Use importlib.metadata to read requirements (#12088)

* Pull runtime dep checks into their own module
* Reimplement `check_requirements` using `importlib`

I've tried to make this clearer. We start by working out which of
Synapse's requirements we need to be installed here and now. I was
surprised that there wasn't an easier way to see which packages were
installed by a given extra.

I've pulled out the error messages into functions that deal with "is
this for an extra or not". And I've rearranged the loop over two
different sets of requirements into one loop with a "must be instaled"
flag.

I hope you agree that this is clearer.

* Test cases
This commit is contained in:
David Robertson 2022-03-01 17:44:41 +00:00 committed by GitHub
parent 4d6b6c17c8
commit 313581e4e9
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13 changed files with 237 additions and 115 deletions

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@ -17,14 +17,7 @@
import itertools
import logging
from typing import List, Set
from pkg_resources import (
DistributionNotFound,
Requirement,
VersionConflict,
get_provider,
)
from typing import Set
logger = logging.getLogger(__name__)
@ -90,6 +83,8 @@ REQUIREMENTS = [
# ijson 3.1.4 fixes a bug with "." in property names
"ijson>=3.1.4",
"matrix-common~=1.1.0",
# For runtime introspection of our dependencies
"packaging~=21.3",
]
CONDITIONAL_REQUIREMENTS = {
@ -144,102 +139,6 @@ def list_requirements():
return list(set(REQUIREMENTS) | ALL_OPTIONAL_REQUIREMENTS)
class DependencyException(Exception):
@property
def message(self):
return "\n".join(
[
"Missing Requirements: %s" % (", ".join(self.dependencies),),
"To install run:",
" pip install --upgrade --force %s" % (" ".join(self.dependencies),),
"",
]
)
@property
def dependencies(self):
for i in self.args[0]:
yield '"' + i + '"'
def check_requirements(for_feature=None):
deps_needed = []
errors = []
if for_feature:
reqs = CONDITIONAL_REQUIREMENTS[for_feature]
else:
reqs = REQUIREMENTS
for dependency in reqs:
try:
_check_requirement(dependency)
except VersionConflict as e:
deps_needed.append(dependency)
errors.append(
"Needed %s, got %s==%s"
% (
dependency,
e.dist.project_name, # type: ignore[attr-defined] # noqa
e.dist.version, # type: ignore[attr-defined] # noqa
)
)
except DistributionNotFound:
deps_needed.append(dependency)
if for_feature:
errors.append(
"Needed %s for the '%s' feature but it was not installed"
% (dependency, for_feature)
)
else:
errors.append("Needed %s but it was not installed" % (dependency,))
if not for_feature:
# Check the optional dependencies are up to date. We allow them to not be
# installed.
OPTS: List[str] = sum(CONDITIONAL_REQUIREMENTS.values(), [])
for dependency in OPTS:
try:
_check_requirement(dependency)
except VersionConflict as e:
deps_needed.append(dependency)
errors.append(
"Needed optional %s, got %s==%s"
% (
dependency,
e.dist.project_name, # type: ignore[attr-defined] # noqa
e.dist.version, # type: ignore[attr-defined] # noqa
)
)
except DistributionNotFound:
# If it's not found, we don't care
pass
if deps_needed:
for err in errors:
logging.error(err)
raise DependencyException(deps_needed)
def _check_requirement(dependency_string):
"""Parses a dependency string, and checks if the specified requirement is installed
Raises:
VersionConflict if the requirement is installed, but with the the wrong version
DistributionNotFound if nothing is found to provide the requirement
"""
req = Requirement.parse(dependency_string)
# first check if the markers specify that this requirement needs installing
if req.marker is not None and not req.marker.evaluate():
# not required for this environment
return
get_provider(req)
if __name__ == "__main__":
import sys