Add redis sentinel support to ruby part of code (#31744)

lib/mastodon/redis_configuration.rb

@@ -1,34 +1,33 @@
 # frozen_string_literal: true
 
 class Mastodon::RedisConfiguration
+  DEFAULTS = {
+    host: 'localhost',
+    port: 6379,
+    db: 0,
+  }.freeze
+
   def base
-    @base ||= {
-      url: setup_base_redis_url,
-      driver: driver,
-      namespace: base_namespace,
-    }
+    @base ||= setup_config(prefix: nil, defaults: DEFAULTS)
+              .merge(namespace: base_namespace)
   end
 
   def sidekiq
-    @sidekiq ||= {
-      url: setup_prefixed_redis_url(:sidekiq),
-      driver: driver,
-      namespace: sidekiq_namespace,
-    }
+    @sidekiq ||= setup_config(prefix: 'SIDEKIQ_')
+                 .merge(namespace: sidekiq_namespace)
   end
 
   def cache
-    @cache ||= {
-      url: setup_prefixed_redis_url(:cache),
-      driver: driver,
-      namespace: cache_namespace,
-      expires_in: 10.minutes,
-      connect_timeout: 5,
-      pool: {
-        size: Sidekiq.server? ? Sidekiq[:concurrency] : Integer(ENV['MAX_THREADS'] || 5),
-        timeout: 5,
-      },
-    }
+    @cache ||= setup_config(prefix: 'CACHE_')
+               .merge({
+                 namespace: cache_namespace,
+                 expires_in: 10.minutes,
+                 connect_timeout: 5,
+                 pool: {
+                   size: Sidekiq.server? ? Sidekiq[:concurrency] : Integer(ENV['MAX_THREADS'] || 5),
+                   timeout: 5,
+                 },
+               })
   end
 
   private
@@ -55,42 +54,53 @@ class Mastodon::RedisConfiguration
     namespace ? "#{namespace}_cache" : 'cache'
   end
 
-  def setup_base_redis_url
-    url = ENV.fetch('REDIS_URL', nil)
-    return url if url.present?
+  def setup_config(prefix: nil, defaults: {})
+    prefix = "#{prefix}REDIS_"
 
-    user     = ENV.fetch('REDIS_USER', '')
-    password = ENV.fetch('REDIS_PASSWORD', '')
-    host     = ENV.fetch('REDIS_HOST', 'localhost')
-    port     = ENV.fetch('REDIS_PORT', 6379)
-    db       = ENV.fetch('REDIS_DB', 0)
+    url       = ENV.fetch("#{prefix}URL", nil)
+    user      = ENV.fetch("#{prefix}USER", nil)
+    password  = ENV.fetch("#{prefix}PASSWORD", nil)
+    host      = ENV.fetch("#{prefix}HOST", defaults[:host])
+    port      = ENV.fetch("#{prefix}PORT", defaults[:port])
+    db        = ENV.fetch("#{prefix}DB", defaults[:db])
+    name      = ENV.fetch("#{prefix}SENTINEL_MASTER", nil)
+    sentinels = parse_sentinels(ENV.fetch("#{prefix}SENTINELS", nil))
 
-    construct_uri(host, port, db, user, password)
-  end
+    return { url:, driver: } if url
 
-  def setup_prefixed_redis_url(prefix)
-    prefix = "#{prefix.to_s.upcase}_"
-    url = ENV.fetch("#{prefix}REDIS_URL", nil)
-
-    return url if url.present?
-
-    user     = ENV.fetch("#{prefix}REDIS_USER", nil)
-    password = ENV.fetch("#{prefix}REDIS_PASSWORD", nil)
-    host     = ENV.fetch("#{prefix}REDIS_HOST", nil)
-    port     = ENV.fetch("#{prefix}REDIS_PORT", nil)
-    db       = ENV.fetch("#{prefix}REDIS_DB", nil)
-
-    if host.nil?
-      base[:url]
+    if name.present? && sentinels.present?
+      host = name
+      port = nil
+      db ||= 0
     else
-      construct_uri(host, port, db, user, password)
+      sentinels = nil
+    end
+
+    url = construct_uri(host, port, db, user, password)
+
+    if url.present?
+      { url:, driver:, name:, sentinels: }
+    else
+      # Fall back to base config. This has defaults for the URL
+      # so this cannot lead to an endless loop.
+      base
     end
   end
 
   def construct_uri(host, port, db, user, password)
+    return nil if host.blank?
+
     Addressable::URI.parse("redis://#{host}:#{port}/#{db}").tap do |uri|
       uri.user = user if user.present?
       uri.password = password if password.present?
     end.normalize.to_str
   end
+
+  def parse_sentinels(sentinels_string)
+    (sentinels_string || '').split(',').map do |sentinel|
+      host, port = sentinel.split(':')
+      port = port.present? ? port.to_i : 26_379
+      { host: host, port: port }
+    end.presence
+  end
 end

