Rdb save incremental fsync

[thejambavan]

Pull Request (PR) description

minor change to the redis.conf EPP template to make it possible to disable rdb_save_incremental_fsync

This Pull Request (PR) fixes the following issues

Fixes #494

[kenyon]

I don't see how this changes anything. If you are providing a non-undef value to redis::rdb_save_incremental_fsync, then it will render either rdb-save-incremental-fsync yes or rdb-save-incremental-fsync no.

To be sure, you could add a test like

puppet-redis/spec/classes/redis_spec.rb

Lines 1683 to 1691 in e8d71af

	describe 'test rdb-save-incremental-fsync for redis6' do
	let(:params) do
	{
	rdb_save_incremental_fsync: true,
	}
	end
	it { is_expected.to contain_file(config_file_orig).with('content' => %r{^rdb-save-incremental-fsync yes$}) }
	end

that sets rdb_save_incremental_fsync to false and checks that the config files contains rdb-save-incremental-fsync no.

[kenyon]

Actually I see the problem now. The if $rdb_save_incremental_fsync evaluates to false when you set rdb_save_incremental_fsync to false, so the line doesn't get rendered. But your patch doesn't fix that bug.

[thejambavan]

I have corrected the if to an unless Undef and have added tests which seem to do the job (apologies for multiple formatting commits) for all three states:

Undef: no config file entry, aka "the default" which may have been "no" in the past but is now "yes"
true: yes
false: no

I have separately verified that this works as intended on a real-world instance.

edit: i clearly do not now how to use rspec properly

[kenyon]

Suggested change

	rdb_save_incremental_fsync: Undef,
	rdb_save_incremental_fsync: nil,

[thejambavan]

no matter what i do with the test, when i set:

            rdb_save_incremental_fsync: nil,

as part of the rspec test, i can't get the test to pass in the Puppet/ruby stages. I don't see any other tests for undef/nil, and have not had any luck finding good examples elsewhere.