diff --git a/api/controller/sysroot.py b/api/controller/sysroot.py
index 332b7a3..0a07647 100644
--- a/api/controller/sysroot.py
+++ b/api/controller/sysroot.py
@@ -25,309 +25,339 @@
 from chromite.service import sysroot
 
 
-_ACCEPTED_LICENSES = '@CHROMEOS'
+_ACCEPTED_LICENSES = "@CHROMEOS"
 
 DEFAULT_BACKTRACK = 30
 
 
 def _GetGomaLogDirectory():
-  """Get goma's log directory based on the env variables.
+    """Get goma's log directory based on the env variables.
 
-  Returns:
-    a string of a directory name where goma's log may exist, or None if no
-    potential directories exist.
-  """
-  # TODO(crbug.com/1045001): Replace environment variable with query to
-  # goma object after goma refactoring allows this.
-  candidates = [
-      'GLOG_log_dir',
-      'GOOGLE_LOG_DIR',
-      'TEST_TMPDIR',
-      'TMPDIR',
-      'TMP',
-  ]
-  for candidate in candidates:
-    value = os.environ.get(candidate)
-    if value and os.path.isdir(value):
-      return value
+    Returns:
+      a string of a directory name where goma's log may exist, or None if no
+      potential directories exist.
+    """
+    # TODO(crbug.com/1045001): Replace environment variable with query to
+    # goma object after goma refactoring allows this.
+    candidates = [
+        "GLOG_log_dir",
+        "GOOGLE_LOG_DIR",
+        "TEST_TMPDIR",
+        "TMPDIR",
+        "TMP",
+    ]
+    for candidate in candidates:
+        value = os.environ.get(candidate)
+        if value and os.path.isdir(value):
+            return value
 
-  # "/tmp" will always exist.
-  return '/tmp'
+    # "/tmp" will always exist.
+    return "/tmp"
 
 
 def ExampleGetResponse():
-  """Give an example response to assemble upstream in caller artifacts."""
-  uabs = common_pb2.UploadedArtifactsByService
-  cabs = common_pb2.ArtifactsByService
-  return uabs.Sysroot(artifacts=[
-      uabs.Sysroot.ArtifactPaths(
-          artifact_type=cabs.Sysroot.ArtifactType.SIMPLE_CHROME_SYSROOT,
-          paths=[
-              common_pb2.Path(
-                  path='/tmp/sysroot_chromeos-base_chromeos-chrome.tar.xz',
-                  location=common_pb2.Path.OUTSIDE)
-          ],
-      ),
-      uabs.Sysroot.ArtifactPaths(
-          artifact_type=cabs.Sysroot.ArtifactType.DEBUG_SYMBOLS,
-          paths=[
-              common_pb2.Path(
-                  path='/tmp/debug.tgz', location=common_pb2.Path.OUTSIDE)
-          ],
-      ),
-      uabs.Sysroot.ArtifactPaths(
-          artifact_type=cabs.Sysroot.ArtifactType.BREAKPAD_DEBUG_SYMBOLS,
-          paths=[
-              common_pb2.Path(
-                  path='/tmp/debug_breakpad.tar.xz',
-                  location=common_pb2.Path.OUTSIDE)
-          ])
-  ])
+    """Give an example response to assemble upstream in caller artifacts."""
+    uabs = common_pb2.UploadedArtifactsByService
+    cabs = common_pb2.ArtifactsByService
+    return uabs.Sysroot(
+        artifacts=[
+            uabs.Sysroot.ArtifactPaths(
+                artifact_type=cabs.Sysroot.ArtifactType.SIMPLE_CHROME_SYSROOT,
+                paths=[
+                    common_pb2.Path(
+                        path="/tmp/sysroot_chromeos-base_chromeos-chrome.tar.xz",
+                        location=common_pb2.Path.OUTSIDE,
+                    )
+                ],
+            ),
+            uabs.Sysroot.ArtifactPaths(
+                artifact_type=cabs.Sysroot.ArtifactType.DEBUG_SYMBOLS,
+                paths=[
+                    common_pb2.Path(
+                        path="/tmp/debug.tgz", location=common_pb2.Path.OUTSIDE
+                    )
+                ],
+            ),
+            uabs.Sysroot.ArtifactPaths(
+                artifact_type=cabs.Sysroot.ArtifactType.BREAKPAD_DEBUG_SYMBOLS,
+                paths=[
+                    common_pb2.Path(
+                        path="/tmp/debug_breakpad.tar.xz",
+                        location=common_pb2.Path.OUTSIDE,
+                    )
+                ],
+            ),
+        ]
+    )
 
