140 lines
4.8 KiB
Python
140 lines
4.8 KiB
Python
"""
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Application Profiler
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====================
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This module provides a middleware that profiles each request with the
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:mod:`cProfile` module. This can help identify bottlenecks in your code
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that may be slowing down your application.
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.. autoclass:: ProfilerMiddleware
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:copyright: 2007 Pallets
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:license: BSD-3-Clause
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"""
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import os.path
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import sys
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import time
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import typing as t
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from pstats import Stats
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try:
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from cProfile import Profile
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except ImportError:
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from profile import Profile # type: ignore
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if t.TYPE_CHECKING:
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from _typeshed.wsgi import StartResponse
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from _typeshed.wsgi import WSGIApplication
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from _typeshed.wsgi import WSGIEnvironment
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class ProfilerMiddleware:
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"""Wrap a WSGI application and profile the execution of each
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request. Responses are buffered so that timings are more exact.
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If ``stream`` is given, :class:`pstats.Stats` are written to it
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after each request. If ``profile_dir`` is given, :mod:`cProfile`
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data files are saved to that directory, one file per request.
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The filename can be customized by passing ``filename_format``. If
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it is a string, it will be formatted using :meth:`str.format` with
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the following fields available:
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- ``{method}`` - The request method; GET, POST, etc.
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- ``{path}`` - The request path or 'root' should one not exist.
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- ``{elapsed}`` - The elapsed time of the request.
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- ``{time}`` - The time of the request.
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If it is a callable, it will be called with the WSGI ``environ``
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dict and should return a filename.
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:param app: The WSGI application to wrap.
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:param stream: Write stats to this stream. Disable with ``None``.
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:param sort_by: A tuple of columns to sort stats by. See
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:meth:`pstats.Stats.sort_stats`.
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:param restrictions: A tuple of restrictions to filter stats by. See
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:meth:`pstats.Stats.print_stats`.
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:param profile_dir: Save profile data files to this directory.
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:param filename_format: Format string for profile data file names,
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or a callable returning a name. See explanation above.
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.. code-block:: python
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from werkzeug.middleware.profiler import ProfilerMiddleware
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app = ProfilerMiddleware(app)
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.. versionchanged:: 0.15
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Stats are written even if ``profile_dir`` is given, and can be
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disable by passing ``stream=None``.
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.. versionadded:: 0.15
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Added ``filename_format``.
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.. versionadded:: 0.9
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Added ``restrictions`` and ``profile_dir``.
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"""
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def __init__(
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self,
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app: "WSGIApplication",
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stream: t.TextIO = sys.stdout,
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sort_by: t.Iterable[str] = ("time", "calls"),
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restrictions: t.Iterable[t.Union[str, int, float]] = (),
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profile_dir: t.Optional[str] = None,
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filename_format: str = "{method}.{path}.{elapsed:.0f}ms.{time:.0f}.prof",
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) -> None:
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self._app = app
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self._stream = stream
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self._sort_by = sort_by
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self._restrictions = restrictions
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self._profile_dir = profile_dir
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self._filename_format = filename_format
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def __call__(
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self, environ: "WSGIEnvironment", start_response: "StartResponse"
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) -> t.Iterable[bytes]:
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response_body: t.List[bytes] = []
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def catching_start_response(status, headers, exc_info=None): # type: ignore
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start_response(status, headers, exc_info)
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return response_body.append
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def runapp() -> None:
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app_iter = self._app(
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environ, t.cast("StartResponse", catching_start_response)
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)
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response_body.extend(app_iter)
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if hasattr(app_iter, "close"):
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app_iter.close() # type: ignore
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profile = Profile()
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start = time.time()
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profile.runcall(runapp)
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body = b"".join(response_body)
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elapsed = time.time() - start
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if self._profile_dir is not None:
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if callable(self._filename_format):
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filename = self._filename_format(environ)
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else:
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filename = self._filename_format.format(
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method=environ["REQUEST_METHOD"],
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path=environ["PATH_INFO"].strip("/").replace("/", ".") or "root",
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elapsed=elapsed * 1000.0,
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time=time.time(),
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)
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filename = os.path.join(self._profile_dir, filename)
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profile.dump_stats(filename)
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if self._stream is not None:
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stats = Stats(profile, stream=self._stream)
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stats.sort_stats(*self._sort_by)
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print("-" * 80, file=self._stream)
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path_info = environ.get("PATH_INFO", "")
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print(f"PATH: {path_info!r}", file=self._stream)
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stats.print_stats(*self._restrictions)
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print(f"{'-' * 80}\n", file=self._stream)
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return [body]
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