Choose between legacy/modern prefixes via prefix_style config (and trivial refactors)

README.md

@@ -15,19 +15,23 @@ explicitly in your Gemfile:
 gem 'redis-objects', '>= 2.0.0.beta'
 ~~~
 You're encouraged to try it out in test code (not production) to ensure it works for you.
-Official release is expected later in 2023.
+Official release is expected eventually.
 
 Key Naming Changes
 ------------------
-The internal key naming scheme has changed for `Nested::Class::Namespaces` to fix a longstanding bug.
-**This means your existing data in Redis will not be accessible until you call `migrate_redis_legacy_keys`.**
+A new method to generate the internal key naming scheme has been added to fix a
+longstanding bug. (Refer to [#213](https://github.com/nateware/redis-objects/issues/231))
+It can be controlled by `Redis::Objects.prefix_style =` either `:legacy` (default)
+or `:modern`.
+If your Redis::Object enhanced classes are nested such as `Nested::Class::Namespaces`
+then you should upgrade them using the below proceedure. (only needed once)
 
-To fix this (only needed once), create a script like this:
+Create a script like this:
 
 ~~~ruby
 class YouClassNameHere < ActiveRecord::Base
   include Redis::Objects
-  # ... your relevant definitions here ...
+  # ... your relevant redis_object definitions here (counters/sets) ...
 end
 
 YourClassName.migrate_redis_legacy_keys
@@ -37,7 +41,10 @@ Then, you need to find a time when you can temporarily pause writes to your redi
 so that you can run that script. It uses `redis.scan` internally so it should be able to
 handle a high number of keys. For large data sets, it could take a while.
 
-For more details on the issue and fix refer to [#213](https://github.com/nateware/redis-objects/issues/231).
+After migrating all of your redis keys, update `Redis::Objects.prefix_style = :modern` to
+start using the new keys.
+**Your existing data in Redis will not be accessible after running `migrate_redis_legacy_keys`
+until the prefix_style has been changed.**
 
 Renaming of `lock` Method
 -------------------------

lib/redis/objects.rb

@@ -66,6 +66,19 @@ def redis
           raise(NotConnected, "Redis::Objects.redis not set to a Redis.new connection")
       end
 
+      # Toggles whether to use the legacy redis key naming scheme, which causes
+      # naming conflicts in certain cases.
+      # (attr_accessor with a default value)
+      attr_writer :prefix_style
+      def prefix_style
+        # NOTE: In a future release the default will change to :modern
+        @prefix_style ||= :legacy
+      end
+
+      def redis_legacy_naming?
+        prefix_style == :legacy
+      end
+
       def included(klass)
         # Core (this file)
         klass.instance_variable_set(:@redis, nil)
@@ -101,11 +114,6 @@ def redis_objects
         @redis_objects ||= {}
       end
 
-      # Toggles whether to use the legacy redis key naming scheme, which causes
-      # naming conflicts in certain cases.
-      attr_accessor :redis_legacy_naming
-      attr_accessor :redis_silence_warnings
-
       # Set the Redis redis_prefix to use. Defaults to class_name.
       def redis_prefix=(redis_prefix)
         @silence_warnings_as_redis_prefix_was_set_manually = true
@@ -114,10 +122,10 @@ def redis_prefix=(redis_prefix)
 
       def redis_prefix(klass = self) #:nodoc:
         @redis_prefix ||=
-          if redis_legacy_naming
+          if Objects.redis_legacy_naming?
+            redis_legacy_naming_warning_message(klass)
             redis_legacy_prefix(klass)
           else
-            redis_legacy_naming_warning_message(klass)
             redis_modern_prefix(klass)
           end
 
@@ -140,33 +148,44 @@ def redis_legacy_prefix(klass = self) #:nodoc:
           downcase
       end
 
-        # Temporary warning to help with migrating key names
+      attr_accessor :redis_silence_warnings
+
+      # Temporary warning to help with migrating key names
       def redis_legacy_naming_warning_message(klass)
         # warn @silence_warnings_as_redis_prefix_was_set_manually.inspect
-        unless redis_legacy_naming || redis_silence_warnings || @silence_warnings_as_redis_prefix_was_set_manually
-          modern = redis_modern_prefix(klass)
-          legacy = redis_legacy_prefix(klass)
-          if modern != legacy
-            warn <<EOW
+        return if redis_silence_warnings || @silence_warnings_as_redis_prefix_was_set_manually
+
+        modern = redis_modern_prefix(klass)
+        legacy = redis_legacy_prefix(klass)
+        return if modern == legacy
+
+        warn <<EOW
 [redis-objects] WARNING: In redis-objects 2.0.0, key naming will change to fix longstanding bugs.
 [redis-objects] Your class #{klass.name.to_s} will be affected by this change!
 [redis-objects] Current key prefix: #{legacy.inspect}
 [redis-objects] Future  key prefix: #{modern.inspect}
 [redis-objects] Read more at https://github.com/nateware/redis-objects/issues/231
 EOW
-          end
-        end
       end
 
       def migrate_redis_legacy_keys
-        cursor = 0
+        unless Objects.redis_legacy_naming?
+          raise "Redis::Objects is already configured to use modern key prefixes."
+        end
+
         legacy = redis_legacy_prefix
-        total_keys = 0
         if legacy == redis_prefix
           raise "Failed to migrate keys for #{self.name.to_s} as legacy and new redis_prefix are the same (#{redis_prefix})"
         end
         warn "[redis-objects] Migrating keys from #{legacy} prefix to #{redis_prefix}"
 
+        cursor = 0
+        total_keys = 0
+
+        # Temporarily update the prefix to modern while we update these keys.
+        # NOTE: we cannot simply adjust the prefix_style, because the prefix is cached by @redis_prefix
+        self.redis_prefix = modern
+
         loop do
           cursor, keys = redis.scan(cursor, :match => "#{legacy}:*")
           total_keys += keys.length
@@ -183,6 +202,10 @@ def migrate_redis_legacy_keys
             warn "[redis-objects] Warning: Rename '#{key}', '#{new_key}' failed: #{ok}" if ok != 'OK'
           end
           break if cursor == "0"
+
+        ensure
+          # Change the prefix back (just in case)
+          self.redis_prefix = legacy
         end
 
         warn "[redis-objects] Migrated #{total_keys} total number of redis keys"