 
-def GetArtifacts(in_proto: common_pb2.ArtifactsByService.Sysroot,
-                 chroot: chroot_lib.Chroot, sysroot_class: sysroot_lib.Sysroot,
-                 build_target: build_target_lib.BuildTarget,
-                 output_dir: str) -> list:
-  """Builds and copies sysroot artifacts to specified output_dir.
+def GetArtifacts(
+    in_proto: common_pb2.ArtifactsByService.Sysroot,
+    chroot: chroot_lib.Chroot,
+    sysroot_class: sysroot_lib.Sysroot,
+    build_target: build_target_lib.BuildTarget,
+    output_dir: str,
+) -> list:
+    """Builds and copies sysroot artifacts to specified output_dir.
 
-  Copies sysroot artifacts to output_dir, returning a list of (output_dir: str)
-  paths to the desired files.
+    Copies sysroot artifacts to output_dir, returning a list of (output_dir: str)
+    paths to the desired files.
 
-  Args:
-    in_proto: Proto request defining reqs.
-    chroot: The chroot class used for these artifacts.
-    sysroot_class: The sysroot class used for these artifacts.
-    build_target: The build target used for these artifacts.
-    output_dir: The path to write artifacts to.
+    Args:
+      in_proto: Proto request defining reqs.
+      chroot: The chroot class used for these artifacts.
+      sysroot_class: The sysroot class used for these artifacts.
+      build_target: The build target used for these artifacts.
+      output_dir: The path to write artifacts to.
 
-  Returns:
-    A list of dictionary mappings of ArtifactType to list of paths.
-  """
-  generated = []
-  artifact_types = {
-      in_proto.ArtifactType.SIMPLE_CHROME_SYSROOT:
-          sysroot.CreateSimpleChromeSysroot,
-      in_proto.ArtifactType.CHROME_EBUILD_ENV:
-          sysroot.CreateChromeEbuildEnv,
-      in_proto.ArtifactType.BREAKPAD_DEBUG_SYMBOLS:
-          sysroot.BundleBreakpadSymbols,
-      in_proto.ArtifactType.DEBUG_SYMBOLS:
-          sysroot.BundleDebugSymbols,
-  }
+    Returns:
+      A list of dictionary mappings of ArtifactType to list of paths.
+    """
+    generated = []
+    artifact_types = {
+        in_proto.ArtifactType.SIMPLE_CHROME_SYSROOT: sysroot.CreateSimpleChromeSysroot,
+        in_proto.ArtifactType.CHROME_EBUILD_ENV: sysroot.CreateChromeEbuildEnv,
+        in_proto.ArtifactType.BREAKPAD_DEBUG_SYMBOLS: sysroot.BundleBreakpadSymbols,
+        in_proto.ArtifactType.DEBUG_SYMBOLS: sysroot.BundleDebugSymbols,
+    }
 
-  for output_artifact in in_proto.output_artifacts:
-    for artifact_type, func in artifact_types.items():
-      if artifact_type in output_artifact.artifact_types:
-        result = func(chroot, sysroot_class, build_target, output_dir)
-        if result:
-          generated.append({
-              'paths': [result] if isinstance(result, str) else result,
-              'type': artifact_type,
-          })
+    for output_artifact in in_proto.output_artifacts:
+        for artifact_type, func in artifact_types.items():
+            if artifact_type in output_artifact.artifact_types:
+                result = func(chroot, sysroot_class, build_target, output_dir)
+                if result:
+                    generated.append(
+                        {
+                            "paths": [result]
+                            if isinstance(result, str)
+                            else result,
+                            "type": artifact_type,
+                        }
+                    )
 
