launchpad-reviewers team mailing list archive

[Raphaël Badin <raphael.badin@xxxxxxxxxxxxx>]

Raphaël Badin has proposed merging lp:~rvb/maas/fix-dns-not-installed into lp:maas.

Commit message:
Raise a proper error with a meaningful error message if a DNS config file cannot be written because there is a missing directory (which means the maas-dns package needs to be installed).

Requested reviews:
  Launchpad code reviewers (launchpad-reviewers)

For more details, see:
https://code.launchpad.net/~rvb/maas/fix-dns-not-installed/+merge/128031

Raise a proper error with a meaningful error message if a DNS config file cannot be written because there is a missing directory (which means the maas-dns package needs to be installed).
-- 
https://code.launchpad.net/~rvb/maas/fix-dns-not-installed/+merge/128031
Your team Launchpad code reviewers is requested to review the proposed merge of lp:~rvb/maas/fix-dns-not-installed into lp:maas.

=== modified file 'src/provisioningserver/dns/config.py'
--- src/provisioningserver/dns/config.py	2012-09-30 22:37:05 +0000
+++ src/provisioningserver/dns/config.py	2012-10-04 14:44:27 +0000
@@ -23,6 +23,7 @@
     abstractproperty,
     )
 from datetime import datetime
+import errno
 from itertools import (
     chain,
     imap,
@@ -48,6 +49,10 @@
 MAAS_RNDC_CONF_NAME = 'rndc.conf.maas'
 
 
+class DNSConfigDirectoryMissing(Exception):
+    """The directory where the config was about to be written is missing."""
+
+
 class DNSConfigFail(Exception):
     """Raised if there's a problem with a DNS config."""
 
@@ -157,6 +162,25 @@
         return {}
 
     def write_config(self, overwrite=True, **kwargs):
+        """Write out this DNS config file.
+
+        This ignores any "No such file or directory" error which would mean
+        that the directory containing the write to be written does not exist.
+        """
+        try:
+            self.inner_write_config(overwrite=overwrite, **kwargs)
+        except OSError as exception:
+            # Only raise a DNSConfigDirectoryMissing exception if this error
+            # is a "No such file or directory" exception.
+            if exception.errno == errno.ENOENT:
+                raise DNSConfigDirectoryMissing(
+                    "The directory where the DNS config files should be "
+                    "written does not exist.  Make sure the 'maas-dns' "
+                    "package installed on this region controller.")
+            else:
+                raise
+
+    def inner_write_config(self, overwrite=True, **kwargs):
         """Write out this DNS config file."""
         template = self.get_template()
         kwargs.update(self.get_context())
@@ -249,7 +273,7 @@
         return os.path.join(
             self.target_dir, 'zone.%s' % self.zone_name)
 
-    def write_config(self, **kwargs):
+    def inner_write_config(self, **kwargs):
         """Write out the DNS config file for this zone."""
         template = self.get_template()
         kwargs.update(self.get_context())

=== modified file 'src/provisioningserver/dns/tests/test_config.py'
--- src/provisioningserver/dns/tests/test_config.py	2012-09-30 22:40:33 +0000
+++ src/provisioningserver/dns/tests/test_config.py	2012-10-04 14:44:27 +0000
@@ -12,6 +12,7 @@
 __metaclass__ = type
 __all__ = []
 
+import errno
 import os.path
 import random
 
@@ -23,6 +24,7 @@
     MatchesAll,
     )
 from maastesting.testcase import TestCase
+from mock import Mock
 from netaddr import (
     IPAddress,
     IPNetwork,
@@ -30,6 +32,7 @@
 from provisioningserver.dns import config
 from provisioningserver.dns.config import (
     DNSConfig,
+    DNSConfigDirectoryMissing,
     DNSConfigFail,
     DNSForwardZoneConfig,
     DNSReverseZoneConfig,
@@ -122,6 +125,20 @@
             DNSConfigFail, dnsconfig.render_template, template)
         self.assertIn("'test' is not defined", exception.message)
 
+    def test_write_config_DNSConfigDirectoryMissing_if_dir_missing(self):
+        dnsconfig = DNSConfig()
+        dir_name = self.make_dir()
+        os.rmdir(dir_name)
+        self.patch(DNSConfig, 'target_dir', dir_name)
+        self.assertRaises(DNSConfigDirectoryMissing, dnsconfig.write_config)
+
+    def test_write_config_errors_if_unexpected_exception(self):
+        dnsconfig = DNSConfig()
+        exception = IOError(errno.EBUSY, factory.getRandomString())
+        self.patch(
+            DNSConfig, 'inner_write_config', Mock(side_effect=exception))
+        self.assertRaises(IOError, dnsconfig.write_config)
+
     def test_write_config_skips_writing_if_overwrite_false(self):
         # If DNSConfig is created with overwrite=False, it won't
         # overwrite an existing config file.