Support installing charms with built wheels

lib/charms/layer/basic.py

@@ -221,6 +221,8 @@ def bootstrap_charm_deps():
             # if not cfg.get('use_venv', True) and pre_eoan:
             if not cfg.get('use_venv', True):
                 reinstall_flag = '--ignore-installed'
+            if not pkgs:
+                continue
             check_call([pip, 'install', '-U', reinstall_flag, '--no-index',
                         '--no-cache-dir', '-f', 'wheelhouse'] + list(pkgs),
                        env=_get_subprocess_env())
@@ -290,7 +292,18 @@ def _load_installed_versions(pip):
 def _load_wheelhouse_versions():
     versions = {}
     for wheel in glob('wheelhouse/*'):
-        pkg, ver = os.path.basename(wheel).rsplit('-', 1)
+        if wheel.endswith('.whl'):
+            # The binary wheel package format has a more stringent definition
+            # of how the filenames are formulated. As such we can safely
+            # extract the exact version string and store that.
+            #
+            # Reference:
+            # PEP 427 https://peps.python.org/pep-0427/#file-name-convention
+            # 'setuptools_scm-6.4.2-py3-none-any.whl'.split('-', 2) ==
+            #     ['setuptools_scm', '6.4.2', 'py3-none-any.whl']
+            pkg, ver, _ = os.path.basename(wheel).split('-', 2)
+        else:
+            pkg, ver = os.path.basename(wheel).rsplit('-', 1)
         # nb: LooseVersion ignores the file extension
         versions[pkg.replace('_', '-')] = LooseVersion(ver)
     return versions

tests/bundles/minimal.yaml

@@ -17,6 +17,10 @@ applications:
     series: focal
     charm: /tmp/charm-builds/minimal
     num_units: 1
+  minimal-binary-wheels-focal:
+    series: focal
+    charm: /tmp/charm-builds/minimal-binary-wheels
+    num_units: 1
   #minimal-no-venv-trusty:
     #series: trusty
     #charm: /tmp/charm-builds/minimal-no-venv

tox.ini

@@ -20,11 +20,13 @@ setenv = CHARM_LAYERS_DIR=/tmp/charm-builds/_tmp/layers
 passenv = HOME
 commands =
     /bin/rm -rf /tmp/charm-builds/_tmp /tmp/charm-builds/minimal
+    /bin/rm -rf /tmp/charm-builds/_tmp /tmp/charm-builds/minimal-binary-wheels
     /bin/rm -rf /tmp/charm-builds/_tmp /tmp/charm-builds/minimal-no-venv
     /bin/mkdir -p /tmp/charm-builds/_tmp/layers
     /bin/bash -c '/bin/ln -sf $(readlink --canonicalize {toxinidir}) /tmp/charm-builds/_tmp/layers/layer-basic'
     /bin/bash -c '/bin/ln -sf $(readlink --canonicalize {toxinidir}/tests/charm-minimal) /tmp/charm-builds/_tmp/layers/charm-minimal'
     charm-build --log-level DEBUG tests/charm-minimal
+    charm-build --log-level DEBUG --binary-wheels -n minimal-binary-wheels tests/charm-minimal
     charm-build --log-level DEBUG tests/charm-minimal-no-venv
     functest-run-suite --keep-model
 

unit_tests/test_lib_charms_layer_basic.py

@@ -11,25 +11,58 @@
 
 class TestLayerBasic(test_utils.BaseTestCase):
 
+    wheelhouse_glob = [
+        'python-dateutil-2.8.1.tar.gz',
+        'setuptools_scm-1.17.0.tar.gz',
+        'wheel-0.33.6.tar.gz',
+        'cffi-1.15.1'
+        '-cp38-cp38-manylinux_2_17_x86_64.manylinux2014_x86_64.whl',
+        'flit_core-3.7.1-py3-none-any.whl',
+    ]
+
     def test__load_wheelhouse_versions(self):
         self.patch_object(basic, 'glob')
         self.patch_object(basic, 'LooseVersion')
-        self.glob.return_value = [
-            'python-dateutil-2.8.1.tar.gz',
-            'setuptools_scm-1.17.0.tar.gz',
-            'wheel-0.33.6.tar.gz',
-        ]
+        self.glob.return_value = self.wheelhouse_glob
         self.assertDictEqual(
             basic._load_wheelhouse_versions(), {
                 'setuptools-scm': mock.ANY,
                 'python-dateutil': mock.ANY,
                 'wheel': mock.ANY,
+                'cffi': mock.ANY,
+                'flit-core': mock.ANY,
             })
         self.LooseVersion.assert_has_calls([
             mock.call('0.33.6.tar.gz'),
             mock.call('2.8.1.tar.gz'),
             mock.call('1.17.0.tar.gz'),
+            mock.call('1.15.1'),
+            mock.call('3.7.1'),
         ], any_order=True)
+        self.assertEqual(
+            self.LooseVersion.call_count,
+            5)
+
+    def test__add_back_versions(self):
+        self.patch_object(basic, 'glob')
+        self.glob.return_value = self.wheelhouse_glob
+        self.assertEqual(
+            basic._add_back_versions(
+                [
+                    'python-dateutil',
+                    'setuptools-scm',
+                    'wheel',
+                    'cffi',
+                    'flit-core',
+                ],
+                basic._load_wheelhouse_versions()),
+            [
+                'python-dateutil==2.8.1',
+                'setuptools-scm==1.17.0',
+                'wheel==0.33.6',
+                'cffi==1.15.1',
+                'flit-core==3.7.1'
+            ])
 
     @patch.dict('os.environ', {'LANG': 'su_SU.UTF-8'})
     def test__get_subprocess_env_lang_set(self):