Add --root-dir option to cli #161

Also fix the root_dir arg of LinuxDistribution() to be an absolute
path to the root of a filesystem and not a path to /etc

Signed-off-by: Philippe Ombredanne <pombredanne@nexb.com>

distro.py

@@ -648,8 +648,10 @@ def __init__(self,
           uses an unexpected encoding.
         """
         self.root_dir = root_dir
+        self.etc_dir = os.path.join(root_dir, 'etc') \
+            if root_dir else _UNIXCONFDIR
         self.os_release_file = os_release_file or \
-            os.path.join(self.root_dir or _UNIXCONFDIR, _OS_RELEASE_BASENAME)
+            os.path.join(self.etc_dir, _OS_RELEASE_BASENAME)
         self.distro_release_file = distro_release_file or ''  # updated later
         self.include_lsb = include_lsb
         self.include_uname = include_uname
@@ -1099,7 +1101,7 @@ def _distro_release_info(self):
             return distro_info
         else:
             try:
-                basenames = os.listdir(self.root_dir or _UNIXCONFDIR)
+                basenames = os.listdir(self.etc_dir)
                 # We sort for repeatability in cases where there are multiple
                 # distro specific files; e.g. CentOS, Oracle, Enterprise all
                 # containing `redhat-release` on top of their own.
@@ -1129,8 +1131,7 @@ def _distro_release_info(self):
                     continue
                 match = _DISTRO_RELEASE_BASENAME_PATTERN.match(basename)
                 if match:
-                    filepath = os.path.join(
-                        self.root_dir or _UNIXCONFDIR, basename)
+                    filepath = os.path.join(self.etc_dir, basename)
                     distro_info = self._parse_distro_release_file(filepath)
                     if 'name' in distro_info:
                         # The name is always present if the pattern matches
@@ -1206,15 +1207,31 @@ def main():
         '-j',
         help="Output in machine readable format",
         action="store_true")
+
+    parser.add_argument(
+        '--root-dir',
+        '-r',
+        type=str,
+        dest='root_dir',
+        help="Path to the root filesystem directory (defaults to /)")
+
     args = parser.parse_args()
 
+    if args.root_dir:
+        dist = LinuxDistribution(
+            include_lsb=False,
+            include_uname=False,
+            root_dir=args.root_dir)
+    else:
+        dist = _distro
+
     if args.json:
-        logger.info(json.dumps(info(), indent=4, sort_keys=True))
+        logger.info(json.dumps(dist.info(), indent=4, sort_keys=True))
     else:
-        logger.info('Name: %s', name(pretty=True))
-        distribution_version = version(pretty=True)
+        logger.info('Name: %s', dist.name(pretty=True))
+        distribution_version = dist.version(pretty=True)
         logger.info('Version: %s', distribution_version)
-        distribution_codename = codename()
+        distribution_codename = dist.codename()
         logger.info('Codename: %s', distribution_codename)
 
 

tests/resources/cli/fedora30/etc/fedora-release

@@ -0,0 +1 @@
+Fedora release 30 (Thirty)

tests/resources/cli/fedora30/etc/os-release

@@ -0,0 +1,19 @@
+NAME=Fedora
+VERSION="30 (Thirty)"
+ID=fedora
+VERSION_ID=30
+VERSION_CODENAME=""
+PLATFORM_ID="platform:f30"
+PRETTY_NAME="Fedora 30 (Thirty)"
+ANSI_COLOR="0;34"
+LOGO=fedora-logo-icon
+CPE_NAME="cpe:/o:fedoraproject:fedora:30"
+HOME_URL="https://fedoraproject.org/"
+DOCUMENTATION_URL="https://docs.fedoraproject.org/en-US/fedora/30/system-administrators-guide/"
+SUPPORT_URL="https://fedoraproject.org/wiki/Communicating_and_getting_help"
+BUG_REPORT_URL="https://bugzilla.redhat.com/"
+REDHAT_BUGZILLA_PRODUCT="Fedora"
+REDHAT_BUGZILLA_PRODUCT_VERSION=30
+REDHAT_SUPPORT_PRODUCT="Fedora"
+REDHAT_SUPPORT_PRODUCT_VERSION=30
+PRIVACY_POLICY_URL="https://fedoraproject.org/wiki/Legal:PrivacyPolicy"

tests/resources/cli/fedora30/etc/redhat-release

@@ -0,0 +1 @@
+Fedora release 30 (Thirty)

tests/resources/cli/fedora30/etc/system-release

@@ -0,0 +1 @@
+Fedora release 30 (Thirty)

tests/test_distro.py

@@ -71,6 +71,10 @@ def test_cli_for_coverage_yuch(self):
         self._parse('distro')
         self._parse('distro -j')
 
+    def test_cli_can_parse_root_dir_args(self):
+        root_dir = os.path.join(RESOURCES, 'cli', 'fedora30')
+        self._parse('distro --root-dir {}'.format(root_dir))
+
     def test_cli(self):
         command = [sys.executable, '-m', 'distro']
         desired_output = 'Name: ' + distro.name(pretty=True)
@@ -85,6 +89,33 @@ def test_cli_json(self):
         command = [sys.executable, '-m', 'distro', '-j']
         assert ast.literal_eval(self._run(command)) == distro.info()
 
+    def test_cli_with_root_dir(self):
+        root_dir = os.path.join(RESOURCES, 'cli', 'fedora30')
+        command = [sys.executable, '-m', 'distro', '--root-dir', root_dir]
+        desired_output = 'Name: Fedora 30 (Thirty)\nVersion: 30\nCodename: \n'
+        assert desired_output == self._run(command)
+
+    def test_cli_with_root_dir_as_json(self):
+        import json
+        root_dir = os.path.join(RESOURCES, 'cli', 'fedora30')
+        command = [sys.executable, '-m', 'distro', '-j', '--root-dir', root_dir]
+        desired_output = '''
+        {
+            "codename": "",
+            "id": "fedora",
+            "like": "",
+            "version": "30",
+            "version_parts": {
+                "build_number": "",
+                "major": "30",
+                "minor": ""
+            }
+        }
+        '''
+        desired_output = json.loads(desired_output)
+        results = json.loads(self._run(command))
+        assert desired_output == results
+
 
 @pytest.mark.skipif(not IS_LINUX, reason='Irrelevant on non-linux')
 class DistroTestCase(object):
@@ -439,7 +470,7 @@ class TestWithRootDir(TestOSRelease):
 
     def setup_method(self, test_method):
         dist = test_method.__name__.split('_')[1]
-        root_dir = os.path.join(DISTROS_DIR, dist, 'etc')
+        root_dir = os.path.join(DISTROS_DIR, dist)
         self.distro = distro.LinuxDistribution(
             os_release_file='',
             distro_release_file='non',
@@ -2075,6 +2106,6 @@ def test_repr(self):
         repr_str = repr(distro._distro)
         assert "LinuxDistribution" in repr_str
         for attr in MODULE_DISTRO.__dict__.keys():
-            if attr == 'root_dir':
+            if attr in ('root_dir', 'etc_dir'):
                 continue
             assert attr + '=' in repr_str