gm/rebaseline_server/server.py

#!/usr/bin/python

"""
Copyright 2013 Google Inc.

Use of this source code is governed by a BSD-style license that can be
found in the LICENSE file.

HTTP server for our HTML rebaseline viewer.
"""

# System-level imports
import argparse
import BaseHTTPServer
import json
import logging
import os
import posixpath
import re
import shutil
import socket
import sys
import thread
import time
import urlparse

# Imports from within Skia
#
# We need to add the 'tools' directory, so that we can import svn.py within
# that directory.
# Make sure that the 'tools' dir is in the PYTHONPATH, but add it at the *end*
# so any dirs that are already in the PYTHONPATH will be preferred.
PARENT_DIRECTORY = os.path.dirname(os.path.realpath(__file__))
TRUNK_DIRECTORY = os.path.dirname(os.path.dirname(PARENT_DIRECTORY))
TOOLS_DIRECTORY = os.path.join(TRUNK_DIRECTORY, 'tools')
if TOOLS_DIRECTORY not in sys.path:
  sys.path.append(TOOLS_DIRECTORY)
import svn

# Imports from local dir
import results

ACTUALS_SVN_REPO = 'http://skia-autogen.googlecode.com/svn/gm-actual'
PATHSPLIT_RE = re.compile('/([^/]+)/(.+)')
TRUNK_DIRECTORY = os.path.dirname(os.path.dirname(os.path.dirname(
    os.path.realpath(__file__))))
EXPECTATIONS_DIR = os.path.join(TRUNK_DIRECTORY, 'expectations', 'gm')
GENERATED_IMAGES_ROOT = os.path.join(PARENT_DIRECTORY, 'static',
                                     'generated-images')

# A simple dictionary of file name extensions to MIME types. The empty string
# entry is used as the default when no extension was given or if the extension
# has no entry in this dictionary.
MIME_TYPE_MAP = {'': 'application/octet-stream',
                 'html': 'text/html',
                 'css': 'text/css',
                 'png': 'image/png',
                 'js': 'application/javascript',
                 'json': 'application/json'
                 }

DEFAULT_ACTUALS_DIR = '.gm-actuals'
DEFAULT_PORT = 8888

_HTTP_HEADER_CONTENT_LENGTH = 'Content-Length'
_HTTP_HEADER_CONTENT_TYPE = 'Content-Type'

_SERVER = None   # This gets filled in by main()

def _get_routable_ip_address():
  """Returns routable IP address of this host (the IP address of its network
     interface that would be used for most traffic, not its localhost
     interface).  See http://stackoverflow.com/a/166589 """
  sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
  sock.connect(('8.8.8.8', 80))
  host = sock.getsockname()[0]
  sock.close()
  return host

def _create_svn_checkout(dir_path, repo_url):
  """Creates local checkout of an SVN repository at the specified directory
  path, returning an svn.Svn object referring to the local checkout.

  Args:
    dir_path: path to the local checkout; if this directory does not yet exist,
              it will be created and the repo will be checked out into it
    repo_url: URL of SVN repo to check out into dir_path (unless the local
              checkout already exists)
  Returns: an svn.Svn object referring to the local checkout.
  """
  local_checkout = svn.Svn(dir_path)
  if not os.path.isdir(dir_path):
    os.makedirs(dir_path)
    local_checkout.Checkout(repo_url, '.')
  return local_checkout


class Server(object):
  """ HTTP server for our HTML rebaseline viewer. """

  def __init__(self,
               actuals_dir=DEFAULT_ACTUALS_DIR,
               port=DEFAULT_PORT, export=False, editable=True,
               reload_seconds=0):
    """
    Args:
      actuals_dir: directory under which we will check out the latest actual
                   GM results
      port: which TCP port to listen on for HTTP requests
      export: whether to allow HTTP clients on other hosts to access this server
      editable: whether HTTP clients are allowed to submit new baselines
      reload_seconds: polling interval with which to check for new results;
                      if 0, don't check for new results at all
    """
    self._actuals_dir = actuals_dir
    self._port = port
    self._export = export
    self._editable = editable
    self._reload_seconds = reload_seconds
    self._actuals_repo = _create_svn_checkout(
        dir_path=actuals_dir, repo_url=ACTUALS_SVN_REPO)

