Module: SchemaMoves::Helpers

Defined in:
lib/schema_moves.rb

Instance Method Summary collapse

Instance Method Details

#appname ⇒ Object 



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# File 'lib/schema_moves.rb', line 204

def appname
  Rails.application.class.parent_name.underscore
end

#ask(*args, &block) ⇒ Object 



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# File 'lib/schema_moves.rb', line 155

def ask(*args, &block)
  HighLine.new.ask(*args, &block)
end

#create_new_triggers(new_schema) ⇒ Object 



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# File 'lib/schema_moves.rb', line 47

def create_new_triggers(new_schema)
  connection = ActiveRecord::Base.connection
  sql = %{
    CREATE FUNCTION #{new_schema}.tg_disallow()
      RETURNS TRIGGER
      AS
      $TRIGGER$
        BEGIN

        IF TG_LEVEL <> 'STATEMENT' THEN
          RAISE EXCEPTION $$You should use a statement-level trigger (trigger %, table %)$$, TG_NAME, TG_RELID::regclass;
        END IF;

        RAISE EXCEPTION $$%s are not allowed on table %$$, TG_OP, TG_RELNAME;

        RETURN NULL;

        END
       $TRIGGER$
       LANGUAGE plpgsql;

    CREATE FUNCTION #{new_schema}.template_revision_ordinal()
      RETURNS TRIGGER
      AS
      $TRIGGER$
        BEGIN

        IF NEW.ordinal IS NOT NULL THEN
          RAISE EXCEPTION $$Must not supply ordinal value manually.$$;
        END IF;

        NEW.ordinal = (SELECT COALESCE(MAX(ordinal)+1,1)
                        FROM #{new_schema}.template_revisions
                        WHERE template_id = NEW.template_id);

        RETURN NEW;

        END
       $TRIGGER$
       LANGUAGE plpgsql;

    CREATE TRIGGER #{new_schema}_template_revisions__bfr_insert
              BEFORE INSERT ON #{new_schema}.template_revisions
              FOR EACH ROW EXECUTE PROCEDURE #{new_schema}.template_revision_ordinal();

    CREATE TRIGGER #{new_schema}_template_revisions__no_delete
            BEFORE DELETE ON #{new_schema}.template_revisions
            FOR EACH STATEMENT EXECUTE PROCEDURE #{new_schema}.tg_disallow();

    CREATE TRIGGER #{new_schema}_template_revisions__no_update
            BEFORE UPDATE OF notes, is_minor, template_id, author_id, created_at, ordinal ON #{new_schema}.template_revisions
            FOR EACH STATEMENT EXECUTE PROCEDURE #{new_schema}.tg_disallow();

    CREATE FUNCTION #{new_schema}.pages_revision_ordinal()
      RETURNS TRIGGER
      AS
      $TRIGGER$
        BEGIN

        IF NEW.ordinal IS NOT NULL THEN
          RAISE EXCEPTION $$Must not supply ordinal value manually.$$;
        END IF;

        NEW.ordinal = (SELECT COALESCE(MAX(ordinal)+1,1)
                        FROM #{new_schema}.page_revisions
                        WHERE page_id = NEW.page_id);

        RETURN NEW;

        END
       $TRIGGER$
       LANGUAGE plpgsql;

    CREATE TRIGGER #{new_schema}_page_revisions__bfr_insert
      BEFORE INSERT ON #{new_schema}.page_revisions
      FOR EACH ROW EXECUTE PROCEDURE #{new_schema}.pages_revision_ordinal();

    CREATE TRIGGER #{new_schema}_page_revisions__no_delete
      BEFORE DELETE ON #{new_schema}.page_revisions
      FOR EACH STATEMENT EXECUTE PROCEDURE #{new_schema}.tg_disallow();

    CREATE TRIGGER #{new_schema}_page_revisions__no_update
      BEFORE UPDATE OF notes, is_minor, page_id, author_id, created_at, ordinal ON #{new_schema}.page_revisions
      FOR EACH STATEMENT EXECUTE PROCEDURE #{new_schema}.tg_disallow();
  }
  puts "Creating new triggers..."
  connection.execute sql
end

#create_schema(schema) ⇒ Object 



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# File 'lib/schema_moves.rb', line 3

def create_schema(schema)
  connection = ActiveRecord::Base.connection

  sql = %{
    CREATE SCHEMA #{schema};
  }
  puts "Creating #{schema} schema"
  connection.execute sql
end

#create_schemas ⇒ Object 



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# File 'lib/schema_moves.rb', line 171

def create_schemas
  create_schema @new_landable
  create_schema @new_traffic
end

