merge branches and enhance with configurable view filtering

.gitignore

@@ -1,6 +1,7 @@
 *.gem
 *.rbc
 .bundle
+Gemfile.lock
 .config
 coverage
 InstalledFiles
@@ -16,3 +17,6 @@ tmp
 .yardoc
 _yardoc
 doc/
+
+# virtual environment configs
+.ruby-*

README.md

@@ -68,8 +68,8 @@ end
 ```ruby
 class ReverseUser < ActiveRecord::Base
   private
-    
-  def self.discriminate_class_for_record(record) 
+
+  def self.discriminate_class_for_record(record)
     User
   end
 end
@@ -97,3 +97,13 @@ end
 ```
 
 As a bonus you will be able to reload views using rake task as well, i.e. `rake reload_views:db:migrate`
+
+### How to conditionally exclude views
+Sometimes selected views may need to be excluded from loading, for example if not valid for a certain environment.
+
+An exclusion filter may be registered (for example in an initialization file):
+
+```ruby
+ActiveRecord::DatabaseViews.register_view_exclusion_filter( lambda { |name| name == 'exclude_this_view' })
+```
+

Rakefile

@@ -2,7 +2,7 @@ require 'rake'
 require 'rake/testtask'
 
 Rake::TestTask.new do |t|
-  t.libs << 'lib'
+  t.libs = ['lib','test']
   t.pattern = 'test/**/*_test.rb'
   t.verbose = false
 end

activerecord-database-views.gemspec

@@ -16,4 +16,9 @@ Gem::Specification.new do |s|
   s.platform      = Gem::Platform::RUBY
   s.require_paths = ['lib']
   s.rubyforge_project = '[none]'
+
+  s.add_development_dependency 'minitest'
+  s.add_development_dependency 'mocha'
+  s.add_development_dependency 'pg'
+  s.add_runtime_dependency 'activerecord', '>= 3.0', '<= 5.0'
 end

lib/activerecord-database-views.rb

@@ -2,19 +2,29 @@
 require 'activerecord-database-views/view_collection'
 
 module ActiveRecord::DatabaseViews
-  def self.views
-    ViewCollection.new
+
+  def self.register_view_exclusion_filter(proc_handle=nil)
+    if proc_handle && proc_handle.respond_to?(:call)
+      @view_exclusion_filter = proc_handle
+    elsif proc_handle == false
+      @view_exclusion_filter = nil
+    end
+    @view_exclusion_filter
+  end
+
+  def self.views(verbose=true)
+    ViewCollection.new verbose
   end
 
-  def self.without
-    views.drop!
+  def self.without(verbose=true)
+    views(verbose).drop!
     yield if block_given?
-    views.load!
+    views(verbose).load!
   end
 
-  def self.reload!
+  def self.reload!(verbose=true)
     ActiveRecord::Base.transaction do
-      without
+      without verbose
     end
   end
 end

lib/activerecord-database-views/view.rb

@@ -1,3 +1,5 @@
+require 'erb'
+
 module ActiveRecord::DatabaseViews
   class View
     FILE_NAME_MATCHER_WITH_PREFIX = /^\d+?_(.+)/
@@ -27,15 +29,19 @@ def name
     private
 
     def basename
-      @basename ||= File.basename(path, '.sql')
+      @basename ||= File.basename(File.basename(path, '.erb'), '.sql')
     end
 
     def full_path
       Rails.root.join(path)
     end
 
     def sql
-      File.read(full_path)
+      if File.extname(path) == '.erb'
+        ERB.new(File.read(full_path)).result
+      else
+        File.read(full_path)
+      end
     end
 
     def call_sql!(sql)

lib/activerecord-database-views/view_collection.rb

@@ -1,15 +1,26 @@
 module ActiveRecord::DatabaseViews
+
   class ViewCollection
     MISSING_RELATION_REGEX = /relation \"(.*)\" does not exist/
+    MISSING_VIEW_REGEX = /view \"(.*)\" does not exist/
+    DROP_COLUMNS_REGEX = /cannot drop columns from view/
+    CHANGE_COLUMNS_REGEX = /cannot change name of view column \"(.*)\" to \"(.*)\"/
+    UNDEFINED_COLUMN_REGEX = /column (.*) does not exist/
 
     include Enumerable
 
-    attr_reader :views
+    attr_reader :views, :verbose
 
     delegate :each, to: :views
 
-    def initialize
-      @views = view_paths.map { |path| View.new(path) }
+    def initialize(verbose=true)
+      @verbose = verbose
+      view_exclusion_filter = ActiveRecord::DatabaseViews.register_view_exclusion_filter
+      @views = view_paths.map do |path|
+        view = View.new(path)
+        next if view_exclusion_filter && view_exclusion_filter.call(view.name)
+        view
+      end.compact
     end
 
     def drop!
@@ -22,14 +33,42 @@ def load!
 
