Add lookup_hiera_hash function

The lookup_hiera_hash function is meant to lookup for the value
of a given key from a given Hiera hash. In the manifests this is
possible by saving the value of the hash in a variable first but
when driving lookups from the Heat templates we can't do it.

Change-Id: Ie31bb70314db44a0a18e86090cc74aa4df5de169

1 files changed, 22 insertions, 0 deletions

diff --git a/lib/puppet/parser/functions/lookup_hiera_hash.rb b/lib/puppet/parser/functions/lookup_hiera_hash.rb
new file mode 100644
index 0000000..d96d65f
--- /dev/null
+++ b/lib/puppet/parser/functions/lookup_hiera_hash.rb
@@ -0,0 +1,22 @@
+module Puppet::Parser::Functions
+  newfunction(:lookup_hiera_hash, :arity => 2, :type => :rvalue,
+              :doc => "Lookup a key->value from a Hiera hash") do |args|
+    hash_name = args[0]
+    key_name = args[1]
+    unless hash_name.is_a?(String) and key_name.is_a?(String)
+      raise Puppet::ParseError, "The hash name and the key name must be given as strings."
+    end
+    if defined? call_function
+      hash = call_function('hiera', [hash_name])
+    else
+      hash = function_hiera([hash_name])
+    end
+    unless hash.is_a?(Hash)
+      raise Puppet::ParseError, "The value Hiera returned for #{hash_name} is not a Hash."
+    end
+    unless hash.key?(key_name)
+      raise Puppet::ParseError, "The Hiera hash #{hash_name} does not contain key #{key_name}."
+    end
+    return hash[key_name]
+  end
+end