tree 7f25616f7c8488f95f3d409f1aa51b3a67db32be
parent 0a10c623befa45d2926d68ea4b036a3840794fe7
author Alexander Rakoczy <alex@golang.org> 1586383800 -0400
committer Alexander Rakoczy <alex@golang.org> 1586967020 +0000

sandbox: timeout runsc commands

The current mechanism for forcing a process to die ater a timeout is not
sufficient. This change fixes issues that were causing processes to run
forever on the sandbox.

- Gracefully terminate processes before we kill them inside of our
gVisor process. This helps capture valuable debug output for the user.

- Return a friendlier error when our run context times out on the
playground.

- Add a test that timeouts are handled gracefully.

- Reduce concurrent goroutines in our sandbox run handler by replacing
goroutine copy functions with a custom writer (limitedWriter) that
returns an error if too much output is returned, halting the program.

- Custom writers (limitedWriter, switchWriter) also fix timing errors
when calling Wait() too soon on a Command, before we have read all of
the data. It also fixes a different error from trying to read data after
a program has terminated.

- Remove goroutine from startContainer, and use a ticker + context
timeout for synchronization.

Updates golang/go#25224
Updates golang/go#38343

Change-Id: Ie9d65220e5c4f39272ea70b45c4b472bcd7069bb
Reviewed-on: https://go-review.googlesource.com/c/playground/+/227652
Run-TryBot: Alexander Rakoczy <alex@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>