Use namespace-aware meta importer for ipaplatform

Instead of symlinks and build-time configuration the ipaplatform module
is now able to auto-detect platforms on import time. The meta importer
uses the platform 'ID' from /etc/os-releases. It falls back to 'ID_LIKE'
on platforms like CentOS, which has ID=centos and ID_LIKE="rhel fedora".

The meta importer is able to handle namespace packages and the
ipaplatform package has been turned into a namespace package in order to
support external platform specifications.

https://fedorahosted.org/freeipa/ticket/6474

Signed-off-by: Christian Heimes <cheimes@redhat.com>
Reviewed-By: Rob Crittenden <rcritten@redhat.com>

ipalib/config.py

@@ -28,6 +28,7 @@ of the process.
 
 For the per-request thread-local information, see `ipalib.request`.
 """
+from __future__ import absolute_import
 
 import os
 from os import path
@@ -39,6 +40,7 @@ from six.moves.urllib.parse import urlparse, urlunparse
 from six.moves.configparser import RawConfigParser, ParsingError
 # pylint: enable=import-error
 
+from ipaplatform.tasks import tasks
 from ipapython.dn import DN
 from ipalib.base import check_name
 from ipalib.constants import (
@@ -47,12 +49,6 @@ from ipalib.constants import (
     TLS_VERSIONS
 )
 from ipalib import errors
-try:
-    # pylint: disable=ipa-forbidden-import
-    from ipaplatform.tasks import tasks
-    # pylint: enable=ipa-forbidden-import
-except ImportError:
-    tasks = None
 
 if six.PY3:
     unicode = str
@@ -451,10 +447,7 @@ class Env(object):
         self.script = path.abspath(sys.argv[0])
         self.bin = path.dirname(self.script)
         self.home = os.environ.get('HOME', None)
-
-        # Set fips_mode only if ipaplatform module was loaded
-        if tasks is not None:
-            self.fips_mode = tasks.is_fips_enabled()
+        self.fips_mode = tasks.is_fips_enabled()
 
         # Merge in overrides:
         self._merge(**overrides)

ipalib/setup.py

@@ -37,6 +37,7 @@ if __name__ == '__main__':
             "ipalib.install",
         ],
         install_requires=[
+            "ipaplatform",
             "ipapython",
             "netaddr",
             "pyasn1",

ipalib/util.py

@@ -55,6 +55,7 @@ from ipalib.constants import (
     TLS_VERSIONS, TLS_VERSION_MINIMAL, TLS_HIGH_CIPHERS
 )
 from ipalib.text import _
+from ipaplatform.paths import paths
 from ipapython.ssh import SSHPublicKey
 from ipapython.dn import DN, RDN
 from ipapython.dnsutil import DNSName
@@ -1101,9 +1102,9 @@ def check_client_configuration():
     """
     Check if IPA client is configured on the system.
     """
-    if (not os.path.isfile(_IPA_DEFAULT_CONF) or
-       not os.path.isdir(_IPA_CLIENT_SYSRESTORE) or
-       not os.listdir(_IPA_CLIENT_SYSRESTORE)):
+    if (not os.path.isfile(paths.IPA_DEFAULT_CONF) or
+            not os.path.isdir(paths.IPA_CLIENT_SYSRESTORE) or
+            not os.listdir(paths.IPA_CLIENT_SYSRESTORE)):
         raise ScriptError('IPA client is not configured on this system')