{{ message }}
forked from sqlalchemy/sqlalchemy
-
Notifications
You must be signed in to change notification settings - Fork 0
Expand file tree
/
Copy pathgenerate_proxy_methods.py
More file actions
446 lines (360 loc) · 14.2 KB
/
Copy pathgenerate_proxy_methods.py
File metadata and controls
446 lines (360 loc) · 14.2 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
"""Generate static proxy code for SQLAlchemy classes that proxy other
objects.
This tool is run at source code authoring / commit time whenever we add new
methods to engines/connections/sessions that need to be generically proxied by
scoped_session or asyncio. The generated code is part of what's committed
to source just as though we typed it all by hand.
The original "proxy" class was scoped_session. Then with asyncio, all the
asyncio objects are essentially "proxy" objects as well; while all the methods
that are "async" needed to be written by hand, there's lots of other attributes
and methods that are proxied exactly.
To eliminate redundancy, all of these classes made use of the
@langhelpers.create_proxy_methods() decorator which at runtime would read a
selected list of methods and attributes from the proxied class and generate new
methods and properties descriptors on the proxying class; this way the proxy
would have all the same methods signatures / attributes / docstrings consumed
by Sphinx and look just like the proxied class.
Then mypy and typing came along, which don't care about runtime generated code
and never will. So this script takes that same
@langhelpers.create_proxy_methods() decorator, keeps its public interface just
as is, and uses it to generate all the code and docs in those proxy classes
statically, as though we sat there and spent seven hours typing it all by hand.
The runtime code generation part is removed from ``create_proxy_methods()``.
Now we have static code that is perfectly consumable by all the typing tools
and we also reduce import time a bit.
A similar approach is used in Alembic where a dynamic approach towards creating
alembic "ops" was enhanced to generate a .pyi stubs file statically for
consumption by typing tools.
Note that the usual OO approach of having a common interface class with
concrete subtypes doesn't really solve any problems here; the concrete subtypes
must still list out all methods, arguments, typing annotations, and docstrings,
all of which is copied by this script rather than requiring it all be
typed by hand.
.. versionadded:: 2.0
"""
# mypy: ignore-errors
from __future__ import annotations
import collections
import importlib
import inspect
import os
from pathlib import Path
import re
import sys
from tempfile import NamedTemporaryFile
import textwrap
from typing import Any
from typing import Callable
from typing import Dict
from typing import Iterable
from typing import TextIO
from typing import Tuple
from typing import Type
from typing import TypeVar
from sqlalchemy import util
from sqlalchemy.util import compat
from sqlalchemy.util import langhelpers
from sqlalchemy.util.langhelpers import format_argspec_plus
from sqlalchemy.util.langhelpers import inject_docstring_text
from sqlalchemy.util.tool_support import code_writer_cmd
is_posix = os.name == "posix"
sys.path.append(str(Path(__file__).parent.parent))
class _repr_sym:
__slots__ = ("sym",)
def __init__(self, sym: str):
self.sym = sym
def __repr__(self) -> str:
return self.sym
classes: collections.defaultdict[
str, Dict[str, Tuple[Any, ...]]
] = collections.defaultdict(dict)
_T = TypeVar("_T", bound="Any")
def create_proxy_methods(
target_cls: Type[Any],
target_cls_sphinx_name: str,
proxy_cls_sphinx_name: str,
classmethods: Iterable[str] = (),
methods: Iterable[str] = (),
attributes: Iterable[str] = (),
use_intermediate_variable: Iterable[str] = (),
) -> Callable[[Type[_T]], Type[_T]]:
"""A class decorator that will copy attributes to a proxy class.
The class to be instrumented must define a single accessor "_proxied".