    # We only update the expectations dir if the server was run with a
    # nonzero --reload argument; otherwise, we expect the user to maintain
    # her own expectations as she sees fit.
    #
    # TODO(epoger): Use git instead of svn to update the expectations dir, since
    # the Skia repo is moving to git.
    # When we make that change, we will have to update the entire workspace,
    # not just the expectations dir, because git only operates on the repo
    # as a whole.
    # And since Skia uses depot_tools to manage its dependencies, we will have
    # to run "gclient sync" rather than a raw "git pull".
    if reload_seconds:
      self._expectations_repo = svn.Svn(EXPECTATIONS_DIR)
    else:
      self._expectations_repo = None

  def is_exported(self):
    """ Returns true iff HTTP clients on other hosts are allowed to access
    this server. """
    return self._export

  def is_editable(self):
    """ Returns true iff HTTP clients are allowed to submit new baselines. """
    return self._editable

  def reload_seconds(self):
    """ Returns the result reload period in seconds, or 0 if we don't reload
    results. """
    return self._reload_seconds

  def update_results(self):
    """ Create or update self.results, based on the expectations in
    EXPECTATIONS_DIR and the latest actuals from skia-autogen.
    """
    logging.info('Updating actual GM results in %s from SVN repo %s ...' % (
        self._actuals_dir, ACTUALS_SVN_REPO))
    self._actuals_repo.Update('.')

    if self._expectations_repo:
      logging.info(
          'Updating expected GM results in %s ...' % EXPECTATIONS_DIR)
      self._expectations_repo.Update('.')

    logging.info(
          ('Parsing results from actuals in %s and expectations in %s, '
          + 'and generating pixel diffs (may take a while) ...') % (
          self._actuals_dir, EXPECTATIONS_DIR))
    self.results = results.Results(
        actuals_root=self._actuals_dir,
        expected_root=EXPECTATIONS_DIR,
        generated_images_root=GENERATED_IMAGES_ROOT)

  def _result_reloader(self):
    """ If --reload argument was specified, reload results at the appropriate
    interval.
    """
    while self._reload_seconds:
      time.sleep(self._reload_seconds)
      self.update_results()

  def run(self):
    self.update_results()
    thread.start_new_thread(self._result_reloader, ())

    if self._export:
      server_address = ('', self._port)
      host = _get_routable_ip_address()
      if self._editable:
        logging.warning('Running with combination of "export" and "editable" '
                        'flags.  Users on other machines will '
                        'be able to modify your GM expectations!')
    else:
      host = '127.0.0.1'
      server_address = (host, self._port)
    http_server = BaseHTTPServer.HTTPServer(server_address, HTTPRequestHandler)
    logging.info('Ready for requests on http://%s:%d' % (
        host, http_server.server_port))
    http_server.serve_forever()


class HTTPRequestHandler(BaseHTTPServer.BaseHTTPRequestHandler):
  """ HTTP request handlers for various types of queries this server knows
      how to handle (static HTML and Javascript, expected/actual results, etc.)
  """
  def do_GET(self):
    """ Handles all GET requests, forwarding them to the appropriate
        do_GET_* dispatcher. """
    if self.path == '' or self.path == '/' or self.path == '/index.html' :
      self.redirect_to('/static/index.html')
      return
    if self.path == '/favicon.ico' :
      self.redirect_to('/static/favicon.ico')
      return

    # All requests must be of this form:
    #   /dispatcher/remainder
    # where 'dispatcher' indicates which do_GET_* dispatcher to run
    # and 'remainder' is the remaining path sent to that dispatcher.
    normpath = posixpath.normpath(self.path)
    (dispatcher_name, remainder) = PATHSPLIT_RE.match(normpath).groups()
    dispatchers = {
      'results': self.do_GET_results,
      'static': self.do_GET_static,
    }
    dispatcher = dispatchers[dispatcher_name]
    dispatcher(remainder)

  def do_GET_results(self, type):
    """ Handle a GET request for GM results.

