Send metrics immediately from the browser

[ikibalnyi]

Hi, how can I use otel to send metrics immediately when meter.add() is called?

[pichlermarc]

Hi @ikibalnyi thanks for reaching out.
A feature like this currently does not exist and will not be added to the metrics SDK unless it's specified in https://github.com/open-telemetry/opentelemetry-specification first.

[ikibalnyi]

Thanks for answering! Are there maybe any options?

• I couldn't find any other MetricReader other than PeriodicExportingMetricReader. But also creating a custom MetricReader doesn't seem to have enough mechanisms to cover such use case.
• I can see the the is a forceFlush method on MeterProvider. But the problem is that metrics.getMeterProvider() doesn't expose it.

[pichlermarc]

It's on purpose that this is not exposed. Instrumentation code should not concern itself with the export of telemetry data it should just write it. You can, of course hold on to MeterProvider after registered with the API and forceFlush it where you need to but I'd consider that an anti-pattern.

What is it that you're trying to achieve? Do you actually want to flush every time an instrument is written to or do you just want to ensure that it's flushed on pagehide/visibiliitychanged? If that's the case, then you could setup of your SDK simply register a function to these events that just forceFlush()es the MeterProvider right then an there.

[ikibalnyi]

We send some metrics from the browser, they are not accumulating over time within same session. Instead I need to monitor how many times a certain event is triggered. If we use periodic exporter and don't send immediately, the user may close a page before this metric is sent and the event will be gone.
What I'm trying to achieve is, when the event handler is called, I thought to trigger meter.add() so that this would be sent right away.

[pichlermarc]

If the forceFlush() approach I mentioned above is not working for you then I think in this case it may be better to send Logs or Events using a SimpleLogRecordProcessor and them counting them somewhere in the pipeline instead.

I'm sorry I can't help but that feature simply does not exist in the OTel Specification.