From 4e9a9706165ee01bc2f5d700dbcbddb051ed8c4e Mon Sep 17 00:00:00 2001
From: Dag Wieers <dag@wieers.com>
Date: Mon, 24 Sep 2012 21:06:34 +0200
Subject: [PATCH] Add an only_if option to vars_prompt to make prompts
 conditional

Sometimes you may want to allow variables through host_vars or inventory, but prompt for a value if it is not set or if the value does not conform to something specific. This option allows you to specify when you want to offer a prompt.

This patch also moves check_conditional to utils, and adds an is_unset() function which is nicer to read:

    only_if: "not is_set('${var}')"

vs

    only_if: "is_unset('${var}')"
---
 lib/ansible/playbook/play.py   | 4 +++-
 lib/ansible/runner/__init__.py | 6 +-----
 lib/ansible/utils.py           | 7 +++++++
 3 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/lib/ansible/playbook/play.py b/lib/ansible/playbook/play.py
index e2b57064e7..4e53449d61 100644
--- a/lib/ansible/playbook/play.py
+++ b/lib/ansible/playbook/play.py
@@ -172,8 +172,10 @@ class Play(object):
                 encrypt = var.get("encrypt", None)
                 salt_size = var.get("salt_size", None)
                 salt = var.get("salt", None)
+                conditional = var.get("only_if", 'True')
 
-                vars[vname] = self.playbook.callbacks.on_vars_prompt(vname, private, prompt,encrypt, confirm, salt_size, salt)
+                if utils.check_conditional(conditional):
+                    vars[vname] = self.playbook.callbacks.on_vars_prompt(vname, private, prompt,encrypt, confirm, salt_size, salt)
 
         elif type(self.vars_prompt) == dict:
             for (vname, prompt) in self.vars_prompt.iteritems():
diff --git a/lib/ansible/runner/__init__.py b/lib/ansible/runner/__init__.py
index 1c3977e86b..328661ddc5 100644
--- a/lib/ansible/runner/__init__.py
+++ b/lib/ansible/runner/__init__.py
@@ -329,12 +329,8 @@ class Runner(object):
             self.module_args = new_args
         self.module_args = utils.template(self.basedir, self.module_args, inject)
 
-        def _check_conditional(conditional):
-            def is_set(var):
-                return not var.startswith("$")
-            return eval(conditional)
         conditional = utils.template(self.basedir, self.conditional, inject)
-        if not _check_conditional(conditional):
+        if not utils.check_conditional(conditional):
             result = utils.jsonify(dict(skipped=True))
             self.callbacks.on_skipped(host, inject.get('item',None))
             return ReturnData(host=host, result=result)
diff --git a/lib/ansible/utils.py b/lib/ansible/utils.py
index 6fefd09164..2e81a5db95 100644
--- a/lib/ansible/utils.py
+++ b/lib/ansible/utils.py
@@ -93,6 +93,13 @@ def is_failed(result):
 
     return ((result.get('rc', 0) != 0) or (result.get('failed', False) in [ True, 'True', 'true']))
 
+def check_conditional(conditional):
+    def is_set(var):
+        return not var.startswith("$")
+    def is_unset(var):
+        return var.startswith("$")
+    return eval(conditional)
+
 def prepare_writeable_dir(tree):
     ''' make sure a directory exists and is writeable '''