Can't connect to Docker after opening a folder/workspace (Docker Toolbox)

[wizcas]

Environment:
Windows 10 Pro 1809 17763.503
Docker Toolbox with Docker 18.09.3

The extension on my machine works fine on a clean startup, i.e. in an empty workspace. It looks as below:

But once I open a folder or a workspace and the window reloaded, the connection won't establish anymore with error:

I have the DOCKER_HOST environment variable in my system setting as tcp://192.168.99.100:2376, and I tried to set docker.host to both tcp://192.168.99.100:2376 and 192.168.99.100:2376 (which was mentioned in another issue saying removing the protocol makes the extension works). None of them works.

Another weird thing is that, the start.sh script provided by Docker Toolbox can't work in VSCode terminal after loading folder/workspace as well, which works fine on startup. It shows an error that 'Docker Machine is not installed, which seems being caused by DOCKER_TOOLBOX_INSTALL_PATH not correctly read.

Is there any log or more information I can provide to figure out how this problem happens?

[wizcas]

Here're more experiments which might lead to easier problem locating:

The extension cannot connect to docker after VS Code reloaded. So there is nothing to do with if there's a folder/workspace loaded, as long as VS Code doesn't reload after startup.

I tried to run code /foo/bar/work in terminal and the docker extension works super good with my the folder open. Then I selected Files->Open a folder->some other folder, VS Code reloads, and docker connection is down again as expected.

[ejizba]

@wizcas there's a lot of discussion in VS Code about how and when process environment variables should be inherited. I'm guessing VS Code is properly inheriting DOCKER_HOST (or some other env var) when you open it the first time, but not after reloading the window. Here's one example issue: microsoft/vscode#15452 Suffice it to say I'm not entirely caught up on all of their design choices/reasoning in this area and you're welcome to poke around in their repo.

In terms of the "docker.host" setting - that is something we can control directly from this extension. We're aware there's issues here and we want to improve this. Take a look at this for an example: #216 (or any issue labeled with "DOCKER_HOST"). I don't have an easy workaround for you at the moment, but we're looking into it

[wizcas]

@EricJizbaMSFT Thank you for you reply. Good to know the problems are spotted. Hopefully there will be a fix in not far future :)