Edit: profiling.py
# testing/profiling.py # Copyright (C) 2005-2025 the SQLAlchemy authors and contributors # <see AUTHORS file> # # This module is part of SQLAlchemy and is released under # the MIT License: https://www.opensource.org/licenses/mit-license.php # mypy: ignore-errors """Profiling support for unit and performance tests. These are special purpose profiling methods which operate in a more fine-grained way than nose's profiling plugin. """ from __future__ import annotations import collections import contextlib import os import platform import pstats import re import sys from . import config from .util import gc_collect from ..util import has_compiled_ext try: import cProfile except ImportError: cProfile = None _profile_stats = None """global ProfileStatsFileInstance. plugin_base assigns this at the start of all tests. """ _current_test = None """String id of current test. plugin_base assigns this at the start of each test using _start_current_test. """ def _start_current_test(id_): global _current_test _current_test = id_ if _profile_stats.force_write: _profile_stats.reset_count() class ProfileStatsFile: """Store per-platform/fn profiling results in a file. There was no json module available when this was written, but now the file format which is very deterministically line oriented is kind of handy in any case for diffs and merges. """ def __init__(self, filename, sort="cumulative", dump=None): self.force_write = ( config.options is not None and config.options.force_write_profiles ) self.write = self.force_write or ( config.options is not None and config.options.write_profiles ) self.fname = os.path.abspath(filename) self.short_fname = os.path.split(self.fname)[-1] self.data = collections.defaultdict( lambda: collections.defaultdict(dict) ) self.dump = dump self.sort = sort self._read() if self.write: # rewrite for the case where features changed, # etc. self._write() @property def platform_key(self): dbapi_key = config.db.name + "_" + config.db.driver if config.db.name == "sqlite" and config.db.dialect._is_url_file_db( config.db.url ): dbapi_key += "_file" # keep it at 2.7, 3.1, 3.2, etc. for now. py_version = ".".join([str(v) for v in sys.version_info[0:2]]) platform_tokens = [ platform.machine(), platform.system().lower(), platform.python_implementation().lower(), py_version, dbapi_key, ] platform_tokens.append("dbapiunicode") _has_cext = has_compiled_ext() platform_tokens.append(_has_cext and "cextensions" or "nocextensions") return "_".join(platform_tokens) def has_stats(self): test_key = _current_test return ( test_key in self.data and self.platform_key in self.data[test_key] ) def result(self, callcount): test_key = _current_test per_fn = self.data[test_key] per_platform = per_fn[self.platform_key] if "counts" not in per_platform: per_platform["counts"] = counts = [] else: counts = per_platform["counts"] if "current_count" not in per_platform: per_platform["current_count"] = current_count = 0 else: current_count = per_platform["current_count"] has_count = len(counts) > current_count if not has_count: counts.append(callcount) if self.write: self._write() result = None else: result = per_platform["lineno"], counts[current_count] per_platform["current_count"] += 1 return result def reset_count(self): test_key = _current_test # since self.data is a defaultdict, don't access a key # if we don't know it's there first. if test_key not in self.data: return per_fn = self.data[test_key] if self.platform_key not in per_fn: return per_platform = per_fn[self.platform_key] if "counts" in per_platform: per_platform["counts"][:] = [] def replace(self, callcount): test_key = _current_test per_fn = self.data[test_key] per_platform = per_fn[self.platform_key] counts = per_platform["counts"] current_count = per_platform["current_count"] if current_count < len(counts): counts[current_count - 1] = callcount else: counts[-1] = callcount if self.write: self._write() def _header(self): return ( "# %s\n" "# This file is written out on a per-environment basis.\n" "# For each test in aaa_profiling, the corresponding " "function and \n" "# environment is located within this file. " "If it doesn't exist,\n" "# the test is skipped.\n" "# If a callcount does exist, it is compared " "to what we received. \n" "# assertions are raised if the counts do not match.\n" "# \n" "# To add a new callcount test, apply the function_call_count \n" "# decorator and re-run the tests using the --write-profiles \n" "# option - this file will be rewritten including the new count.\n" "# \n" ) % (self.fname) def _read(self): try: profile_f = open(self.fname) except OSError: return for lineno, line in enumerate(profile_f): line = line.strip() if not line or line.startswith("#"): continue test_key, platform_key, counts = line.split() per_fn = self.data[test_key] per_platform = per_fn[platform_key] c = [int(count) for count in counts.split(",")] per_platform["counts"] = c per_platform["lineno"] = lineno + 1 per_platform["current_count"] = 0 profile_f.close() def _write(self): print("Writing profile file %s" % self.fname) profile_f = open(self.fname, "w") profile_f.write(self._header()) for test_key in sorted(self.data): per_fn = self.data[test_key] profile_f.write("\n# TEST: %s\n\n" % test_key) for platform_key in sorted(per_fn): per_platform = per_fn[platform_key] c = ",".join(str(count) for count in per_platform["counts"]) profile_f.write("%s %s %s\n" % (test_key, platform_key, c)) profile_f.close() def function_call_count(variance=0.05, times=1, warmup=0): """Assert a target for a test case's function call count. The main purpose of this assertion is to detect changes in callcounts for various functions - the actual number is not as important. Callcounts are stored in a file keyed to Python version and OS platform information. This file is generated automatically for new tests, and versioned so that unexpected changes in callcounts will be detected. """ # use signature-rewriting decorator function so that pytest fixtures # still work on py27. In Py3, update_wrapper() alone is good enough, # likely due to the introduction of __signature__. from sqlalchemy.util import decorator @decorator def wrap(fn, *args, **kw): for warm in range(warmup): fn(*args, **kw) timerange = range(times) with count_functions(variance=variance): for time in timerange: rv = fn(*args, **kw) return rv return wrap @contextlib.contextmanager def count_functions(variance=0.05): if cProfile is None: raise config._skip_test_exception("cProfile is not installed") if not _profile_stats.has_stats() and not _profile_stats.write: config.skip_test( "No profiling stats available on this " "platform for this function. Run tests with " "--write-profiles to add statistics to %s for " "this platform." % _profile_stats.short_fname ) gc_collect() pr = cProfile.Profile() pr.enable() # began = time.time() yield # ended = time.time() pr.disable() # s = StringIO() stats = pstats.Stats(pr, stream=sys.stdout) # timespent = ended - began callcount = stats.total_calls expected = _profile_stats.result(callcount) if expected is None: expected_count = None else: line_no, expected_count = expected print("Pstats calls: %d Expected %s" % (callcount, expected_count)) stats.sort_stats(*re.split(r"[, ]", _profile_stats.sort)) stats.print_stats() if _profile_stats.dump: base, ext = os.path.splitext(_profile_stats.dump) test_name = _current_test.split(".")[-1] dumpfile = "%s_%s%s" % (base, test_name, ext or ".profile") stats.dump_stats(dumpfile) print("Dumped stats to file %s" % dumpfile) # stats.print_callers() if _profile_stats.force_write: _profile_stats.replace(callcount) elif expected_count: deviance = int(callcount * variance) failed = abs(callcount - expected_count) > deviance if failed: if _profile_stats.write: _profile_stats.replace(callcount) else: raise AssertionError( "Adjusted function call count %s not within %s%% " "of expected %s, platform %s. Rerun with " "--write-profiles to " "regenerate this callcount." % ( callcount, (variance * 100), expected_count, _profile_stats.platform_key, ) )
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