cpython/Lib/packaging/depgraph.py

273 lines
9.5 KiB
Python

"""Class and functions dealing with dependencies between distributions.
This module provides a DependencyGraph class to represent the
dependencies between distributions. Auxiliary functions can generate a
graph, find reverse dependencies, and print a graph in DOT format.
"""
import sys
from io import StringIO
from packaging.errors import PackagingError
from packaging.version import VersionPredicate, IrrationalVersionError
__all__ = ['DependencyGraph', 'generate_graph', 'dependent_dists',
'graph_to_dot']
class DependencyGraph:
"""
Represents a dependency graph between distributions.
The dependency relationships are stored in an ``adjacency_list`` that maps
distributions to a list of ``(other, label)`` tuples where ``other``
is a distribution and the edge is labeled with ``label`` (i.e. the version
specifier, if such was provided). Also, for more efficient traversal, for
every distribution ``x``, a list of predecessors is kept in
``reverse_list[x]``. An edge from distribution ``a`` to
distribution ``b`` means that ``a`` depends on ``b``. If any missing
dependencies are found, they are stored in ``missing``, which is a
dictionary that maps distributions to a list of requirements that were not
provided by any other distributions.
"""
def __init__(self):
self.adjacency_list = {}
self.reverse_list = {}
self.missing = {}
def add_distribution(self, distribution):
"""Add the *distribution* to the graph.
:type distribution: :class:`packaging.database.Distribution` or
:class:`packaging.database.EggInfoDistribution`
"""
self.adjacency_list[distribution] = []
self.reverse_list[distribution] = []
self.missing[distribution] = []
def add_edge(self, x, y, label=None):
"""Add an edge from distribution *x* to distribution *y* with the given
*label*.
:type x: :class:`packaging.database.Distribution` or
:class:`packaging.database.EggInfoDistribution`
:type y: :class:`packaging.database.Distribution` or
:class:`packaging.database.EggInfoDistribution`
:type label: ``str`` or ``None``
"""
self.adjacency_list[x].append((y, label))
# multiple edges are allowed, so be careful
if not x in self.reverse_list[y]:
self.reverse_list[y].append(x)
def add_missing(self, distribution, requirement):
"""
Add a missing *requirement* for the given *distribution*.
:type distribution: :class:`packaging.database.Distribution` or
:class:`packaging.database.EggInfoDistribution`
:type requirement: ``str``
"""
self.missing[distribution].append(requirement)
def _repr_dist(self, dist):
return '%s %s' % (dist.name, dist.metadata['Version'])
def repr_node(self, dist, level=1):
"""Prints only a subgraph"""
output = []
output.append(self._repr_dist(dist))
for other, label in self.adjacency_list[dist]:
dist = self._repr_dist(other)
if label is not None:
dist = '%s [%s]' % (dist, label)
output.append(' ' * level + str(dist))
suboutput = self.repr_node(other, level + 1)
subs = suboutput.split('\n')
output.extend(subs[1:])
return '\n'.join(output)
def __repr__(self):
"""Representation of the graph"""
output = []
for dist, adjs in self.adjacency_list.items():
output.append(self.repr_node(dist))
return '\n'.join(output)
def graph_to_dot(graph, f, skip_disconnected=True):
"""Writes a DOT output for the graph to the provided file *f*.
If *skip_disconnected* is set to ``True``, then all distributions
that are not dependent on any other distribution are skipped.
:type f: has to support ``file``-like operations
:type skip_disconnected: ``bool``
"""
disconnected = []
f.write("digraph dependencies {\n")
for dist, adjs in graph.adjacency_list.items():
if len(adjs) == 0 and not skip_disconnected:
disconnected.append(dist)
for other, label in adjs:
if not label is None:
f.write('"%s" -> "%s" [label="%s"]\n' %
(dist.name, other.name, label))
else:
f.write('"%s" -> "%s"\n' % (dist.name, other.name))
if not skip_disconnected and len(disconnected) > 0:
f.write('subgraph disconnected {\n')
f.write('label = "Disconnected"\n')
f.write('bgcolor = red\n')
for dist in disconnected:
f.write('"%s"' % dist.name)
f.write('\n')
f.write('}\n')
f.write('}\n')
def generate_graph(dists):
"""Generates a dependency graph from the given distributions.
