Re: [Configobj-develop] ConfigObj Supporting toggles used in mysql configurations

[Michael F. <fuz...@vo...>]

Brian Jones wrote:
> Ok, so I took a quick break from reading the March stuff to look this
> over. I haven't read the *entire* thing, but I have a question about
> ConfigObj, and I hope I've read enough of the article that it's not
> too dumb a question :)
>   

It's definitely not a dumb question.

What you are saying is that the presence of:

x

Implies 'x = True'

This is fine - except it means changing the parser (which can be 
fiddly), making it an option, making it an option to specify how 'x = 
True' should be written back out (maybe both those could be a single 
option) and so on.

For config files *created* by ConfigObj I wouldn't want it to be the 
default but I am happy for ConfigObj to be compatible with a wider range 
of files created by other applications.

I'm afraid I have another rather pressing writing task at the moment - 
so I'm afraid the default response is 'patches welcomed'.

I'm forwarding this to the ConfigObj mailing list in case anyone else 
has an interest in implementing this...

Michael
http://www.manning.com/foord

> Given the very simple interface, and some of the complex things that
> ConfigObj does, I'm wondering how hard it would be to add support for
> "toggles" in a config file. In other words, single values on a line by
> themselves in a config file that, by their presence, signal the
> application to do (or not do) something specific.
>
> As an example, I actually needed this feature to write a mysql backup
> script that would parse the system's my.cnf file instead of having to
> edit a bunch of vars at the top of the script before use. However, the
> config file contains "toggle" config variables: if they exist in the
> file at all, they are basically read in by MySQL as "true", and it
> does what it needs to do. Here's a bit of the my.cnf file in question:
>
> [mysqld]
> server-id=2
> log-bin=mysql-binlog
> log-slave-updates
> relay-log=db2-relay-bin
> datadir=/var/lib/mysql
> tmpdir=/var/lib/mysql
> socket=/var/lib/mysql/mysql.sock
> enable-locking
> max_allowed_packet = 4M
> skip-name-resolve
> skip-host-cache
> skip-innodb
> back_log=128
> connect_timeout=10
> ft_min_word_len=3
> key_buffer_size=512M
> max_allowed_packet=1024M
> max_connections=200
> max_connect_errors=100
> myisam_sort_buffer_size=512M
>
> There's a lot of information implied by some of those floating, lonely
> values (and there are more that are available for use as well). If my
> application, for example, could do something like this:
>
> if not 'skip-innodb' in mysqlcnf:
>     do_innodb_backup()
>
> or, better:
>
> if not mysqlcnf['skip-innodb']
>     do_innodb_backup()
>
> So, I guess the short question is: can't ConfigObj just store these
> "toggle" values in a dictionary along with everything else, but since
> it doesn't have a value, just store the toggle value as the key, and
> the boolean True as the value?
>
> If this is all very neophyte-level banter, please forgive my
> ignorance. I don't profess to be a Python guru. That's why I created
> PyMag and hired tech editors :-P - but I do like Python, and would
> love to use ConfigObj for this particular project :-D
>
> Thanks for your work on this, and for working with us at PyMag!
> brian.
>
>
>
>
> On Thu, Feb 21, 2008 at 8:28 PM, Doug Hellmann <dou...@gm...> wrote:
>   
>> Thanks, Michael,
>>
>>  We're catching our breath from working on the March issue right now,
>>  but one of us will be looking at this shortly and will get back to you.
>>
>>  Doug
>>
>>  On Feb 21, 2008, at 3:34 PM, Michael Foord wrote:
>>
>>  > Hello guys,
>>  >
>>  > Attached is the first draft of my ConfigObj article. I have ignored
>>  > formatting issues so far...
>>     
>
>