# Copyright 2021 The Fuchsia Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

from contextlib import contextmanager

from recipe_engine import recipe_api

# For builds using the goma input processor, sometimes the deps cache file is
# too big for the default setting.  So just set the max file size permitted to
# be large enough.
_DEPS_CACHE_MAX_MB = "512"

# Updated from https://chrome-infra-packages.appspot.com/p/infra/rbe/client
# and should be kept in sync with the version in the engine DEPS file at
# https://github.com/flutter/engine/blob/9cb60de37b6d582d886f46b86b90ccb9d6323fea/DEPS#L47
RBE_VERSION = 're_client_version:0.185.0.db415f21-gomaip'


class RbeApi(recipe_api.RecipeApi):
  """RemoteExecutionApi contains helper functions for using remote execution
    services via re-client/re-proxy."""

  def __init__(self, props, *args, **kwargs):
    super().__init__(*args, **kwargs)

    self._reclient_path = None
    self._platform = props.platform
    self._instance = props.instance

    if not self._platform and self._test_data.enabled:
      self._platform = "fake_rbe_platform"
    if not self._instance and self._test_data.enabled:
      self._instance = "fake_rbe_instance"
    self._log_format = props.log_format or "reducedtext"
    self._started = False  # A flag tracking if rbe service is running.
    self._rbe_triggered = False  # A flag tracking if rbe service has ever been started.

  def set_rbe_triggered(self, triggered):
    self._rbe_triggered = triggered

  def wait_and_collect_logs(self, collect_rbe_logs_latency, working_dir):
    """Collect logs if build running time exceeds collect_rbe_logs_latency.

    collect_rbe_logs_latency(int): the latency (in seconds) to wait before collecting rbe logs.
    working_dir(path): the working path.
    """
    timer_seconds = 0  # tracks how long this has been waiting
    sleep_period_seconds = 60  # in seconds
    while True:
      # If build has been running over the `collect_rbe_logs_latency`,
      # we will proactivelly collect rbe logs to avoid logs loss when
      # timeout happens.
      if timer_seconds > collect_rbe_logs_latency:
        self._collect_logs(working_dir)
        break
      # If rbe service started before and is not running now, it means
      # rbe has finished building and has been shutdown normally. For
      # This case, we just exit.
      if self._rbe_triggered and not self._started:
        break
      timer_seconds += sleep_period_seconds
      self.m.time.sleep(sleep_period_seconds)

  @contextmanager
  def __call__(
      self,
      reclient_path=None,
      config_path=None,
      working_path=None,
      collect_rbe_logs_latency=None,
  ):
    """Make context wrapping reproxy start/stop.

        Args:
          reclient_path (Path): if set, use this Path to reclient tools,
            otherwise, automatically use the Path to a loaded CIPD package.
          config_path (Path): The config file within the checkout.

        Raises:
            StepFailure or InfraFailure if it fails to start/stop.
        """
    # Spawns a backend process to wait and collect rbe build logs in case build timing out.
    self.m.futures.spawn(
        self.wait_and_collect_logs, collect_rbe_logs_latency, working_path
    )

    if reclient_path:
      self._reclient_path = reclient_path
    else:
      self._reclient_path = self._ensure_reclient_path

    assert self._reclient_path
    assert self._instance, "No RBE backend in builder properties."

    # Save current value of infra_step so we can reset it when we
    # yield back.
    is_infra_step = self.m.context.infra_step

    # Separate invocations of RBE tools should use unique paths to avoid
    # conflicts between log/metric files.
    working_dir = working_path

    with self.m.context(env=self._environment(working_dir), infra_steps=True):
      try:
        self._start(config_path=config_path)
        self.set_rbe_triggered(True)
        with self.m.context(infra_steps=is_infra_step):
          yield
      finally:
        self._stop(working_dir=working_dir, config_path=config_path)

  @property
  def _ensure_reclient_path(self):
    return self.m.cipd.ensure_tool(
        'infra/rbe/client/${platform}', RBE_VERSION, executable_path=''
    )

  @property
  def _bootstrap_path(self):
    assert self._reclient_path
    return self._reclient_path / "bootstrap"

  def _environment(self, working_dir):
    cache_dir = self.m.path.cache_dir / "rbe"
    deps_cache_dir = cache_dir / "deps"
    self.m.file.ensure_directory("create rbe cache dir", deps_cache_dir)
    rbe_server_address = 'pipe://reproxy.pipe' if self.m.platform.is_win else f"unix://{working_dir / 'reproxy.sock'}"
    # Environment. These values are used to modify the configuration in
    # Infrastructure when appropriate. These should not be used to modify
    # the behavior of the build in a meaningful way.
    return {
        "RBE_service": "remotebuildexecution.googleapis.com:443",
        # Override default instance. Infrastructure uses different RBE
        # backends for different environments.
        "RBE_instance": self._instance,
        # Set deps cache path.
        "RBE_enable_deps_cache": "true",
        "RBE_cache_dir": deps_cache_dir,
        "RBE_deps_cache_max_mb": _DEPS_CACHE_MAX_MB,
        # Set preferred log format for reproxy.
        "RBE_log_format": self._log_format,
        # Set log paths within the task working directory.
        "RBE_log_dir": working_dir,
        "RBE_output_dir": working_dir,
        "RBE_proxy_log_dir": working_dir,
        "RBE_server_address": rbe_server_address,
        "RBE_socket_path": working_dir / "reproxy.sock",
        # Use GCE credentials by default. Infrastructure presents an
        # emulated GCE metadata server in all environments for uniformity.
        "RBE_use_application_default_credentials": "false",
        "RBE_use_gce_credentials": "true",
    }

