Record submission counts

Gemfile

@@ -62,7 +62,9 @@ gem "lograge"
 
 # For distributed tracing and telemetry
 gem "opentelemetry-exporter-otlp", "~> 0.34.1"
+gem "opentelemetry-exporter-otlp-metrics", "~> 0.10.0"
 gem "opentelemetry-instrumentation-all", "~> 0.94.0"
+gem "opentelemetry-metrics-sdk", "~> 0.15.0"
 gem "opentelemetry-propagator-xray", "~> 0.27.0"
 gem "opentelemetry-sdk", "~> 1.12"
 

Gemfile.lock

@@ -358,6 +358,15 @@ GEM
       opentelemetry-common (~> 0.20)
       opentelemetry-sdk (~> 1.10)
       opentelemetry-semantic_conventions
+    opentelemetry-exporter-otlp-metrics (0.10.0)
+      google-protobuf (>= 3.18, < 5.0)
+      googleapis-common-protos-types (~> 1.3)
+      opentelemetry-api (~> 1.1)
+      opentelemetry-common (~> 0.20)
+      opentelemetry-metrics-api (~> 0.2)
+      opentelemetry-metrics-sdk (~> 0.5)
+      opentelemetry-sdk (~> 1.2)
+      opentelemetry-semantic_conventions
     opentelemetry-helpers-mysql (0.6.0)
       opentelemetry-api (~> 1.7)
       opentelemetry-common (~> 0.21)
@@ -512,6 +521,12 @@ GEM
       opentelemetry-helpers-sql-processor
       opentelemetry-instrumentation-base (~> 0.25)
       opentelemetry-semantic_conventions (>= 1.8.0)
+    opentelemetry-metrics-api (0.6.1)
+      opentelemetry-api (~> 1.0)
+    opentelemetry-metrics-sdk (0.15.0)
+      opentelemetry-api (~> 1.1)
+      opentelemetry-metrics-api (~> 0.2)
+      opentelemetry-sdk (~> 1.2)
     opentelemetry-propagator-xray (0.27.0)
       opentelemetry-api (~> 1.7)
     opentelemetry-registry (0.6.3)
@@ -776,7 +791,9 @@ DEPENDENCIES
   omniauth-rails_csrf_protection
   omniauth_govuk_one_login!
   opentelemetry-exporter-otlp (~> 0.34.1)
+  opentelemetry-exporter-otlp-metrics (~> 0.10.0)
   opentelemetry-instrumentation-all (~> 0.94.0)
+  opentelemetry-metrics-sdk (~> 0.15.0)
   opentelemetry-propagator-xray (~> 0.27.0)
   opentelemetry-sdk (~> 1.12)
   pg (~> 1.6)
@@ -918,6 +935,7 @@ CHECKSUMS
   opentelemetry-api (1.10.1) sha256=5db9535a8aa9e569808518aa103b2cfac44728672a1799e1dd217fe6d9c5642e
   opentelemetry-common (0.25.1) sha256=38fe87c751e4e13fcd47a8290b4ad67bbedf76c4ed89aeced5ea5c620e66bfb1
   opentelemetry-exporter-otlp (0.34.1) sha256=4697d81e03aff80ea6fbcc741b1c3c700d3624eddea14b453602ee23275450ca
+  opentelemetry-exporter-otlp-metrics (0.10.0) sha256=d8cbff9b8a3391eb61486b8be9b6ad74e3b9306a3c60fb4c906b28bc857167c8
   opentelemetry-helpers-mysql (0.6.0) sha256=7eeb5e6950c434775a8cf28b5fde4defc12e8b865c86479ce3119fcf593d9337
   opentelemetry-helpers-sql (0.4.0) sha256=b10e8c3a2cca28a98af951bbb3e4efdc59e68b25ba0825e055574af543420afb
   opentelemetry-helpers-sql-processor (0.5.0) sha256=b199241bc9451fcbd9f00b2f454830af19d4ca27c2219ea379c9b0d53cd0e0f1
@@ -967,6 +985,8 @@ CHECKSUMS
   opentelemetry-instrumentation-sidekiq (0.29.0) sha256=b1d2a0cb9041a5e14239fe7c94d99e3dd07f870e2759460ab63592d7cdd8aadc
   opentelemetry-instrumentation-sinatra (0.30.0) sha256=b67301153420f43264a0c68cdb3ca5bd77467cf5054e57b83a2bf891aaaa0361
   opentelemetry-instrumentation-trilogy (0.69.0) sha256=0676dd720eeab284abfa52f273967442156fcac7084a1e1411373cf14ec026ad
+  opentelemetry-metrics-api (0.6.1) sha256=e1785d317c0b4fe5bb128ab9dd4644486107fe28fba844f5329bf3db90aaa5ec
+  opentelemetry-metrics-sdk (0.15.0) sha256=611a9cd9f473c461095c7401b8c25f9774160d286a1acbfcbf044da2972aeada
   opentelemetry-propagator-xray (0.27.0) sha256=753f756c7ad3146f182d428b06041084eecc77769edfd280f365e0bc09b9c4d1
   opentelemetry-registry (0.6.3) sha256=568fa8eaea94394f29f4fce3f0339ab10c3bf6d6c8beed6b3cfee6fd37fcc608
   opentelemetry-sdk (1.12.0) sha256=a224abe0c59023d41cb7ac1c634d9d28843907efcd045ed1ae320796c48b864b

