reclient: Clear log dir between builds

Bug: b/287650736
Change-Id: I87c0226f428211ac99520b024edeaf5ccb6a674c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/4629861
Commit-Queue: Ben Segall <bentekkie@google.com>
Reviewed-by: Takuto Ikuta <tikuta@chromium.org>
Auto-Submit: Ben Segall <bentekkie@google.com>

reclient_helper.py

@@ -9,6 +9,7 @@ for any reason e.g. build completion, keyboard interrupt etc."""
 import contextlib
 import hashlib
 import os
+import shutil
 import subprocess
 import sys
 
@@ -142,6 +143,9 @@ def set_reproxy_path_flags(out_dir, make_dirs=True):
   log_dir = os.path.join(tmp_dir, 'logs')
   cache_dir = find_cache_dir(tmp_dir)
   if make_dirs:
+    if os.path.exists(log_dir):
+      # Clear log dir before each build to ensure correct metric aggregation.
+      shutil.rmtree(log_dir)
     os.makedirs(tmp_dir, exist_ok=True)
     os.makedirs(log_dir, exist_ok=True)
     os.makedirs(cache_dir, exist_ok=True)

tests/ninja_reclient_test.py

@@ -196,6 +196,40 @@ class NinjaReclientTest(trial_dir.TestCase):
         ]),
     ])
 
+  @unittest.mock.patch.dict(os.environ, {})
+  @unittest.mock.patch('subprocess.call', return_value=0)
+  @unittest.mock.patch('ninja.main', return_value=0)
+  @unittest.mock.patch('reclient_metrics.check_status', return_value=True)
+  def test_ninja_reclient_clears_log_dir(self, mock_metrics_status, mock_ninja,
+                                         mock_call):
+    reclient_bin_dir = os.path.join('src', 'buildtools', 'reclient')
+    reclient_cfg = os.path.join('src', 'buildtools', 'reclient_cfgs',
+                                'reproxy.cfg')
+    write('.gclient', '')
+    write('.gclient_entries', 'entries = {"buildtools": "..."}')
+    write(os.path.join(reclient_bin_dir, 'version.txt'), '0.0')
+    write(reclient_cfg, '0.0')
+    argv = ["ninja_reclient.py", "-C", "out/a", "chrome"]
+
+    os.makedirs(os.path.join(self.root_dir, "out", "a", ".reproxy_tmp", "logs"),
+                exist_ok=True)
+    with open(
+        os.path.join(self.root_dir, "out", "a", ".reproxy_tmp", "logs",
+                     "reproxy.rpl"), "w") as f:
+      print("Content", file=f)
+
+    self.assertEqual(0, ninja_reclient.main(argv))
+
+    self.assertTrue(
+        os.path.isdir(os.path.join(self.root_dir, "out", "a", ".reproxy_tmp")))
+    self.assertTrue(
+        os.path.isdir(
+            os.path.join(self.root_dir, "out", "a", ".reproxy_tmp", "logs")))
+    self.assertFalse(
+        os.path.isfile(
+            os.path.join(self.root_dir, "out", "a", ".reproxy_tmp", "logs",
+                         "reproxy.rpl")))
+
   @unittest.mock.patch('subprocess.call', return_value=0)
   @unittest.mock.patch('ninja.main', side_effect=KeyboardInterrupt())
   def test_ninja_reclient_ninja_interrupted(self, mock_ninja, mock_call):