[neutron-dhcp-agent] creating resolv.conf in namespaces #68
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that is indeed the next item on the agenda :) update: tests are there now |
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mutax
changed the title
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| for line in f.readlines(): | ||
| if ' ' in line: | ||
| keyword, value = line.strip().split(' ', 1) | ||
| if keyword in ('search', 'options', | ||
| 'nameserver'): | ||
| found_settings.add((keyword, value)) |
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[optional] If this were a resolv.conf parsing function like described above you could also just return the options as a set and do something like assertEqual(set(), settings - set(self._parse_resolv_conf(resolvconf)))
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this would not catch the case where the resulting resolv.conf has more settings than intended:
In [1]: set([1,2,3]) - set([1,2,3,4])
Out[1]: set()
what is the advantage for that approach? Given that the assertion will give a verbose error message, e.g.:
AssertionError: Items in the first set but not the second:
('nameserver', '::1')
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The advantage would be that you could write one "resolv.conf parsing function" and use it everywhere and that I like set operations. We can keep it as is though :) For the case you're mentioning you can just compare the sets if they're equal or if you want the extra elements, do an xor:
In [2]: set([1,2,3]) ^ set([1,2,3,4])
Out[2]: {4}
Anyway, as marked as optional you can also keep it as is.
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I implemented the resolv.conf parsing function, that totally makes sense, even to me ;)
I just don't get why I should do the set operation myself when the unittest framework is giving me nice output already when comparing the sets
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| for line in f.readlines(): | ||
| if ' ' in line: | ||
| keyword, value = line.strip().split(' ', 1) | ||
| if keyword in ('search', 'options', | ||
| 'nameserver'): | ||
| found_settings.add((keyword, value)) |
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The advantage would be that you could write one "resolv.conf parsing function" and use it everywhere and that I like set operations. We can keep it as is though :) For the case you're mentioning you can just compare the sets if they're equal or if you want the extra elements, do an xor:
In [2]: set([1,2,3]) ^ set([1,2,3,4])
Out[2]: {4}
Anyway, as marked as optional you can also keep it as is.
| with open(resolvconf, 'rt') as f: | ||
| for line in f.readlines(): | ||
| if ' ' in line: | ||
| keyword, value = line.strip().split(' ', 1) | ||
| if keyword in ('search', 'options', 'nameserver'): | ||
| found_settings.add((keyword, value)) |
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Could this also be covered by _read_resolvconf()?
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hmm. need to adapt _read_resolvconf for that, but is doable,
The test is only looking for the given three keywords and ignoring everything else in the file, so it would only fail if the setting for one of these keywords is not correct, making the test specific to that corner case.
If for example the code adds an additional keyword (because an additional linebreak is added by accident in a comment when the code is modified), now all tests that check the resolv.conf will fail, because a new keyword-value pair is found by the helper function that parses the file. This could make it unneccessarily hard for the developer to verify the root cause with 4 tests failing.
The parser has been updated and got its own test, so that should work in the same way as before, with a parameter to the parser function.
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Using the 'regular' /etc/resolv.conf inside the network namespaces prevents proper DNS resolution, as these nameservers usually are unreachable from within the namespaces. This change enables creation of a resolv.conf in each namespace. The new setting netns_resolvconf enables this feature, by default it is disabled. Default nameservers are 127.0.0.1 and ::1 if IPv6 is enabled, for search domains the networks dns_domain is used if set. These defaults can be overwritten via settings file. To skip setting nameservers, search domains or options in the generated file and not use the dynamic defaults, one can add the settings key in the configuration file but leave out any value, e.g.: netns_resolvconf = yes netns_resolvconf_search = netns_resolvconf_options = netns_resolvconf_nameservers = This would create an empty resolv.conf.
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Using the 'regular' /etc/resolv.conf inside the network namespaces prevents proper DNS resolution, as these nameservers usually are unreachable from within the namespaces.
This change enables creation of a resolv.conf in each namespace.
The new setting netns_resolvconf enables this feature, by default its disabled.
Default nameservers are 127.0.0.1 and ::1 if IPv6 is enabled, for search domains the dns_domain is used if set.
These internal defaults can be overwritten via settings file.
To skip setting nameservers, search domains or options in the generated file and not use the dynamic defaults, one can add the settings key in the configuration file but leave out any value, e.g.:
netns_resolvconf = yes
netns_resolvconf_search =
netns_resolvconf_options =
netns_resolvconf_nameservers =
This would create an empty resolv.conf.