"""
def decorate(cls: Type[_T]) -> Type[_T]:
# collect the class as a separate step. since the decorator
# is called as a result of imports, the order in which classes
# are collected (like in asyncio) can't be well controlled. however,
# the proxies (specifically asyncio session and asyncio scoped_session)
# have to be generated in dependency order, so run them in order in a
# second step.
classes[cls.__module__][cls.__name__] = (
target_cls,
target_cls_sphinx_name,
proxy_cls_sphinx_name,
classmethods,
methods,
attributes,
use_intermediate_variable,
cls,
)
return cls
return decorate
def _grab_overloads(fn):
"""grab @overload entries for a function, assuming black-formatted
code ;) so that we can do a simple regex
"""
# functions that use @util.deprecated and whatnot will have a string
# generated fn. we can look at __wrapped__ but these functions don't
# have any overloads in any case right now so skip
if fn.__code__.co_filename == "<string>":
return []
with open(fn.__code__.co_filename) as f:
lines = [l for i, l in zip(range(fn.__code__.co_firstlineno), f)]
lines.reverse()
output = []
current_ov = []
for line in lines[1:]:
current_ov.append(line)
outside_block_match = re.match(r"^\w", line)
if outside_block_match:
current_ov[:] = []
break
fn_match = re.match(r"^ (?: )?(?:async )?def (.*)\(", line)
if fn_match and fn_match.group(1) != fn.__name__:
current_ov[:] = []
break
ov_match = re.match(r"^ (?: )?@overload$", line)
if ov_match:
output.append("".join(reversed(current_ov)))
current_ov[:] = []
if re.match(r"^ if (?:typing\.)?TYPE_CHECKING:", line):
output.append(line)
current_ov[:] = []
output.reverse()
return output
def process_class(
buf: TextIO,
target_cls: Type[Any],
target_cls_sphinx_name: str,
proxy_cls_sphinx_name: str,
classmethods: Iterable[str],
methods: Iterable[str],
attributes: Iterable[str],
use_intermediate_variable: Iterable[str],
cls: Type[Any],
):
sphinx_symbol_match = re.match(r":class:`(.+)`", target_cls_sphinx_name)
if not sphinx_symbol_match:
raise Exception(
f"Couldn't match sphinx class identifier from "
f"target_cls_sphinx_name f{target_cls_sphinx_name!r}. Currently "
'this program expects the form ":class:`_<prefix>.<clsname>`"'
)
sphinx_symbol = sphinx_symbol_match.group(1)
require_intermediate = set(use_intermediate_variable)
def instrument(buf: TextIO, name: str, clslevel: bool = False) -> None:
fn = getattr(target_cls, name)
overloads = _grab_overloads(fn)
for overload in overloads:
buf.write(overload)
spec = compat.inspect_getfullargspec(fn)
iscoroutine = inspect.iscoroutinefunction(fn)
if spec.defaults or spec.kwonlydefaults:
elem = list(spec)
if spec.defaults:
new_defaults = tuple(
_repr_sym("util.EMPTY_DICT")
if df is util.EMPTY_DICT
else df
for df in spec.defaults
)
elem[3] = new_defaults
if spec.kwonlydefaults:
new_kwonlydefaults = {
name: _repr_sym("util.EMPTY_DICT")
if df is util.EMPTY_DICT
else df
for name, df in spec.kwonlydefaults.items()
}
elem[5] = new_kwonlydefaults
spec = compat.FullArgSpec(*elem)
caller_argspec = format_argspec_plus(spec, grouped=False)
metadata = {
"name": fn.__name__,
"async": "async " if iscoroutine else "",
"await": "await " if iscoroutine else "",
"apply_pos_proxied": caller_argspec["apply_pos_proxied"],
"target_cls_name": target_cls.__name__,
"apply_kw_proxied": caller_argspec["apply_kw_proxied"],
"grouped_args": caller_argspec["grouped_args"],
"self_arg": caller_argspec["self_arg"],
"doc": textwrap.indent(
inject_docstring_text(
fn.__doc__,
textwrap.indent(
".. container:: class_bases\n\n"
f" Proxied for the {target_cls_sphinx_name} "
"class on \n"
f" behalf of the {proxy_cls_sphinx_name} "
"class.",
" ",
),
1,
),
" ",
).lstrip(),
}
if fn.__name__ in require_intermediate:
metadata["line_prefix"] = "result ="
metadata["after_line"] = "return result\n"
else:
metadata["line_prefix"] = "return"
metadata["after_line"] = ""
if clslevel:
code = (
'''\
@classmethod
%(async)sdef %(name)s%(grouped_args)s:
r"""%(doc)s\n """ # noqa: E501
%(line_prefix)s %(await)s%(target_cls_name)s.%(name)s(%(apply_kw_proxied)s)
%(after_line)s
'''
% metadata
)
else:
code = (
'''\
%(async)sdef %(name)s%(grouped_args)s:
r"""%(doc)s\n """ # noqa: E501
%(line_prefix)s %(await)s%(self_arg)s._proxied.%(name)s(%(apply_kw_proxied)s)
%(after_line)s
''' # noqa: E501
% metadata
)
buf.write(textwrap.indent(code, " "))
def makeprop(buf: TextIO, name: str) -> None:
attr = target_cls.__dict__.get(name, None)
return_type = target_cls.__annotations__.get(name, "Any")
assert isinstance(return_type, str), (
"expected string annotations, is from __future__ "
"import annotations set up?"