     private
 
+    def log(msg)
+      return unless verbose
+      puts msg
+    end
+
     def load_view(view)
+      name = view.name
+
       begin
         view.load! and views.delete(view)
+        log "#{name}: Loaded"
       rescue ActiveRecord::StatementInvalid => exception
-        if (related_view = retrieve_related_view(exception))
+        ActiveRecord::Base.connection.rollback_db_transaction
+
+        if schema_changed?(exception)
+          log "#{name}: Column definitions have changed"
+          # Drop the view
+          view.drop!
+          # Load it again
+          load_view(view)
+        elsif undefined_column?(exception)
+          log "#{name}: Undefined column"
+          # Drop all the remaining views since we can't detect which one it is
+          views.each(&:drop!)
+          # Load the view again (which will trigger a missing relation error and proceed to load that view)
+          load_view(view)
+        elsif (related_view = retrieve_related_view(exception))
+          log "#{name}: Contains missing relation"
+          # Load the relation that is mentioned
+          load_view(related_view) and retry
+        elsif (related_view = retrieve_missing_view(exception))
+          log "#{name}: Contains missing view"
+          # Load the view that is mentioned
           load_view(related_view) and retry
         else
-          raise exc
+          raise exception
         end
       end
     end
@@ -40,8 +79,23 @@ def retrieve_related_view(exception)
       find { |view| view.name == related_view_name }
     end
 
+    def retrieve_missing_view(exception)
+      related_view_name = exception.message.scan(MISSING_VIEW_REGEX).flatten.first
+      return false if related_view_name.blank?
+      find { |view| view.name == related_view_name }
+    end
+
+    def schema_changed?(exception)
+      exception.message =~ DROP_COLUMNS_REGEX ||
+      exception.message =~ CHANGE_COLUMNS_REGEX
+    end
+
+    def undefined_column?(exception)
+      exception.message =~ UNDEFINED_COLUMN_REGEX
+    end
+
     def view_paths
-      Dir.glob('db/views/**/*.sql').sort
+      Dir.glob('db/views/**/*.{sql,sql.erb}').sort
     end
   end
 end

test/test_helper.rb

@@ -1,2 +1,5 @@
 require 'bundler/setup'
-
+require 'minitest/autorun'
+require 'mocha/test_unit'
+require 'active_record'
+require 'activerecord-database-views'

test/view_collection_test.rb

@@ -0,0 +1,59 @@
+require File.dirname(__FILE__) + '/test_helper'
+
+class ViewCollectionTests < MiniTest::Test
+  def test_it_can_find_sql_files
+    collection = ActiveRecord::DatabaseViews::ViewCollection.new
+    assert_equal 2, collection.views.length
+  end
+
+  def test_it_can_properly_catch_and_execute_a_relation_dependency
+    collection = ActiveRecord::DatabaseViews::ViewCollection.new
+    ActiveRecord::DatabaseViews::View.any_instance.expects(:load!).raises(ActiveRecord::StatementInvalid, 'relation "sql_base_view" does not exist')
+    assert_raises (ActiveRecord::ConnectionNotEstablished) {
+      collection.load!
+    }
+  end
+
+  def test_it_can_properly_catch_and_execute_a_dependency
+    collection = ActiveRecord::DatabaseViews::ViewCollection.new
+    ActiveRecord::DatabaseViews::View.any_instance.expects(:load!).raises(ActiveRecord::StatementInvalid, 'view "sql_base_view" does not exist')
+    assert_raises (ActiveRecord::ConnectionNotEstablished) {
+      collection.load!
+    }
+  end
+
+  def test_it_can_properly_catch_and_execute_when_columns_are_dropped
+    collection = ActiveRecord::DatabaseViews::ViewCollection.new
+    ActiveRecord::DatabaseViews::View.any_instance.expects(:load!).raises(ActiveRecord::StatementInvalid, 'cannot drop columns from view')
+    assert_raises (ActiveRecord::ConnectionNotEstablished) {
+      collection.load!
+    }
+  end
+
+  def test_it_can_properly_catch_and_execute_when_columns_are_changed
+    collection = ActiveRecord::DatabaseViews::ViewCollection.new
+    ActiveRecord::DatabaseViews::View.any_instance.expects(:load!).raises(ActiveRecord::StatementInvalid, 'cannot change name of view column "test1" to "test1_full"')
+    assert_raises (ActiveRecord::ConnectionNotEstablished) {
+      collection.load!
+    }
+  end
+
+  def test_it_can_property_catch_and_execute_when_a_column_is_undefined
+    collection = ActiveRecord::DatabaseViews::ViewCollection.new
+    ActiveRecord::DatabaseViews::View.any_instance.expects(:load!).raises(ActiveRecord::StatementInvalid, 'column test1 does not exist')
+    assert_raises (ActiveRecord::ConnectionNotEstablished) {
+      collection.load!
+    }
+  end
+
+  def test_it_respects_view_exclusion_filter
+    ActiveRecord::DatabaseViews.register_view_exclusion_filter( lambda { |name| name == 'sql_a_queries_from_base_view' })
+    assert ActiveRecord::DatabaseViews.register_view_exclusion_filter.is_a?(Proc)
+    collection = ActiveRecord::DatabaseViews::ViewCollection.new
+    assert_equal ['sql_base_view'], collection.collect(&:name)
+
+    ActiveRecord::DatabaseViews.register_view_exclusion_filter(false)
+    assert ActiveRecord::DatabaseViews.register_view_exclusion_filter.nil?
+  end
+
+end