[Policy] Consolidate check() across policies

There is a common theme for new policies to subclass an existing one and
just update the `check()` method. In almost all instances, the `check()`
method remains almost entirely the same, simply changing a release file
name or string.

Reduce repeating ourselves by consolidating this into the base
`LinuxPolicy.check()`, and leverage per-policy class attributes
`os_release_file`, `os_release_name`, and `os_release_id`. The first of
which will enable a policy if the specified file is found. Failing that,
`os_release_name` is used to check the `NAME` field in
`/etc/os-release`, and `os_release_id` is used to check the `ID` field
in the same file if the name pattern does not match (or is not set).

Note that we do _not_ check the `ID_LIKE` field.

This allows a policy to be defined with as little as something like the
following:

```
class MyPolicy(LinuxPolicy):
    vendor = 'Myself'
    os_release_file = '/etc/mylinux-release'
    os_release_name = 'MyLinux'
    os_release_id ='mynix'
```

Resolves: #1934

Signed-off-by: Jake Hunsaker <[email protected]>

sos/collector/sosnode.py

@@ -160,7 +160,7 @@ def set_node_manifest(self, manifest):
         """
         self.manifest = manifest
         self.manifest.add_field('hostname', self._hostname)
-        self.manifest.add_field('policy', self.host.distro)
+        self.manifest.add_field('policy', self.host.os_release_name)
         self.manifest.add_field('sos_version', self.sos_info['version'])
         self.manifest.add_field('final_sos_command', '')
         self.manifest.add_field('transport', self._transport.name)
@@ -390,14 +390,14 @@ def determine_host_policy(self):
         """
         if self.local:
             self.log_info(
-                f"using local policy {self.commons['policy'].distro}")
+                f"using local policy {self.commons['policy'].os_release_name}")
             return self.commons['policy']
         host = load(cache={}, sysroot=self.opts.sysroot, init=InitSystem(),
                     probe_runtime=True,
                     remote_exec=self._transport.run_command,
                     remote_check=self.read_file('/etc/os-release'))
         if host:
-            self.log_info(f"loaded policy {host.distro} for host")
+            self.log_info(f"loaded policy {host.os_release_name} for host")
             return host
         self.log_error('Unable to determine host installation. Ignoring node')
         raise UnsupportedHostException

sos/component.py

@@ -131,7 +131,7 @@ def __init__(self, parser, parsed_args, cmdline_args):
             self.manifest.add_field('compression', '')
             self.manifest.add_field('tmpdir', self.tmpdir)
             self.manifest.add_field('tmpdir_fs_type', self.tmpfstype)
-            self.manifest.add_field('policy', self.policy.distro)
+            self.manifest.add_field('policy', self.policy.os_release_name)
             self.manifest.add_section('components')
 
     def load_local_policy(self):

sos/policies/__init__.py

@@ -42,6 +42,7 @@ def load(cache={}, sysroot=None, init=None, probe_runtime=True,
                 cache['policy'] = policy(sysroot=sysroot, init=init,
                                          probe_runtime=probe_runtime,
                                          remote_exec=remote_exec)
+                break
 
     if sys.platform != 'linux':
         raise Exception("SoS is not supported on this platform")
@@ -75,8 +76,16 @@ class Policy():
                             SoSTransport in use
     :type remote_exec:      ``SoSTranport.run_command()``
 
-    :cvar distro: The name of the distribution the Policy represents
-    :vartype distro: ``str``
+    :cvar os_release_name: The name of the distribution as it appears in the
+                           os-release (-esque) file for the NAME variable.
+    :vartype os_release_name: ``str``
+
+    :cvar os_release_id: The ID variable to match in a distribution's release
+                         file.
+    :vartype os_release_id: ``str``
+
+    :cvar os_release_file: The filepath of the distribution's os-release file
+    :vartype os_release_file: ``str``
 
     :cvar vendor: The name of the vendor producing the distribution
     :vartype vendor: ``str``
@@ -97,7 +106,7 @@ class Policy():
 
     msg = _("""\
 This command will collect system configuration and diagnostic information \
-from this %(distro)s system.
+from this %(os_release_name)s system.
 
 For more information on %(vendor)s visit:
 
@@ -111,8 +120,9 @@ class Policy():
 
 %(vendor_text)s
 """)
-
-    distro = "Unknown"
+    os_release_name = 'Unknown'
+    os_release_file = ''
+    os_release_id = ''
     vendor = "Unknown"
     vendor_urls = [('Example URL', "http://www.example.com/")]
     vendor_text = ""
@@ -459,8 +469,8 @@ def display_results(self, archive, directory, checksum, archivestat=None,
 
     def get_msg(self):
         """This method is used to prepare the preamble text to display to
-        the user in non-batch mode. If your policy sets self.distro that
-        text will be substituted accordingly. You can also override this
+        the user in non-batch mode. If your policy sets self.os_release_name,
+        that text will be substituted accordingly. You can also override this
         method to do something more complicated.
 
