WIP parser params and service change

- Check for array & flatten to string
- SHA 1 fingerprint
- Compare with parsed fingerprint

app/models/alert_management/alert.rb

@@ -135,6 +135,10 @@ module AlertManagement
       monitoring_tool == Gitlab::AlertManagement::AlertParams::MONITORING_TOOLS[:prometheus]
     end
 
+    def register_new_event!
+      increment!(:events, 1)
+    end
+
     private
 
     def hosts_length

app/services/projects/alerting/notify_service.rb

@@ -10,7 +10,7 @@ module Projects
         return forbidden unless alerts_service_activated?
         return unauthorized unless valid_token?(token)
 
-        alert = create_alert
+        alert = process_alert
         return bad_request unless alert.persisted?
 
         process_incident_issues(alert) if process_issues?
@@ -26,13 +26,29 @@ module Projects
       delegate :alerts_service, :alerts_service_activated?, to: :project
 
       def am_alert_params
-        Gitlab::AlertManagement::AlertParams.from_generic_alert(project: project, payload: params.to_h)
+        strong_memoize(:am_alert_params) do
+          Gitlab::AlertManagement::AlertParams.from_generic_alert(project: project, payload: params.to_h)
+        end
+      end
+
+      def process_alert
+        if alert = find_alert_by_fingerprint(am_alert_params[:fingerprint])
+          alert.register_new_event!
+        else
+          create_alert
+        end
       end
 
       def create_alert
         AlertManagement::Alert.create(am_alert_params)
       end
 
+      def find_alert_by_fingerprint(fingerprint)
+        return unless fingerprint
+
+        AlertManagement::Alert.for_fingerprint(project, fingerprint).first
+      end
+
       def send_email?
         incident_management_setting.send_email?
       end

changelogs/unreleased/214556-user-defined-alert-identification.yml

+---
+title: Set fingerprints and increment events count for Alert Management alerts
+merge_request: 32613
+author:
+type: added

doc/user/project/integrations/generic_alerts.md

@@ -28,7 +28,7 @@ To set up the generic alerts integration:
 
 ## Customizing the payload
 
-You can customize the payload by sending the following parameters. All fields are optional:
+You can customize the payload by sending the following parameters. All fields other than `title` are optional:
 
 | Property | Type | Description |
 | -------- | ---- | ----------- |
@@ -39,6 +39,7 @@ You can customize the payload by sending the following parameters. All fields ar
 | `monitoring_tool` | String |  The name of the associated monitoring tool. |
 | `hosts` | String or Array | One or more hosts, as to where this incident occurred. |
 | `severity` | String | The severity of the alert. Must be one of `critical`, `high`, `medium`, `low`, `info`, `unknown`. Default is `critical`. |
+| `fingerprint` | String or Array | The unique identifier of the alert. This can be used to group occurrences of the same alert. |
 