app/services/form_submission_service.rb

@@ -29,6 +29,8 @@ def submit
     submission = create_submission_record
     enqueue_deliveries(submission)
 
+    Metrics.record_submission(form_id: form.id, form_name: form.name, mode:)
+
     LogEventService.log_submit(
       current_context,
       requested_email_confirmation: requested_confirmation?,

app/services/metrics.rb

@@ -0,0 +1,45 @@
+module Metrics
+  METER_NAME = "forms-runner".freeze
+  METER_VERSION = "1.0".freeze
+
+  # Forms with these names are used for automated testing of the platform
+  TEST_FORM_NAME_PATTERNS = [/\Acapybara/, /smoke/, /\As3/].freeze
+
+  class << self
+    def record_submission(form_id:, form_name:, mode:)
+      submission_counter.add(
+        1,
+        attributes: {
+          "form.id" => form_id.to_s,
+          "form.submission.mode" => mode_label(form_name:, mode:),
+        },
+      )
+    rescue StandardError => e
+      Sentry.capture_exception(e)
+    end
+
+  private
+
+    def mode_label(form_name:, mode:)
+      return "test" if test_form?(form_name)
+
+      mode.to_s
+    end
+
+    def test_form?(form_name)
+      TEST_FORM_NAME_PATTERNS.any? { |pattern| pattern.match?(form_name.to_s) }
+    end
+
+    def submission_counter
+      @submission_counter ||= meter.create_counter(
+        "form.submission.created",
+        unit: "{submission}",
+        description: "The number of form submissions queued for delivery",
+      )
+    end
+
+    def meter
+      @meter ||= OpenTelemetry.meter_provider.meter(METER_NAME, version: METER_VERSION)
+    end
+  end
+end

config/initializers/opentelemetry.rb

@@ -1,5 +1,7 @@
 require "opentelemetry/sdk"
 require "opentelemetry/instrumentation/all"
+require "opentelemetry-metrics-sdk"
+require "opentelemetry-exporter-otlp-metrics"
 
 return unless ENV["ENABLE_OTEL"] == "true"
 
@@ -12,6 +14,14 @@
     c.id_generator = OpenTelemetry::Propagator::XRay::IDGenerator
   end
 
+  unless ENV.fetch("OTEL_METRICS_EXPORTER", "otlp") == "none"
+    c.add_metric_reader(
+      OpenTelemetry::SDK::Metrics::Export::PeriodicMetricReader.new(
+        exporter: OpenTelemetry::Exporter::OTLP::Metrics::MetricsExporter.new,
+      ),
+    )
+  end
+
   # Disable logging for Rake tasks to avoid cluttering output
   c.logger = Logger.new(File::NULL) if Rails.const_defined?(:Rake) && Rake.application.top_level_tasks.any?
 end

spec/services/form_submission_service_spec.rb

@@ -98,6 +98,16 @@
       expect(log_line["submission_reference"]).to eq(reference)
     end
 
+    it "records a submission count metric" do
+      expect(Metrics).to receive(:record_submission).with(
+        form_id: form.id,
+        form_name: form.name,
+        mode:,
+      )
+
+      service.submit
+    end
+
     shared_examples "logging" do
       it "logs submission" do
         allow(LogEventService).to receive(:log_submit).once
@@ -152,6 +162,12 @@
             allow(SendS3SubmissionJob).to receive(:perform_later).and_yield(instance_double(SendS3SubmissionJob, successfully_enqueued?: false, enqueue_error:))
           end
 
+          it "does not record a submission count metric" do
+            expect(Metrics).not_to receive(:record_submission)
+
+            expect { service.submit }.to raise_error(StandardError)
+          end
+
           context "and there is no enqueue error" do
             it "raises an error" do
               expect { service.submit }
@@ -238,6 +254,12 @@
             allow(SendSubmissionJob).to receive(:perform_later).and_yield(instance_double(SendSubmissionJob, successfully_enqueued?: false, enqueue_error:))
           end
 