         :returns: Formatted banner message string
@@ -471,7 +481,8 @@ def get_msg(self):
         else:
             changes_text = "No changes will be made to system configuration."
         width = 72
-        _msg = self.msg % {'distro': self.distro, 'vendor': self.vendor,
+        _msg = self.msg % {'os_release_name': self.os_release_name,
+                           'vendor': self.vendor,
                            'vendor_urls': self._fmt_vendor_urls(),
                            'vendor_text': self.vendor_text,
                            'tmpdir': self.commons['tmpdir'],

sos/policies/distros/__init__.py

@@ -40,6 +40,7 @@
 except ImportError:
     BOTO3_LOADED = False
 
+OS_RELEASE = "/etc/os-release"
 # Container environment variables for detecting if we're in a container
 ENV_CONTAINER = 'container'
 ENV_HOST_SYSROOT = 'HOST'
@@ -48,11 +49,14 @@
 class LinuxPolicy(Policy):
     """This policy is meant to be an abc class that provides common
     implementations used in Linux distros"""
-
-    distro = "Linux"
     vendor = "None"
     PATH = "/bin:/sbin:/usr/bin:/usr/sbin"
     init = None
+    # the following will be used, in order, as part of check() to validate that
+    # we are running on a particular distro
+    os_release_file = ''
+    os_release_name = ''
+    os_release_id = ''
     # _ prefixed class attrs are used for storing any vendor-defined defaults
     # the non-prefixed attrs are used by the upload methods, and will be set
     # to the cmdline/config file values, if provided. If not provided, then
@@ -145,7 +149,25 @@ def check(cls, remote=''):
         This function is responsible for determining if the underlying system
         is supported by this policy.
         """
-        raise NotImplementedError
+        def _check_release(content):
+            _matches = [cls.os_release_name]
+            if cls.os_release_id:
+                _matches.append(cls.os_release_id)
+            for line in content.splitlines():
+                if line.startswith(('NAME=', 'ID=')):
+                    _distro = line.split('=')[1:][0].strip("\"'")
+                    if _distro in _matches:
+                        return True
+            return False
+
+        if remote:
+            return _check_release(remote)
+        # use the os-specific file primarily
+        if os.path.isfile(cls.os_release_file):
+            return True
+        # next check os-release for a NAME or ID value we expect
+        with open(OS_RELEASE, "r", encoding='utf-8') as f:
+            return _check_release(f.read())
 
     def kernel_version(self):
         return self.release
@@ -171,7 +193,7 @@ def display_help(cls, section):
         if cls == LinuxPolicy:
             cls.display_self_help(section)
         else:
-            section.set_title(f"{cls.distro} Distribution Policy")
+            section.set_title(f"{cls.os_release_name} Distribution Policy")
             cls.display_distro_help(section)
 
     @classmethod

sos/policies/distros/almalinux.py

@@ -8,13 +8,14 @@
 #
 # See the LICENSE file in the source distribution for further information.
 
-import os
-from sos.policies.distros.redhat import RedHatPolicy, OS_RELEASE
+from sos.policies.distros.redhat import RedHatPolicy
 
 
 class AlmaLinuxPolicy(RedHatPolicy):
-    distro = "AlmaLinux"
     vendor = "AlmaLinux OS Foundation"
+    os_release_file = '/etc/almalinux-release'
+    os_release_name = 'AlmaLinux'
+
     vendor_urls = [
         ('Distribution Website', 'https://www.almalinux.org/'),
         ('Commercial Support', 'https://tuxcare.com/linux-support-services/')
@@ -26,21 +27,4 @@ def __init__(self, sysroot=None, init=None, probe_runtime=True,
                          probe_runtime=probe_runtime,
                          remote_exec=remote_exec)
 
-    @classmethod
-    def check(cls, remote=''):
-        if remote:
-            return cls.distro in remote
-
-        if not os.path.isfile('/etc/almalinux-release'):
-            return False
-
-        if os.path.exists(OS_RELEASE):
-            with open(OS_RELEASE, 'r', encoding='utf-8') as f:
-                for line in f:
-                    if line.startswith('NAME'):
-                        if 'AlmaLinux' in line:
-                            return True
-
-        return False
-
 # vim: set et ts=4 sw=4 :

sos/policies/distros/amazon.py

@@ -8,36 +8,19 @@
 #
 # See the LICENSE file in the source distribution for further information.
 
-import os
-from sos.policies.distros.redhat import RedHatPolicy, OS_RELEASE
+from sos.policies.distros.redhat import RedHatPolicy
 
 
 class AmazonPolicy(RedHatPolicy):
-
-    distro = "Amazon Linux"
     vendor = "Amazon"
     vendor_urls = [('Distribution Website', 'https://aws.amazon.com')]
+    os_release_file = ''
+    os_release_name = 'Amazon Linux'
 
     def __init__(self, sysroot=None, init=None, probe_runtime=True,
                  remote_exec=None):
         super().__init__(sysroot=sysroot, init=init,
                          probe_runtime=probe_runtime,
                          remote_exec=remote_exec)
 
-    @classmethod
-    def check(cls, remote=''):
-
-        if remote:
-            return cls.distro in remote
-
-        if not os.path.exists(OS_RELEASE):
-            return False
-
-        with open(OS_RELEASE, 'r', encoding='utf-8') as f:
-            for line in f:
-                if line.startswith('NAME'):
-                    if 'Amazon Linux' in line:
-                        return True
-        return False
-
 # vim: set et ts=4 sw=4 :

sos/policies/distros/anolis.py

@@ -6,41 +6,19 @@
 #
 # See the LICENSE file in the source distribution for further information.
 
