"No connection to Gradle server" in versions 2.6+

[h0use]

Since 2.6 (and, I'm guessing, as a result of the gRPC refactor?) my VS Code shows "no connection to Gradle server" whenever it starts, in spite of the log showing "Server started, listening on XXX".

This is on VS Code 1.45.1 on Mac OS Catalina, running Zulu JDK 11.

Thanks so much for your work on this plugin! It's really appreciated :)

[badsyntax]

Odd. Can you send me a screenshot of the output of the "Gradle Tasks Server" task in the terminal panel?
Can you also send a screenshot of the output of "Gradle Tasks" in the output panel?

Can you also confirm if the extension is actually broken for you, or if you're just seeing that message?

[h0use]

Hope these are helpful! Please let me know anything else I can do

With v2.5

With v3.0.2 (or anything 2.6 and above)

[vinzlee97]

Same here. I’m on Windows 10 and the extension sometimes manage or doesn’t manage to connect to the Gradle tasks server. Whenever it fails to connect, I press on Restart Server and the terminal window pops up only to say that the server has been listened on certain port, but in the end, the Gradle Tasks explorer pane never shows up.

[badsyntax]

@h0use thanks for sending these.

@vinzlee97 in your case can you also please add any more info, like a screenshot of the output for "Gradle Tasks". Do you get the same "failed to connect" error?

Sadly I can't replicate this problem on neither MacOS Catalina nor Windows 10.

Seems like a network thing, do you have any local firewalls or proxing enabled for localhost?

[vinzlee97]

In my case, as I said earlier, the extension sometimes connects successfully to the Gradle Tasks server, and sometimes it doesn't. Here is the failure case screencast:

And here's the successful case screencast for the same project:

I think it's not the network issue, but if that's the case, can you please tell me the debugging steps? Sorry for the laggy footage, and thanks.

[badsyntax]

@vinzlee97 thanks for this. can you try disabling all extensions, then only enable the Gradle Tasks extension, and see if this issue still occurs?

You can disable all extensions with the command palette:

Can you also send a list of your installed extensions? You can do this with the vscode command line executable:

code --list-extensions

Also, when the issue occurs, can you try run "Refresh Gradle Tasks" from the command palette and see if that loads the treeview? (although i don't think this will help, but give it a try)

[badsyntax]

@vinzlee97 can you also let me know what that green icon on the left of the statusbar is? Are you developing on remotely WSL? Can you let me know any other "non-standard" things you are doing? I'll need to replicate your setup to replicate the bug. If you can give me a good description of your exact setup, then I might be able to replicate. Thanks.

[badsyntax]

@h0use It's also appears you're using the remote development feature. Can you also describe your exact setup to help me replicate your scenario.
Can you also try disabling all other extensions as mentioned above? Thanks.

[badsyntax]

Ok I have a theory for this. It seems like it's a race condition due to the time it takes to bootstrap the Java Server process and when the client tries to connect.

Series of events:

1. Server Task is started (but process is not yet started)
2. Server Task tells client to connect
3. Client attempts to connect but fails. In most cases the client will successfully connect if the machine is able to bootstrap the server process in a short amount of time.

I was able to replicate this once, when my machine was under heavy load, and with the manual retries disabled, which supports this theory.

I think i'm using the wrong vscode API here:

https://github.com/badsyntax/vscode-gradle/blob/a1330db1a977795054fbc8e597a8efbc30f5f0d8/extension/src/server.ts#L32-L36

I need to be using onDidStartTaskProcess instead.

I was using the onDidStartTask API due to internal vscode issues when setting the Server Task presentation options, which I've since removed with PR #405

This is the smelly code to handle client retries:

https://github.com/badsyntax/vscode-gradle/blob/a1330db1a977795054fbc8e597a8efbc30f5f0d8/extension/src/client.ts#L433-L440

I was always suspicious of why i needed to do this, as the grpc client should be retrying itself. This code is fishy and again supports my theory above. It's a patch over a deeper problem. I believe I've fixed the deeper problem with how i construct the server task.

So in simple terms, the fix to only tell the client to connect once the underlying server process has been successfully bootstrapped.

I will try get a potential fix out for this today.

[vinzlee97]

Yeah, it has to do with Java Extension Pack by Microsoft (in my case).

So I reopened the same project 10 times for each case of extension disabling scenario, and here are the results:

It turned out when I disabled all extensions except Gradle Extension Pack, everything worked fine (10/10 successful connection attempts).

The next experiment I tried was to disable all extensions except Gradle Extension Pack and Java Extension Pack, and there was 2 failed attempts at the first and second try, then it connected successfully in the next attempts (8/10 successful connection attempts).

And finally, I tried to enable all extensions except Java Extension Pack, which surprised me that all attempts resulted in successful connection (10/10 successful connection attempts).

Here is my list of extensions:

aaron-bond.better-comments
alphabotsec.vscode-eclipse-keybindings
auchenberg.vscode-browser-preview
bierner.markdown-emoji
CoenraadS.bracket-pair-colorizer-2
Dart-Code.dart-code
Dart-Code.flutter
dkundel.vscode-new-file
eamodio.gitlens
FelixAngelov.bloc
Flutterando.flutter-mobx
formulahendry.code-runner
Gruntfuggly.todo-tree
jeroen-meijer.pubspec-assist
localizely.flutter-intl
mathiasfrohlich.Kotlin
ms-dotnettools.csharp
ms-python.python
ms-vscode-remote.remote-wsl
ms-vscode.cpptools
ms-vscode.Go
msjsdiag.debugger-for-chrome
naco-siren.gradle-language
Nash.awesome-flutter-snippets
pnp.polacode
quicktype.quicktype
redhat.java
richardwillis.vscode-gradle
richardwillis.vscode-gradle-extension-pack
scala-lang.scala
silverlakesoftware.searchdocsets-vscode
VisualStudioExptTeam.vscodeintellicode
vscjava.vscode-java-debug
vscjava.vscode-java-dependency
vscjava.vscode-java-pack
vscjava.vscode-java-test
vscjava.vscode-maven

[badsyntax]

I know the Java language server is quite heavy and perhaps it's just a machine load issue. (In that it takes a while to start 2 different Java servers.)

I've made a couple changes that can help with this issue.

Can you test this fix using Gradle Tasks v3.0.4? Can you test with all extensions enabled? Many thanks.

[vinzlee97]

Unfortunately, I got this in v3.0.4.

The Gradle: Connecting indicator keeps running though.
UPDATE: At some point long enough, the indicator then stops.

[badsyntax]

Arg. I just spotted this too. Sorry. I assume you're using Git Bash on windows? I'll get a fix out asap. Refs #420

[vinzlee97]

Yeah, it's Git Bash.