git_trace2: Add socket timeout

repo blocks indefinitely until trace collector receives trace events,
which is not desired. This change adds a fixed timeout to connect and
send operations. It is possible that some events will be lost. repo logs
any failed trace operation.

Bug: b/316227772
Change-Id: I017636421b8e22ae3fcbab9e4eb2bee1d4fbbff4
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/398717
Tested-by: Josip Sokcevic <sokcevic@google.com>
Commit-Queue: Josip Sokcevic <sokcevic@google.com>
Reviewed-by: Jason Chang <jasonnc@google.com>

git_trace2_event_log_base.py

@@ -38,6 +38,8 @@ import tempfile
 import threading
 
 
+# Timeout when sending events via socket (applies to connect, send)
+SOCK_TIMEOUT = 0.5  # in seconds
 # BaseEventLog __init__ Counter that is consistent within the same process
 p_init_count = 0
 
@@ -296,6 +298,7 @@ class BaseEventLog:
                     with socket.socket(
                         socket.AF_UNIX, socket.SOCK_STREAM
                     ) as sock:
+                        sock.settimeout(SOCK_TIMEOUT)
                         sock.connect(path)
                         self._WriteLog(sock.sendall)
                     return f"af_unix:stream:{path}"