Get specific Metric data by metric.type and subscription_id

[arturmkr]

Hello,

Having following in Metrics explorer:

I need using Java client to get a current amount of undelivered_messages in the specific subscription_id. It's not clear how to do this.

Found following article:

https://cloud.google.com/monitoring/custom-metrics/reading-metrics

ListTimeSeriesRequest.Builder requestBuilder =
    ListTimeSeriesRequest.newBuilder()
        .setName(name.toString())
        .setFilter(
            "metric.type=\"pubsub.googleapis.com/subscription/num_undelivered_messages\" AND metric.label.subscription_id = \"myexporter\"")
        .setInterval(interval)
        .setView(ListTimeSeriesRequest.TimeSeriesView.HEADERS);

But it's not clear:

- how to filter data by subscription_id

- how to get not TimeSeries data, but current value