Theia: Restore workspace open files across multiple instances

[gbodeen]

Bug Description:

Expected: When re-opening a workspace, the editor pane should display the same open files as were open last time the workspace was in use.

Actual: Instances of Theia after the first open the workspace but do not restore tabs. This error appears in the console:

This becomes relevant when Theia is bundled as an application (for distribution similar to VS Code). Users will commonly try to launch multiple instances of the application, each for use with a different workspace, but currently this will not give the expected user experience.

I'm not 100% confident this is a bug rather than an intentional, temporary limitation. In any case, VS Code does not have this limitation.

Steps to Reproduce:

1. In a local copy of the Theia repo, run yarn && yarn start:electron. Assuming you've previously opened multiple different workspaces, use File > Open Recent Workspace to launch new windows with those workspace. This works as expected, displaying the files that were last open. Close all instances.
2. In two terminals, run yarn start:electron to start separate instances. The first instance will display the files that were last open; the second will not. Use File > Open Recent Workspace in each instance for additional examples; the first instance will continue to restore open files, because it has access to the indexedDB, and the second will not restore them.

Additional Information

• Operating System: RHEL7
• Theia Version: 1.2.0 plus subsequent commits as of 2020-06-09.

[akosyakov]

The error is weird. We have a guard that if indexeddb is not available then we don't use it. It seems in your env there is indexeddb support but it throws internal errors. Could you dig what is causing internal errors?

[kittaakos]

Maybe it's a generic issue with electron: https://github.com/electron/electron/issues/10792#issuecomment-336528812

Edit: here is another useful comment:

I saw if an electron process is running in the background and you're starting a new electron process, the IndexedDB is locked for the first process. So I get an error: "UnknownError: Internal error opening backing store for indexedDB.open.".

[gbodeen]

Here is a partial solution:

If you need completely separate IndexedDB, use different partition partition: "persist:part1", partition: "persist:part2", ... see https://www.electronjs.org/docs/api/browser-window#new-browserwindowoptions

In a couple places there's code using session.defaultSession to return the default session object, which I presume can be replaced by session.fromPartition("persist:partitionName"). However, in my initial tests, the websocket connection gets refused, indicating I'm missing something.

[akosyakov]

Could you test whether it is still the issue with Electron 9? Here is a PR which we hope to land next month: https://github.com/eclipse-theia/theia/pull/7968

[gbodeen]

I tested that PR branch this afternoon on RHEL 7.8. The issue still exists in Electron 9.

Incidentally, as I do not have root access, I had to run that branch as yarn && yarn start:electron --no-sandbox. Without the no-sandbox flag, the yarn start:electron command prints a message:

[6277:0623/151502.149582:FATAL:setuid_sandbox_host.cc(158)] The SUID sandbox helper binary was found, but is not configured correctly. Rather than run without sandboxing I'm aborting now. You need to make sure that /repo/theia/node_modules/electron/dist/chrome-sandbox is owned by root and has mode 4755.

[kittaakos]

I am also interested in this issue and will try to share my findings here.

[gbodeen]

The PR to allow electron-main process customization is almost a solution for us, except for the error below. If we set theia.backend.config.singleInstance = true in package.json, then the attempted second instance defers to the first instance, and the first instance opens a second window. The new window therefore has full access to workspaces and themes. That's great! However, it throws an error:

It looks like it's interpreting process.execPath as a workspace, maybe due to expecting the wrong number of arguments on the command line.

In the existing master branch, by contrast, singleInstance mode simply causes the window belonging to the first instance to focus. No second window is opened.

[marechal-p]

@gbodeen Do you get this error when running Theia from sources or is it from a bundled app?

[marechal-p]

@gbodeen I think the issue you've reported has been fixed by the latest commit pushed on that branch/PR.

[kittaakos]

I think the issue you've reported has been fixed

I can confirm this. I had the same problem and we fixed it here.