Make QC fail with versions of PG < 9.6, add notes in readme and chang…

CHANGELOG.md

@@ -1,13 +1,15 @@
 # Changelog
 
-## Unreleased
+## Unreleased, 3.3.0
 - Fixed a bug in the offset calculation of `.enqueue_at`.
 - Use the jsonb type for the args column from now on. If not available, fall back to json or text.
 - `enqueue`, `enqueue_at`, `enqueue_in` return job hash with id.
 - Fixed unlock query for versions below Postgres 9.2
 - Change ruby versions tested in Travis to currently supported ones.
 - Switched project to use CircleCI, as it's way more consistent speed wise
 - Automatically retry after a connection reset #294
+- Change to only support >= Postgres 9.6. We will be bringing in newer changes and testing on only 9.6+ going forward.
+- Change to only support currently supported Ruby versions: 2.4, 2.5 and 2.6.
 
 ## Version 3.0.0rc
 - Improved signal handling

README.md

@@ -184,13 +184,14 @@ $ ruby -r queue_classic -e "QC::Worker.new.work"
 
 Declare dependencies in Gemfile.
 ```ruby
-source "https://rubygems.org"
-gem "queue_classic"
+source 'https://rubygems.org' do
+  gem 'queue_classic'
+end
 ```
 
 Add the database tables and stored procedures.
 
-```
+```bash
 rails generate queue_classic:install
 bundle exec rake db:migrate
 ```
@@ -221,14 +222,15 @@ Starting with with queue_classic 3.1, Rails is automatically detected and its co
 
 If you don't want to use the automatic database connection, set this environment variable to false: `export QC_RAILS_DATABASE=false`
 
-**Note on using ActiveRecord migrations:** If you use the migration, and you wish to use commands that reset the database from the stored schema (e.g. `rake db:reset`), your application must be configured with `config.active_record.schema_format = :sql` in `config/application.rb`.  If you don't do this, the PL/pgSQL function that queue_classic creates will be lost when you reset the database.
+**Note on using ActiveRecord migrations:** If you use the migration, and you wish to use commands that reset the database from the stored schema (e.g. `rake db:reset`), your application must be configured with `config.active_record.schema_format = :sql` in `config/application.rb`. If you don't do this, the PL/pgSQL function that queue_classic creates will be lost when you reset the database.
 
 
 #### Other Ruby apps
 
-By default, queue_classic will use the QC_DATABASE_URL falling back on DATABASE_URL. The URL must be in the following format: `postgres://username:password@localhost/database_name`.  If you use Heroku's PostgreSQL service, this will already be set. If you don't want to set this variable, you can set the connection in an initializer. **QueueClassic will maintain its own connection to the database.** This may double the number of connections to your database.
+By default, queue_classic will use the QC_DATABASE_URL falling back on DATABASE_URL. The URL must be in the following format: `postgres://username:password@localhost/database_name`. If you use Heroku's PostgreSQL service, this will already be set. If you don't want to set this variable, you can set the connection in an initializer. **QueueClassic will maintain its own connection to the database.** This may double the number of connections to your database.
 
 ## Upgrade from earlier versions
+
 If you are upgrading from a previous version of queue_classic, you might need some new database columns and/or functions. Luckily enough for you, it is easy to do so.
 
 ### Ruby on Rails
@@ -265,16 +267,18 @@ By default queue_classic does not talk very much.
 If you find yourself in a situation where you need to know what's happening inside QC, there are two different kind of logging you can enable: DEBUG and MEASURE.
 
 ### Measure
+
 This will output the time to process and that kind of thing. To enable it, set the `QC_MEASURE`:
 
-```
+```bash
 export QC_MEASURE="true"
 ```
 
 ### Debug
+
 You can enable the debug output by setting the `DEBUG` environment variable:
 
-```
+```bash
 export DEBUG="true"
 ```
 
@@ -287,18 +291,13 @@ If you think you have found a bug, feel free to open an issue. Use the following
 3. List what actually happened.
 4. Provide sample codes & commands which will reproduce the problem.
 
-If you have general questions about how to use queue_classic, send a message to the mailing list:
-
-https://groups.google.com/d/forum/queue_classic
-
 ## Hacking on queue_classic
 
 ### Dependencies
 
-* Ruby 1.9.2
-* Postgres ~> 9.0
-* Rubygem: pg ~> 0.11.0
-* For JRuby, see [queue_classic_java](https://github.com/bdon/queue_classic_java)
+* Ruby 2.4, 2.5 or 2.6
+* Postgres ~> 9.6
+* Rubygem: pg ~> 0.17
 
 ### Running Tests
 

lib/queue_classic/config.rb

@@ -58,7 +58,6 @@ def fork_worker?
 
     # The worker class instantiated by QC's rake tasks.
     def default_worker_class
-
       @worker_class ||= (ENV["QC_DEFAULT_WORKER_CLASS"] && Kernel.const_get(ENV["QC_DEFAULT_WORKER_CLASS"]) ||
                          QC::Worker)
 

lib/queue_classic/conn_adapter.rb

@@ -81,6 +81,11 @@ def establish_new
       if conn.status != PG::CONNECTION_OK
         QC.log(:error => conn.error)
       end
+
+      if conn.server_version < 90600
+        raise "This version of Queue Classic does not support Postgres older than 9.6 (90600). This version is #{conn.server_version}. If you need that support, please use an older version."
+      end
+
       conn.exec("SET application_name = '#{QC.app_name}'")
       conn
     end
@@ -106,6 +111,5 @@ def db_url
             raise(ArgumentError, "missing QC_DATABASE_URL or DATABASE_URL")
       @db_url = URI.parse(url)
     end
-
   end
 end

lib/queue_classic/queue.rb

@@ -5,8 +5,8 @@
 module QC
   # The queue class maps a queue abstraction onto a database table.
   class Queue
-
     attr_reader :name, :top_bound
+
     def initialize(name, top_bound=nil)
       @name = name
       @top_bound = top_bound || QC.top_bound
@@ -132,6 +132,5 @@ def count
         r["count"].to_i
       end
     end
-
   end
 end

lib/queue_classic/version.rb

@@ -1,3 +1,3 @@
 module QC
-  VERSION = "3.2.0.RC1"
+  VERSION = "3.3.0.ALPHA"
 end