diff options
Diffstat (limited to 'puppet/modules/stdlib/README_DEVELOPER.markdown')
m--------- | puppet/modules/stdlib | 0 | ||||
-rw-r--r-- | puppet/modules/stdlib/README_DEVELOPER.markdown | 35 |
2 files changed, 35 insertions, 0 deletions
diff --git a/puppet/modules/stdlib b/puppet/modules/stdlib deleted file mode 160000 -Subproject 71123634744b9fe2ec7d6a3e38e9789fd84801e diff --git a/puppet/modules/stdlib/README_DEVELOPER.markdown b/puppet/modules/stdlib/README_DEVELOPER.markdown new file mode 100644 index 00000000..04349ed7 --- /dev/null +++ b/puppet/modules/stdlib/README_DEVELOPER.markdown @@ -0,0 +1,35 @@ +Puppet Specific Facts +===================== + +Facter is meant to stand alone and apart from Puppet. However, Facter often +runs inside Puppet and all custom facts included in the stdlib module will +almost always be evaluated in the context of Puppet and Facter working +together. + +Still, we don't want to write custom facts that blow up in the users face if +Puppet is not loaded in memory. This is often the case if the user runs +`facter` without also supplying the `--puppet` flag. + +Ah! But Jeff, the custom fact won't be in the `$LOAD_PATH` unless the user +supplies `--facter`! You might say... + +Not (always) true I say! If the user happens to have a CWD of +`<modulepath>/stdlib/lib` then the facts will automatically be evaluated and +blow up. + +In any event, it's pretty easy to write a fact that has no value if Puppet is +not loaded. Simply do it like this: + + Facter.add(:node_vardir) do + setcode do + # This will be nil if Puppet is not available. + Facter::Util::PuppetSettings.with_puppet do + Puppet[:vardir] + end + end + end + +The `Facter::Util::PuppetSettings.with_puppet` method accepts a block and +yields to it only if the Puppet library is loaded. If the Puppet library is +not loaded, then the method silently returns `nil` which Facter interprets as +an undefined fact value. The net effect is that the fact won't be set. |