User Defined Metrics API

Ryan Williams

Jan 5, 2019

Delete: “such”

Anonymous

Mar 27, 2018

Format: alignment

Vikas RK

Jan 26, 2017

Is there any plan to also include Gauges? I have found them to be very useful. http://metrics.dropwizard.io/3.1.0/apidocs/com/codahale/metrics/Gauge.html

Ben Chambers

Jan 26, 2017

Not currently, although once we have the basic Metrics framework we could look at adding them without much effort.

If I understand correctly, the most useful case is for periodically recording metrics about some external system possibly at a source or sink. I'd like to think about if there was a way to more cleanly support that use case -- eg., maybe a source or sink reports metrics about the external system it interacts with, and does so in a way that we can associate it with the source or sink directly.

What have you found them useful for?

Vikas RK

Jan 26, 2017

In general, useful for anything not a counter or histogram. For Beam, agreed that the most utility seems to be when interacting with external systems. Although given that a DoFn is an arbitrary piece of code written by the user, I can see it being useful. A DoFn could be talking to an external system or using a data structure and want to record metrics periodically. Given that it is not much effort, it might be worth adding at some point.

2 replies

Robert Bradshaw

Feb 27, 2017

Any objection to actually spelling out increment/decrement. Reviewing some code that actually used this, it wasn't as obvious without context.

Ben Chambers

Feb 27, 2017

Not particularly, although it would require a change to both Python and Java metrics APIs. It does decrease comparability to Dropwizard's Counter interface.

Robert Bradshaw

Feb 28, 2017

Mirroring an existing interface is a fair justification (though I suppose so is internal consistency, it seems other than "P[ar]" we've shunned abbreviations in the beam API).

2 replies

Ben Chambers

Oct 5, 2016

Should this be "Distribution" (which suggests CDF and/or descriptive statics about the distribution), "Histogram" (to mirror DropWizard metrics) or something else to capture the fact we don't plan to support quantiles (yet)?

Zur

Mar 3, 2017

Replace link: “http://timer” with “http://metrics.dropwizard.io/3.1.0/apidocs/com/codahale/metrics/Timer.html”

Zur

Mar 3, 2017

Add row: with text “Gauge - Last value reported. (Compare to Gauge) void set(long value);”

Ryan Williams

Jan 5, 2019

Delete: “connect a call to”

Robert Burke

Mar 27, 2018

Format list: remove from list

Format: indent first line, indent left

Katarzyna Kucharczyk

Oct 30, 2018

Replace: “teh” with “the”

Ryan Williams

Jan 5, 2019

Replace: “s`” with “`s”

Jean-Baptiste Onofré

Oct 6, 2016

The API sounds good. I have a question, how to collect and "expose" those metrics. For instance, JMX is an interesting way to do that. I guess it's the responsibility of the runner (or another Beam module) to deal with metric. Right ?

Robert Bradshaw

Oct 6, 2016

The returned PipelineResult would have handles to access these metrics (API TBD).

Ben Chambers

Oct 6, 2016

I'll add something about the in-language querying capability. In addition to being able to access metrics from the PipelineResult, runners may provide other ways of accessing the metrics. In the future, it would be good to add a plugin that allows reporting them.

As far as JMX, I don't think it works for our needs. We'll need the runner (Fn API) to collect the metrics and aggregate them across workers and it will need to do so in a way that is consistent with committed bundles.

Ben Chambers

Oct 6, 2016

Added a sketch of querying metrics above.

Apache Beam Project

Oct 6, 2016

I could see a runner using JMX internally to do this as a solution but we
should keep that as a runner implementation detail.

4 replies

Rafał Wojdyła

Oct 12, 2016

+1, is there a ticket open for this?

Ben Chambers

Oct 12, 2016

No Jira yet. I suspect it will be a while before we implement this extension, but it is definitely something we'd like. Feel free to create a feature request for adding this ability!

Scott Wegner

Jun 28, 2017

@neverme@gmail.com discusses this in a follow-up doc: https://docs.google.com/document/d/1-35iyCIJ9P4EQONlakgXBFRGUYoOLanq2Uf2sw5EjJw/edit?usp=sharing

2 replies