1:51 a.m.
Hi,
I'd personally would want to see another type of functional language,
such that would look like the one when you do Streams / RxJava. I guess
it's closer to the one in MongoDB/RethinkDB/InfluxDB 2.0/Riemann, than
the one in Prometheus/Graphite (PromQL is mostly evolution of Graphite's
query language).
And it could allow us to provide features such as streaming metrics,
since we could transform those queries directly to reactive queries (we
should take advantage of the fact that we process the metrics by
reacting to them in the backend).
- Micke
On 07/19/2017 06:36 PM, Joel Takvorian wrote:
Hi,
I just want to share some ideas about the eventuality of having a
language to perform some arithmetic / aggregations on metrics, before
it goes out of my head...
Here's an example of what I would personally love to see in Hawkular:
----------------------------------------------
*Example:*
/sum(stats(rate((id(my_metric), tags(a=foo AND b=bar),
regexp(something_.+)), 5m), 10m))/
|
|=> "id", "tags" and "regexp" all return a set of raw
metrics (0-1 for
id, 0-n for tags and regexp)
|==> "(a,b,c)" takes n parameters, all sets of metrics, and flatten
them in a single set
|===> rate(set_of_raw_metrics, rate_period) computes the rate for each
of them and return a set of metrics (map n=>n)
|====> stats(set_of_raw_metrics, bucket_size) bucketize the raw
metrics, returning the same number of bucketized metrics (map n=>n)
|=====> sum(set_of_stats_metrics) sums every buckets, returning a
single bucketized metric (fold n=>1)
*Other:*
Functions like "sum" that take stats_metrics could have overloaded
shortcut "sum(set_of_raw_metrics, bucket_size)" to perform the bucketing.
In other words above example could be rewritten:
/sum(rate((id(my_metric), tags(a=foo AND b=bar),
regexp(something_.+)), 5m), 10m)/
Note: we can do aggregations like "sum" on raw data if necessary, it
just means we have to interpolate.
*Scalar operations:*
/sum((id(a_metric_in_milliseconds), *1000**id(a_metric_in_seconds)), 10m)/
----------------------------------------------
Of course many other functions could come growing the library.
Now I suppose the big question, if we want to do such thing, is "are
we going to invent our own language?" I don't know if there are
standards for this, and if they are good.
The Prometheus query language cannot be transposed because a label is
not a tag and it makes no sense for us to write something like
"my_metric{tag=foo}", it's either "my_metric" or
"tag=foo".
The same language could be used both for read-time on-the-fly
aggregations and write-time / cron-based rollups.
WDYT?
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