commit 18334545954e6d9f3d2bf11d08be2d03893876cc
author David Fang <fangism@google.com> Fri Apr 21 02:40:43 2023 +0000
committer CQ Bot <fuchsia-internal-scoped@luci-project-accounts.iam.gserviceaccount.com> Fri Apr 21 02:40:43 2023 +0000
tree 0def9506d9a5aef03aab3bc6b57e6e988fece4d2
parent 6aea8d27dfc46687fb9bbf19c423ed31ef2862a2

[rbe] Re-launch self in subprocess for reproxy

This fixes the issue where python print statements (from --verbose
debugging) disappeared when re-launched.

It would be more efficient to use os.execv() than to fork a subprocess,
however, this does not effect the `fx build` flow because that
is already running with reproxy, and will never trigger the re-launch
path.  (The overhead will be unnoticeable for interactive debugging
and manual repro.)

Tested: --verbosity prints message in the relaunched call

```
$ prebuilt/third_party/python3/linux-x64/bin/python3 build/rbe/remote_action.py --verbose -- echo jello
[remote_action.py] Detected RBE_proxy_log_dir=None
[remote_action.py] Detected RBE_log_dir=None
[remote_action.py] Automatically re-launching: build/rbe/fuchsia-reproxy-wrap.sh -- prebuilt/third_party/python3/linux-x64/bin/python3 -S build/rbe/remote_action.py --verbose -- echo jello
Proxy started successfully.
[remote_action.py] Detected RBE_proxy_log_dir=/tmp/reproxy.20230420-091549.cdoD
[remote_action.py] Detected RBE_log_dir=/tmp/reproxy.20230420-091549.cdoD/rewrapper-logs
[remote_action.py] prebuilt/proprietary/third_party/reclient/linux-x64/rewrapper --exec_root=/usr/local/google/home/fangism/fuchsia/fuchsia --cfg build/rbe/fuchsia-rewrapper.cfg -- echo jello
jello
RBE Stats: Downloaded: 6 B, Uploaded: 325 B
```

Bug: 125841
Change-Id: I9a61b2660dd9ce9ac349b775f6ff36e77b4915c1
Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/841216
Reviewed-by: Jay Zhuang <jayzhuang@google.com>
Commit-Queue: Auto-Submit <auto-submit@fuchsia-infra.iam.gserviceaccount.com>
Fuchsia-Auto-Submit: David Fang <fangism@google.com>