# frozen_string_literal: true

require 'spec_helper'

RSpec.describe Gitlab::Metrics::Subscribers::ActiveRecord do
  using RSpec::Parameterized::TableSyntax

  let(:env) { {} }
  let(:subscriber) { described_class.new }
  let(:connection) { double(:connection) }

  describe '#transaction' do
    let(:web_transaction) { double('Gitlab::Metrics::WebTransaction') }
    let(:background_transaction) { double('Gitlab::Metrics::WebTransaction') }

    let(:event) do
      double(
        :event,
        name: 'transaction.active_record',
        duration: 230,
        payload:  { connection: connection }
      )
    end

    before do
      allow(background_transaction).to receive(:observe)
      allow(web_transaction).to receive(:observe)
    end

    context 'when both web and background transaction are available' do
      before do
        allow(::Gitlab::Metrics::WebTransaction).to receive(:current)
          .and_return(web_transaction)
        allow(::Gitlab::Metrics::BackgroundTransaction).to receive(:current)
          .and_return(background_transaction)
      end

      it 'captures the metrics for web only' do
        expect(web_transaction).to receive(:observe).with(:gitlab_database_transaction_seconds, 0.23)

        expect(background_transaction).not_to receive(:observe)
        expect(background_transaction).not_to receive(:increment)

        subscriber.transaction(event)
      end
    end

    context 'when web transaction is available' do
      let(:web_transaction) { double('Gitlab::Metrics::WebTransaction') }

      before do
        allow(::Gitlab::Metrics::WebTransaction).to receive(:current)
          .and_return(web_transaction)
        allow(::Gitlab::Metrics::BackgroundTransaction).to receive(:current)
          .and_return(nil)
      end

      it 'captures the metrics for web only' do
        expect(web_transaction).to receive(:observe).with(:gitlab_database_transaction_seconds, 0.23)

        expect(background_transaction).not_to receive(:observe)
        expect(background_transaction).not_to receive(:increment)

        subscriber.transaction(event)
      end
    end

    context 'when background transaction is available' do
      let(:background_transaction) { double('Gitlab::Metrics::BackgroundTransaction') }

      before do
        allow(::Gitlab::Metrics::WebTransaction).to receive(:current)
          .and_return(nil)
        allow(::Gitlab::Metrics::BackgroundTransaction).to receive(:current)
          .and_return(background_transaction)
      end

      it 'captures the metrics for web only' do
        expect(background_transaction).to receive(:observe).with(:gitlab_database_transaction_seconds, 0.23)

        expect(web_transaction).not_to receive(:observe)
        expect(web_transaction).not_to receive(:increment)

        subscriber.transaction(event)
      end
    end
  end

  describe '#sql' do
    let(:payload) { { sql: 'SELECT * FROM users WHERE id = 10', connection: connection } }

    let(:event) do
      double(
        :event,
        name: 'sql.active_record',
        duration: 2,
        payload:  payload
      )
    end

    # Emulate Marginalia pre-pending comments
    def sql(query, comments: true)
      if comments && !%w[BEGIN COMMIT].include?(query)
        "/*application:web,controller:badges,action:pipeline,correlation_id:01EYN39K9VMJC56Z7808N7RSRH*/ #{query}"
      else
        query
      end
    end

    shared_examples 'track generic sql events' do
      where(:name, :sql_query, :record_query, :record_write_query, :record_cached_query) do
        'SQL' | 'SELECT * FROM users WHERE id = 10' | true | false | false
        'SQL' | 'WITH active_milestones AS (SELECT COUNT(*), state FROM milestones GROUP BY state) SELECT * FROM active_milestones' | true | false | false
        'SQL' | 'SELECT * FROM users WHERE id = 10 FOR UPDATE' | true | true | false
        'SQL' | 'WITH archived_rows AS (SELECT * FROM users WHERE archived = true) INSERT INTO products_log SELECT * FROM archived_rows' | true | true | false
        'SQL' | 'DELETE FROM users where id = 10' | true | true | false
        'SQL' | 'INSERT INTO project_ci_cd_settings (project_id) SELECT id FROM projects' | true | true | false
        'SQL' | 'UPDATE users SET admin = true WHERE id = 10' | true | true | false
        'CACHE' | 'SELECT * FROM users WHERE id = 10' | true | false | true
        'SCHEMA' | "SELECT attr.attname FROM pg_attribute attr INNER JOIN pg_constraint cons ON attr.attrelid = cons.conrelid AND attr.attnum = any(cons.conkey) WHERE cons.contype = 'p' AND cons.conrelid = '\"projects\"'::regclass" | false | false | false
        nil | 'BEGIN' | false | false | false
        nil | 'COMMIT' | false | false | false
      end

      with_them do
        let(:payload) { { name: name, sql: sql(sql_query, comments: comments), connection: connection } }
        let(:record_wal_query) { false }

        it 'marks the current thread as using the database' do
          # since it would already have been toggled by other specs
          Thread.current[:uses_db_connection] = nil

          expect { subscriber.sql(event) }.to change { Thread.current[:uses_db_connection] }.from(nil).to(true)
        end

        it_behaves_like 'record ActiveRecord metrics'
        it_behaves_like 'store ActiveRecord info in RequestStore'
      end
    end

    context 'without Marginalia comments' do
      let(:comments) { false }

      it_behaves_like 'track generic sql events'
    end

    context 'with Marginalia comments' do
      let(:comments) { true }

      it_behaves_like 'track generic sql events'
    end
  end

  context 'Database Load Balancing enabled' do
    let(:payload) { { sql: 'SELECT * FROM users WHERE id = 10', connection: connection } }

    let(:event) do
      double(
        :event,
        name: 'sql.active_record',
        duration: 2,
        payload:  payload
      )
    end

