Deprecate prometheus.enable and prometheus.listen_address

We introduced `prometheus.server_address` setting in `gitlab.yml` which
is to be Rails application's SSOT regarding a Prometheus address.
Hence, we can deprecate the existing settings `enable` and
`listen_address`.

Changes:
* To `Gitlab::Prometheus::Internal` class methods:
  * `server_address` method renamed to `uri_without_protocol`, to
    reflect what the method actually does.
  * `listen_address` method renamed to `server_address`.
  * `promtheus_enabled?` method now depends on presence of
    `server_address`.

* To `Gitlab::DatabaseImporters::SelfMonitoring::Project::CreateService`
  class methods:
  * `prometheus_listen_address` method renamed to
    `prometheus_server_address`.
  * `internal_prometheus_listen_address_uri` renamed to
    `internal_prometheus_server_address_uri`.
Signed-off-by: Balasankar "Balu" C <balasankarc@autistici.org>

changelogs/unreleased/deprecate-prometheus-listen-address.yml

+---
+title: Deprecate prometheus.listen_address and prometheus.enable
+merge_request: 50500
+author:
+type: deprecated

config/gitlab.yml.example

@@ -1207,10 +1207,7 @@ production: &base
   # yourself, and then update the values here.
   # https://docs.gitlab.com/ee/administration/monitoring/prometheus/
   prometheus:
-    # Do not use `enable` and `listen_address` in any new code, as they are deprecated. Use `server_address` instead.
-    # https://gitlab.com/gitlab-org/gitlab/-/issues/227111
-    # enable: true
-    # listen_address: 'localhost:9090'
+    # enabled: true
     # server_address: 'localhost:9090'
 
   ## Consul settings
@@ -1499,8 +1496,8 @@ test:
         group_base: 'ou=groups,dc=example,dc=com'
         admin_group: ''
   prometheus:
-    enable: true
-    listen_address: 'localhost:9090'
+    enabled: true
+    server_address: 'localhost:9090'
 
 staging:
   <<: *base

config/initializers/1_settings.rb

@@ -851,6 +851,18 @@ Settings.monitoring.web_exporter['enabled'] ||= false
 Settings.monitoring.web_exporter['address'] ||= 'localhost'
 Settings.monitoring.web_exporter['port'] ||= 8083
 
+#
+# Prometheus settings
+#
+Settings['prometheus'] ||= Settingslogic.new({})
+# TODO: Remove listen_address and enable in GitLab 14.0 and set default value
+# of server_address to be nil and enabled to be false -
+# https://gitlab.com/gitlab-org/gitlab/-/issues/296022
+Settings.prometheus['enable'] ||= false
+Settings.prometheus['listen_address'] ||= nil
+Settings.prometheus['enabled'] = Settings.prometheus['enable'] if Settings.prometheus['enabled'].nil?
+Settings.prometheus['server_address'] ||= Settings.prometheus['listen_address']
+
 #
 # Shutdown settings
 #

lib/gitlab/database_importers/self_monitoring/project/create_service.rb

@@ -75,7 +75,7 @@ module Gitlab
 
             if response
               # In the add_prometheus_manual_configuration method, the Prometheus
-              # listen_address config is saved as an api_url in the PrometheusService
+              # server_address config is saved as an api_url in the PrometheusService
               # model. There are validates hooks in the PrometheusService model that
               # check if the project associated with the PrometheusService is the
               # self_monitoring project. It checks
@@ -105,7 +105,7 @@ module Gitlab
 
           def add_prometheus_manual_configuration(result)
             return success(result) unless prometheus_enabled?
-            return success(result) unless prometheus_listen_address.present?
+            return success(result) unless prometheus_server_address.present?
 
             service = result[:project].find_or_initialize_service('prometheus')
 
@@ -132,8 +132,8 @@ module Gitlab
             ::Gitlab::Prometheus::Internal.prometheus_enabled?
           end
 