 TIP: **Payload size:**
 Ensure your requests are smaller than the [payload application limits](../../../administration/instance_limits.md#generic-alert-json-payloads).
@@ -65,5 +66,7 @@ Example payload:
   "service": "service affected",
   "monitoring_tool": "value",
   "hosts": "value",
+  "severity": "high",
+  "fingerprint": "d19381d4e8ebca87b55cda6e8eee7385"
 }
 ```

lib/gitlab/alert_management/alert_params.rb

@@ -20,7 +20,8 @@ module Gitlab
           hosts: Array(annotations[:hosts]),
           payload: payload,
           started_at: parsed_payload['startsAt'],
-          severity: annotations[:severity]
+          severity: annotations[:severity],
+          fingerprint: annotations[:fingerprint]
         }
       end
 

lib/gitlab/alert_management/fingerprint.rb

+# frozen_string_literal: true
+
+module Gitlab
+  module AlertManagement
+    class Fingerprint
+      def self.generate(data)
+        new.generate(data)
+      end
+
+      def generate(data)
+        return unless data.present?
+
+        if data.is_a?(Array)
+          data = flatten_array(data)
+        end
+
+        Digest::SHA1.hexdigest(data.to_s)
+      end
+
+      private
+
+      def flatten_array(array)
+        array.flatten.map!(&:to_s).join
+      end
+    end
+  end
+end

lib/gitlab/alerting/alert.rb

@@ -106,7 +106,7 @@ module Gitlab
       end
 
       def gitlab_fingerprint
-        Digest::SHA1.hexdigest(plain_gitlab_fingerprint)
+        Gitlab::AlertManagement::Fingerprint.generate(plain_gitlab_fingerprint)
       end
 
       def valid?

lib/gitlab/alerting/notification_payload_parser.rb

@@ -35,6 +35,10 @@ module Gitlab
         payload[:severity].presence || DEFAULT_SEVERITY
       end
 
+      def fingerprint
+        Gitlab::AlertManagement::Fingerprint.generate(payload[:fingerprint])
+      end
+
       def annotations
         primary_params
           .reverse_merge(flatten_secondary_params)
@@ -49,7 +53,8 @@ module Gitlab
           'monitoring_tool' => payload[:monitoring_tool],
           'service' => payload[:service],
           'hosts' => hosts.presence,
-          'severity' => severity
+          'severity' => severity,
+          'fingerprint' => fingerprint
         }
       end
 

spec/lib/gitlab/alert_management/alert_params_spec.rb

@@ -32,7 +32,8 @@ describe Gitlab::AlertManagement::AlertParams do
         severity: 'critical',
         hosts: ['gitlab.com'],
         payload: payload,
-        started_at: started_at
+        started_at: started_at,
+        fingerprint: nil
       )
     end
 

spec/lib/gitlab/alert_management/fingerprint_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe Gitlab::AlertManagement::Fingerprint do
+  using RSpec::Parameterized::TableSyntax
+
+  let_it_be(:alert) { create(:alert_management_alert) }
+
+  describe '.generate' do
+    subject { described_class.generate(data) }
+
+    context 'when data is an array' do
+      let(:data) { [1, 'fingerprint', 'given'] }
+
+      it 'flattens the array' do
+        expect_next_instance_of(described_class) do |obj|
+          expect(obj).to receive(:flatten_array)
+        end
+
+        subject
+      end
+
+      it 'returns the hashed fingerprint' do
+        expected_fingerprint = Digest::SHA1.hexdigest(data.flatten.map!(&:to_s).join)
+        expect(subject).to eq(expected_fingerprint)
+      end
+    end
+
+    context 'when data is a non-array type' do
+      where(:data) do
+        [
+          111,
+          'fingerprint',
+          :fingerprint,
+          true,
+          { test: true }
+        ]
+      end
+
+      with_them do
+        it 'performs like a hashed fingerprint' do
+          expect(subject).to eq(Digest::SHA1.hexdigest(data.to_s))
+        end
+      end
+    end
+  end
+end

spec/lib/gitlab/alerting/notification_payload_parser_spec.rb

 # frozen_string_literal: true
 
-require 'fast_spec_helper'
+require 'spec_helper'
 
 describe Gitlab::Alerting::NotificationPayloadParser do
   describe '.call' do
@@ -89,6 +89,39 @@ describe Gitlab::Alerting::NotificationPayloadParser do
       end
     end
 
+    context 'with fingerprint' do
+      before do
+        payload[:fingerprint] = data
+      end
+
+      shared_examples 'fingerprint generation' do
+        it 'generates the fingerprint correctly' do
+          expect(result).to eq(Gitlab::AlertManagement::Fingerprint.generate(data))
+        end
+      end
+
+      context 'with blank fingerprint' do
+        it_behaves_like 'fingerprint generation' do
+          let(:data) { '   ' }
+          let(:result) { subject.dig('annotations', 'fingerprint') }
+        end
+      end
+
+      context 'with fingerprint given' do
+        it_behaves_like 'fingerprint generation' do
+          let(:data) { 'fingerprint' }
+          let(:result) { subject.dig('annotations', 'fingerprint') }
+        end
+      end
+
+      context 'with array fingerprint given' do
+        it_behaves_like 'fingerprint generation' do
+          let(:data) { [1, 'fingerprint', 'given'] }
+          let(:result) { subject.dig('annotations', 'fingerprint') }
+        end
+      end
+    end
+
     context 'when payload attributes have blank lines' do
       let(:payload) do
         {

spec/models/alert_management/alert_spec.rb

@@ -317,4 +317,14 @@ describe AlertManagement::Alert do
       expect { subject }.to change { alert.reload.ended_at }.to nil
     end
   end
+
+  describe '#register_new_event!' do
+    subject { alert.register_new_event! }
+
+    let(:alert) { create(:alert_management_alert) }
+
+    it 'increments the events count by 1' do
+      expect { subject }.to change { alert.events}.by(1)
+    end
+  end
 end

spec/services/projects/alerting/notify_service_spec.rb

@@ -73,6 +73,7 @@ describe Projects::Alerting::NotifyService do
   describe '#execute' do
     let(:token) { 'invalid-token' }
     let(:starts_at) { Time.current.change(usec: 0) }
+    let(:fingerprint) { 'testing' }
     let(:service) { described_class.new(project, nil, payload) }
     let(:payload_raw) do
       {
@@ -82,7 +83,8 @@ describe Projects::Alerting::NotifyService do
         monitoring_tool: 'GitLab RSpec',
         service: 'GitLab Test Suite',
         description: 'Very detailed description',
-        hosts: ['1.1.1.1', '2.2.2.2']
+        hosts: ['1.1.1.1', '2.2.2.2'],
+        fingerprint: fingerprint
       }.with_indifferent_access
     end
     let(:payload) { ActionController::Parameters.new(payload_raw).permit! }
@@ -131,11 +133,23 @@ describe Projects::Alerting::NotifyService do
               description: payload_raw.fetch(:description),
               monitoring_tool: payload_raw.fetch(:monitoring_tool),
               service: payload_raw.fetch(:service),
-              fingerprint: nil,
+              fingerprint: Digest::SHA1.hexdigest(fingerprint),
               ended_at: nil
             )
           end
 
+          context 'existing alert with same fingerprint' do
+            let!(:existing_alert) { create(:alert_management_alert, project: project, fingerprint: Digest::SHA1.hexdigest(fingerprint)) }
+
+            it 'does not create AlertManagement::Alert' do
+              expect { subject }.not_to change(AlertManagement::Alert, :count)
+            end
+
+            it 'increments the existing alert count' do
+              expect { subject }.to change { existing_alert.reload.events }.from(1).to(2)
+            end
+          end
+
           context 'with a minimal payload' do
             let(:payload_raw) do
               {