Component balm_streampublisher [Package balm]

Provide a balm::Publisher implementation that writes to a stream. More...

Namespaces
namespace	balm

---

Detailed Description

Outline

• Purpose
• Classes
• Description
  • Alternative Systems for Telemetry
  • Usage

Purpose:

Provide a balm::Publisher implementation that writes to a stream.

Classes:

balm::StreamPublisher

publishes collected metric samples to a stream

See also:

Component balm_publisher, Component balm_metricrecord, Component balm_metricsmanager

Description:

This component defines a concrete class balm::StreamPublisher that implements the balm::Publisher protocol for publishing metric records:

               ( balm::StreamPublisher )
                           |              ctor
                           |
                           V
                   ( balm::Publisher )
                                          dtor
                                          publish

This implementation of the publisher protocol publishes records to an output stream that is supplied at construction.

Alternative Systems for Telemetry:

Bloomberg software may alternatively use the GUTS telemetry API, which is integrated into Bloomberg infrastructure.

Usage:

In the following example we illustrate how to create and publish records with a balm::StreamPublisher. First we define a couple of metric ids. Note that we create the balm::MetricId objects by hand, but in practice an id should be obtained from a balm::MetricRegistry object (such as the one owned by a balm::MetricsManager).

  balm::Category myCategory("MyCategory");
  balm::MetricDescription descA(&myCategory, "MetricA");
  balm::MetricDescription descB(&myCategory, "MetricB");

  balm::MetricId metricA(&descA);
  balm::MetricId metricB(&descB);

Now we create a balm::StreamPublisher object, supplying it the stdout stream:

  balm::StreamPublisher myPublisher(bsl::cout);

Next we create a metric sample containing some records and pass it to the balm::StreamPublisher we created. Note that because we are not actually collecting the metrics we set the elapsed time of the sample to an arbitrary 5s interval.

  bslma::Allocator *allocator = bslma::Default::allocator(0);
  bsl::vector<balm::MetricRecord> records(allocator);

  records.push_back(balm::MetricRecord(metricA, 5, 25.0, 6.0, 25.0));
  records.push_back(balm::MetricRecord(metricB, 2,  7.0, 3.0, 11.0));

  balm::MetricSample sample(allocator);

  sample.setTimeStamp(bdlt::DatetimeTz(bdlt::CurrentTime::utc(), 0));
  sample.appendGroup(records.data(),
                     static_cast<int>(records.size()),
                     bsls::TimeInterval(5, 0));

  myPublisher.publish(sample);

The output of this example would look similar to:

 05FEB2009_19:52:11.723+0000 2 Records
     Elapsed Time: 5s
         MyCategory.MetricA [ count = 5, total = 25, min = 6, max = 25 ]
         MyCategory.MetricB [ count = 2, total = 7, min = 3, max = 11 ]