spec/lib/mastodon/redis_configuration_spec.rb

@@ -45,6 +45,20 @@ RSpec.describe Mastodon::RedisConfiguration do
       it 'uses the url from the base config' do
         expect(subject[:url]).to eq 'redis://localhost:6379/0'
       end
+
+      context 'when the base config uses sentinel' do
+        around do |example|
+          ClimateControl.modify REDIS_SENTINELS: '192.168.0.1:3000,192.168.0.2:4000', REDIS_SENTINEL_MASTER: 'mainsentinel' do
+            example.run
+          end
+        end
+
+        it 'uses the sentinel configuration from base config' do
+          expect(subject[:url]).to eq 'redis://mainsentinel/0'
+          expect(subject[:name]).to eq 'mainsentinel'
+          expect(subject[:sentinels]).to contain_exactly({ host: '192.168.0.1', port: 3000 }, { host: '192.168.0.2', port: 4000 })
+        end
+      end
     end
 
     context "when the `#{prefix}_REDIS_URL` environment variable is present" do
@@ -72,6 +86,39 @@ RSpec.describe Mastodon::RedisConfiguration do
     end
   end
 
+  shared_examples 'sentinel support' do |prefix = nil|
+    prefix = prefix ? "#{prefix}_" : ''
+
+    context 'when configuring sentinel support' do
+      around do |example|
+        ClimateControl.modify "#{prefix}REDIS_PASSWORD": 'testpass1', "#{prefix}REDIS_HOST": 'redis2.example.com', "#{prefix}REDIS_SENTINELS": '192.168.0.1:3000,192.168.0.2:4000', "#{prefix}REDIS_SENTINEL_MASTER": 'mainsentinel' do
+          example.run
+        end
+      end
+
+      it 'constructs the url using the sentinel master name' do
+        expect(subject[:url]).to eq 'redis://:testpass1@mainsentinel/0'
+      end
+
+      it 'includes the sentinel master name and list of sentinels' do
+        expect(subject[:name]).to eq 'mainsentinel'
+        expect(subject[:sentinels]).to contain_exactly({ host: '192.168.0.1', port: 3000 }, { host: '192.168.0.2', port: 4000 })
+      end
+    end
+
+    context 'when giving sentinels without port numbers' do
+      around do |example|
+        ClimateControl.modify "#{prefix}REDIS_SENTINELS": '192.168.0.1,192.168.0.2', "#{prefix}REDIS_SENTINEL_MASTER": 'mainsentinel' do
+          example.run
+        end
+      end
+
+      it 'uses the default sentinel port' do
+        expect(subject[:sentinels]).to contain_exactly({ host: '192.168.0.1', port: 26_379 }, { host: '192.168.0.2', port: 26_379 })
+      end
+    end
+  end
+
   describe '#base' do
     subject { redis_environment.base }
 
@@ -81,6 +128,8 @@ RSpec.describe Mastodon::RedisConfiguration do
           url: 'redis://localhost:6379/0',
           driver: :hiredis,
           namespace: nil,
+          name: nil,
+          sentinels: nil,
         })
       end
     end
@@ -113,12 +162,15 @@ RSpec.describe Mastodon::RedisConfiguration do
           url: 'redis://:testpass@redis.example.com:3333/3',
           driver: :hiredis,
           namespace: nil,
+          name: nil,
+          sentinels: nil,
         })
       end
     end
 
     include_examples 'setting a different driver'
     include_examples 'setting a namespace'
+    include_examples 'sentinel support'
   end
 
   describe '#sidekiq' do
@@ -127,6 +179,7 @@ RSpec.describe Mastodon::RedisConfiguration do
     include_examples 'secondary configuration', 'SIDEKIQ'
     include_examples 'setting a different driver'
     include_examples 'setting a namespace'
+    include_examples 'sentinel support', 'SIDEKIQ'
   end
 
   describe '#cache' do
@@ -139,6 +192,8 @@ RSpec.describe Mastodon::RedisConfiguration do
         namespace: 'cache',
         expires_in: 10.minutes,
         connect_timeout: 5,
+        name: nil,
+        sentinels: nil,
         pool: {
           size: 5,
           timeout: 5,
@@ -166,5 +221,6 @@ RSpec.describe Mastodon::RedisConfiguration do
 
     include_examples 'secondary configuration', 'CACHE'
     include_examples 'setting a different driver'
+    include_examples 'sentinel support', 'CACHE'
   end
 end