Add stickiness_cookie_enabled configuration option

.app-image-tag

@@ -1 +1 @@
-v0.10.1.13
+v0.10.1.15

Gemfile

@@ -21,7 +21,7 @@ gem "pry", "~> 0.16.0"
 
 # for documentation server
 gem "puma"
-gem "rack", "~> 2.2.21"
+gem "rack", "~> 2.2.22"
 gem "yard"
 
 group :test do

Gemfile.lock

@@ -73,7 +73,7 @@ GEM
     puma (7.2.0)
       nio4r (~> 2.0)
     racc (1.8.1)
-    rack (2.2.21)
+    rack (2.2.22)
     rainbow (3.1.1)
     rake (13.3.1)
     readline (0.0.4)
@@ -98,7 +98,7 @@ GEM
       diff-lcs (>= 1.2.0, < 2.0)
       rspec-support (~> 3.13.0)
     rspec-support (3.13.6)
-    rubocop (1.84.1)
+    rubocop (1.84.2)
       json (~> 2.3)
       language_server-protocol (~> 3.17.0.2)
       lint_roller (~> 1.1.0)
@@ -150,7 +150,7 @@ DEPENDENCIES
   pg (~> 1.6)
   pry (~> 0.16.0)
   puma
-  rack (~> 2.2.21)
+  rack (~> 2.2.22)
   rake (~> 13.3)
   readline
   redis (~> 5.4.1)

