(FACT-1277) Ensure Puppet external facts are loaded

[MikaelSmith]

The external facts path needs to be registered before doing anything to
resolve facts - such as call Facter.add. Otherwise that path will not
be used to resolve facts. Register pluginfactdest before adding core
Puppet facts.

[peterhuene]

👍

[joshcooper]

makes sense, just waiting for checks.

[MikaelSmith]

Passed.

[joshcooper]

Puppet's facter terminus calls both Facter.search and Facter.search_external. The former includes custom facts from all modules in the environment. The latter includes external facts from all modules in the environment, and the external facts in pluginfactdest.

This commit is only adding external fact search path for pluginfactdest. Do we care about omitting custom and external facts from modules? For example facter -p will return different facts than puppet apply. I think we made explicit decision to skip those, but I don't remember the details?

[peterhuene]

I believe we didn't do it this way to keep it consistent with what Facter 2.x was doing to support -p, although given that we originally didn't plan on supporting -p that should be revisited, but IMO that's for a later release.

[MikaelSmith]

We find pluginsynced custom facts, but not custom facts for modules in codedir. This was a decision carried forward from 2.x. This commit doesn't change that, it just rearranges code.

[joshcooper]

Just to confirm, puppet 3.x includes facts from 5 sources:

• non-pluginsynced external facts (/etc/facter/facts.d)
• module external (/etc/puppet/modules/foo/facts.d/) and custom (/etc/puppet/modules/foo/lib/facter) facts
• pluginsynced external (/var/lib/puppet/facts.d/) and custom (/var/lib/puppet/lib/facter) facts

facter 2.x only reports on

• non-pluginsynced external facts (/etc/facter/facts.d)
• custom (/etc/puppet/modules/foo/lib/facter) facts

$ sudo bundle exec puppet facts find . | jq .values | grep myfact | sort
  "myfact_external": "true",
  "myfact_module_custom": "true",
  "myfact_module_external": "true",
  "myfact_pluginsync_custom": "true",
  "myfact_pluginsync_external": "true",
$ sudo bundle exec facter -p | grep myfact | sort
myfact_external => true
myfact_pluginsync_custom => true

Also both puppet 3.x and facter 2.x include puppetversion:

$ sudo bundle exec facter -p | grep puppetversion
puppetversion => 3.8.4
$ sudo bundle exec puppet facts find . | jq .values | grep puppetversion
  "puppetversion": "3.8.4",

We fixed facter (in 3.x series) to include pluginsynced external facts, so both puppet and facter return the same set of fact excluding custom and external facts from modules:

# /opt/puppetlabs/bin/puppet facts find  | grep myfact
    "myfact_external": "true",
    "myfact_module_custom": true,
    "myfact_module_external": "true",
    "myfact_pluginsync_custom": true,
    "myfact_pluginsync_external": "true",
# /opt/puppetlabs/bin/facter -p  | grep myfact
myfact_external => true
myfact_pluginsync_custom => true
myfact_pluginsync_external => true

And without this PR, facter -p omits puppetversion:

# /opt/puppetlabs/bin/facter -p | grep puppetversion
# /opt/puppetlabs/bin/puppet facts find  | grep puppetversion
    "puppetversion": "4.3.0",

So 👍