feat: add /metrics endpoint

lib/pact_broker/api.rb

@@ -91,6 +91,7 @@ module PactBroker
 
         add ['integrations'], Api::Resources::Integrations, {resource_name: "integrations"}
         add ['integrations', 'provider', :provider_name, 'consumer', :consumer_name], Api::Resources::Integration, {resource_name: "integration"}
+        add ['metrics'], Api::Resources::Metrics, {resource_name: 'metrics'}
         add [], Api::Resources::Index, {resource_name: "index"}
       end
     end

lib/pact_broker/api/resources/index.rb

@@ -106,6 +106,11 @@ def links
               title: "Get, create or delete a tag for a pacticipant version",
               templated: true
             },
+            'pb:metrics' =>
+            {
+              href: base_url + '/metrics',
+              title: "Get Pact Broker metrics",
+            },
             'beta:pending-provider-pacts' =>
             {
               href: base_url + '/pacts/provider/{provider}/pending',

lib/pact_broker/api/resources/metrics.rb

@@ -0,0 +1,21 @@
+require 'pact_broker/api/resources/base_resource'
+
+module PactBroker
+  module Api
+    module Resources
+      class Metrics < BaseResource
+        def content_types_provided
+          [["application/hal+json", :to_json]]
+        end
+
+        def allowed_methods
+          ["GET", "OPTIONS"]
+        end
+
+        def to_json
+          metrics_service.metrics.to_json
+        end
+      end
+    end
+  end
+end

lib/pact_broker/metrics/service.rb

@@ -0,0 +1,56 @@
+require 'pact_broker/pacts/pact_publication'
+require 'pact_broker/pacts/pact_version'
+require 'pact_broker/domain/pacticipant'
+require 'pact_broker/integrations/integration'
+require 'pact_broker/domain/verification'
+require 'pact_broker/domain/version'
+require 'pact_broker/api/decorators/format_date_time'
+require 'pact_broker/webhooks/webhook'
+require 'pact_broker/webhooks/triggered_webhook'
+require 'pact_broker/webhooks/execution'
+
+module PactBroker
+  module Metrics
+    module Service
+      include PactBroker::Api::Decorators::FormatDateTime
+
+      extend self
+
+      def metrics
+        {
+          pacticipants: {
+            count: PactBroker::Domain::Pacticipant.count
+          },
+          integrations: {
+            count: PactBroker::Integrations::Integration.count
+          },
+          pactPublications: {
+            count: PactBroker::Pacts::PactPublication.count,
+            first: format_date_time(PactBroker::Pacts::PactPublication.order(:id).first&.created_at),
+            last: format_date_time(PactBroker::Pacts::PactPublication.order(:id).last&.created_at)
+          },
+          pactVersions: {
+            count: PactBroker::Pacts::PactVersion.count
+          },
+          verificationResults: {
+            count: PactBroker::Domain::Verification.count,
+            first: format_date_time(PactBroker::Domain::Verification.order(:id).first.created_at),
+            last: format_date_time(PactBroker::Domain::Verification.order(:id).last.created_at)
+          },
+          pacticipantVersions: {
+            count: PactBroker::Domain::Version.count
+          },
+          webhooks: {
+            count: PactBroker::Webhooks::Webhook.count
+          },
+          triggeredWebhooks: {
+            count: PactBroker::Webhooks::TriggeredWebhook.count
+          },
+          webhookExecutions: {
+            count: PactBroker::Webhooks::Execution.count
+          }
+        }
+      end
+    end
+  end
+end

lib/pact_broker/services.rb

@@ -71,5 +71,10 @@ def webhook_trigger_service
       require 'pact_broker/webhooks/trigger_service'
       Webhooks::TriggerService
     end
+
+    def metrics_service
+      require 'pact_broker/metrics/service'
+      Metrics::Service
+    end
   end
 end

spec/features/metrics_spec.rb

@@ -0,0 +1,23 @@
+describe "get metrics" do
+  let(:path) { "/metrics"}
+  let(:json_response_body) { JSON.parse(subject.body, symbolize_names: true) }
+
+  subject { get(path)  }
+
+  before do
+    TestDataBuilder.new
+      .create_consumer("Consumer")
+      .create_provider("Provider")
+      .create_consumer_version("1.2.3")
+      .create_consumer_version_tag("prod")
+      .create_pact
+      .create_verification(provider_version: "4.5.6")
+      .create_webhook
+      .create_triggered_webhook
+      .create_webhook_execution
+  end
+
+  it "returns some metrics" do
+    expect(json_response_body).to be_instance_of(Hash)
+  end
+end