[Hawkular-dev] [inventory] Reading and querying metric type data type

[Lukas Krejci]

On Tuesday, August 16, 2016 6:18:51 PM CEST Thomas Segismont wrote:
> Shouldn't we standardize on what Hawkular Metrics uses? 'gauge', 'counter',
> 'availability'
>

Which brings me to another question... How do you represent units of the 
metrics, if at all? 

Inventory right now uses again an uppercase representation of them defined in 
https://github.com/hawkular/hawkular-inventory/blob/master/hawkular-inventory-api/src/main/java/org/hawkular/inventory/api/model/MetricUnit.java
 
> 2016-08-16 17:53 GMT+02:00 Lukas Krejci <lkrejci at redhat.com>:
> > Hi all,
> > 
> > while working on [1] I came across an incosistency in how the data type of
> > a
> > metric type (i.e. gauge, availability, counter, ...) are stored and
> > presented.
> > 
> > When you read a metric type using the REST API, you get something like
> > this
> > back (some fields ommitted for brevity):
> > 
> > {
> > 
> >   "path" : "/t;tnt/mt;myMetricType",
> >   "unit" : "NONE",
> >   "type" : "GAUGE",
> >   "collectionInterval" : 0,
> >   "id" : "myMetricType"
> > 
> > }
> > 
> > The metric data type is called "type" here (somewhat confusingly) and
> > contains
> > the value in upper case.
> > 
> > If you wanted to filter by it, prior to fix to the above mentioned JIRA,
> > you
> > had to:
> > 
> > /traversal/...;propertyName=__metric_data_type;propertyValue=gauge
> > 
> > Notice 2 things:
> > * the name of the property is different
> > * the value is in lower case
> > 
> > Now the question is how to bring order to this mess. Because the ideal fix
> > will break the format of the data, I'd like to discuss this with the rest
> > of
> > the team so that we come to a compromise that will amount to the least
> > amount
> > of work for all the inventory clients.
> > 
> > There are 2 obvious problems here:
> > 1) the mismatch between the property name in the JSON output and the
> > property
> > name used when querying
> > 2) the mismatch of the letter case in JSON output and queried property
> > value
> > 
> > For 1) I'd like rename BOTH the JSON output and queried property name to
> > "metricDataType". We can't "type" because its already taken to mean the
> > type
> > of the entity and we can't use "__metric_data_type" because it's
> > inconsistent
> > with the rest of the properties.
> > 
> > For 2) I'd like to consolidate on the upper case usage because that's the
> > default Jackson serialization of the enum.
> > 
> > Both of these (and especially 1)) can break existing clients.
> > 
> > What would be the path of least resistance for your usecase?
> > 
> > [1] https://issues.jboss.org/browse/HWKINVENT-192
> > 
> > Thanks,
> > 
> > --
> > Lukas Krejci
> > _______________________________________________
> > hawkular-dev mailing list
> > hawkular-dev at lists.jboss.org
> > https://lists.jboss.org/mailman/listinfo/hawkular-dev


-- 
Lukas Krejci