Add 'pip cache' command.

src/pip/_internal/commands/__init__.py

@@ -60,6 +60,10 @@
         'pip._internal.commands.search', 'SearchCommand',
         'Search PyPI for packages.',
     )),
+    ('cache', CommandInfo(
+        'pip._internal.commands.cache', 'CacheCommand',
+        "Inspect and manage pip's caches.",
+    )),
     ('wheel', CommandInfo(
         'pip._internal.commands.wheel', 'WheelCommand',
         'Build wheels from your requirements.',

src/pip/_internal/commands/cache.py

@@ -0,0 +1,105 @@
+from __future__ import absolute_import
+
+import logging
+import os
+import textwrap
+
+from pip._internal.cli.base_command import Command
+from pip._internal.exceptions import CommandError
+from pip._internal.utils.filesystem import find_files
+
+logger = logging.getLogger(__name__)
+
+
+class CacheCommand(Command):
+    """
+    Inspect and manage pip's caches.
+
+    Subcommands:
+        info:
+            Show information about the caches.
+        list [name]:
+            List filenames of packages stored in the cache.
+        remove <pattern>:
+            Remove one or more package from the cache.
+            `pattern` can be a glob expression or a package name.
+        purge:
+            Remove all items from the cache.
+    """
+    actions = ['info', 'list', 'remove', 'purge']
+    name = 'cache'
+    usage = """
+      %prog <command>"""
+    summary = "View and manage which packages are available in pip's caches."
+
+    def __init__(self, *args, **kw):
+        super(CacheCommand, self).__init__(*args, **kw)
+
+    def run(self, options, args):
+        if not args:
+            raise CommandError('Please provide a subcommand.')
+
+        if args[0] not in self.actions:
+            raise CommandError('Invalid subcommand: %s' % args[0])
+
+        self.wheel_dir = os.path.join(options.cache_dir, 'wheels')
+
+        method = getattr(self, 'action_%s' % args[0])
+        return method(options, args[1:])
+
+    def action_info(self, options, args):
+        format_args = (options.cache_dir, len(self.find_wheels('*.whl')))
+        result = textwrap.dedent(
+            """\
+            Cache info:
+              Location: %s
+              Packages: %s""" % format_args
+        )
+        logger.info(result)
+
+    def action_list(self, options, args):
+        if args and args[0]:
+            pattern = args[0]
+        else:
+            pattern = '*'
+
+        files = self.find_wheels(pattern)
+        wheels = map(self._wheel_info, files)
+        wheels = sorted(set(wheels))
+
+        if not wheels:
+            logger.info('Nothing is currently cached.')
+            return
+
+        result = 'Current cache contents:\n'
+        for wheel in wheels:
+            result += ' - %s\n' % wheel
+        logger.info(result.strip())
+
+    def action_remove(self, options, args):
+        if not args:
+            raise CommandError('Please provide a pattern')
+
+        files = self.find_wheels(args[0])
+        if not files:
+            raise CommandError('No matching packages')
+
+        wheels = map(self._wheel_info, files)
+        result = 'Removing cached wheels for:\n'
+        for wheel in wheels:
+            result += '- %s\n' % wheel
+
+        for filename in files:
+            os.unlink(filename)
+        logger.info(result.strip())
+
+    def action_purge(self, options, args):
+        return self.action_remove(options, '*')
+
+    def _wheel_info(self, path):
+        filename = os.path.splitext(os.path.basename(path))[0]
+        name, version = filename.split('-')[0:2]
+        return '%s-%s' % (name, version)
+
+    def find_wheels(self, pattern):
+        return find_files(self.wheel_dir, pattern + '-*.whl')

src/pip/_internal/utils/filesystem.py

@@ -1,3 +1,4 @@
+import fnmatch
 import os
 import os.path
 import shutil
@@ -15,7 +16,7 @@
 from pip._internal.utils.typing import MYPY_CHECK_RUNNING
 
 if MYPY_CHECK_RUNNING:
-    from typing import BinaryIO, Iterator
+    from typing import BinaryIO, Iterator, List
 
     class NamedTemporaryFileResult(BinaryIO):
         @property
@@ -113,3 +114,14 @@ def replace(src, dest):
 
 else:
     replace = _replace_retry(os.replace)
+
+
+def find_files(path, pattern):
+    # type: (str, str) -> List[str]
+    """Returns a list of absolute paths of files beneath path, recursively,
+    with filenames which match the UNIX-style shell glob pattern."""
+    result = []  # type: List[str]
+    for root, dirs, files in os.walk(path):
+        matches = fnmatch.filter(files, pattern)
+        result.extend(os.path.join(root, f) for f in matches)
+    return result

tests/functional/test_cache.py

@@ -0,0 +1,60 @@
+import os
+import shutil
+
+from pip._internal.utils import appdirs
+
+
+def test_cache_info(script, monkeypatch):
+    result = script.pip('cache', 'info')
+
+    cache_dir = appdirs.user_cache_dir('pip')
+
+    assert 'Location: %s' % cache_dir in result.stdout
+    assert 'Packages: ' in result.stdout
+
+
+def test_cache_list(script, monkeypatch):
+    cache_dir = appdirs.user_cache_dir('pip')
+    wheel_cache_dir = os.path.join(cache_dir, 'wheels')
+    destination = os.path.join(wheel_cache_dir, 'arbitrary', 'pathname')
+    os.makedirs(destination)
+    with open(os.path.join(destination, 'yyy-1.2.3.whl'), 'w'):
+        pass
+    with open(os.path.join(destination, 'zzz-4.5.6.whl'), 'w'):
+        pass
+    result = script.pip('cache', 'list')
+    assert 'yyy-1.2.3' in result.stdout
+    assert 'zzz-4.5.6' in result.stdout
+    shutil.rmtree(os.path.join(wheel_cache_dir, 'arbitrary'))
+
+
+def test_cache_list_with_pattern(script, monkeypatch):
+    cache_dir = appdirs.user_cache_dir('pip')
+    wheel_cache_dir = os.path.join(cache_dir, 'wheels')
+    destination = os.path.join(wheel_cache_dir, 'arbitrary', 'pathname')
+    os.makedirs(destination)
+    with open(os.path.join(destination, 'yyy-1.2.3.whl'), 'w'):
+        pass
+    with open(os.path.join(destination, 'zzz-4.5.6.whl'), 'w'):
+        pass
+    result = script.pip('cache', 'list', 'zzz')
+    assert 'yyy-1.2.3' not in result.stdout
+    assert 'zzz-4.5.6' in result.stdout
+    shutil.rmtree(os.path.join(wheel_cache_dir, 'arbitrary'))
+
+
+def test_cache_remove(script, monkeypatch):
+    cache_dir = appdirs.user_cache_dir("pip")
+    wheel_cache_dir = os.path.join(cache_dir, "wheels")
+    destination = os.path.join(wheel_cache_dir, 'arbitrary', 'pathname')
+    os.makedirs(destination)
+    with open(os.path.join(wheel_cache_dir, "yyy-1.2.3.whl"), "w"):
+        pass
+    with open(os.path.join(wheel_cache_dir, "zzz-4.5.6.whl"), "w"):
+        pass
+
+    script.pip("cache", "remove", expect_error=True)
+    result = script.pip("cache", "remove", "zzz")
+    assert 'yyy-1.2.3' not in result.stdout
+    assert '- zzz-4.5.6' in result.stdout
+    shutil.rmtree(os.path.join(wheel_cache_dir, 'arbitrary'))