Added telemetry test metric network.py.

tools/perf/metrics/network.py

+# Copyright 2014 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import base64
+import gzip
+import hashlib
+import io
+import logging
+import zlib
+
+from metrics import Metric
+from telemetry.page import page_measurement
+# All network metrics are Chrome only for now.
+from telemetry.core.backends.chrome import inspector_network
+from telemetry.core.timeline import recording_options
+
+
+class NetworkMetricException(page_measurement.MeasurementFailure):
+  pass
+
+
+class HTTPResponse(object):
+  """ Represents an HTTP response from a timeline event."""
+  def __init__(self, event):
+    self._response = (
+        inspector_network.InspectorNetworkResponseData.FromTimelineEvent(event))
+    self._content_length = None
+
+  @property
+  def response(self):
+    return self._response
+
+  @property
+  def url_signature(self):
+    return hashlib.md5(self.response.url).hexdigest()
+
+  @property
+  def content_length(self):
+    if self._content_length is None:
+      self._content_length = self.GetContentLength()
+    return self._content_length
+
+  @property
+  def has_original_content_length(self):
+    return 'X-Original-Content-Length' in self.response.headers
+
+  @property
+  def original_content_length(self):
+    if self.has_original_content_length:
+      return int(self.response.GetHeader('X-Original-Content-Length'))
+    return 0
+
+  @property
+  def data_saving_rate(self):
+    if (self.response.served_from_cache or
+        not self.has_original_content_length or
+        self.original_content_length <= 0):
+      return 0.0
+    return (float(self.original_content_length - self.content_length) /
+            self.original_content_length)
+
+  def GetContentLengthFromBody(self):
+    resp = self.response
+    body, base64_encoded = resp.GetBody()
+    if not body:
+      return 0
+    # The binary data like images, etc is base64_encoded. Decode it to get
+    # the actualy content length.
+    if base64_encoded:
+      decoded = base64.b64decode(body)
+      return len(decoded)
+
+    encoding = resp.GetHeader('Content-Encoding')
+    if not encoding:
+      return len(body)
+    # The response body returned from a timeline event is always decompressed.
+    # So, we need to compress it to get the actual content length if headers
+    # say so.
+    encoding = encoding.lower()
+    if encoding == 'gzip':
+      return self.GetGizppedBodyLength(body)
+    elif encoding == 'deflate':
+      return len(zlib.compress(body, 9))
+    else:
+      raise NetworkMetricException, (
+          'Unknown Content-Encoding %s for %s' % (encoding, resp.url))
+
+  def GetContentLength(self):
+    cl = 0
+    try:
+      cl = self.GetContentLengthFromBody()
+    except Exception, e:
+      resp = self.response
+      logging.warning('Fail to get content length for %s from body: %s',
+                      resp.url[:100], e)
+      cl_header = resp.GetHeader('Content-Length')
+      if cl_header:
+        cl = int(cl_header)
+      else:
+        body, _ = resp.GetBody()
+        if body:
+          cl = len(body)
+    return cl
+
+  @staticmethod
+  def GetGizppedBodyLength(body):
+    if not body:
+      return 0
+    bio = io.BytesIO()
+    try:
+      with gzip.GzipFile(fileobj=bio, mode="wb", compresslevel=9) as f:
+        f.write(body.encode('utf-8'))
+    except Exception, e:
+      logging.warning('Fail to gzip response body: %s', e)
+      raise e
+    return len(bio.getvalue())
+
+
+class NetworkMetric(Metric):
+  """A network metric based on timeline events."""
+
+  def __init__(self):
+    super(NetworkMetric, self).__init__()
+
+    # Whether to add detailed result for each sub-resource in a page.
+    self.add_result_for_resource = False
+    self.compute_data_saving = False
+    self._events = None
+
+  def Start(self, page, tab):
+    self._events = None
+    opts = recording_options.TimelineRecordingOptions()
+    opts.record_network = True
+    tab.StartTimelineRecording(opts)
+
+  def Stop(self, page, tab):
+    assert self._events is None
+    tab.StopTimelineRecording()
+
+  def IterResponses(self, tab):
+    if self._events is None:
+      self._events = tab.timeline_model.GetAllEventsOfName('HTTPResponse')
+    if len(self._events) == 0:
+      return
+    for e in self._events:
+      yield self.ResponseFromEvent(e)
+
+  def ResponseFromEvent(self, event):
+    return HTTPResponse(event)
+
+  def AddResults(self, tab, results):
+    content_length = 0
+    original_content_length = 0
+
+    for resp in self.IterResponses(tab):
+      # Ignore content length calculation for cache hit.
+      if resp.response.served_from_cache:
+        continue
+
+      resource = resp.response.url
+      resource_signature = resp.url_signature
+      cl = resp.content_length
+      if resp.has_original_content_length:
+        ocl = resp.original_content_length
+        if ocl < cl:
+          logging.warning('original content length (%d) is less than content '
+                        'lenght(%d) for resource %s', ocl, cl, resource)
+        if self.add_result_for_resource:
+          results.Add('resource_data_saving_' + resource_signature,
+                      'percent', resp.data_saving_rate * 100)
+          results.Add('resource_original_content_length_' + resource_signature,
+                      'bytes', ocl)
+        original_content_length += ocl
+      else:
+        original_content_length += cl
+      if self.add_result_for_resource:
+        results.Add(
+            'resource_content_length_' + resource_signature, 'bytes', cl)
+      content_length += cl
+
+    results.Add('content_length', 'bytes', content_length)
+    results.Add('original_content_length', 'bytes', original_content_length)
+    if self.compute_data_saving:
+      if (original_content_length > 0 and
+          original_content_length >= content_length):
+        saving = (float(original_content_length-content_length) * 100 /
+                  original_content_length)
+        results.Add('data_saving', 'percent', saving)
+      else:
+        results.Add('data_saving', 'percent', 0.0)