Set up CodSpeed (#7831)

* Set up CodSpeed

* CodSpeed: update permissions

.github/workflows/codspeed.yml

@@ -0,0 +1,45 @@
+---
+name: codspeed
+
+on:
+    push:
+        branches:
+            - master
+    pull_request:
+        paths:
+            - scrapy/**
+            - tests/benchmarks/**
+            - .github/workflows/codspeed.yml
+            - tox.ini
+    workflow_dispatch:
+
+concurrency:
+    group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
+    cancel-in-progress: true
+
+permissions: {}
+
+jobs:
+    benchmark:
+        runs-on: ubuntu-latest
+        permissions:
+            contents: read
+            id-token: write  # OIDC authentication with CodSpeed
+
+        steps:
+            - uses: actions/checkout@v6
+
+            - name: Set up Python 3.14
+              uses: actions/setup-python@v6
+              with:
+                  python-version: '3.14'
+            - name: Install dependencies
+              run: |
+                  pip install --upgrade pip
+                  pip install --upgrade tox
+                  tox -n -e benchmark
+            - name: Run benchmarks
+              uses: CodSpeedHQ/action@v4
+              with:
+                  mode: simulation
+                  run: tox -e benchmark

conftest.py

@@ -54,6 +54,9 @@ if not H2_ENABLED:
 if find_spec("httpx2") is None and find_spec("httpx") is None:
     collect_ignore.append("scrapy/core/downloader/handlers/_httpx.py")
 
+if find_spec("pytest_codspeed") is None:
+    collect_ignore.append("tests/benchmarks")
+
 
 def pytest_addoption(parser, pluginmanager):
     if pluginmanager.hasplugin("twisted"):

tests/benchmarks/__init__.py

@@ -0,0 +1,28 @@
+from __future__ import annotations
+
+from typing import TYPE_CHECKING, Any
+
+from scrapy.utils.test import get_crawler
+
+if TYPE_CHECKING:
+    from scrapy import Spider
+    from scrapy.crawler import Crawler
+
+
+def crawl(spidercls: type[Spider], settings: dict[str, Any], **kwargs: Any) -> Crawler:
+    """Run a crawl to completion and return its crawler.
+
+    Unlike the rest of the test suite, benchmarks run without ``pytest-twisted``
+    and drive the reactor themselves, since the code being measured must be
+    callable synchronously by ``pytest-codspeed``.
+    """
+    from twisted.internet import reactor
+
+    crawler = get_crawler(spidercls, settings)
+    result: list[Any] = []
+    crawler.crawl(**kwargs).addBoth(result.append)
+    while not result:
+        reactor.iterate(0.001)
+    if isinstance(result[0], BaseException):
+        raise result[0]
+    return crawler

tests/benchmarks/conftest.py

@@ -0,0 +1,27 @@
+from __future__ import annotations
+
+from typing import TYPE_CHECKING
+
+import pytest
+
+from scrapy.utils.reactor import install_reactor
+
+if TYPE_CHECKING:
+    from collections.abc import Generator
+
+
+@pytest.fixture(scope="session", autouse=True)
+def running_reactor() -> Generator[None]:
+    install_reactor("twisted.internet.asyncioreactor.AsyncioSelectorReactor")
+
+    from twisted.internet import reactor
+
+    # Marks the reactor as running without blocking, so that crawls can be
+    # driven with reactor.iterate(), see tests.benchmarks.crawl().
+    reactor.startRunning(installSignalHandlers=False)
+
+    yield
+
+    reactor.stop()
+    # Lets the shutdown event triggers run, e.g. to join the thread pool.
+    reactor.iterate(0)

tests/benchmarks/test_benchmark_crawl.py

@@ -0,0 +1,64 @@
+from __future__ import annotations
+
+from typing import TYPE_CHECKING, Any
+from urllib.parse import urlencode
+
+import pytest
+
+from scrapy import Field, Item, Request, Spider
+from scrapy.linkextractors import LinkExtractor
+from tests.benchmarks import crawl
+
+if TYPE_CHECKING:
+    from collections.abc import AsyncIterator
+
+    from pytest_codspeed import BenchmarkFixture  # type: ignore[import-not-found]
+
+    from scrapy.http import Response
+    from tests.mockserver.http import MockServer
+
+pytest.importorskip("pytest_codspeed", reason="Benchmarks require pytest-codspeed")
+
+PAGES = 100
+LINKS_PER_PAGE = 5
+
+
+class _Page(Item):
+    url = Field()
+    anchors = Field()
+
+
+class _FollowSpider(Spider):
+    name = "benchmark"
+    url: str
+    link_extractor = LinkExtractor()
+
+    async def start(self) -> AsyncIterator[Any]:
+        yield Request(self.url, dont_filter=True)
+
+    def parse(self, response: Response) -> Any:
+        yield _Page(
+            url=response.url,
+            anchors=response.css("a::text").getall(),
+        )
+        for link in self.link_extractor.extract_links(response):  # type: ignore[arg-type]
+            yield Request(link.url)
+
+
+class _Pipeline:
+    def process_item(self, item: Any) -> Any:
+        return item
+
+
+def test_benchmark_crawl(benchmark: BenchmarkFixture, mockserver: MockServer) -> None:
+    """Crawl of a set of interlinked pages served over HTTP."""
+    query = urlencode({"total": PAGES, "show": LINKS_PER_PAGE, "order": "desc"})
+    url = mockserver.url(f"/follow?{query}")
+    settings = {"ITEM_PIPELINES": {_Pipeline: 100}, "LOG_ENABLED": False}
+
+    def run() -> None:
+        crawler = crawl(_FollowSpider, settings, url=url)
+        assert crawler.stats
+        assert crawler.stats.get_value("item_scraped_count") == PAGES + 1
+
+    benchmark(run)

tox.ini

@@ -30,6 +30,7 @@ envlist =
     botocore
     pypy3
     pypy3-extra-deps
+    benchmark
 minversion = 1.7.0
 
 [test-requirements]
@@ -317,3 +318,20 @@ setenv =
     {[min]setenv}
 commands =
     pytest {posargs:--cov-config=pyproject.toml --cov=scrapy --cov-report=xml --cov-report= tests --junitxml=min-botocore.junit.xml -o junit_family=legacy} -m requires_botocore
+
+
+# CPU benchmarks, tracked on CodSpeed.
+#
+# pytest-twisted is left out on purpose: benchmarked code must be callable
+# synchronously, so tests/benchmarks drives the reactor itself.
+
+[testenv:benchmark]
+basepython = python3.14
+deps =
+    pytest >= 8.4.1
+    pytest-codspeed
+passenv =
+    *codspeed*
+    *ci*
+commands =
+    pytest {posargs:tests/benchmarks} --codspeed --codspeed-mode=simulation