Dry run didn't catch improperly formatted MX record, broke with --doit #600

zachlatta · 2020-08-31T14:11:14Z

Hi there, we use OctoDNS to manage Hack Club's DNS records and it's amazing! It means we can open source all of our DNS records at hackclub/dns. I love the idea of "infrastructure as code" and OctoDNS helps us a lot.

We recently ran into an issue where someone added an MX record with the exchange value 100 mx.sendgrid.net.. We have a test suite that does a dry run, which didn't surface any issues with this value, but when it was ran with --doit, we got an ambiguous error.

I was able to figure out that we had to remove 100 from the record value, which fixed --doit. Setting exchange to just mx.sendgrid.net. worked fine, but as a user I would expect OctoDNS to surface this error during the dry run.

Here's the error log:

...(many lines above this)...
*   Create <MxRecord MX 1, front-mail.hackclub.com., [''1 100 mx.sendgrid.net.'']> (config)
*   Create <TxtRecord TXT 1, front-mail.hackclub.com., ['v=spf1 include:sendgrid.net ~all']> (config)
*   Summary: Creates=3, Updates=1, Deletes=0, Existing Records=184
********************************************************************************


2020-08-30T23:28:15  [140229093717632] INFO  DnsimpleProvider[dnsimple] apply: making changes
Traceback (most recent call last):
  File "/opt/hostedtoolcache/Python/2.7.18/x64/bin/octodns-sync", line 11, in <module>
    load_entry_point('octodns==0.9.10', 'console_scripts', 'octodns-sync')()
  File "/opt/hostedtoolcache/Python/2.7.18/x64/lib/python2.7/site-packages/octodns/cmds/sync.py", line 39, in main
    dry_run=not args.doit, force=args.force)
  File "/opt/hostedtoolcache/Python/2.7.18/x64/lib/python2.7/site-packages/octodns/manager.py", line 344, in sync
    total_changes += target.apply(plan)
  File "/opt/hostedtoolcache/Python/2.7.18/x64/lib/python2.7/site-packages/octodns/provider/base.py", line 95, in apply
    self._apply(plan)
  File "/opt/hostedtoolcache/Python/2.7.18/x64/lib/python2.7/site-packages/octodns/provider/dnsimple.py", line 416, in _apply
    getattr(self, '_apply_{}'.format(class_name))(change)
  File "/opt/hostedtoolcache/Python/2.7.18/x64/lib/python2.7/site-packages/octodns/provider/dnsimple.py", line 387, in _apply_Create
    self._client.record_create(new.zone.name[:-1], params)
  File "/opt/hostedtoolcache/Python/2.7.18/x64/lib/python2.7/site-packages/octodns/provider/dnsimple.py", line 78, in record_create

And here's the commit in our repo that ran into this issue: hackclub/dns@48ac4d1#diff-be3b615b181f7f7bf89114f9ef473a86R416


        Revise 48ac4d1 to fix DNS syncing

It looks like there was an issue where "exchange: 100 mx.sendgrid.net." should have been "exchange: mx.sendgrid.net.". OctoDNS should have caught this with its tests, but missed it. Please note: if the "100" was intended to specify the preference (AKA priority) for the MX record, the preference value should be updated from "1" to "100" in the YAML. I filed github/octodns#600 in OctoDNS so they can hopefully fix this.

ross · 2020-08-31T15:05:43Z

Hi @zachlatta. There are some existing "validations" on MX records,

octodns/octodns/record/__init__.py

Lines 847 to 871 in 8e62bd9

    
           @classmethod 
        
           def validate(cls, data, _type): 
        
               if not isinstance(data, (list, tuple)): 
        
                   data = (data,) 
        
               reasons = [] 
        
               for value in data: 
        
                   try: 
        
                       try: 
        
                           int(value['preference']) 
        
                       except KeyError: 
        
                           int(value['priority']) 
        
                   except KeyError: 
        
                       reasons.append('missing preference') 
        
                   except ValueError: 
        
                       reasons.append('invalid preference "{}"' 
        
                                      .format(value['preference'])) 
        
                   exchange = None 
        
                   try: 
        
                       exchange = value.get('exchange', None) or value['value'] 
        
                       if not exchange.endswith('.'): 
        
                           reasons.append('MX value "{}" missing trailing .' 
        
                                          .format(exchange)) 
        
                   except KeyError: 
        
                       reasons.append('missing exchange') 
        
               return reasons

, but nothing that specifically look for that sort of case.

It could probably be caught by looking for spaces in the name and would likely apply equally well to a number of other types of values: ALIAS, CNAME, SRV. Would welcome PRs w/tests to that effect. Otherwise this issue can track it as a TODO.

github / octodns

Dry run didn't catch improperly formatted MX record, broke with --doit #600

Dry run didn't catch improperly formatted MX record, broke with --doit #600

zachlatta commented Aug 31, 2020 •

edited

ross commented Aug 31, 2020

github / octodns

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Dry run didn't catch improperly formatted MX record, broke with --doit #600

Dry run didn't catch improperly formatted MX record, broke with --doit #600

Comments

zachlatta commented Aug 31, 2020 • edited

ross commented Aug 31, 2020

zachlatta commented Aug 31, 2020 •

edited