-          def prometheus_listen_address
-            ::Gitlab::Prometheus::Internal.listen_address
+          def prometheus_server_address
+            ::Gitlab::Prometheus::Internal.server_address
           end
 
           def docs_path
@@ -152,13 +152,13 @@ module Gitlab
             }
           end
 
-          def internal_prometheus_listen_address_uri
+          def internal_prometheus_server_address_uri
             ::Gitlab::Prometheus::Internal.uri
           end
 
           def prometheus_service_attributes
             {
-              api_url: internal_prometheus_listen_address_uri,
+              api_url: internal_prometheus_server_address_uri,
               manual_configuration: true,
               active: true
             }

lib/gitlab/prometheus/internal.rb

@@ -4,43 +4,39 @@ module Gitlab
   module Prometheus
     class Internal
       def self.uri
-        return if listen_address.blank?
+        return if server_address.blank?
 
-        if listen_address.starts_with?('0.0.0.0:')
+        if server_address.starts_with?('0.0.0.0:')
           # 0.0.0.0:9090
-          port = ':' + listen_address.split(':').second
+          port = ':' + server_address.split(':').second
           'http://localhost' + port
 
-        elsif listen_address.starts_with?(':')
+        elsif server_address.starts_with?(':')
           # :9090
-          'http://localhost' + listen_address
+          'http://localhost' + server_address
 
-        elsif listen_address.starts_with?('http')
+        elsif server_address.starts_with?('http')
           # https://localhost:9090
-          listen_address
+          server_address
 
         else
           # localhost:9090
-          'http://' + listen_address
+          'http://' + server_address
         end
       end
 
       def self.server_address
-        uri&.strip&.sub(/^http[s]?:\/\//, '')
-      end
-
-      def self.listen_address
-        Gitlab.config.prometheus.listen_address.to_s if Gitlab.config.prometheus
+        Gitlab.config.prometheus.server_address.to_s if Gitlab.config.prometheus
       rescue Settingslogic::MissingSetting
-        Gitlab::AppLogger.error('Prometheus listen_address is not present in config/gitlab.yml')
+        Gitlab::AppLogger.error('Prometheus server_address is not present in config/gitlab.yml')
 
         nil
       end
 
       def self.prometheus_enabled?
-        Gitlab.config.prometheus.enable if Gitlab.config.prometheus
+        Gitlab.config.prometheus.enabled if Gitlab.config.prometheus
       rescue Settingslogic::MissingSetting
-        Gitlab::AppLogger.error('prometheus.enable is not present in config/gitlab.yml')
+        Gitlab::AppLogger.error('prometheus.enabled is not present in config/gitlab.yml')
 
         false
       end

lib/gitlab/utils/usage_data.rb

@@ -145,7 +145,8 @@ module Gitlab
 
       def prometheus_server_address
         if Gitlab::Prometheus::Internal.prometheus_enabled?
-          Gitlab::Prometheus::Internal.server_address
+          # Stripping protocol from URI
+          Gitlab::Prometheus::Internal.uri&.strip&.sub(%r{^https?://}, '')
         elsif Gitlab::Consul::Internal.api_url
           Gitlab::Consul::Internal.discover_prometheus_server_address
         end

spec/lib/gitlab/database_importers/self_monitoring/project/create_service_spec.rb

@@ -8,8 +8,8 @@ RSpec.describe Gitlab::DatabaseImporters::SelfMonitoring::Project::CreateService
 
     let(:prometheus_settings) do
       {
-        enable: true,
-        listen_address: 'localhost:9090'
+        enabled: true,
+        server_address: 'localhost:9090'
       }
     end
 
@@ -63,13 +63,13 @@ RSpec.describe Gitlab::DatabaseImporters::SelfMonitoring::Project::CreateService
         application_setting.update(allow_local_requests_from_web_hooks_and_services: true)
       end
 
