Set Up Metrics

npx @sentry/dotagents add getsentry/sentry-agent-skills --name sentry-setup-metrics

Sentry metrics help you pinpoint and solve issues that impact user experience and app performance by measuring the data points that are important to you. You can track things like processing time, event size, user signups, and conversion rates, then correlate them back to tracing data in order to get deeper insights and solve issues faster.

Once in Sentry, these metrics can be viewed alongside relevant errors, and searched using their individual attributes.

Requirements

Metrics for Ruby are supported in Sentry Ruby SDK version 6.3.0 and above.

gem install sentry-ruby

Or add it to your Gemfile:

gem "sentry-ruby"

Usage

Metrics are enabled by default. Once you initialize the SDK, you can send metrics using the Sentry.metrics APIs.

The metrics namespace exposes three methods that you can use to capture different types of metric information: count, gauge, and distribution.

Emit a Counter

Counters are one of the more basic types of metrics and can be used to count certain event occurrences.

To emit a counter, do the following:

# Record five total button clicks
Sentry.metrics.count(
	"button_click",
	value: 5,
	attributes: { browser: "Firefox", app_version: "1.0.0" }
)

Emit a Distribution

Distributions help you get the most insights from your data by allowing you to obtain aggregations such as p90, min, max, and avg.

To emit a distribution, do the following:

# Add '15.0' to a distribution used for tracking the loading times per page.
Sentry.metrics.distribution(
	"page_load",
	15.0,
	unit: "millisecond",
	attributes: { page: "/home" }
)

Emit a Gauge

Gauges let you obtain aggregates like min, max, avg, sum, and count. They can be represented in a more space-efficient way than distributions, but they can't be used to get percentiles. If percentiles aren't important to you, we recommend using gauges.

To emit a gauge, do the following:

# Add '15.0' to a gauge used for tracking the loading times for a page.
Sentry.metrics.gauge(
	"page_load",
	15.0,
	unit: "millisecond",
	attributes: { "page": "/home" }
)

Options

before_send_metric

To filter metrics, or update them before they are sent to Sentry, you can use the before_send_metric option. If the callback returns nil, the metric is not emitted. Attributes can also be updated in the callback function.

Sentry.init do |config|
  config.dsn = "___PUBLIC_DSN___"

  config.before_send_metric = lambda do |metric|
    # filter metric
    return nil if metric.name == "removed-metric"

    # add attributes
    metric.attributes[:extra] = "foo"

    # remove attributes
    metric.attributes.delete(:browser) if metric.attributes.has_key?(:browser)

    metric
  end
end

The before_send_metric function receives a MetricEvent object, and should return a MetricEvent object if you want it to be sent to Sentry, or nil if you want to discard it.

The MetricEvent object has the following attributes:

• name: (String) The name of the metric.
• type: (Symbol) - one of :counter, :gauge, :distribution) The type of metric.
• value: (Float) The numeric value of the metric.
• unit: (Optional[String]) The unit of measurement for the metric value.
• attributes: (Hash) Additional attributes to be sent with the metric.
• timestamp: (Time) Timestamp indicating when the metric was recorded.
• trace_id: (Optional[String]) The trace ID of the trace this metric belongs to.
• span_id: (Optional[String]) The span ID of the span that was active when the metric was emitted.

Default Attributes

The Ruby SDK automatically sets several default attributes on all metrics to provide context and improve debugging:

Core Attributes

• environment: The environment set in the SDK if defined. This is sent from the SDK as sentry.environment.
• release: The release set in the SDK if defined. This is sent from the SDK as sentry.release.
• sdk.name: The name of the SDK that sent the metric. This is sent from the SDK as sentry.sdk.name.
• sdk.version: The version of the SDK that sent the metric. This is sent from the SDK as sentry.sdk.version.

Server Attributes

• server.address: The address of the server that sent the metric. Equivalent to server_name that gets attached to Sentry errors.

User Attributes

If user information is available in the current scope, the following attributes are added to the metric:

• user.id: The user ID.
• user.name: The username.
• user.email: The email address.