UUID

UUIDs metrics are used to record values that uniquely identify some entity, such as a client id.

Recording API

generateAndSet

Sets a UUID metric to a randomly generated UUID value (UUID v4) .

import org.mozilla.yourApplication.GleanMetrics.User

// Generate a new UUID and record it
User.clientId.generateAndSet()

import org.mozilla.yourApplication.GleanMetrics.User;

// Generate a new UUID and record it
User.INSTANCE.clientId().generateAndSet();

// Generate a new UUID and record it
User.clientId.generateAndSet()

from glean import load_metrics
metrics = load_metrics("metrics.yaml")

# Generate a new UUID and record it
metrics.user.client_id.generate_and_set()

use uuid::Uuid;
use glean_metrics::user;

// Generate a new UUID and record it
user::client_id.generate_and_set();

import * as user from "./path/to/generated/files/user.js";

user.clientId.generateAndSet();

C++

#include "mozilla/glean/GleanMetrics.h"

// Generate a new UUID and record it.
mozilla::glean::user::client_id.GenerateAndSet();

JavaScript

// Generate a new UUID and record it.
Glean.user.clientId.generateAndSet();

set

Sets a UUID metric to a specific value. Accepts any UUID version.

import org.mozilla.yourApplication.GleanMetrics.User

// Set a UUID explicitly
User.clientId.set(UUID.randomUUID())  // Set a UUID explicitly

import org.mozilla.yourApplication.GleanMetrics.User;

// Set a UUID explicitly
User.INSTANCE.clientId().set(UUID.randomUUID());

User.clientId.set(UUID())  // Set a UUID explicitly

import uuid

from glean import load_metrics
metrics = load_metrics("metrics.yaml")

# Set a UUID explicitly
metrics.user.client_id.set(uuid.uuid4())

use uuid::Uuid;
use glean_metrics::user;

// Set a UUID explicitly
user::client_id.set(Uuid::new_v4());

import * as user from "./path/to/generated/files/user.js";

const uuid = "decafdec-afde-cafd-ecaf-decafdecafde";
user.clientId.set(uuid);

C++

#include "mozilla/glean/GleanMetrics.h"

// Set a specific value.
nsCString kUuid("decafdec-afde-cafd-ecaf-decafdecafde");
mozilla::glean::user::client_id.Set(kUuid);

JavaScript

// Set a specific value.
const uuid = "decafdec-afde-cafd-ecaf-decafdecafde";
Glean.user.clientId.set(uuid);

Recorded errors

  • invalid_value: if the value is set to a string that is not a UUID (only applies for dynamically-typed languages, such as Python).
  • invalid_type: if a non-string or non-UUID value is given.

Testing API

testGetValue

Gets the recorded value for a given UUID metric.
Returns a UUID if data is stored.
Returns a language-specific empty/null value if no data is stored. Has an optional argument to specify the name of the ping you wish to retrieve data from, except in Rust where it's required. None or no argument will default to the first value found for send_in_pings.

import org.mozilla.yourApplication.GleanMetrics.User

// Was it the expected value?
assertEquals(uuid, User.clientId.testGetValue())

import org.mozilla.yourApplication.GleanMetrics.User;

// Was it the expected value?
assertEquals(uuid, User.INSTANCE.clientId().testGetValue());

// Was it the expected value?
XCTAssertEqual(uuid, try User.clientId.testGetValue())

from glean import load_metrics
metrics = load_metrics("metrics.yaml")

# Was it the expected value?
assert uuid == metrics.user.client_id.test_get_value()

use uuid::Uuid;
use glean_metrics::user;

let u = Uuid::new_v4();
// Does it have the expected value?
assert_eq!(u, user::client_id.test_get_value(None).unwrap());

import * as user from "./path/to/generated/files/user.js";

const uuid = "decafdec-afde-cafd-ecaf-decafdecafde";
assert(uuid, await user.clientId.testGetValue());

C++

#include "mozilla/glean/GleanMetrics.h"

// Is it clear of errors?
ASSERT_TRUE(mozilla::glean::user::client_id.TestGetValue().isOk());
// Does it have an expected values?
ASSERT_STREQ(kUuid.get(), mozilla::glean::user::client_id.TestGetValue().unwrap().value().get());

JavaScript

const uuid = "decafdec-afde-cafd-ecaf-decafdecafde";
// testGetValue will throw NS_ERROR_LOSS_OF_SIGNIFICANT_DATA on error.
Assert.equal(Glean.user.clientId.testGetValue(), uuid);

testGetNumRecordedErrors

Gets the number of errors recorded for a given UUID metric.

import org.mozilla.yourApplication.GleanMetrics.User

assertEquals(
    0,
    User.clientId.testGetNumRecordedErrors(ErrorType.INVALID_VALUE)
)

import org.mozilla.yourApplication.GleanMetrics.User;

assertEquals(
    0,
    User.INSTANCE.clientId().testGetNumRecordedErrors(ErrorType.INVALID_VALUE)
);

XCTAssertEqual(0, User.clientId.testGetNumRecordedErrors(.invalidValue))

from glean import load_metrics
metrics = load_metrics("metrics.yaml")

from glean.testing import ErrorType

assert 0 == metrics.user.client_id.test_get_num_recorded_errors(
    ErrorType.INVALID_VALUE
)

use glean::ErrorType;
use glean_metrics::user;

assert_eq!(
  0,
  user::client_id.test_get_num_recorded_errors(
    ErrorType::InvalidValue
  )
);

import * as user from "./path/to/generated/files/user.js";
import { ErrorType } from "@mozilla/glean/error";

// Was the string truncated, and an error reported?
assert.strictEqual(
  0,
  await user.clientId.testGetNumRecordedErrors(ErrorType.InvalidValue)
);

Metric Parameters

You first need to add an entry for it to the metrics.yaml file:

user:
  client_id:
    type: uuid
    description: >
      A unique identifier for the client's profile
    bugs:
      - https://bugzilla.mozilla.org/000000
    data_reviews:
      - https://bugzilla.mozilla.org/show_bug.cgi?id=000000#c3
    notification_emails:
      - me@mozilla.com
    expires: 2020-10-01

For a full reference on metrics parameters common to all metric types, refer to the metrics YAML registry format reference page.

Extra metric parameters

N/A

Data questions

  • A unique identifier for the client.

Reference