-      shared_examples 'has prometheus service' do |listen_address|
+      shared_examples 'has prometheus service' do |server_address|
         it do
           expect(result[:status]).to eq(:success)
 
           prometheus = project.prometheus_service
           expect(prometheus).not_to eq(nil)
-          expect(prometheus.api_url).to eq(listen_address)
+          expect(prometheus.api_url).to eq(server_address)
           expect(prometheus.active).to eq(true)
           expect(prometheus.manual_configuration).to eq(true)
         end
@@ -202,25 +202,25 @@ RSpec.describe Gitlab::DatabaseImporters::SelfMonitoring::Project::CreateService
       end
 
       context 'with non default prometheus address' do
-        let(:listen_address) { 'https://localhost:9090' }
+        let(:server_address) { 'https://localhost:9090' }
 
         let(:prometheus_settings) do
           {
-            enable: true,
-            listen_address: listen_address
+            enabled: true,
+            server_address: server_address
           }
         end
 
         it_behaves_like 'has prometheus service', 'https://localhost:9090'
 
         context 'with :9090 symbol' do
-          let(:listen_address) { :':9090' }
+          let(:server_address) { :':9090' }
 
           it_behaves_like 'has prometheus service', 'http://localhost:9090'
         end
 
         context 'with 0.0.0.0:9090' do
-          let(:listen_address) { '0.0.0.0:9090' }
+          let(:server_address) { '0.0.0.0:9090' }
 
           it_behaves_like 'has prometheus service', 'http://localhost:9090'
         end
@@ -251,8 +251,8 @@ RSpec.describe Gitlab::DatabaseImporters::SelfMonitoring::Project::CreateService
       context 'when prometheus setting is disabled in gitlab.yml' do
         let(:prometheus_settings) do
           {
-            enable: false,
-            listen_address: 'http://localhost:9090'
+            enabled: false,
+            server_address: 'http://localhost:9090'
           }
         end
 
@@ -262,8 +262,8 @@ RSpec.describe Gitlab::DatabaseImporters::SelfMonitoring::Project::CreateService
         end
       end
 
-      context 'when prometheus listen address is blank in gitlab.yml' do
-        let(:prometheus_settings) { { enable: true, listen_address: '' } }
+      context 'when prometheus server address is blank in gitlab.yml' do
+        let(:prometheus_settings) { { enabled: true, server_address: '' } }
 
         it 'does not configure prometheus' do
           expect(result).to include(status: :success)
@@ -296,8 +296,8 @@ RSpec.describe Gitlab::DatabaseImporters::SelfMonitoring::Project::CreateService
       context 'when prometheus manual configuration cannot be saved' do
         let(:prometheus_settings) do
           {
-            enable: true,
-            listen_address: 'httpinvalid://localhost:9090'
+            enabled: true,
+            server_address: 'httpinvalid://localhost:9090'
           }
         end
 

spec/lib/gitlab/prometheus/internal_spec.rb

@@ -3,12 +3,12 @@
 require 'spec_helper'
 
 RSpec.describe Gitlab::Prometheus::Internal do
-  let(:listen_address) { 'localhost:9090' }
+  let(:server_address) { 'localhost:9090' }
 
   let(:prometheus_settings) do
     {
-      enable: true,
-      listen_address: listen_address
+      enabled: true,
+      server_address: server_address
     }
   end
 
@@ -27,25 +27,25 @@ RSpec.describe Gitlab::Prometheus::Internal do
     it_behaves_like 'returns valid uri', 'http://localhost:9090'
 
     context 'with non default prometheus address' do
-      let(:listen_address) { 'https://localhost:9090' }
+      let(:server_address) { 'https://localhost:9090' }
 
       it_behaves_like 'returns valid uri', 'https://localhost:9090'
 
       context 'with :9090 symbol' do
-        let(:listen_address) { :':9090' }
+        let(:server_address) { :':9090' }
 
         it_behaves_like 'returns valid uri', 'http://localhost:9090'
       end
 
       context 'with 0.0.0.0:9090' do
-        let(:listen_address) { '0.0.0.0:9090' }
+        let(:server_address) { '0.0.0.0:9090' }
 
