Adding config flag role_path for common/global roles

Using ANSIBLE_ROLE_PATH environment variable or role_path in ansible.cfg
can configure paths where roles will be searched for
extra paths will only be used as a backup once regular locations are exhausted

examples/ansible.cfg

@@ -12,6 +12,7 @@
 
 hostfile       = /etc/ansible/hosts
 library        = /usr/share/ansible
+#roles_path    = /etc/ansible/roles
 remote_tmp     = $HOME/.ansible/tmp
 pattern        = *
 forks          = 5

lib/ansible/constants.py

@@ -95,6 +95,7 @@ DEFAULTS='defaults'
 # configurable things
 DEFAULT_HOST_LIST         = shell_expand_path(get_config(p, DEFAULTS, 'hostfile', 'ANSIBLE_HOSTS', '/etc/ansible/hosts'))
 DEFAULT_MODULE_PATH       = get_config(p, DEFAULTS, 'library',          'ANSIBLE_LIBRARY',          DIST_MODULE_PATH)
+DEFAULT_ROLES_PATH        = get_config(p, DEFAULTS, 'roles_path',       'ANSIBLE_ROLES_PATH',       None)
 DEFAULT_REMOTE_TMP        = shell_expand_path(get_config(p, DEFAULTS, 'remote_tmp',       'ANSIBLE_REMOTE_TEMP',      '$HOME/.ansible/tmp'))
 DEFAULT_MODULE_NAME       = get_config(p, DEFAULTS, 'module_name',      None,                       'command')
 DEFAULT_PATTERN           = get_config(p, DEFAULTS, 'pattern',          None,                       '*')

lib/ansible/playbook/play.py

@@ -21,6 +21,7 @@ from ansible.utils.template import template
 from ansible import utils
 from ansible import errors
 from ansible.playbook.task import Task
+import ansible.constants as C
 import pipes
 import shlex
 import os
@@ -148,16 +149,27 @@ class Play(object):
             role_vars = orig_path
             orig_path = role_name
 
-        path = utils.path_dwim(self.basedir, os.path.join('roles', orig_path))
+        role_path = None
-        if not os.path.isdir(path) and not orig_path.startswith(".") and not orig_path.startswith("/"):
-            path2 = utils.path_dwim(self.basedir, orig_path)
-            if not os.path.isdir(path2):
-                raise errors.AnsibleError("cannot find role in %s or %s" % (path, path2))
-            path = path2
-        elif not os.path.isdir(path):
-            raise errors.AnsibleError("cannot find role in %s" % (path))
 
-        return (path, role_vars)
+        possible_paths = [
+            utils.path_dwim(self.basedir, os.path.join('roles', orig_path)),
+            utils.path_dwim(self.basedir, orig_path)
+        ]
+
+        if C.DEFAULT_ROLES_PATH:
+            search_locations = C.DEFAULT_ROLES_PATH.split(os.pathsep)
+            for loc in search_locations:
+                possible_paths.append(utils.path_dwim(loc, orig_path))
+
+        for path_option in possible_paths:
+            if os.path.isdir(path_option):
+                role_path = path_option
+                break
+
+        if role_path is None:
+            raise errors.AnsibleError("cannot find role in %s" % " or ".join(possible_paths))
+
+        return (role_path, role_vars)
 
     def _build_role_dependencies(self, roles, dep_stack, passed_vars={}, level=0):
         # this number is arbitrary, but it seems sane