-  return generated
+    return generated
 
 
 @faux.all_empty
-@validate.require('build_target.name')
+@validate.require("build_target.name")
 @validate.validation_complete
 def Create(input_proto, output_proto, _config):
-  """Create or replace a sysroot."""
-  update_chroot = not input_proto.flags.chroot_current
-  replace_sysroot = input_proto.flags.replace
+    """Create or replace a sysroot."""
+    update_chroot = not input_proto.flags.chroot_current
+    replace_sysroot = input_proto.flags.replace
 
-  build_target = controller_util.ParseBuildTarget(input_proto.build_target,
-                                                  input_proto.profile)
-  package_indexes = [
-      binpkg.PackageIndexInfo.from_protobuf(x)
-      for x in input_proto.package_indexes
-  ]
-  run_configs = sysroot.SetupBoardRunConfig(
-      force=replace_sysroot,
-      upgrade_chroot=update_chroot,
-      package_indexes=package_indexes,
-      backtrack=DEFAULT_BACKTRACK,
-  )
+    build_target = controller_util.ParseBuildTarget(
+        input_proto.build_target, input_proto.profile
+    )
+    package_indexes = [
+        binpkg.PackageIndexInfo.from_protobuf(x)
+        for x in input_proto.package_indexes
+    ]
+    run_configs = sysroot.SetupBoardRunConfig(
+        force=replace_sysroot,
+        upgrade_chroot=update_chroot,
+        package_indexes=package_indexes,
+        backtrack=DEFAULT_BACKTRACK,
+    )
 
-  try:
-    created = sysroot.Create(
-        build_target, run_configs, accept_licenses=_ACCEPTED_LICENSES)
-  except sysroot.Error as e:
-    cros_build_lib.Die(e)
+    try:
+        created = sysroot.Create(
+            build_target, run_configs, accept_licenses=_ACCEPTED_LICENSES
+        )
+    except sysroot.Error as e:
+        cros_build_lib.Die(e)
 
-  output_proto.sysroot.path = created.path
-  output_proto.sysroot.build_target.name = build_target.name
+    output_proto.sysroot.path = created.path
+    output_proto.sysroot.build_target.name = build_target.name
 
-  return controller.RETURN_CODE_SUCCESS
+    return controller.RETURN_CODE_SUCCESS
 
 
 @faux.all_empty
-@validate.require('build_target.name', 'packages')
-@validate.require_each('packages', ['category', 'package_name'])
+@validate.require("build_target.name", "packages")
+@validate.require_each("packages", ["category", "package_name"])
 @validate.validation_complete
 def GenerateArchive(input_proto, output_proto, _config):
-  """Generate a sysroot. Typically used by informational builders."""
-  build_target_name = input_proto.build_target.name
-  pkg_list = []
-  for package in input_proto.packages:
-    pkg_list.append('%s/%s' % (package.category, package.package_name))
+    """Generate a sysroot. Typically used by informational builders."""
+    build_target_name = input_proto.build_target.name
+    pkg_list = []
+    for package in input_proto.packages:
+        pkg_list.append("%s/%s" % (package.category, package.package_name))
 
-  with osutils.TempDir(delete=False) as temp_output_dir:
-    sysroot_tar_path = sysroot.GenerateArchive(temp_output_dir,
-                                               build_target_name, pkg_list)
+    with osutils.TempDir(delete=False) as temp_output_dir:
+        sysroot_tar_path = sysroot.GenerateArchive(
+            temp_output_dir, build_target_name, pkg_list
+        )
 
-  # By assigning this Path variable to the tar path, the tar file will be
-  # copied out to the input_proto's ResultPath location.
-  output_proto.sysroot_archive.path = sysroot_tar_path
-  output_proto.sysroot_archive.location = common_pb2.Path.INSIDE
+    # By assigning this Path variable to the tar path, the tar file will be
+    # copied out to the input_proto's ResultPath location.
+    output_proto.sysroot_archive.path = sysroot_tar_path
+    output_proto.sysroot_archive.location = common_pb2.Path.INSIDE
 
