github.com/pmoroney/dnscontrol@v0.2.4-0.20171024134423-fad98f73f44a/docs/_functions/domain/IMPORT_TRANSFORM.md (about)

     1  ---
     2  name: IMPORT_TRANSFORM
     3  parameters:
     4    - transform table
     5    - domain
     6    - ttl
     7    - modifiers...
     8  ---
     9  
    10  Don't use this feature. It was added for a very specific situation. Bugs
    11  and feature requests from outside that situation will be rejected.
    12  
    13  IMPORT_TRANSFORM adds to the domain all the records from another
    14  domain, after making certain transformations and resetting the TTL.
    15  
    16  Example:
    17  
    18  Suppose foo.com is a regular domain.  bar.com is a regular domain,
    19  but certain records should be the same as foo.com with these
    20  exceptions: "bar.com" is added to the name, the TTL is changed to
    21  300, if the IP address is between 1.2.3.10 and 1.2.3.20 then rewrite
    22  the IP address to be based on 123.123.123.100 (i.e. .113 or .114).
    23  
    24  You wouldn't want to maintain bar.com manually, would you?  It would
    25  be very error prone. Therefore instead you maintain foo.com and
    26  let IMPORT_TRANSFORM automatically generate bar.com.
    27  
    28  {% include startExample.html %}
    29  {% highlight html %}
    30  
    31  foo.com:
    32      one.foo.com.    IN A 1.2.3.1
    33      two.foo.com.    IN A 1.2.3.2
    34      three.foo.com.  IN A 1.2.3.13
    35      four.foo.com.   IN A 1.2.3.14
    36  
    37  bar.com:
    38      www.bar.com.    IN 123.123.123.123
    39      one.foo.com.bar.com.    IN A 1.2.3.1
    40      two.foo.com.bar.com.    IN A 1.2.3.2
    41      three.foo.com.bar.com.  IN A 123.123.123.113
    42      four.foo.com.bar.com.   IN A 123.123.123.114
    43  
    44  {%endhighlight%}
    45  {% include endExample.html %}
    46  
    47  Here's how you'd implement this in DNSControl:
    48  
    49  {% include startExample.html %}
    50  {% highlight js %}
    51  
    52  var TRANSFORM_INT = [
    53      // RANGE_START, RANGE_END, NEW_BASE
    54      { low: "1.2.3.10", high: "1.2.3.20", newBase: "123.123.123.100" },  //   .10 to .20 rewritten as 123.123.123.100+IP
    55      { low: "2.4.6.80", high: "2.4.6.90", newBase: "123.123.123.200" },  //   Another rule, just to show that you can have many.
    56  ]
    57  
    58  D("foo.com", .... ,
    59    A("one","1.2.3.1")
    60    A("two","1.2.3.2")
    61    A("three","1.2.3.13")
    62    A("four","1.2.3.14")
    63  );
    64  
    65  D("bar.com", .... ,
    66    A("www","123.123.123.123")
    67    IMPORT_TRANSFORM(TRANSFORM_INT, 'foo.com', 300),
    68  );
    69  
    70  {%endhighlight%}
    71  {% include endExample.html %}
    72  
    73  Transform rules are: RANGE_START, RANGE_END, NEW_BASE.  NEW_BASE may be:
    74  
    75  * An IP address.  Rebase the IP address on this IP address. Extract the host part of the /24 and add it to the "new base" address.
    76  * A list of IP addresses. For each A record, inject an A record for each item in the list: `newBase: ['1.2.3.100', '2.4.6.8.100']` would produce 2 records for each A record.