[Blocking] [ci] CI for R freeze

[guolinke]

refer to https://github.com/microsoft/LightGBM/runs/955837580
It seems the installation of Rtools (with R 4.0) freezes.
ping @jameslamb

[jameslamb]

Ok I can look in 10 minutes

[jameslamb]

ok looking right now

[jameslamb]

I'm going to push changes to #3277 to test, since that is a small R change that was already approved.

[jameslamb]

😕 I tried removing /VERYSILENT so we could get more logs installing Rtools, but no luck. I don't see any other configuration options that can help here.

https://github.com/microsoft/LightGBM/pull/3277/checks?check_run_id=956113469

Telling R to use MinGW
Downloading R and Rtools
Downloading https://cloud.r-project.org/bin/windows/base/old/3.6.3/R-3.6.3-win.exe
Downloading https://cloud.r-project.org/bin/windows/Rtools/Rtools35.exe
Installing R
Done installing R
Installing Rtools
##[error]The operation was canceled.

Those logs tell us that:

• R was found and could be downloaded
• Rtools was found and could be downloaded
• installation of R succeeds
• installation of Rtools times out

Since there has not been an Rtools release since June 22, and since we're seeing this issue even on Rtools35, I have these theories:

1. Some service Rtools relies on (like a CTAN mirror or a package server for pacman) is down
2. some subtle networking thing has changed in Azure that is blocking traffic to some place Rtools wants to hit

I just looked on the pacman mirrors and I see a LOT of errors recently!!!

and other mirrors not reporting errors are way out of sync

Given this, @guolinke I think you should use your administrator privileges to merge #3071 . We don't know how long it will take for this to be resolved, and it shouldn't hold up releases for all the other non-R components any longer.

[guolinke]

@jameslamb thank you so much.
No problem, I will merge it first.

[jameslamb]

I just checked and the pacman repos still seem to be down. I hope it's resolved soon.

[jameslamb]

I have been trying with #3277 and I still see this issue :/

This is difficult because even after removing the /VERYSILENT, we're still not getting any logs. Going to pull out my Windows laptop and try running this code there.

It seems that a lot of the pacman mirrors are working now...maybe that was never the issue to begin with, I don't know. Maybe something in Rtools is asking for a user input and hung waiting on it.

[jameslamb]

Ok making progress!!! Now I think that the pacman thing was completely unrelated.

I found that the download code we've been using to get Rtools is returning a successful status, but not actually downloading anything!!!

and then if you run the code to install Rtools and the file doesn't exist, you get a dialog box that has to be confirmed in a GUI. That is why it's hanging in CI!!

I'm investigating how to fix this. Maybe the download link from CRAN is now redirecting and the powershell code in test_r_package_windows.ps1 isn't following that?

[jameslamb]

hmmmm doesn't seem like it's a redirect.

[StrikerRUS]

According to your screenshots you are downloading from cran.r-project.org, but our CI tries to download from cloud.r-project.org. Maybe this matters...

https://github.com/microsoft/LightGBM/blob/33af069cc174a4c56c5f1e2f351196a284248f80/.ci/test_r_package_windows.ps1#L105-L106

On my local machine CI code works fine and downloads both R and Rtools sucessfully.

[jameslamb]

😱 😱 😱 😱 😱

[jameslamb]

when I change to cloud, it still does not download a file on my laptop