)
if attr is not None:
if isinstance(attr, property):
readonly = attr.fset is None
elif isinstance(attr, langhelpers.generic_fn_descriptor):
readonly = True
else:
readonly = not hasattr(attr, "__set__")
doc = textwrap.indent(
inject_docstring_text(
attr.__doc__,
textwrap.indent(
".. container:: class_bases\n\n"
f" Proxied for the {target_cls_sphinx_name} "
"class \n"
f" on behalf of the {proxy_cls_sphinx_name} "
"class.",
" ",
),
1,
),
" ",
).lstrip()
else:
readonly = False
doc = (
f"Proxy for the :attr:`{sphinx_symbol}.{name}` "
"attribute \n"
f" on behalf of the {proxy_cls_sphinx_name} "
"class.\n"
)
code = (
"@property\n"
"def %(name)s(self) -> %(return_type)s:\n"
' r"""%(doc)s\n """ # noqa: E501\n\n'
" return self._proxied.%(name)s\n\n"
) % {"name": name, "doc": doc, "return_type": return_type}
if not readonly:
code += (
"@%(name)s.setter\n"
"def %(name)s(self, attr: %(return_type)s) -> None:\n"
" self._proxied.%(name)s = attr\n\n"
) % {"name": name, "return_type": return_type}
buf.write(textwrap.indent(code, " "))
for meth in methods:
instrument(buf, meth)
for prop in attributes:
makeprop(buf, prop)
for prop in classmethods:
instrument(buf, prop, clslevel=True)
def process_module(modname: str, filename: str, cmd: code_writer_cmd) -> str:
class_entries = classes[modname]
# use tempfile in same path as the module, or at least in the
# current working directory, so that black / zimports use
# local pyproject.toml
with NamedTemporaryFile(
mode="w",
delete=False,
suffix=".py",
) as buf, open(filename) as orig_py:
in_block = False
current_clsname = None
for line in orig_py:
m = re.match(r" # START PROXY METHODS (.+)$", line)
if m:
current_clsname = m.group(1)
args = class_entries[current_clsname]
cmd.write_status(
f"Generating attributes for class {current_clsname}\n"
)
in_block = True
buf.write(line)
buf.write(
"\n # code within this block is "
"**programmatically, \n"
" # statically generated** by"
f" tools/{os.path.basename(__file__)}\n\n"
)
process_class(buf, *args)
if line.startswith(f" # END PROXY METHODS {current_clsname}"):
in_block = False
if not in_block:
buf.write(line)
return buf.name
def run_module(modname: str, cmd: code_writer_cmd) -> None:
cmd.write_status(f"importing module {modname}\n")
mod = importlib.import_module(modname)
destination_path = mod.__file__
assert destination_path is not None
tempfile = process_module(modname, destination_path, cmd)
cmd.run_zimports(tempfile)
cmd.run_black(tempfile)
cmd.write_output_file_from_tempfile(tempfile, destination_path)
def main(cmd: code_writer_cmd) -> None:
from sqlalchemy import util
from sqlalchemy.util import langhelpers
util.create_proxy_methods = (
langhelpers.create_proxy_methods
) = create_proxy_methods
for entry in entries:
if cmd.args.module in {"all", entry}:
run_module(entry, cmd)
entries = [
"sqlalchemy.orm.scoping",
"sqlalchemy.ext.asyncio.engine",
"sqlalchemy.ext.asyncio.session",
"sqlalchemy.ext.asyncio.scoping",
]
if __name__ == "__main__":
cmd = code_writer_cmd(__file__)
with cmd.add_arguments() as parser:
parser.add_argument(
"--module",
choices=entries + ["all"],
default="all",
help="Which file to generate. Default is to regenerate all files",
)
with cmd.run_program():
main(cmd)
You can’t perform that action at this time.