BIND 10 #2342: MySQL IPv6 lease database access functions

[BIND 10 Development]

#2342: MySQL IPv6 lease database access functions
-------------------------------------+-------------------------------------
                   Reporter:         |                 Owner:  tomek
  stephen                            |                Status:  reviewing
                       Type:  task   |             Milestone:  Sprint-
                   Priority:         |  DHCP-20121101
  medium                             |            Resolution:
                  Component:         |             Sensitive:  0
  dhcpdb                             |           Sub-Project:  DHCP
                   Keywords:         |  Estimated Difficulty:  0
            Defect Severity:  N/A    |           Total Hours:  0
Feature Depending on Ticket:         |
        Add Hours to Ticket:  0      |
                  Internal?:  0      |
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Changes (by stephen):

 * owner:  stephen => tomek


Comment:

 '''configure.ac'''
 >> To avoid confusion, I've also removed the MySQL listing from the final
 report.
 > Why? Printing out MySQL parameters is very useful, we just need to make
 them as DHCP-only. It makes sense to also...
 I wanted to avoid over-complicating configure.ac, but it turned out not to
 be too much trouble to add this.  It only appears if the --with-dhcp-mysql
 has been specified, to avoid confusing people building DNS.

 ''' dhcpdb_create.mysql'''
 > Our customer asks to do two conflicting things at the same time: keep
 portability and be as efficient as possible (with implies using MySQL
 specific things).
 I think the aim is that we don't use anything in MySQL that we can't
 duplicate elsewhere.  Here, all we are talking about is the format by
 which the data is stored in the database.  That can vary between
 databases: providing we write the database layer appropriately, the code
 will work on any database.  However, if we were to rely on stored
 procedures, we would have difficultly with something like SQLite3 which
 doesn't have that feature.

 '''lease_mgr.h'''
 >>> Please do not use defines with two leading underscores. These are
 reserved for compiler. LEASE_MGR_H will just fine instead.
 >> Unfortunately that is used elsewhere in BIND 10 - see the .h files in
 other directories.
 > Mistakes made elsewhere does not warrant creating new mistakes. Double
 underscore defines are reserved for compiler's internal use ...
 Good point.  Double underscores removed.

 '''lease_mgr.cc'''
 > There are 11 includes in lease_mgr.cc. I seriously doubt we need them
 all, especially that we are not doing anything fancy there.
 Turns out that all but lease_mgr.h can be removed.  Done.

 '''mysql_lease_mgr_unittest.cc'''
 > Ok, there's one more issue: BasicLease6 test started failing for me.
 That appears to be down to overflows when adding a large number of seconds
 to the cltt field - the time can go beyond 2038.  Ticket #2413 has been
 created for that.  In the meanwhile, the tests deliberately don't cause an
 overflow and a TODO has been added to the code.

 '''General'''
 The code now has the basic add/get/update lease6 capability.  Variants of
 these are defined using fields other than the address as the key.
 However, if this is enough for now, I suggest we merge the current ticket
 and create a new ticket for the remainder.

 If you agree, the suggested !ChangeLog entry is:
 {{{
 nnn.    [func]          stephen
         Add initial version of a MySQL backend for the DHCP code. (This
         is enabled by specifying --with-dhcp-mysql on the "configure"
         command line.)  The backend implements the basic IPv6 lease access
         functions - add lease, get lease, delete lease, update lease.
         (Trac #2342, git xxx)
 }}}

-- 
Ticket URL: <http://bind10.isc.org/ticket/2342#comment:16>
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