:parameter dists: a list of distributions
:type dists: list of :class:`packaging.database.Distribution` and
:class:`packaging.database.EggInfoDistribution` instances
:rtype: a :class:`DependencyGraph` instance
"""
graph = DependencyGraph()
provided = {} # maps names to lists of (version, dist) tuples
# first, build the graph and find out the provides
for dist in dists:
graph.add_distribution(dist)
provides = (dist.metadata['Provides-Dist'] +
dist.metadata['Provides'] +
['%s (%s)' % (dist.name, dist.metadata['Version'])])
for p in provides:
comps = p.strip().rsplit(" ", 1)
name = comps[0]
version = None
if len(comps) == 2:
version = comps[1]
if len(version) < 3 or version[0] != '(' or version[-1] != ')':
raise PackagingError('Distribution %s has ill formed' \
'provides field: %s' % (dist.name, p))
version = version[1:-1] # trim off parenthesis
if not name in provided:
provided[name] = []
provided[name].append((version, dist))
# now make the edges
for dist in dists:
requires = dist.metadata['Requires-Dist'] + dist.metadata['Requires']
for req in requires:
try:
predicate = VersionPredicate(req)
except IrrationalVersionError:
# XXX compat-mode if cannot read the version
name = req.split()[0]
predicate = VersionPredicate(name)
name = predicate.name
if not name in provided:
graph.add_missing(dist, req)
else:
matched = False
for version, provider in provided[name]:
try:
match = predicate.match(version)
except IrrationalVersionError:
# XXX small compat-mode
if version.split(' ') == 1:
match = True
else:
match = False
if match:
graph.add_edge(dist, provider, req)
matched = True
break
if not matched:
graph.add_missing(dist, req)
return graph
def dependent_dists(dists, dist):
"""Recursively generate a list of distributions from *dists* that are
dependent on *dist*.
:param dists: a list of distributions
:param dist: a distribution, member of *dists* for which we are interested
"""
if not dist in dists:
raise ValueError('The given distribution is not a member of the list')
graph = generate_graph(dists)
dep = [dist] # dependent distributions
fringe = graph.reverse_list[dist] # list of nodes we should inspect
while not len(fringe) == 0:
node = fringe.pop()
dep.append(node)
for prev in graph.reverse_list[node]:
if not prev in dep:
fringe.append(prev)
dep.pop(0) # remove dist from dep, was there to prevent infinite loops
return dep
def main():
from packaging.database import get_distributions
tempout = StringIO()
try:
old = sys.stderr
sys.stderr = tempout
try:
dists = list(get_distributions(use_egg_info=True))
graph = generate_graph(dists)
finally:
sys.stderr = old
except Exception as e:
tempout.seek(0)
tempout = tempout.read()
print('Could not generate the graph')
print(tempout)
print(e)
sys.exit(1)
for dist, reqs in graph.missing.items():
if len(reqs) > 0:
print("Warning: Missing dependencies for %s:" % dist.name,
", ".join(reqs))
# XXX replace with argparse
if len(sys.argv) == 1:
print('Dependency graph:')
print(' ', repr(graph).replace('\n', '\n '))
sys.exit(0)
elif len(sys.argv) > 1 and sys.argv[1] in ('-d', '--dot'):
if len(sys.argv) > 2:
filename = sys.argv[2]
else:
filename = 'depgraph.dot'
with open(filename, 'w') as f:
graph_to_dot(graph, f, True)
tempout.seek(0)
tempout = tempout.read()
print(tempout)
print('Dot file written at "%s"' % filename)
sys.exit(0)
else:
print('Supported option: -d [filename]')
sys.exit(1)
if __name__ == '__main__':
main()