Add config.metrics.before_emit callback

CHANGELOG.md

@@ -9,6 +9,7 @@
  - Add main APIs and `Aggregator` thread [#2247](https://github.com/getsentry/sentry-ruby/pull/2247)
  - Add `Sentry::Metrics.timing` API for measuring block duration [#2254](https://github.com/getsentry/sentry-ruby/pull/2254)
  - Add metric summaries on spans [#2255](https://github.com/getsentry/sentry-ruby/pull/2255)
+ - Add `config.metrics.before_emit` callback [#2258](https://github.com/getsentry/sentry-ruby/pull/2258)
 
  The SDK now supports recording and aggregating metrics. A new thread will be started
  for aggregation and will flush the pending data to Sentry every 5 seconds.
@@ -44,6 +45,18 @@
  Sentry::Metrics.timing('how_long') { sleep(1) }
  # timing - measure duration of code block in other duraton units
  Sentry::Metrics.timing('how_long_ms', unit: 'millisecond') { sleep(0.5) }
+
+ # add a before_emit callback to filter keys or update tags
+ Sentry.init do |config|
+ # ...
+ config.metrics.enabled = true
+ config.metrics.before_emit = lambda do |key, tags|
+ return nil if key == 'foo'
+ tags[:bar] = 42
+ tags.delete(:baz)
+ true
+ end
+ end
  ```
 
 ### Bug Fixes

sentry-ruby/lib/sentry/configuration.rb

@@ -576,12 +576,6 @@ def error_messages
 
  private
 
- def check_callable!(name, value)
- unless value == nil || value.respond_to?(:call)
- raise ArgumentError, "#{name} must be callable (or nil to disable)"
- end
- end
-
  def init_dsn(dsn_string)
  return if dsn_string.nil? || dsn_string.empty?
 

sentry-ruby/lib/sentry/metrics/aggregator.rb

@@ -24,6 +24,7 @@ class Aggregator
  def initialize(configuration, client)
  @client = client
  @logger = configuration.logger
+ @before_emit = configuration.metrics.before_emit
 
  @default_tags = {}
  @default_tags['release'] = configuration.release if configuration.release
@@ -55,8 +56,11 @@ def add(type,
  # this is integer division and thus takes the floor of the division
  # and buckets into 10 second intervals
  bucket_timestamp = (timestamp / ROLLUP_IN_SECONDS) * ROLLUP_IN_SECONDS
+ updated_tags = get_updated_tags(tags)
 
- serialized_tags = serialize_tags(get_updated_tags(tags))
+ return if @before_emit && !@before_emit.call(key, updated_tags)
+
+ serialized_tags = serialize_tags(updated_tags)
  bucket_key = [type, key, unit, serialized_tags]
 
  added = @mutex.synchronize do

sentry-ruby/lib/sentry/metrics/configuration.rb

@@ -3,15 +3,38 @@
 module Sentry
  module Metrics
  class Configuration
+ include ArgumentCheckingHelper
+
  # Enable metrics usage
  # Starts a new {Sentry::Metrics::Aggregator} instance to aggregate metrics
  # and a thread to aggregate flush every 5 seconds.
  # @return [Boolean]
  attr_accessor :enabled
 
+ # Optional Proc, called before emitting a metric to the aggregator.
+ # Use it to filter keys (return false/nil) or update tags.
+ # Make sure to return true at the end.
+ #
+ # @example
+ # config.metrics.before_emit = lambda do |key, tags|
+ # return nil if key == 'foo'
+ # tags[:bar] = 42
+ # tags.delete(:baz)
+ # true
+ # end
+ #
+ # @return [Proc, nil]
+ attr_reader :before_emit
+
  def initialize
  @enabled = false
  end
+
+ def before_emit=(value)
+ check_callable!("metrics.before_emit", value)
+
+ @before_emit = value
+ end
  end
  end
 end

sentry-ruby/lib/sentry/utils/argument_checking_helper.rb

@@ -15,5 +15,11 @@ def check_argument_includes!(argument, values)
  raise ArgumentError, "expect the argument to be one of #{values.map(&:inspect).join(' or ')}, got #{argument.inspect}"
  end
  end
+
+ def check_callable!(name, value)
+ unless value == nil || value.respond_to?(:call)
+ raise ArgumentError, "#{name} must be callable (or nil to disable)"
+ end
+ end
  end
 end

sentry-ruby/spec/sentry/metrics/aggregator_spec.rb

@@ -188,6 +188,38 @@
  expect(metric.value).to eq(Set[1])
  end
 
+ describe 'with before_emit callback' do
+ before do
+ perform_basic_setup do |config|
+ config.metrics.enabled = true
+ config.enable_tracing = true
+ config.release = 'test-release'
+ config.environment = 'test'
+ config.logger = Logger.new(string_io)
+
+ config.metrics.before_emit = lambda do |key, tags|
+ return nil if key == 'foo'
+ tags[:add_tag] = 42
+ tags.delete(:remove_tag)
+ true
+ end
+ end
+ end
+
+ it 'does not emit metric with filtered key' do
+ expect(Sentry::Metrics::CounterMetric).not_to receive(:new)
+ subject.add(:c, 'foo', 1)
+ expect(subject.buckets).to eq({})
+ end
+
+ it 'updates the tags according to the callback' do
+ subject.add(:c, 'bar', 1, tags: { remove_tag: 99 })
+ _, _, _, tags = subject.buckets.values.first.keys.first
+ expect(tags).not_to include(['remove_tag', '99'])
+ expect(tags).to include(['add_tag', '42'])
+ end
+ end
+
  describe 'local aggregation for span metric summaries' do
  it 'does nothing without an active scope span' do
  expect_any_instance_of(Sentry::Metrics::LocalAggregator).not_to receive(:add)

sentry-ruby/spec/sentry/metrics/configuration_spec.rb

@@ -0,0 +1,11 @@
+require 'spec_helper'
+
+RSpec.describe Sentry::Metrics::Configuration do
+ describe '#before_emit=' do
+ it 'raises error when setting before_emit to anything other than callable or nil' do
+ subject.before_emit = -> { }
+ subject.before_emit = nil
+ expect { subject.before_emit = true }.to raise_error(ArgumentError, 'metrics.before_emit must be callable (or nil to disable)')
+ end
+ end
+end