Merge pull request #291 from zendesk/bquorning.backport-master-branch-features

Backport of pull request #280 & make a new release

Author: bquorning

Changelog.md

@@ -6,6 +6,14 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## v3.21.0
+
+### Added
+
+Add a global setting to disable marking instances from replicas as read-only. To enable:
+
+`ActiveRecordShards.disable_replica_readonly_records = true`
+
 ## v3.20.0
 
 ### Changed

README.md

@@ -148,12 +148,16 @@ ActiveRecord::Base.on_replica do
 end
 ```
 
-This will perform the query on the replica, and mark the returned instances as read only. There is also a shortcut for this:
+This will perform the query on the replica, and mark the returned instances as read-only. There is also a shortcut for this:
 
 ```ruby
 Account.on_replica.find_by_big_expensive_query
 ```
 
+If you do not want instances returned from replicas to be marked as read-only, this can be disabled globally:
+
+`ActiveRecordShards.disable_replica_readonly_records = true`
+
 ## Debugging
 
 Show if a query went to primary or replica in the logs:

active_record_shards.gemspec

@@ -1,4 +1,4 @@
-Gem::Specification.new "active_record_shards", "3.20.0" do |s|
+Gem::Specification.new "active_record_shards", "3.21.0" do |s|
   s.authors     = ["Benjamin Quorning", "Gabe Martin-Dempesy", "Pierre Schambacher", "Mick Staugaard", "Eric Chapweske", "Ben Osheroff"]
   s.email       = ["[email protected]", "[email protected]", "[email protected]", "[email protected]"]
   s.homepage    = "https://github.com/zendesk/active_record_shards"

lib/active_record_shards.rb

@@ -12,6 +12,10 @@
 require 'active_record_shards/schema_dumper_extension'
 
 module ActiveRecordShards
+  class << self
+    attr_accessor :disable_replica_readonly_records
+  end
+
   def self.app_env
     env = Rails.env if defined?(Rails.env)
     env ||= RAILS_ENV if Object.const_defined?(:RAILS_ENV)

lib/active_record_shards/connection_switcher.rb

@@ -125,7 +125,7 @@ def on_cx_switch_block(which, force: false, construct_ro_scope: nil, &block)
 
       # we avoid_readonly_scope to prevent some stack overflow problems, like when
       # .columns calls .with_scope which calls .columns and onward, endlessly.
-      if self == ActiveRecord::Base || !switch_to_replica || construct_ro_scope == false
+      if self == ActiveRecord::Base || !switch_to_replica || construct_ro_scope == false || ActiveRecordShards.disable_replica_readonly_records == true
         yield
       else
         readonly.scoping(&block)

test/connection_switching_test.rb

@@ -501,14 +501,42 @@ def spec_name
           assert_equal('replica_name', @model.name)
         end
 
-        it "be marked as read only" do
+        it "be marked as read-only" do
           assert(@model.readonly?)
         end
 
         it "be marked as comming from the replica" do
           assert(@model.from_replica?)
         end
 
+        describe "when ActiveRecordShards.disable_replica_readonly_records is true" do
+          before do
+            @original_disable_replica_readonly_records = ActiveRecordShards.disable_replica_readonly_records
+            ActiveRecordShards.disable_replica_readonly_records = true
+
+            @model = Account.on_replica.find(1000)
+            assert(@model)
+            assert_equal('replica_name', @model.name)
+          end
+
+          it "read from replica on reload" do
+            @model.reload
+            assert_equal('replica_name', @model.name)
+          end
+
+          it "not be marked as read-only" do
+            refute(@model.readonly?)
+          end
+
+          it "be marked as comming from the replica" do
+            assert(@model.from_replica?)
+          end
+
+          after do
+            ActiveRecordShards.disable_replica_readonly_records = @original_disable_replica_readonly_records
+          end
+        end
+
         after do
           Account.on_replica_by_default = false
         end
@@ -543,7 +571,7 @@ def spec_name
           assert(@model.readonly?)
         end
 
-        it "not be marked as read only" do
+        it "not be marked as read-only" do
           assert(!@model.readonly?)
         end