-to-prevent-ff-close-websocket-connection-on-esc

I wasn't aware of this, that is really bad...

[Sharon Machlis]

I'm having a similar problem in Chrome. I'm running Windows 8 and R 3.0.0. I was just getting error messages when trying to run any shiny code, after installing from GitHub instead of CRAN the code runs very briefly but then the browser window is grayed out along with the R error message

Error: object '.setDummyField' not found

In addition: Warning message:

In rm(list = as.character(handle), pos = .wsconns) :

  object '<a different object number each time>' not found

Hitting F5 does not help, that just gives an error message

Google Chrome could not connect to localhost:8100

[Dieter Menne]

I (the OP) have received a few private email on the subject. For me, this problem has disappeared, but I cannot remember after which version.

Dieter

[Winston Chang]

Your issue may be related to the one discussed here:

https://groups.google.com/d/msg/shiny-discuss/poNAAtyYuS4/V4cdR7K4QU4J

Installing R 3.0.1 should (hopefully) fix the problem. If that's doesn't do it, also try re-installing httpuv from CRAN.

-Winston

[Matthew Leonawicz]

This post appears a little old, but my current observation of "gray outs" and lost server connections seems maybe related.

I've found with at least one of my apps hosted on Spark, the browser will gray out and the connection to the shiny server is lost, apparently due to inactivity. If I am interacting with the app, I have not seen this happen. If I leave it idle in the browser, however, it may (but not always) gray out. It works again on refresh. I thought maybe Spark has some kind of inactivity time out feature that is somewhat new, since I have never seen this happen before and I have many times had apps open in my browser for very long periods of time without issue. But I also noticed that the gray out does not always happen, and when it does, it can be 45 seconds after loading the app and leaving it idle, or after five minutes, or 15 minutes. It is highly variable. My last observation is that it does not seem to happen on our self-hosted shiny server, only on Spark. Though, with the intermittent nature of the gray out, it is hard to know for sure.

Here is an example of three log files on Spark from two runs of the app, the first where it does not gray out and I close the connection myself by exiting the browser, and the second and third where I get the gray out:

@spark:~/.log

Listening on port 38875

Execution halted

@spark:~/.log

Listening on port 54443

Execution halted

Warning message:

In rm(list = as.character(handle), pos = .wsconns) :

  object '118693888' not found

@spark:~/.log

Listening on port 43337

Execution halted

Warning message:

In rm(list = as.character(handle), pos = .wsconns) :

  object '105862624' not found

Any ideas on what this may be? Is it by design, or an error? Is there something I can do to avoid the problem. The rm() call is definitely not part of my app code.

Thanks,

Matt

[Fereshteh Karimeddini]

Matt,

Thanks for reporting this, with such good investigation.

Did you notice that this started happening very recently (in the past week)? If so, I think you have actually pointed to a problem, and we will look into that very soon.

If that has always happened, could you please point me to your application(s) so we take closer look.

But to answer your question, by default the sessions do not time out as long as there is an open connection, and that is the behavior you see in your local server. On spark and glimmer servers we have setup a session limit which should apply to some applications, but not all. 

Hope this helps, and we will let you know when we have an update on the issue.

Fereshteh

[Joe Cheng]

Fereshteh's investigation revealed a crashing bug in the version of Shiny Server that was deployed to Glimmer and Spark last week. We've fixed the bug and redeployed to our servers, which will hopefully fix it. Please let us know if the issue persists.

Thanks Matt!

[Matthew Leonawicz]

Hi Joe and Fereshteh,

Sorry for my delay in replying, I have been away. And thank you for looking into this issue.

I have found another issue, which I have seen both on our local instance of shiny-server, and the past few days for the first time on Spark. I will make a new topic for it now.

Matt