(MODULES-1738) Don't modify global seed in fqdn_rotate()

As per puppetlabs/puppet@292233c, this leaves the global seed in a
deterministic state, which is bad. Puppet::Util.deterministic_rand()
exists to avoid running into this issue, but is only present starting in
Puppet 3.2.0.

1 files changed, 14 insertions, 2 deletions

diff --git a/lib/puppet/parser/functions/fqdn_rotate.rb b/lib/puppet/parser/functions/fqdn_rotate.rb
index 7f4d37d..cf22d36 100644
--- a/lib/puppet/parser/functions/fqdn_rotate.rb
+++ b/lib/puppet/parser/functions/fqdn_rotate.rb
@@ -31,8 +31,20 @@ Rotates an array a random number of times based on a nodes fqdn.
 
     elements = result.size
 
-    srand(Digest::MD5.hexdigest([lookupvar('::fqdn'),arguments].join(':')).hex)
-    rand(elements).times {
+    seed = Digest::MD5.hexdigest([lookupvar('::fqdn'),arguments].join(':')).hex
+    # deterministic_rand() was added in Puppet 3.2.0; reimplement if necessary
+    if Puppet::Util.respond_to?(:deterministic_rand)
+      offset = Puppet::Util.deterministic_rand(seed, elements).to_i
+    else
+      if defined?(Random) == 'constant' && Random.class == Class
+        offset = Random.new(seed).rand(elements)
+      else
+        srand(seed)
+        offset = rand(elements)
+        srand()
+      end
+    end
+    offset.times {
        result.push result.shift
     }