         it_behaves_like 'returns valid uri', 'http://localhost:9090'
       end
     end
 
-    context 'when listen_address is nil' do
-      let(:listen_address) { nil }
+    context 'when server_address is nil' do
+      let(:server_address) { nil }
 
       it 'does not fail' do
         expect(described_class.uri).to be_nil
@@ -53,7 +53,7 @@ RSpec.describe Gitlab::Prometheus::Internal do
     end
 
     context 'when prometheus listen address is blank in gitlab.yml' do
-      let(:listen_address) { '' }
+      let(:server_address) { '' }
 
       it 'does not configure prometheus' do
         expect(described_class.uri).to be_nil
@@ -61,26 +61,6 @@ RSpec.describe Gitlab::Prometheus::Internal do
     end
   end
 
-  describe '.server_address' do
-    context 'self.uri returns valid uri' do
-      ['http://localhost:9090', 'https://localhost:9090 '].each do |valid_uri|
-        it 'returns correct server address' do
-          expect(described_class).to receive(:uri).and_return(valid_uri)
-
-          expect(described_class.server_address).to eq('localhost:9090')
-        end
-      end
-    end
-
-    context 'self.uri returns nil' do
-      it 'returns nil' do
-        expect(described_class).to receive(:uri).and_return(nil)
-
-        expect(described_class.server_address).to be_nil
-      end
-    end
-  end
-
   describe '.prometheus_enabled?' do
     it 'returns correct value' do
       expect(described_class.prometheus_enabled?).to eq(true)
@@ -89,8 +69,8 @@ RSpec.describe Gitlab::Prometheus::Internal do
     context 'when prometheus setting is disabled in gitlab.yml' do
       let(:prometheus_settings) do
         {
-          enable: false,
-          listen_address: listen_address
+          enabled: false,
+          server_address: server_address
         }
       end
 
@@ -110,9 +90,9 @@ RSpec.describe Gitlab::Prometheus::Internal do
     end
   end
 
-  describe '.listen_address' do
+  describe '.server_address' do
     it 'returns correct value' do
-      expect(described_class.listen_address).to eq(listen_address)
+      expect(described_class.server_address).to eq(server_address)
     end
 
     context 'when prometheus setting is not present in gitlab.yml' do
@@ -121,7 +101,7 @@ RSpec.describe Gitlab::Prometheus::Internal do
       end
 
       it 'does not fail' do
-        expect(described_class.listen_address).to be_nil
+        expect(described_class.server_address).to be_nil
       end
     end
   end

spec/lib/gitlab/utils/usage_data_spec.rb

@@ -284,7 +284,7 @@ RSpec.describe Gitlab::Utils::UsageData do
     context 'when Prometheus server address is available from settings' do
       before do
         expect(Gitlab::Prometheus::Internal).to receive(:prometheus_enabled?).and_return(true)
-        expect(Gitlab::Prometheus::Internal).to receive(:server_address).and_return('prom:9090')
+        expect(Gitlab::Prometheus::Internal).to receive(:uri).and_return('http://prom:9090')
       end
 
       it_behaves_like 'try to query Prometheus with given address'

spec/models/project_services/prometheus_service_spec.rb

@@ -95,7 +95,7 @@ RSpec.describe PrometheusService, :use_clean_rails_memory_store_caching, :snowpl
           service.api_url = 'http://localhost:9090'
 
           stub_application_setting(self_monitoring_project_id: project.id)
-          stub_config(prometheus: { enable: true, listen_address: 'localhost:9090' })
+          stub_config(prometheus: { enable: true, server_address: 'localhost:9090' })
         end
 
         it 'allows self-monitoring project to connect to internal Prometheus' do
@@ -242,7 +242,7 @@ RSpec.describe PrometheusService, :use_clean_rails_memory_store_caching, :snowpl
 
           stub_config(prometheus: {
             enable: true,
-            listen_address: api_url
+            server_address: api_url
           })
         end