README.md

@@ -159,6 +159,11 @@ ActiveRecordProxyAdapters.configure do |config|
 
   # How long proxy should wait for replica to connect.
   config.checkout_timeout = 5.seconds # defaults to 2.seconds
+
+  # Whether to persist write timestamps in a cookie for cross-request stickiness.
+  # When false, the middleware still creates a fresh context per request (preventing
+  # thread-local leaks in multi-threaded servers) but skips reading/writing the cookie.
+  config.stickiness_cookie_enabled = false # defaults to true
 end
 ```
 

gemfiles/ar_7.2.gemfile

@@ -15,7 +15,7 @@ gem "logger"
 gem "readline"
 gem "pry", "~> 0.16.0"
 gem "puma"
-gem "rack", "~> 2.2.21"
+gem "rack", "~> 2.2.22"
 gem "yard"
 gem "activerecord", "~> 7.2.0"
 gem "activesupport", "~> 7.2.0"

gemfiles/ar_8.0.gemfile

@@ -15,7 +15,7 @@ gem "logger"
 gem "readline"
 gem "pry", "~> 0.16.0"
 gem "puma"
-gem "rack", "~> 2.2.21"
+gem "rack", "~> 2.2.22"
 gem "yard"
 gem "activerecord", "~> 8.0.0"
 gem "activesupport", "~> 8.0.0"

gemfiles/ar_8.1.gemfile

@@ -15,7 +15,7 @@ gem "logger"
 gem "readline"
 gem "pry", "~> 0.16.0"
 gem "puma"
-gem "rack", "~> 2.2.21"
+gem "rack", "~> 2.2.22"
 gem "yard"
 gem "activerecord", "~> 8.1.0"
 gem "activesupport", "~> 8.1.0"

lib/active_record_proxy_adapters/configuration.rb

@@ -45,22 +45,19 @@ class Configuration
     }.freeze
 
     # @return [Class] The context that is used to store the current request's state.
-    attr_reader :context_store
-
     # @return [Proc] The timeout strategy to use for regex matching.
-    attr_reader :regexp_timeout_strategy
-
     # @return [Logger] The logger to use for logging messages.
-    attr_reader :logger
+    # @return [Boolean] Whether to use cookies for cross-request stickiness.
+    attr_reader :context_store, :regexp_timeout_strategy, :logger, :stickiness_cookie_enabled
 
     def initialize
       @lock = Monitor.new
-
-      self.cache_configuration     = CacheConfiguration.new(@lock)
-      self.context_store           = ActiveRecordProxyAdapters::Context
-      self.regexp_timeout_strategy = :log
-      self.logger                  = ActiveRecord::Base.logger || Logger.new($stdout)
-      @database_configurations     = {}
+      self.cache_configuration       = CacheConfiguration.new(@lock)
+      self.context_store             = ActiveRecordProxyAdapters::Context
+      self.regexp_timeout_strategy   = :log
+      self.logger                    = ActiveRecord::Base.logger || Logger.new($stdout)
+      self.stickiness_cookie_enabled = true
+      @database_configurations       = {}
     end
 
     def log_subscriber_primary_prefix=(prefix)
@@ -95,6 +92,12 @@ def checkout_timeout=(checkout_timeout)
       default_database_config.checkout_timeout = checkout_timeout
     end
 
+    def stickiness_cookie_enabled=(enabled)
+      synchronize_update(:stickiness_cookie_enabled, from: @stickiness_cookie_enabled, to: enabled) do
+        @stickiness_cookie_enabled = enabled
+      end
+    end
+
     def logger=(logger)
       synchronize_update(:logger, from: @logger, to: logger) do
         @logger = logger

lib/active_record_proxy_adapters/middleware.rb

@@ -51,11 +51,15 @@ def initialize(app, cookie_options = {})
     def call(env)
       return @app.call(env) if ignore_request?(env)
 
-      self.current_context = context_store.new(COOKIE_READER.call(env))
+      self.current_context = if stickiness_cookie_enabled
+                               context_store.new(COOKIE_READER.call(env))
+                             else
+                               context_store.new({})
+                             end
 
       status, headers, body = @app.call(env)
 
-      update_cookie_from_context(headers)
+      update_cookie_from_context(headers) if stickiness_cookie_enabled
 
       [status, headers, body]
     end

lib/active_record_proxy_adapters/mixin/configuration.rb

@@ -46,6 +46,13 @@ def logger
         proxy_config.logger
       end
 
+      # Helper to retrieve whether stickiness cookies are enabled from the configuration stored in
+      # {ActiveRecordProxyAdapters::Configuration#stickiness_cookie_enabled}.
+      # @return [Boolean]
+      def stickiness_cookie_enabled
+        proxy_config.stickiness_cookie_enabled
+      end
+
       # Helper to retrieve the timeout strategy from the configuration stored in
       # {ActiveRecordProxyAdapters::Configuration#regexp_timeout_strategy}.
       # @return [Proc]

spec/active_record_proxy_adapters/configuration_spec.rb

@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+RSpec.describe ActiveRecordProxyAdapters::Configuration do
+  describe "#stickiness_cookie_enabled" do
+    subject(:stickiness_cookie_enabled) { configuration.stickiness_cookie_enabled }
+
+    let(:configuration) { described_class.new }
+
+    it "defaults to true" do
+      expect(stickiness_cookie_enabled).to be(true)
+    end
+
+    context "when overridden" do
+      it "equals the overridden value" do
+        configuration.stickiness_cookie_enabled = false
+
+        expect(stickiness_cookie_enabled).to be(false)
+      end
+    end
+  end
+end

spec/active_record_proxy_adapters/middleware_spec.rb

@@ -91,6 +91,39 @@ def from_cookie_string(cookie_string)
       end
     end
 
+    context "when stickiness_cookie_enabled is false" do
+      before do
+        ActiveRecordProxyAdapters.config.stickiness_cookie_enabled = false
+      end
+
+      after do
+        ActiveRecordProxyAdapters.config.stickiness_cookie_enabled = true
+      end
+
+      it "does not write a Set-Cookie header" do
+        env = {}
+        _, headers, = middleware.call(env)
+
+        expect(headers["Set-Cookie"]).to be_nil
+      end
+
+      it "creates a fresh context for the request" do
+        env = {}
+        middleware.call(env)
+
+        expect(middleware.send(:current_context)).to be_a(ActiveRecordProxyAdapters::Context)
+      end
+
+      it "does not read a previous request's cookie into the context" do
+        cookie_hash = { "sqlite3_primary" => Time.current.utc.to_f }
+        env = { "HTTP_COOKIE" => to_cookie_string(cookie_hash) }
+
+        middleware.call(env)
+
+        expect(middleware.send(:current_context).to_h).to eq({})
+      end
+    end
+
     context "when request comes from rails asset prefix" do
       before do
         rails       = double("Rails") # rubocop:disable RSpec/VerifiedDoubles