    Args:
      type: string indicating which set of results to return;
            must be one of the results.RESULTS_* constants
    """
    logging.debug('do_GET_results: sending results of type "%s"' % type)
    try:
      # Since we must make multiple calls to the Results object, grab a
      # reference to it in case it is updated to point at a new Results
      # object within another thread.
      #
      # TODO(epoger): Rather than using a global variable for the handler
      # to refer to the Server object, make Server a subclass of
      # HTTPServer, and then it could be available to the handler via
      # the handler's .server instance variable.
      results_obj = _SERVER.results
      response_dict = results_obj.get_results_of_type(type)
      time_updated = results_obj.get_timestamp()

      response_dict['header'] = {
        # Timestamps:
        # 1. when this data was last updated
        # 2. when the caller should check back for new data (if ever)
        #
        # We only return these timestamps if the --reload argument was passed;
        # otherwise, we have no idea when the expectations were last updated
        # (we allow the user to maintain her own expectations as she sees fit).
        'timeUpdated': time_updated if _SERVER.reload_seconds() else None,
        'timeNextUpdateAvailable': (
            (time_updated+_SERVER.reload_seconds()) if _SERVER.reload_seconds()
            else None),

        # The type we passed to get_results_of_type()
        'type': type,

        # Hash of testData, which the client must return with any edits--
        # this ensures that the edits were made to a particular dataset.
        'dataHash': str(hash(repr(response_dict['testData']))),

        # Whether the server will accept edits back.
        'isEditable': _SERVER.is_editable(),

        # Whether the service is accessible from other hosts.
        'isExported': _SERVER.is_exported(),
      }
      self.send_json_dict(response_dict)
    except:
      self.send_error(404)
      raise

  def do_GET_static(self, path):
    """ Handle a GET request for a file under the 'static' directory.
    Only allow serving of files within the 'static' directory that is a
    filesystem sibling of this script.

    Args:
      path: path to file (under static directory) to retrieve
    """
    # Strip arguments ('?resultsToLoad=all') from the path
    path = urlparse.urlparse(path).path

    logging.debug('do_GET_static: sending file "%s"' % path)
    static_dir = os.path.realpath(os.path.join(PARENT_DIRECTORY, 'static'))
    full_path = os.path.realpath(os.path.join(static_dir, path))
    if full_path.startswith(static_dir):
      self.send_file(full_path)
    else:
      logging.error(
          'Attempted do_GET_static() of path [%s] outside of static dir [%s]'
          % (full_path, static_dir))
      self.send_error(404)

  def do_POST(self):
    """ Handles all POST requests, forwarding them to the appropriate
        do_POST_* dispatcher. """
    # All requests must be of this form:
    #   /dispatcher
    # where 'dispatcher' indicates which do_POST_* dispatcher to run.
    normpath = posixpath.normpath(self.path)
    dispatchers = {
      '/edits': self.do_POST_edits,
    }
    try:
      dispatcher = dispatchers[normpath]
      dispatcher()
      self.send_response(200)
    except:
      self.send_error(404)
      raise

  def do_POST_edits(self):
    """ Handle a POST request with modifications to GM expectations, in this
    format:

    {
      'oldResultsType': 'all',    # type of results that the client loaded
                                  # and then made modifications to
      'oldResultsHash': 39850913, # hash of results when the client loaded them
                                  # (ensures that the client and server apply
                                  # modifications to the same base)
      'modifications': [
        {
          'builder': 'Test-Android-Nexus10-MaliT604-Arm7-Debug',
          'test': 'strokerect',
          'config': 'gpu',
          'expectedHashType': 'bitmap-64bitMD5',
          'expectedHashDigest': '1707359671708613629',
        },
        ...
      ],
    }

