summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
-rw-r--r--lib/puppet/parser/functions/pick.rb29
-rw-r--r--spec/unit/puppet/parser/functions/pick_spec.rb34
2 files changed, 63 insertions, 0 deletions
diff --git a/lib/puppet/parser/functions/pick.rb b/lib/puppet/parser/functions/pick.rb
new file mode 100644
index 0000000..cbc0300
--- /dev/null
+++ b/lib/puppet/parser/functions/pick.rb
@@ -0,0 +1,29 @@
+module Puppet::Parser::Functions
+ newfunction(:pick, :type => :rvalue, :doc => <<-EOS
+
+This function is similar to a coalesce function in SQL in that it will return
+the first value in a list of values that is not undefined or an empty string
+(two things in Puppet that will return a boolean false value). Typically,
+this function is used to check for a value in the Puppet Dashboard/Enterprise
+Console, and failover to a default value like the following:
+
+ $real_jenkins_version = pick($::jenkins_version, '1.449')
+
+The value of $real_jenkins_version will first look for a top-scope variable
+called 'jenkins_version' (note that parameters set in the Puppet Dashboard/
+Enterprise Console are brought into Puppet as top-scope variables), and,
+failing that, will use a default value of 1.449.
+
+EOS
+) do |args|
+ args = args.compact
+ args.delete(:undef)
+ args.delete(:undefined)
+ args.delete("")
+ if args[0].to_s.empty? then
+ fail "Must provide non empty value."
+ else
+ return args[0]
+ end
+ end
+end
diff --git a/spec/unit/puppet/parser/functions/pick_spec.rb b/spec/unit/puppet/parser/functions/pick_spec.rb
new file mode 100644
index 0000000..761db6b
--- /dev/null
+++ b/spec/unit/puppet/parser/functions/pick_spec.rb
@@ -0,0 +1,34 @@
+#!/usr/bin/env ruby -S rspec
+require 'spec_helper'
+
+describe "the pick function" do
+ let(:scope) { PuppetlabsSpec::PuppetInternals.scope }
+
+ it "should exist" do
+ Puppet::Parser::Functions.function("pick").should == "function_pick"
+ end
+
+ it 'should return the correct value' do
+ scope.function_pick(['first', 'second']).should == 'first'
+ end
+
+ it 'should return the correct value if the first value is empty' do
+ scope.function_pick(['', 'second']).should == 'second'
+ end
+
+ it 'should remove empty string values' do
+ scope.function_pick(['', 'first']).should == 'first'
+ end
+
+ it 'should remove :undef values' do
+ scope.function_pick([:undef, 'first']).should == 'first'
+ end
+
+ it 'should remove :undefined values' do
+ scope.function_pick([:undefined, 'first']).should == 'first'
+ end
+
+ it 'should error if no values are passed' do
+ expect { scope.function_pick([]) }.to raise_error(Puppet::Error, /Must provide non empty value./)
+ end
+end