Reland "[fuchsia] Collect Fuchsia system logs from Chrome-Fuchsia tests."

This is a reland of e2eb7388

System log collection is enabled by specifying a --enable-fuchsia-system-log argument which causes the test runner scripts to write the fuchsia system log to the test system_log file instead of writing the fuchsia kernel log file.

Original change's description:
> [fuchsia] Collect Fuchsia system logs from Chrome-Fuchsia tests.
>
> The Fuchsia system logs contain more detailed information than the Fuchsia kernel logs.
>
> Currently only Fuchsia kernel logs are collected.  The kernel logs are:
> - written to the swarming task output log along with the actual test output
> - optionally written to a "system_log" file in the test isolate output
>
> This CL will:
> - optionally write the Fuchsia system log to a "log_listener_log" in the test isolate output
>
> The Fuchsia system log will be written if the kernel log is written.
>
> The Fuchsia system log is written to "log_listener_log".  The name "log_listener_log" was used because the Fuchsia kernel log contents are already saved in "system_log".
>
> Bug: 1042512
> Change-Id: I900b5dfe9f6587f1901c19612060b979fae4da99
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2130679
> Reviewed-by: Kevin Marshall <kmarshall@chromium.org>
> Commit-Queue: Stephen Roe <steveroe@google.com>
> Cr-Commit-Position: refs/heads/master@{#756118}

Bug: 1042512
Change-Id: I9edf2991e697e09b81b7c206cce0de04ca42b500
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2136143
Commit-Queue: Stephen Roe <steveroe@google.com>
Reviewed-by: Kevin Marshall <kmarshall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#758636}

build/fuchsia/common_args.py

@@ -62,6 +62,10 @@ def AddCommonArgs(arg_parser):
   common_args.add_argument('--ssh-config', '-F',
                            help='The path to the SSH configuration used for '
                                 'connecting to the target device.')
+  common_args.add_argument('--enable-fuchsia-system-log',
+                           action='store_true',
+                           help='Write the Fuchsia system log to the test '
+                           'system_log instead of the Fuchsia kernel log.')
   common_args.add_argument('--fuchsia-out-dir',
                            help='Path to a Fuchsia build output directory. '
                                 'Equivalent to setting --ssh_config and '

build/fuchsia/run_package.py

@@ -20,6 +20,7 @@ import time
 import threading
 import uuid
 
+from symbolizer import RunSymbolizer
 from symbolizer import SymbolizerFilter
 
 FAR = common.GetHostToolPathFromPlatform('far')
@@ -36,6 +37,49 @@ def _AttachKernelLogReader(target):
                                 stdout=subprocess.PIPE)
 
 
+def _BuildIdsPaths(package_paths):
+  """Generate build ids paths for symbolizer processes."""
+  build_ids_paths = map(
+      lambda package_path: os.path.join(
+          os.path.dirname(package_path), 'ids.txt'),
+      package_paths)
+  return build_ids_paths
+
+
+class SystemLogReader(object):
+  """Collects and symbolizes Fuchsia system log to a file."""
+
+  def __init__(self):
+    self._listener_proc = None
+    self._symbolizer_proc = None
+    self._system_log = None
+
+  def __enter__(self):
+      return self
+
+  def __exit__(self, exc_type, exc_val, exc_tb):
+    """Stops the system logging processes and closes the output file."""
+    if self._symbolizer_proc:
+      self._symbolizer_proc.kill()
+    if self._listener_proc:
+      self._listener_proc.kill()
+    if self._system_log:
+      self._system_log.close()
+
+  def Start(self, target, package_paths, system_log_file):
+    """Start a system log reader as a long-running SSH task."""
+    logging.debug('Writing fuchsia system log to %s' % system_log_file)
+
+    self._listener_proc = target.RunCommandPiped(['log_listener'],
+                                                  stdout=subprocess.PIPE,
+                                                  stderr=subprocess.STDOUT)
+
+    self._system_log = open(system_log_file,'w', buffering=1)
+    self._symbolizer_proc = RunSymbolizer(self._listener_proc.stdout,
+                                          self._system_log,
+                                          _BuildIdsPaths(package_paths))
+
+
 class MergedInputStream(object):
   """Merges a number of input streams into a UNIX pipe on a dedicated thread.
   Terminates when the file descriptor of the primary stream (the first in
@@ -194,11 +238,8 @@ def RunPackage(output_dir, target, package_paths, package_name,
         output_stream = process.stdout
 
       # Run the log data through the symbolizer process.
-      build_ids_paths = map(
-          lambda package_path: os.path.join(
-              os.path.dirname(package_path), 'ids.txt'),
-          package_paths)
-      output_stream = SymbolizerFilter(output_stream, build_ids_paths)
+      output_stream = SymbolizerFilter(output_stream,
+                                       _BuildIdsPaths(package_paths))
 
       for next_line in output_stream:
         print(next_line.rstrip())

build/fuchsia/test_runner.py

@@ -18,7 +18,7 @@ import time
 
 from common_args import AddCommonArgs, ConfigureLogging, GetDeploymentTargetForArgs
 from net_test_server import SetupTestServer
-from run_package import RunPackage, RunPackageArgs
+from run_package import RunPackage, RunPackageArgs, SystemLogReader
 
 DEFAULT_TEST_SERVER_CONCURRENCY = 4
 
@@ -139,32 +139,37 @@ def main():
     child_args.extend(args.child_args)
 
   with GetDeploymentTargetForArgs(args) as target:
-    target.Start()
+    with SystemLogReader() as system_logger:
+      target.Start()
 
-    if args.test_launcher_filter_file:
-      target.PutFile(args.test_launcher_filter_file, TEST_FILTER_PATH,
-                     for_package=args.package_name)
-      child_args.append('--test-launcher-filter-file=' + TEST_FILTER_PATH)
+      if args.enable_fuchsia_system_log:
+        if args.system_log_file and args.system_log_file != '-':
+          system_logger.Start(target, args.package, args.system_log_file)
 
-    test_server = None
-    if args.enable_test_server:
-      assert test_concurrency
-      test_server = SetupTestServer(target, test_concurrency,
-                                    args.package_name)
+      if args.test_launcher_filter_file:
+        target.PutFile(args.test_launcher_filter_file, TEST_FILTER_PATH,
+                      for_package=args.package_name)
+        child_args.append('--test-launcher-filter-file=' + TEST_FILTER_PATH)
 
-    run_package_args = RunPackageArgs.FromCommonArgs(args)
-    returncode = RunPackage(
-        args.output_directory, target, args.package, args.package_name,
-        child_args, run_package_args)
+      test_server = None
+      if args.enable_test_server:
+        assert test_concurrency
+        test_server = SetupTestServer(target, test_concurrency,
+                                      args.package_name)
 
-    if test_server:
-      test_server.Stop()
+      run_package_args = RunPackageArgs.FromCommonArgs(args)
+      returncode = RunPackage(
+          args.output_directory, target, args.package, args.package_name,
+          child_args, run_package_args)
 
-    if args.test_launcher_summary_output:
-      target.GetFile(TEST_RESULT_PATH, args.test_launcher_summary_output,
-                     for_package=args.package_name)
+      if test_server:
+        test_server.Stop()
 
-    return returncode
+      if args.test_launcher_summary_output:
+        target.GetFile(TEST_RESULT_PATH, args.test_launcher_summary_output,
+                      for_package=args.package_name)
+
+      return returncode
 
 
 if __name__ == '__main__':