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

[John Sanda]

Metrics does not manage units. Units can be specified as metric tags, but we don’t do any special handling like converting MB —> KB for example.

> On Aug 17, 2016, at 12:48 PM, Thomas Segismont <tsegismo at redhat.com> wrote:
> 
> I don't believe Metrics manages units. If it does I would expect user can submit values ignoring case.
> 
> 2016-08-17 11:32 GMT+02:00 Lukas Krejci <lkrejci at redhat.com <mailto:lkrejci at redhat.com>>:
> 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 <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 <mailto: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 <https://issues.jboss.org/browse/HWKINVENT-192>
> > >
> > > Thanks,
> > >
> > > --
> > > Lukas Krejci
> > > _______________________________________________
> > > hawkular-dev mailing list
> > > hawkular-dev at lists.jboss.org <mailto:hawkular-dev at lists.jboss.org>
> > > https://lists.jboss.org/mailman/listinfo/hawkular-dev <https://lists.jboss.org/mailman/listinfo/hawkular-dev>
> 
> 
> --
> Lukas Krejci
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