 
 def _MockFailedPackagesResponse(_input_proto, output_proto, _config):
-  """Mock error response that populates failed packages."""
-  fail = output_proto.failed_package_data.add()
-  fail.name.package_name = 'package'
-  fail.name.category = 'category'
-  fail.name.version = '1.0.0_rc-r1'
-  fail.log_path.path = '/path/to/package:category-1.0.0_rc-r1:20210609-1337.log'
-  fail.log_path.location = common_pb2.Path.INSIDE
+    """Mock error response that populates failed packages."""
+    fail = output_proto.failed_package_data.add()
+    fail.name.package_name = "package"
+    fail.name.category = "category"
+    fail.name.version = "1.0.0_rc-r1"
+    fail.log_path.path = (
+        "/path/to/package:category-1.0.0_rc-r1:20210609-1337.log"
+    )
+    fail.log_path.location = common_pb2.Path.INSIDE
 
-  fail2 = output_proto.failed_package_data.add()
-  fail2.name.package_name = 'bar'
-  fail2.name.category = 'foo'
-  fail2.name.version = '3.7-r99'
-  fail2.log_path.path = '/path/to/foo:bar-3.7-r99:20210609-1620.log'
-  fail2.log_path.location = common_pb2.Path.INSIDE
+    fail2 = output_proto.failed_package_data.add()
+    fail2.name.package_name = "bar"
+    fail2.name.category = "foo"
+    fail2.name.version = "3.7-r99"
+    fail2.log_path.path = "/path/to/foo:bar-3.7-r99:20210609-1620.log"
+    fail2.log_path.location = common_pb2.Path.INSIDE
 
 
 @faux.empty_success
 @faux.error(_MockFailedPackagesResponse)
-@validate.require('sysroot.path', 'sysroot.build_target.name')
-@validate.exists('sysroot.path')
+@validate.require("sysroot.path", "sysroot.build_target.name")
+@validate.exists("sysroot.path")
 @validate.validation_complete
 def InstallToolchain(input_proto, output_proto, _config):
-  """Install the toolchain into a sysroot."""
-  compile_source = (
-      input_proto.flags.compile_source or input_proto.flags.toolchain_changed)
+    """Install the toolchain into a sysroot."""
+    compile_source = (
+        input_proto.flags.compile_source or input_proto.flags.toolchain_changed
+    )
 
-  sysroot_path = input_proto.sysroot.path
+    sysroot_path = input_proto.sysroot.path
 
-  build_target = controller_util.ParseBuildTarget(
-      input_proto.sysroot.build_target)
-  target_sysroot = sysroot_lib.Sysroot(sysroot_path)
-  run_configs = sysroot.SetupBoardRunConfig(usepkg=not compile_source)
+    build_target = controller_util.ParseBuildTarget(
+        input_proto.sysroot.build_target
+    )
+    target_sysroot = sysroot_lib.Sysroot(sysroot_path)
+    run_configs = sysroot.SetupBoardRunConfig(usepkg=not compile_source)
 
-  _LogBinhost(build_target.name)
+    _LogBinhost(build_target.name)
 
-  try:
-    sysroot.InstallToolchain(build_target, target_sysroot, run_configs)
-  except sysroot_lib.ToolchainInstallError as e:
-    controller_util.retrieve_package_log_paths(e.failed_toolchain_info,
-                                               output_proto, target_sysroot)
+    try:
+        sysroot.InstallToolchain(build_target, target_sysroot, run_configs)
+    except sysroot_lib.ToolchainInstallError as e:
+        controller_util.retrieve_package_log_paths(
+            e.failed_toolchain_info, output_proto, target_sysroot
+        )
 
-    return controller.RETURN_CODE_UNSUCCESSFUL_RESPONSE_AVAILABLE
+        return controller.RETURN_CODE_UNSUCCESSFUL_RESPONSE_AVAILABLE
 
-  return controller.RETURN_CODE_SUCCESS
+    return controller.RETURN_CODE_SUCCESS
 