-import os
-from sos.policies.distros.redhat import RedHatPolicy, OS_RELEASE
+from sos.policies.distros.redhat import RedHatPolicy
 
 
 class AnolisPolicy(RedHatPolicy):
-
-    distro = "Anolis OS"
     vendor = "The OpenAnolis Project"
     vendor_urls = [('Distribution Website', 'https://openanolis.org/')]
+    os_release_file = '/etc/anolis-release'
+    os_release_name = 'Anolis OS'
 
     def __init__(self, sysroot=None, init=None, probe_runtime=True,
                  remote_exec=None):
         super().__init__(sysroot=sysroot, init=init,
                          probe_runtime=probe_runtime,
                          remote_exec=remote_exec)
 
-    @classmethod
-    def check(cls, remote=''):
-
-        if remote:
-            return cls.distro in remote
-
-        # Return False if /etc/os-release is missing
-        if not os.path.exists(OS_RELEASE):
-            return False
-
-        # Return False if /etc/anolis-release is missing
-        if not os.path.isfile('/etc/anolis-release'):
-            return False
-
-        with open(OS_RELEASE, 'r', encoding='utf-8') as f:
-            for line in f:
-                if line.startswith('NAME'):
-                    if 'Anolis OS' in line:
-                        return True
-        return False
-
 # vim: set et ts=4 sw=4 :

sos/policies/distros/azure.py

@@ -8,18 +8,17 @@
 #
 # See the LICENSE file in the source distribution for further information.
 
-import os
 from sos.report.plugins import AzurePlugin
-from sos.policies.distros.redhat import RedHatPolicy, OS_RELEASE
+from sos.policies.distros.redhat import RedHatPolicy
 
 
 class AzurePolicy(RedHatPolicy):
-
-    distro = "Azure Linux"
     vendor = "Microsoft"
     vendor_urls = [
         ('Distribution Website', 'https://github.com/microsoft/azurelinux')
     ]
+    os_release_name = 'Microsoft Azure Linux'
+    os_release_file = ''
 
     def __init__(self, sysroot=None, init=None, probe_runtime=True,
                  remote_exec=None):
@@ -28,22 +27,8 @@ def __init__(self, sysroot=None, init=None, probe_runtime=True,
                          remote_exec=remote_exec)
         self.valid_subclasses += [AzurePlugin]
 
-    @classmethod
-    def check(cls, remote=''):
-
-        if remote:
-            return cls.distro in remote
-
-        if not os.path.exists(OS_RELEASE):
-            return False
 
-        with open(OS_RELEASE, 'r', encoding='utf-8') as f:
-            for line in f:
-                if line.startswith('NAME'):
-                    if 'Common Base Linux Mariner' in line:
-                        return True
-                    if 'Microsoft Azure Linux' in line:
-                        return True
-        return False
+class CBLMarinerPolicy(AzurePolicy):
+    os_release_name = 'Common Base Linux Mariner'
 
 # vim: set et ts=4 sw=4 :

sos/policies/distros/circle.py

@@ -8,42 +8,19 @@
 #
 # See the LICENSE file in the source distribution for further information.
 
-import os
-from sos.policies.distros.redhat import RedHatPolicy, OS_RELEASE
+from sos.policies.distros.redhat import RedHatPolicy
 
 
 class CirclePolicy(RedHatPolicy):
-
-    distro = "Circle Linux"
     vendor = "The Circle Linux Project"
     vendor_urls = [('Distribution Website', 'https://cclinux.org')]
+    os_release_file = '/etc/circle-release'
+    os_release_name = 'Circle Linux'
 
     def __init__(self, sysroot=None, init=None, probe_runtime=True,
                  remote_exec=None):
         super().__init__(sysroot=sysroot, init=init,
                          probe_runtime=probe_runtime,
                          remote_exec=remote_exec)
 
-    @classmethod
-    def check(cls, remote=''):
-
-        if remote:
-            return cls.distro in remote
-
-        # Return False if /etc/os-release is missing
-        if not os.path.exists(OS_RELEASE):
-            return False
-
-        # Return False if /etc/circle-release is missing
-        if not os.path.isfile('/etc/circle-release'):
-            return False
-
-        with open(OS_RELEASE, 'r', encoding='utf-8') as f:
-            for line in f:
-                if line.startswith('NAME'):
-                    if 'Circle Linux' in line:
-                        return True
-
-        return False
-
 # vim: set et ts=4 sw=4 :