    Raises an Exception if there were any problems.
    """
    if not _SERVER.is_editable():
      raise Exception('this server is not running in --editable mode')

    content_type = self.headers[_HTTP_HEADER_CONTENT_TYPE]
    if content_type != 'application/json;charset=UTF-8':
      raise Exception('unsupported %s [%s]' % (
          _HTTP_HEADER_CONTENT_TYPE, content_type))

    content_length = int(self.headers[_HTTP_HEADER_CONTENT_LENGTH])
    json_data = self.rfile.read(content_length)
    data = json.loads(json_data)
    logging.debug('do_POST_edits: received new GM expectations data [%s]' %
                  data)

    # Since we must make multiple calls to the Results object, grab a
    # reference to it in case it is updated to point at a new Results
    # object within another thread.
    results_obj = _SERVER.results
    oldResultsType = data['oldResultsType']
    oldResults = results_obj.get_results_of_type(oldResultsType)
    oldResultsHash = str(hash(repr(oldResults['testData'])))
    if oldResultsHash != data['oldResultsHash']:
      raise Exception('results of type "%s" changed while the client was '
                      'making modifications. The client should reload the '
                      'results and submit the modifications again.' %
                      oldResultsType)
    results_obj.edit_expectations(data['modifications'])

    # Now that the edits have been committed, update results to reflect them.
    _SERVER.update_results()

  def redirect_to(self, url):
    """ Redirect the HTTP client to a different url.

    Args:
      url: URL to redirect the HTTP client to
    """
    self.send_response(301)
    self.send_header('Location', url)
    self.end_headers()

  def send_file(self, path):
    """ Send the contents of the file at this path, with a mimetype based
        on the filename extension.

    Args:
      path: path of file whose contents to send to the HTTP client
    """
    # Grab the extension if there is one
    extension = os.path.splitext(path)[1]
    if len(extension) >= 1:
      extension = extension[1:]

    # Determine the MIME type of the file from its extension
    mime_type = MIME_TYPE_MAP.get(extension, MIME_TYPE_MAP[''])

    # Open the file and send it over HTTP
    if os.path.isfile(path):
      with open(path, 'rb') as sending_file:
        self.send_response(200)
        self.send_header('Content-type', mime_type)
        self.end_headers()
        self.wfile.write(sending_file.read())
    else:
      self.send_error(404)

  def send_json_dict(self, json_dict):
    """ Send the contents of this dictionary in JSON format, with a JSON
        mimetype.

    Args:
      json_dict: dictionary to send
    """
    self.send_response(200)
    self.send_header('Content-type', 'application/json')
    self.end_headers()
    json.dump(json_dict, self.wfile)


def main():
  logging.basicConfig(level=logging.INFO)
  parser = argparse.ArgumentParser()
  parser.add_argument('--actuals-dir',
                    help=('Directory into which we will check out the latest '
                          'actual GM results. If this directory does not '
                          'exist, it will be created. Defaults to %(default)s'),
                    default=DEFAULT_ACTUALS_DIR)
  parser.add_argument('--editable', action='store_true',
                      help=('Allow HTTP clients to submit new baselines.'))
  parser.add_argument('--export', action='store_true',
                      help=('Instead of only allowing access from HTTP clients '
                            'on localhost, allow HTTP clients on other hosts '
                            'to access this server.  WARNING: doing so will '
                            'allow users on other hosts to modify your '
                            'GM expectations, if combined with --editable.'))
  parser.add_argument('--port', type=int,
                      help=('Which TCP port to listen on for HTTP requests; '
                            'defaults to %(default)s'),
                      default=DEFAULT_PORT)
  parser.add_argument('--reload', type=int,
                      help=('How often (a period in seconds) to update the '
                            'results.  If specified, both expected and actual '
                            'results will be updated.  '
                            'By default, we do not reload at all, and you '
                            'must restart the server to pick up new data.'),
                      default=0)
  args = parser.parse_args()
  global _SERVER
  _SERVER = Server(actuals_dir=args.actuals_dir,
                   port=args.port, export=args.export, editable=args.editable,
                   reload_seconds=args.reload)
  _SERVER.run()

if __name__ == '__main__':
  main()