 
 @faux.empty_success
 @faux.error(_MockFailedPackagesResponse)
-@validate.require('sysroot.build_target.name')
-@validate.exists('sysroot.path')
-@validate.require_each('packages', ['category', 'package_name'])
-@validate.require_each('use_flags', ['flag'])
+@validate.require("sysroot.build_target.name")
+@validate.exists("sysroot.path")
+@validate.require_each("packages", ["category", "package_name"])
+@validate.require_each("use_flags", ["flag"])
 @validate.validation_complete
 @metrics_lib.collect_metrics
 def InstallPackages(input_proto, output_proto, _config):
-  """Install packages into a sysroot, building as necessary and permitted."""
-  compile_source = (
-      input_proto.flags.compile_source or input_proto.flags.toolchain_changed)
+    """Install packages into a sysroot, building as necessary and permitted."""
+    compile_source = (
+        input_proto.flags.compile_source or input_proto.flags.toolchain_changed
+    )
 
-  use_remoteexec = bool(input_proto.remoteexec_config.reproxy_cfg_file and
-                        input_proto.remoteexec_config.reclient_dir)
+    use_remoteexec = bool(
+        input_proto.remoteexec_config.reproxy_cfg_file
+        and input_proto.remoteexec_config.reclient_dir
+    )
 
-  # Testing if Goma will support unknown compilers now.
-  use_goma = input_proto.flags.use_goma and not use_remoteexec
+    # Testing if Goma will support unknown compilers now.
+    use_goma = input_proto.flags.use_goma and not use_remoteexec
 
-  target_sysroot = sysroot_lib.Sysroot(input_proto.sysroot.path)
-  build_target = controller_util.ParseBuildTarget(
-      input_proto.sysroot.build_target)
+    target_sysroot = sysroot_lib.Sysroot(input_proto.sysroot.path)
+    build_target = controller_util.ParseBuildTarget(
+        input_proto.sysroot.build_target
+    )
 
-  # Get the package atom for each specified package. The field is optional, so
-  # error only when we cannot parse an atom for each of the given packages.
-  packages = [
-      controller_util.PackageInfoToCPV(x).cp for x in input_proto.packages
-  ]
+    # Get the package atom for each specified package. The field is optional, so
+    # error only when we cannot parse an atom for each of the given packages.
+    packages = [
+        controller_util.PackageInfoToCPV(x).cp for x in input_proto.packages
+    ]
 
-  package_indexes = [
-      binpkg.PackageIndexInfo.from_protobuf(x)
-      for x in input_proto.package_indexes
-  ]
+    package_indexes = [
+        binpkg.PackageIndexInfo.from_protobuf(x)
+        for x in input_proto.package_indexes
+    ]
 
-  # Calculate which packages would have been merged, but don't install anything.
-  dryrun = input_proto.flags.dryrun
+    # Calculate which packages would have been merged, but don't install anything.
+    dryrun = input_proto.flags.dryrun
 
-  if not target_sysroot.IsToolchainInstalled():
-    cros_build_lib.Die('Toolchain must first be installed.')
+    if not target_sysroot.IsToolchainInstalled():
+        cros_build_lib.Die("Toolchain must first be installed.")
 
-  _LogBinhost(build_target.name)
+    _LogBinhost(build_target.name)
 
-  use_flags = [u.flag for u in input_proto.use_flags]
-  build_packages_config = sysroot.BuildPackagesRunConfig(
-      use_any_chrome=False,
-      usepkg=not compile_source,
-      install_debug_symbols=True,
-      packages=packages,
-      package_indexes=package_indexes,
-      use_flags=use_flags,
-      use_goma=use_goma,
-      use_remoteexec=use_remoteexec,
-      incremental_build=False,
-      dryrun=dryrun,
-      backtrack=DEFAULT_BACKTRACK,
-  )
+    use_flags = [u.flag for u in input_proto.use_flags]
+    build_packages_config = sysroot.BuildPackagesRunConfig(
+        use_any_chrome=False,
+        usepkg=not compile_source,
+        install_debug_symbols=True,
+        packages=packages,
+        package_indexes=package_indexes,
+        use_flags=use_flags,
+        use_goma=use_goma,
+        use_remoteexec=use_remoteexec,
+        incremental_build=False,
+        dryrun=dryrun,
+        backtrack=DEFAULT_BACKTRACK,
+    )
 
