Implement fact memoization

[ekohl]

Subsequent calls to on_supported_os with the same options should result in the same facts. This can greatly speed up testing by reducing calls to FacterDB.

This currently fails, probably because it's not taking environment variables into account. I did want to submit this since it's at least a start to collaborate.

Fixes #114

[coveralls]

Coverage increased (+0.03%) to 99.346% when pulling 1693e78 on ekohl:fact-memoization into 7ef35f3 on mcanevet:master.

[ekohl]

I missed some cache keys, but I think I have them all now. Locally the tests were green so I think this is ready for review.

[ekohl]

The build failed on out of date components. Doesn't look related to my PR, just something that changed externally and probably also shows up in master.

[ekohl]

@mcanevet could you have a look?

[DavidS]

added the updated agent components

[mcanevet]

@DavidS is it OK for you to merge this?

[DavidS]

I'm running some local tests to confirm it working and being beneficial before merging.

I've also noticed that https://github.com/puppetlabs/puppet-module-gems/blob/9c488b456b3d3c1bc6fd02718ee95c102eb78211/config/dependencies.yml#L67 currently is excluding RPF v2 from being installed, so I'll fix that too.

[DavidS]

Results from my local tests:

# with released rspec-puppet-facts

Finished in 44 minutes 23 seconds (files took 3 minutes 20.2 seconds to load)
7803 examples, 0 failures


real	47m48.315s
user	46m6.912s
sys	1m16.671s
david@zion:~/git/puppetlabs-apache (main)$

# with modified rspec-puppet-facts
Finished in 42 minutes 47 seconds (files took 14.31 seconds to load)
7803 examples, 0 failures


real	43m5.625s
user	41m43.348s
sys	1m8.159s
david@zion:~/git/puppetlabs-apache (main)$

As you can see the file load time was reduced from 3 minutes 20 seconds down to 14 seconds. I consider that a great win (even when it doesn't make a big difference for this particular test suite).

[ekohl]

Thanks for merging this. Looking forward to a release that includes this.

As you can see the file load time was reduced from 3 minutes 20 seconds down to 14 seconds. I consider that a great win (even when it doesn't make a big difference for this particular test suite).

It also helps greatly if you run something like rspec -e mytest. Note that the 14 seconds is dominated by a single on_supported_os. There's room for more improvement so I opened #123 with some of my ideas.