#drop_old_schemas ⇒ Object 



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# File 'lib/schema_moves.rb', line 191

def drop_old_schemas
  drop_schema @old_landable
  drop_schema @old_traffic
end

#drop_old_triggers(old_schema, new_schema) ⇒ Object 



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# File 'lib/schema_moves.rb', line 136

def drop_old_triggers(old_schema, new_schema)
  connection = ActiveRecord::Base.connection
  sql = %{
    DROP TRIGGER IF EXISTS #{old_schema}_page_revisions__bfr_insert ON #{new_schema}.page_revisions;
    DROP TRIGGER IF EXISTS #{old_schema}_page_revisions__no_delete  ON #{new_schema}.page_revisions;
    DROP TRIGGER IF EXISTS #{old_schema}_page_revisions__no_update  ON #{new_schema}.page_revisions;

    DROP TRIGGER IF EXISTS #{old_schema}_template_revisions__bfr_insert ON #{new_schema}.template_revisions;
    DROP TRIGGER IF EXISTS #{old_schema}_template_revisions__no_delete  ON #{new_schema}.template_revisions;
    DROP TRIGGER IF EXISTS #{old_schema}_template_revisions__no_update  ON #{new_schema}.template_revisions;

    DROP FUNCTION IF EXISTS #{old_schema}.pages_revision_ordinal();
    DROP FUNCTION IF EXISTS #{old_schema}.template_revision_ordinal();
    DROP FUNCTION IF EXISTS #{old_schema}.tg_disallow();
  }
  puts "Dropping old triggers..."
  connection.execute sql
end

#drop_schema(schema) ⇒ Object 



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# File 'lib/schema_moves.rb', line 13

def drop_schema(schema)
  connection = ActiveRecord::Base.connection

  sql = %{
    DROP SCHEMA #{schema};
  }
  puts "Dropping #{schema} schema"
  connection.execute sql
end

#get_schema_names(new = true) ⇒ Object 



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# File 'lib/schema_moves.rb', line 159

def get_schema_names(new = true)
  # Always get old schemas
  @old_landable = ask("Enter the OLD main landable schema: ") { |q| q.default = 'landable' }
  @old_traffic = ask("Enter the OLD traffic schema: ") { |q| q.default = 'landable_traffic' }

  # Only ask for new names if new == true
  if new
    @new_landable = ask("Enter the NEW main landable schema: ") { |q| q.default = "#{appname}_landable" }
    @new_traffic = ask("Enter the NEW traffic schema: ") { |q| q.default = "#{appname}_landable_traffic" }
  end
end

#migrate_objects ⇒ Object 



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# File 'lib/schema_moves.rb', line 176

def migrate_objects
  # move_tables
  move_objects(@old_landable, @new_landable, 'r', 'TABLE')
  move_objects(@old_traffic, @new_traffic, 'r', 'TABLE')
  # move_sequences
  move_objects(@old_landable, @new_landable, 's', 'SEQUENCE')
  move_objects(@old_traffic, @new_traffic, 's', 'SEQUENCE')
  # move_views
  move_objects(@old_landable, @new_landable, 'v', 'TABLE')
  move_objects(@old_traffic, @new_traffic, 'v', 'TABLE')
  # move_triggers
  create_new_triggers(@new_landable)
  drop_old_triggers(@old_landable, @new_landable)
end

#move_objects(from_schema, to_schema, relkind, object_type) ⇒ Object 



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# File 'lib/schema_moves.rb', line 23

def move_objects(from_schema, to_schema, relkind, object_type)
  connection = ActiveRecord::Base.connection

  # move objects from public to new schema
  objects = connection.select_all("
    SELECT o.relname
      FROM pg_class o
      JOIN pg_namespace n
      ON n.oid=o.relnamespace
      AND n.nspname = '#{from_schema}'
      AND o.relkind = '#{relkind}'
      ORDER BY o.relname
  ")

  objects.each do |object|
    sql = %{
      ALTER #{object_type} #{from_schema}.#{object['relname']}
        SET SCHEMA #{to_schema}
    }
    puts "Moving #{from_schema}.#{object['relname']} TO #{to_schema}"
    connection.execute sql
  end
end

#want_to_drop_old_schemas? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/schema_moves.rb', line 196

def want_to_drop_old_schemas?
  drop = nil
  until ['yes', 'no'].include?(drop.to_s.downcase)
    drop = ask("Would you like to drop the old schemas? (Yes or No)") { |q| q.default = 'no' }
  end
  drop.to_s.downcase == 'yes'
end