Fix application name sent to TinyTDS (rails-sqlserver#941)

* Fix application name

* Updated changelog

* No longer support configuring the application name by overriding the 'configure_application_name' method.

Co-authored-by: Aidan Haran <aharan@fusioneer.com>

Author: 2 people

CHANGELOG.md

@@ -6,7 +6,7 @@
 
 #### Changed
 
-- ...
+- [#941](https://github.com/rails-sqlserver/activerecord-sqlserver-adapter/pull/941) No longer support configuring the application name by overriding the 'configure_application_name' method.
 
 #### Added
 

README.md

@@ -82,28 +82,34 @@ end
 ```
 
 
-#### Configure Connection & App Name
+#### Configure Connection
 
-We currently conform to an unpublished and non-standard AbstractAdapter interface to configure connections made to the database. To do so, just override the `configure_connection` method in an initializer like so. In this case below we are setting the `TEXTSIZE` to 64 megabytes. Also, TinyTDS supports an application name when it logs into SQL Server. This can be used to identify the connection in SQL Server's activity monitor. By default it will use the `appname` from your database.yml file or a lowercased version of your Rails::Application name. It is now possible to define a `configure_application_name` method that can give you per instance details. Below shows how you might use this to get the process id and thread id of the current connection.
+We currently conform to an unpublished and non-standard AbstractAdapter interface to configure connections made to the database. To do so, just override the `configure_connection` method in an initializer like so. In this case below we are setting the `TEXTSIZE` to 64 megabytes.
 
 ```ruby
 module ActiveRecord
   module ConnectionAdapters
     class SQLServerAdapter < AbstractAdapter
-
       def configure_connection
         raw_connection_do "SET TEXTSIZE #{64.megabytes}"
       end
-
-      def configure_application_name
-        "myapp_#{$$}_#{Thread.current.object_id}".to(29)
-      end
-
     end
   end
 end
 ```
 
+#### Configure Application Name
+
+TinyTDS supports an application name when it logs into SQL Server. This can be used to identify the connection in SQL Server's activity monitor. By default it will use the `appname` from your database.yml file or your Rails::Application name.
+
+Below shows how you might use the database.yml file to use the process ID in your application name.
+
+```yaml
+development:
+  adapter: sqlserver
+  appname: <%= myapp_#{Process.pid} %>
+```
+
 #### Executing Stored Procedures
 
 Every class that sub classes ActiveRecord::Base will now have an execute_procedure class method to use. This method takes the name of the stored procedure which can be a string or symbol and any number of variables to pass to the procedure. Arguments will automatically be quoted per the connection's standards as normal. For example:

lib/active_record/connection_adapters/sqlserver_adapter.rb

@@ -128,7 +128,23 @@ def odbc_connect(config)
         end
 
         def config_appname(config)
-          config[:appname] || configure_application_name || Rails.application.class.name.split("::").first rescue nil
+          if self.instance_methods.include?(:configure_application_name)
+            ActiveSupport::Deprecation.warn <<~MSG.squish
+            Configuring the application name used by TinyTDS by overriding the
+            `ActiveRecord::ConnectionAdapters::SQLServerAdapter#configure_application_name`
+            instance method is no longer supported. The application name should configured
+            using the `appname` setting in the `database.yml` file instead. Consult the
+            README for further information."
+            MSG
+          end
+
+          config[:appname] || rails_application_name
+        end
+
+        def rails_application_name
+          return nil if Rails.application.nil?
+
+          Rails.application.class.name.split("::").first
         end
 
         def config_login_timeout(config)
@@ -509,8 +525,6 @@ def connection_errors
         end
       end
 
-      def configure_application_name; end
-
       def initialize_dateformatter
         @database_dateformat = user_options_dateformat
         a, b, c = @database_dateformat.each_char.to_a