    # Emulate Marginalia pre-pending comments
    def sql(query, comments: true)
      if comments && !%w[BEGIN COMMIT].include?(query)
        "/*application:web,controller:badges,action:pipeline,correlation_id:01EYN39K9VMJC56Z7808N7RSRH*/ #{query}"
      else
        query
      end
    end

    shared_examples 'track sql events for each role' do
      where(:name, :sql_query, :record_query, :record_write_query, :record_cached_query, :record_wal_query) do
        'SQL' | 'SELECT * FROM users WHERE id = 10' | true | false | false | false
        'SQL' | 'WITH active_milestones AS (SELECT COUNT(*), state FROM milestones GROUP BY state) SELECT * FROM active_milestones' | true | false | false | false
        'SQL' | 'SELECT * FROM users WHERE id = 10 FOR UPDATE' | true | true | false | false
        'SQL' | 'WITH archived_rows AS (SELECT * FROM users WHERE archived = true) INSERT INTO products_log SELECT * FROM archived_rows' | true | true | false | false
        'SQL' | 'DELETE FROM users where id = 10' | true | true | false | false
        'SQL' | 'INSERT INTO project_ci_cd_settings (project_id) SELECT id FROM projects' | true | true | false | false
        'SQL' | 'UPDATE users SET admin = true WHERE id = 10' | true | true | false | false
        'SQL' | 'SELECT pg_current_wal_insert_lsn()::text AS location' | true | false | false | true
        'SQL' | 'SELECT pg_last_wal_replay_lsn()::text AS location' | true | false | false | true
        'CACHE' | 'SELECT * FROM users WHERE id = 10' | true | false | true | false
        'SCHEMA' | "SELECT attr.attname FROM pg_attribute attr INNER JOIN pg_constraint cons ON attr.attrelid = cons.conrelid AND attr.attnum = any(cons.conkey) WHERE cons.contype = 'p' AND cons.conrelid = '\"projects\"'::regclass" | false | false | false | false
        nil | 'BEGIN' | false | false | false | false
        nil | 'COMMIT' | false | false | false | false
      end

      with_them do
        let(:payload) { { name: name, sql: sql(sql_query, comments: comments), connection: connection } }

        before do
          allow(Gitlab::Database::LoadBalancing).to receive(:enable?).and_return(true)
        end

        context 'query using a connection to a replica' do
          before do
            allow(Gitlab::Database::LoadBalancing).to receive(:db_role_for_connection).and_return(:replica)
          end

          it 'queries connection db role' do
            subscriber.sql(event)

            if record_query
              expect(Gitlab::Database::LoadBalancing).to have_received(:db_role_for_connection).with(connection)
            end
          end

          it_behaves_like 'record ActiveRecord metrics', :replica
          it_behaves_like 'store ActiveRecord info in RequestStore', :replica
        end

        context 'query using a connection to a primary' do
          before do
            allow(Gitlab::Database::LoadBalancing).to receive(:db_role_for_connection).and_return(:primary)
          end

          it 'queries connection db role' do
            subscriber.sql(event)

            if record_query
              expect(Gitlab::Database::LoadBalancing).to have_received(:db_role_for_connection).with(connection)
            end
          end

          it_behaves_like 'record ActiveRecord metrics', :primary
          it_behaves_like 'store ActiveRecord info in RequestStore', :primary
        end

        context 'query using a connection to an unknown source' do
          let(:transaction) { double('Gitlab::Metrics::WebTransaction') }

          before do
            allow(Gitlab::Database::LoadBalancing).to receive(:db_role_for_connection).and_return(nil)

            allow(::Gitlab::Metrics::WebTransaction).to receive(:current).and_return(transaction)
            allow(::Gitlab::Metrics::BackgroundTransaction).to receive(:current).and_return(nil)

            allow(transaction).to receive(:increment)
            allow(transaction).to receive(:observe)
          end

          it 'does not record DB role metrics' do
            expect(transaction).not_to receive(:increment).with("gitlab_transaction_db_primary_count_total".to_sym, any_args)
            expect(transaction).not_to receive(:increment).with("gitlab_transaction_db_replica_count_total".to_sym, any_args)

            expect(transaction).not_to receive(:increment).with("gitlab_transaction_db_primary_cached_count_total".to_sym, any_args)
            expect(transaction).not_to receive(:increment).with("gitlab_transaction_db_replica_cached_count_total".to_sym, any_args)

            expect(transaction).not_to receive(:observe).with("gitlab_sql_primary_duration_seconds".to_sym, any_args)
            expect(transaction).not_to receive(:observe).with("gitlab_sql_replica_duration_seconds".to_sym, any_args)

            subscriber.sql(event)
          end

          it 'does not store DB roles into into RequestStore' do
            Gitlab::WithRequestStore.with_request_store do
              subscriber.sql(event)

              expect(described_class.db_counter_payload).to include(
                db_primary_cached_count: 0,
                db_primary_count: 0,
                db_primary_duration_s: 0,
                db_replica_cached_count: 0,
                db_replica_count: 0,
                db_replica_duration_s: 0
              )
            end
          end
        end
      end
    end

    context 'without Marginalia comments' do
      let(:comments) { false }

      it_behaves_like 'track sql events for each role'
    end

    context 'with Marginalia comments' do
      let(:comments) { true }

      it_behaves_like 'track sql events for each role'
    end
  end
end