+          it "does not record a submission count metric" do
+            expect(Metrics).not_to receive(:record_submission)
+
+            expect { service.submit }.to raise_error(StandardError)
+          end
+
           context "and there is no enqueue error" do
             it "raises an error" do
               expect { service.submit }

spec/services/metrics_spec.rb

@@ -0,0 +1,141 @@
+require "rails_helper"
+require "opentelemetry-metrics-sdk"
+
+describe Metrics do
+  let(:meter_provider) { OpenTelemetry::SDK::Metrics::MeterProvider.new }
+  let(:metric_exporter) { OpenTelemetry::SDK::Metrics::Export::InMemoryMetricPullExporter.new }
+  let(:form_id) { 42 }
+  let(:form_name) { "Apply for a juggling licence" }
+  let(:mode) { Mode.new("form") }
+
+  before do
+    allow(OpenTelemetry).to receive(:meter_provider).and_return(meter_provider)
+    meter_provider.add_metric_reader(metric_exporter)
+    reset_memoized_instruments
+  end
+
+  after do
+    reset_memoized_instruments
+  end
+
+  describe ".record_submission" do
+    it "records a submission count metric" do
+      described_class.record_submission(form_id:, form_name:, mode:)
+
+      expect(exported_data_points).to contain_exactly(
+        have_attributes(
+          value: 1,
+          attributes: {
+            "form.id" => form_id.to_s,
+            "form.submission.mode" => "form",
+          },
+        ),
+      )
+    end
+
+    context "when mode is preview" do
+      let(:mode) { Mode.new("preview-live") }
+
+      it "records a metric with the preview mode label" do
+        described_class.record_submission(form_id:, form_name:, mode:)
+
+        expect(exported_data_points).to contain_exactly(
+          have_attributes(
+            value: 1,
+            attributes: include("form.submission.mode" => "preview-live"),
+          ),
+        )
+      end
+    end
+
+    it "accumulates counts for the same form" do
+      2.times { described_class.record_submission(form_id:, form_name:, mode:) }
+
+      expect(exported_data_points).to contain_exactly(
+        have_attributes(
+          value: 2,
+          attributes: include("form.id" => form_id.to_s),
+        ),
+      )
+    end
+
+    it "records separate counts per form" do
+      described_class.record_submission(form_id:, form_name:, mode:)
+      described_class.record_submission(form_id: 99, form_name:, mode:)
+
+      expect(exported_data_points).to contain_exactly(
+        have_attributes(
+          value: 1,
+          attributes: include("form.id" => form_id.to_s),
+        ),
+        have_attributes(
+          value: 1,
+          attributes: include("form.id" => "99"),
+        ),
+      )
+    end
+
+    it "records separate counts per mode" do
+      described_class.record_submission(form_id:, form_name:, mode:)
+      described_class.record_submission(form_id:, form_name:, mode: Mode.new("preview-draft"))
+
+      expect(exported_data_points).to contain_exactly(
+        have_attributes(
+          value: 1,
+          attributes: include("form.submission.mode" => "form"),
+        ),
+        have_attributes(
+          value: 1,
+          attributes: include("form.submission.mode" => "preview-draft"),
+        ),
+      )
+    end
+
+    context "when the form is a test form" do
+      [
+        "capybara test form",
+        "Automated smoke test form",
+        "s3 submission test form",
+      ].each do |test_form_name|
+        context "with the name #{test_form_name.inspect}" do
+          let(:form_name) { test_form_name }
+
+          it "records a metric with the test mode label" do
+            described_class.record_submission(form_id:, form_name:, mode:)
+
+            expect(exported_data_points).to contain_exactly(
+              have_attributes(
+                value: 1,
+                attributes: include("form.submission.mode" => "test"),
+              ),
+            )
+          end
+        end
+      end
+    end
+
+    context "when recording the metric raises an error" do
+      let(:error) { StandardError.new("metrics unavailable") }
+
+      before do
+        allow(described_class).to receive(:submission_counter).and_raise(error)
+      end
+
+      it "captures the exception in Sentry and does not raise" do
+        expect(Sentry).to receive(:capture_exception).with(error)
+
+        expect { described_class.record_submission(form_id:, form_name:, mode:) }.not_to raise_error
+      end
+    end
+  end
+
+  def exported_data_points
+    metric_exporter.pull
+    metric_exporter.metric_snapshots.flat_map(&:data_points)
+  end
+
+  def reset_memoized_instruments
+    described_class.instance_variable_set(:@meter, nil)
+    described_class.instance_variable_set(:@submission_counter, nil)
+  end
+end