[Hawkular-dev] About configuration

[Thomas Segismont]

I believe the way we read/use config can be decided at the sub-project 
level (provided we don't use an exotic format).

Le 05/02/2015 11:41, Lukas Krejci a écrit :
> I am not for or against using properties for config simply because I do not
> yet know what the requirements for the configuration will end up being.
>
> On the other hand I feel we should from the start use something that is
> capable of handling more structured configuration formats without us needing
> to rewrite all the configuration handling code if that need arose (by
> abandoning java's Properties and moving to something different).
>
> Hence I propose using Apache Commons Configuration for reading the
> configuration files. I think Artificer uses it, too, so Brett et al. can
> comment if that would be the right thing to do or not.
>
> Commons configuration supports XPATH for accessing nested data so working with
> hierarchical properties should be quite nice with it. The disadvantage is that
> it drags several other deps with it -
> http://commons.apache.org/proper/commons-configuration/dependencies_1_10.html.
>
> Other option could be to commit to a single configuration format and use a
> dedicated parser for that with minimal deps. For example if we chose JSON as
> the config format we could use JBoss DMR for reading/writing such configs. The
> advantage of that approach is that DMR is absolutely tiny with no external
> deps. The disadvantage is that JSON cannot have comments (which is easily
> amended by a custom reader that would strip the comments before the contents
> are passed to DMR for parsing (a recommended approach from the author of JSON
> - https://plus.google.com/118095276221607585885/posts/RK8qyGVaGSr)).
>
> On Thursday, February 05, 2015 11:01:53 Thomas Segismont wrote:
>> Hi everyone,
>>
>> Yesterday Lukas asked on IRC if there was a discussion about
>> configuration. AFAIK, there wasn't, hence I'm sharing how we support
>> configuration in metrics.
>>
>> # Metrics REST server
>>
>> The REST server runs on top of Wildfly.
>>
>> Configuration is a set of key/value pairs (configuration properties)
>> defined by the following sources, in order of precedence:
>>
>> * system properties (-Dkey=value)
>> * external java.util.Properties file, which path is defined by the
>> metrics.conf system property; by default, <user.home>/.metrics.conf is
>> used (if it exists)
>> * internal java.util.Properties file (META-INF/metrics.conf)
>>
>> The rationale behind is that the system should be able to:
>>
>> 1. start with reasonable defaults
>> 2. switch to another configuration easily
>>
>> # pTrans
>>
>> pTrans is different because it's a standalone application, so it's much
>> easier to follow the daemon configuration habits.
>>
>> pTrans takes a path to a properties configuration file as a program
>> argument. This argument is mandatory.
>>
>> # Configuration file format.
>>
>> metrics started with properties file and I think it's fine.
>>
>> But if we feel the need for a more structured format, we should pick
>> something which can be easily parsed by a variety of programming
>> languages, especially languages widely used for administration (Python
>> and Ruby).
>>
>>
>> Regards,
>> Thomas
>> _______________________________________________
>> hawkular-dev mailing list
>> hawkular-dev at lists.jboss.org
>> https://lists.jboss.org/mailman/listinfo/hawkular-dev
>
> _______________________________________________
> hawkular-dev mailing list
> hawkular-dev at lists.jboss.org
> https://lists.jboss.org/mailman/listinfo/hawkular-dev
>