  @property
  def _reproxy_path(self):
    assert self._reclient_path
    return self._reclient_path / "reproxy"

  def _start(self, config_path):
    """Start reproxy."""
    assert not self._started

    with self.m.step.nest("setup remote execution"):
      cmd = [self._bootstrap_path, f"--re_proxy={self._reproxy_path}"]
      if config_path:
        cmd += [f"--cfg={config_path}"]
      self.m.step("start reproxy", cmd)
      self._started = True

  def _stop(self, working_dir, config_path):
    """Stop reproxy."""
    with self.m.step.nest("teardown remote execution"):
      cmd = [self._bootstrap_path, "--shutdown"]
      if config_path:
        cmd += [f"--cfg={config_path}"]
      try:
        self.m.step("stop reproxy", cmd)
        self._started = False
      finally:
        self._collect_logs(working_dir)

  def _collect_logs(self, working_dir):
    # reproxy/rewrapper/bootstrap record various log information in
    # a number of locations. At the time of this implementation,
    # the following log files are used:
    # 1. bootstrap.<INFO|WARNING|ERROR|FATAL> is standard logging
    # for `bootstrap`. Each log file includes more severe logging
    # levels, e.g. bootstrap.WARNING includes WARNING, ERROR & FATAL
    # log messages.
    # 2. rbe_metrics.txt is the text representation of a proto
    # message that describes metrics related to the rbe execution.
    # 3. reproxy.<INFO|WARNING|ERROR|FATAL> is standard logging for
    # `reproxy`. See notes in #1 for more details.
    # 4. reproxy_log.txt is the log file that records all info
    # about all actions that are processed through reproxy.
    # 5. reproxy_outerr.log is merged stderr/stdout of `reproxy`.
    # 6. rewrapper.<INFO|WARNING|ERROR|FATAL> is standard logging
    # for `rewrapper`. See notes in #1 for more details.
    # 7. reproxy-gomaip.<INFO|WARNING|ERROR|FATAL> is logging
    # for `gomaip` which is the input processor used by `reclient`
    # for finding dependencies of `clang` compile invocations.
    #
    # We extract the WARNING log messages for each portion of the
    # local rbe client as well as reproxy stdout/stderr and metrics
    # from the build by default. If further debugging is required,
    # you could increase the verbosity of log messages that we
    # retain in logdog or add the full reproxy_log.txt log file to
    # the list of outputs.
    with self.m.step.nest("collect rbe logs"):
      diagnostic_outputs = [
          "bootstrap.WARNING",
          "rbe_metrics.txt",
          "reproxy.WARNING",
          "reproxy-gomaip.WARNING",
          "reproxy_outerr.log",
          "rewrapper.WARNING",
      ]

      for output in diagnostic_outputs:
        path = working_dir / output
        # Not all builds use rbe, so it might not exist.
        self.m.path.mock_add_paths(path)
        if self.m.path.exists(path):
          # Read the log so it shows up in Milo for debugging.
          self.m.file.read_text(f"read {output}", path)

      # reproxy also produces a log file of all the actions which
      # it handles including more detailed debugging information
      # useful for debugging.
      rpl_ext = {
          "text": "rpl",
          "reducedtext": "rrpl",
      }[self._log_format]
      rpl_file_glob = f"*.{rpl_ext}"
      rpl_paths = self.m.file.glob_paths(
          name=f"find {rpl_ext} files",
          source=working_dir,
          pattern=rpl_file_glob,
          test_data=[
              f"reproxy_2021-10-16_22_52_23.{rpl_ext}",
          ],
      )

      # More than 1 rpl file is likely a bug but we can punt until
      # that breaks someone.
      for p in rpl_paths:
        self.m.path.mock_add_paths(p)
        # Not all builds use rbe, so it might not exist.
        if self.m.path.exists(p):
          # Read the log so it shows up in Milo for debugging.
          self.m.file.read_text(f"read {self.m.path.basename(p)}", p)

  def prepare_rbe_gn(self, rbe_working_path, gn):
    """Appends rbe server address to GN config."""
    rbe_server_address = 'pipe://reproxy.pipe' if self.m.platform.is_win else f'unix://{rbe_working_path}/reproxy.sock'
    gn.append(f'--rbe-server-address={rbe_server_address}')