Measurement Metadata

You can provide custom metadata when creating a new instrument or when invoking the done() or fail() methods of an instrument.

Providing metadata is useful for:

• Filtering measurements when creating indicators in Polaris.
• Providing additional context when debugging issues.

Let's take a look at an example of each.

Add Metadata

Let's add custom metadata to a measurement.

const instrument = getInstrument('event-name');

instrument.start({
  tier: user.tier,
});

Let's review the code above.

• First, we create a new instrument using the getInstrument() method.
• Next, we call the start() method of the instrument and provide an object with custom metadata.

Add Metadata when Completing a Measurement

You can also add metadata when invoking the done() or fail() methods on the Instrument.

const instrument = getInstrument('event-name');

try {
  instrument.start({
    tier: user.tier,
  });

  // code we want to measure

  instrument.done({
    attribute3: 'value3',
    attribute4: 'value4',
  });
} catch (error) {
  instrument.fail(error, {
    attribute5: 'value5',
    attribute6: 'value6',
  });
}

Let's review the code above.

• First, we create a new instrument using the getInstrument() method.
• Next, we invoke the start() method of the instrument and provide an object with custom metadata.
• Then, we invoke the done() method of the instrument and provide an object with custom metadata.
• Finally, we call the fail() method of the instrument and provide an object with custom metadata.