-  try:
-    sysroot.BuildPackages(build_target, target_sysroot, build_packages_config)
-  except sysroot_lib.PackageInstallError as e:
-    if not e.failed_packages:
-      # No packages to report, so just exit with an error code.
-      return controller.RETURN_CODE_COMPLETED_UNSUCCESSFULLY
+    try:
+        sysroot.BuildPackages(
+            build_target, target_sysroot, build_packages_config
+        )
+    except sysroot_lib.PackageInstallError as e:
+        if not e.failed_packages:
+            # No packages to report, so just exit with an error code.
+            return controller.RETURN_CODE_COMPLETED_UNSUCCESSFULLY
 
-    controller_util.retrieve_package_log_paths(e.failed_packages, output_proto,
-                                               target_sysroot)
+        controller_util.retrieve_package_log_paths(
+            e.failed_packages, output_proto, target_sysroot
+        )
 
-    return controller.RETURN_CODE_UNSUCCESSFUL_RESPONSE_AVAILABLE
-  finally:
-    # Copy goma logs to specified directory if there is a goma_config and
-    # it contains a log_dir to store artifacts.
-    if input_proto.goma_config.log_dir.dir:
-      log_source_dir = _GetGomaLogDirectory()
-      archiver = goma_lib.LogsArchiver(
-          log_source_dir,
-          dest_dir=input_proto.goma_config.log_dir.dir,
-          stats_file=input_proto.goma_config.stats_file,
-          counterz_file=input_proto.goma_config.counterz_file)
-      archiver_tuple = archiver.Archive()
-      if archiver_tuple.stats_file:
-        output_proto.goma_artifacts.stats_file = archiver_tuple.stats_file
-      if archiver_tuple.counterz_file:
-        output_proto.goma_artifacts.counterz_file = archiver_tuple.counterz_file
-      output_proto.goma_artifacts.log_files[:] = archiver_tuple.log_files
+        return controller.RETURN_CODE_UNSUCCESSFUL_RESPONSE_AVAILABLE
+    finally:
+        # Copy goma logs to specified directory if there is a goma_config and
+        # it contains a log_dir to store artifacts.
+        if input_proto.goma_config.log_dir.dir:
+            log_source_dir = _GetGomaLogDirectory()
+            archiver = goma_lib.LogsArchiver(
+                log_source_dir,
+                dest_dir=input_proto.goma_config.log_dir.dir,
+                stats_file=input_proto.goma_config.stats_file,
+                counterz_file=input_proto.goma_config.counterz_file,
+            )
+            archiver_tuple = archiver.Archive()
+            if archiver_tuple.stats_file:
+                output_proto.goma_artifacts.stats_file = (
+                    archiver_tuple.stats_file
+                )
+            if archiver_tuple.counterz_file:
+                output_proto.goma_artifacts.counterz_file = (
+                    archiver_tuple.counterz_file
+                )
+            output_proto.goma_artifacts.log_files[:] = archiver_tuple.log_files
 
-  # Return without populating the response if it is a dryrun.
-  if dryrun:
-    return controller.RETURN_CODE_SUCCESS
+    # Return without populating the response if it is a dryrun.
+    if dryrun:
+        return controller.RETURN_CODE_SUCCESS
 
-  # Read metric events log and pipe them into output_proto.events.
-  deserialize_metrics_log(output_proto.events, prefix=build_target.name)
+    # Read metric events log and pipe them into output_proto.events.
+    deserialize_metrics_log(output_proto.events, prefix=build_target.name)
 
 
 def _LogBinhost(board):
-  """Log the portage binhost for the given board."""
-  binhost = portage_util.PortageqEnvvar(
-      'PORTAGE_BINHOST', board=board, allow_undefined=True)
-  if not binhost:
-    logging.warning('Portage Binhost not found.')
-  else:
-    logging.info('Portage Binhost: %s', binhost)
+    """Log the portage binhost for the given board."""
+    binhost = portage_util.PortageqEnvvar(
+        "PORTAGE_BINHOST", board=board, allow_undefined=True
+    )
+    if not binhost:
+        logging.warning("Portage Binhost not found.")
+    else:
+        logging.info("Portage Binhost: %s", binhost)