cloud-init-dev team mailing list archive

[Joshua Harlow <harlowja@xxxxxxxxx>]

Joshua Harlow has proposed merging ~harlowja/cloud-init:config-entrypoints into cloud-init:master.

Requested reviews:
  cloud init development team (cloud-init-dev)

For more details, see:
https://code.launchpad.net/~harlowja/cloud-init/+git/cloud-init/+merge/302609
-- 
Your team cloud init development team is requested to review the proposed merge of ~harlowja/cloud-init:config-entrypoints into cloud-init:master.

diff --git a/cloudinit/config/__init__.py b/cloudinit/config/__init__.py
index d57453b..948ce5f 100644
--- a/cloudinit/config/__init__.py
+++ b/cloudinit/config/__init__.py
@@ -39,8 +39,6 @@ def form_module_name(name):
     canon_name = canon_name.strip()
     if not canon_name:
         return None
-    if not canon_name.startswith(MOD_PREFIX):
-        canon_name = '%s%s' % (MOD_PREFIX, canon_name)
     return canon_name
 
 
diff --git a/cloudinit/importer.py b/cloudinit/importer.py
index fb57253..fb68d99 100644
--- a/cloudinit/importer.py
+++ b/cloudinit/importer.py
@@ -20,6 +20,7 @@
 #    You should have received a copy of the GNU General Public License
 #    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
+import pkg_resources
 import sys
 
 
@@ -56,3 +57,13 @@ def find_module(base_name, search_paths, required_attrs=None):
         if found_attrs == len(required_attrs):
             found_paths.append(full_path)
     return (found_paths, lookup_paths)
+
+
+def iter_entry_points(namespace, loader=None, name=None):
+    for e in pkg_resources.iter_entry_points(namespace, name=name):
+        if loader is None:
+            thing = e.load()
+        else:
+            thing = loader(e)
+        if thing is not None:
+            yield (e.name, thing)
diff --git a/cloudinit/stages.py b/cloudinit/stages.py
index 47deac6..beb3cba 100644
--- a/cloudinit/stages.py
+++ b/cloudinit/stages.py
@@ -54,6 +54,7 @@ LOG = logging.getLogger(__name__)
 
 NULL_DATA_SOURCE = None
 NO_PREVIOUS_INSTANCE_ID = "NO_PREVIOUS_INSTANCE_ID"
+EP_CONFIG_NAMESPACE = 'cloudinit.config'
 
 
 class Init(object):
@@ -731,21 +732,39 @@ class Modules(object):
             raw_name = raw_mod['mod']
             freq = raw_mod.get('freq')
             run_args = raw_mod.get('args') or []
-            mod_name = config.form_module_name(raw_name)
-            if not mod_name:
+            canon_name = config.form_module_name(raw_name)
+            if not canon_name:
                 continue
+            ep_locs = list(
+                importer.iter_entry_points(EP_CONFIG_NAMESPACE,
+                                           name=canon_name))
+            if not ep_locs:
+                LOG.warn("Could not find entrypoint matching name '%s'"
+                         " (which is the canonicalized form of '%s')"
+                         " registered under namespace '%s'",
+                         canon_name, raw_name, EP_CONFIG_NAMESPACE)
+                continue
+            ep_names = [mod_name for (mod_name, _mod) in ep_locs]
+            if len(ep_names) > 1:
+                LOG.warn("Selecting '%s' entrypoint for configuration"
+                         " module '%s' (which is the canonicalized form"
+                         " of '%s') even though %s other entrypoints were"
+                         " found", ep_names[0], canon_name, raw_name,
+                         ep_names)
+            else:
+                LOG.debug("Selecting '%s' entrypoint for configuration"
+                          " module '%s' (which is the canonicalized"
+                          " form of '%s')", ep_names[0], canon_name, raw_name)
+            # Entry points are yielded from the active distributions in
+            # the order that the distributions appear on sys.path
+            ep_name, mod = ep_locs[0]
+            mod = config.fixup_module(mod)
             if freq and freq not in FREQUENCIES:
-                LOG.warn(("Config specified module %s"
-                          " has an unknown frequency %s"), raw_name, freq)
+                LOG.warn("Config specified module '%s' (found at entrypoint"
+                         " '%s') has an unknown frequency %s",
+                         raw_name, ep_name, freq)
                 # Reset it so when ran it will get set to a known value
                 freq = None
-            mod_locs, looked_locs = importer.find_module(
-                mod_name, ['', type_utils.obj_name(config)], ['handle'])
-            if not mod_locs:
-                LOG.warn("Could not find module named %s (searched %s)",
-                         mod_name, looked_locs)
-                continue
-            mod = config.fixup_module(importer.import_module(mod_locs[0]))
             mostly_mods.append([mod, raw_name, freq, run_args])
         return mostly_mods
 
diff --git a/setup.py b/setup.py
index 4abbb67..1949dd1 100755
--- a/setup.py
+++ b/setup.py
@@ -196,6 +196,21 @@ requirements = read_requires()
 if sys.version_info < (3,):
     requirements.append('cheetah')
 
+config_eps = []
+for filename in os.listdir(os.path.join(os.getcwd(), "cloudinit", "config")):
+    if filename.startswith("_"):
+        continue
+    else:
+        if filename.endswith(".py"):
+            realname = filename[0:-3]
+            if realname.startswith("cc_"):
+                basename = realname[3:]
+            else:
+                basename = realname
+            config_eps.append(
+                "%s = cloudinit.config.%s" % (basename, realname))
+
+
 setuptools.setup(
     name='cloud-init',
     version=get_version(),
@@ -213,5 +228,6 @@ setuptools.setup(
         'console_scripts': [
             'cloud-init = cloudinit.cmd.main:main'
         ],
+        'cloudinit.config': config_eps,
     }
 )