Use distros.CONFIG_MODULE_SUPPORT_ALL_DISTROS in runcmd to advertise that runcmd is supported on every distro. Add distros.get_all_distro_names() which will list all discovered distros in cloudinit.distros package. cloudinit.stages uses get_all_distro_names when determining whether to skip a given module due to lack of distro support

3 files changed, 27 insertions, 4 deletions

diff --git a/cloudinit/config/cc_runcmd.py b/cloudinit/config/cc_runcmd.py
index 7c3ccd4..0899d15 100644
--- a/cloudinit/config/cc_runcmd.py
+++ b/cloudinit/config/cc_runcmd.py
@@ -9,6 +9,7 @@
 """Runcmd: run arbitrary commands at rc.local with output to the console"""
 
 from cloudinit.config.schema import validate_cloudconfig_schema
+from cloudinit.distros import CONFIG_MODULE_SUPPORT_ALL_DISTROS
 from cloudinit.settings import PER_INSTANCE
 from cloudinit import util
 
@@ -22,7 +23,7 @@ from textwrap import dedent
 # configuration options before actually attempting to deploy with said
 # configuration.
 
-distros = ['all']
+distros = [CONFIG_MODULE_SUPPORT_ALL_DISTROS]
 
 schema = {
     'id': 'cc_runcmd',
diff --git a/cloudinit/distros/__init__.py b/cloudinit/distros/__init__.py
index b714b9a..bfefb3d 100755
--- a/cloudinit/distros/__init__.py
+++ b/cloudinit/distros/__init__.py
@@ -30,6 +30,10 @@ from cloudinit import util
 from cloudinit.distros.parsers import hosts
 
 
+# Used when a cloud-config module can be run on all cloud-init distibutions.
+# The value 'all' is surfaced in module documentation for distro support.
+CONFIG_MODULE_SUPPORT_ALL_DISTROS = 'all'
+
 OSFAMILIES = {
     'debian': ['debian', 'ubuntu'],
     'redhat': ['centos', 'fedora', 'rhel'],
@@ -742,6 +746,20 @@ def fetch(name):
     return cls
 
 
+def get_all_distro_names():
+    """Return a list of all distribution names found in cloudinit.distro."""
+    distro_dir = os.path.dirname(os.path.abspath(__file__))
+    potential_handlers = util.find_modules(distro_dir)
+    distro_names = []
+    for (fname, mod_name) in potential_handlers.items():
+        mod_locs, looked_locs = importer.find_module(
+            mod_name, [__name__], ['Distro'])
+        if mod_locs and '__init__' not in mod_locs[0]:
+            # Grab module basename e.g. ubuntu
+            distro_names.append(mod_locs[0].split('.')[-1])
+    return distro_names
+
+
 def set_etc_timezone(tz, tz_file=None, tz_conf="/etc/timezone",
                      tz_local="/etc/localtime"):
     util.write_file(tz_conf, str(tz).rstrip() + "\n")
diff --git a/cloudinit/stages.py b/cloudinit/stages.py
index a1c4a51..a5f88ec 100644
--- a/cloudinit/stages.py
+++ b/cloudinit/stages.py
@@ -821,10 +821,14 @@ class Modules(object):
         skipped = []
         forced = []
         overridden = self.cfg.get('unverified_modules', [])
+        all_distros = distros.get_all_distro_names()
         for (mod, name, _freq, _args) in mostly_mods:
-            worked_distros = set(mod.distros)
-            worked_distros.update(
-                distros.Distro.expand_osfamily(mod.osfamilies))
+            if mod.distros == [distros.CONFIG_MODULE_SUPPORT_ALL_DISTROS]:
+                worked_distros = set(all_distros)
+            else:
+                worked_distros = set(mod.distros)
+                worked_distros.update(
+                    distros.Distro.expand_osfamily(mod.osfamilies))
 
             # module does not declare 'distros' or lists this distro
             if not worked_distros or d_name in worked_distros: