Migrate all the bound BindProvider calls to dynamically loaded methods

- adds the load_class call to common to return a pointer to the class
  passed in
- refactors out BindProvider to be Provider, to adhere to the spec

preliminary work for #12

contrib/bind/provider.py

@@ -8,7 +8,7 @@
 from common import resolve_hostname_to_ip
 
 
-class BindProvider(object):
+class Provider(object):
 
     def config_changed(self, domain='example.com'):
         zp = ZoneParser(domain)

contrib/common.py

@@ -63,10 +63,22 @@ def existing_nameservers():
 
 def load_module(full_class_string):
     """
-    dynamically load a class from a string
+    dynamically load a module from a string
     """
 
     class_data = full_class_string.split(".")
     module_path = ".".join(class_data[:-1])
 
     return importlib.import_module(module_path)
+
+def load_class(full_class_string):
+    """
+    dynamically load a class from a string
+    """
+
+    class_data = full_class_string.split(".")
+    module_path = ".".join(class_data[:-1])
+    class_str = class_data[-1]
+
+    module = importlib.import_module(module_path)
+    return getattr(module, class_str)

contrib/tests/test_bind_provider.py

@@ -3,7 +3,7 @@
 import os
 import sys
 
-from bind.provider import BindProvider
+from bind.provider import Provider
 
 
 class TestBindProvider(unittest.TestCase):
@@ -13,7 +13,7 @@ class TestBindProvider(unittest.TestCase):
     @patch('bind.provider.unit_get')
     def test_first_setup(self, ugm, spcom):
         spcom.return_value = '10.0.0.1'
-        bp = BindProvider()
+        bp = Provider()
         parser = MagicMock()
         bp.first_setup(parser)
         ugm.assert_called_once()
@@ -24,7 +24,7 @@ def test_first_setup(self, ugm, spcom):
     @patch('bind.provider.ZoneParser.dict_to_zone')
     @patch('bind.provider.ZoneParser.save')
     def test_add_record(self, zps, zpm):
-        bp = BindProvider()
+        bp = Provider()
         bp.reload_config = Mock()
         bp.add_record({'rr': 'A', 'alias': 'foo', 'addr': '127.0.0.1'})
         zps.assert_called_once()
@@ -35,7 +35,7 @@ def test_add_record(self, zps, zpm):
     @patch('os.path.exists')
     def test_config_changed(self, osem, zpsm):
         osem.return_value = False
-        bp = BindProvider()
+        bp = Provider()
         bp.reload_config = Mock()
         bp.first_setup = Mock()
         bp.config_changed()
@@ -45,7 +45,7 @@ def test_config_changed(self, osem, zpsm):
 
     @patch('bind.provider.ZoneParser')
     def test_remove_record(self, zpm):
-        bp = BindProvider()
+        bp = Provider()
         bp.reload_config = Mock()
         zpm.zone.remove = Mock()
         zpm.save = Mock()

hooks/config-changed

@@ -5,8 +5,9 @@ sys.path.insert(0, os.path.abspath(os.path.join(os.environ['CHARM_DIR'],
                                                 'contrib')))
 
 from charmhelpers.core.hookenv import config
-from common import sanity_check
-from bind.provider import BindProvider
+from common import sanity_check, load_class
+
+#from bind.provider import BindProvider
 
 
 class ConfigChanged(object):
@@ -15,10 +16,11 @@ class ConfigChanged(object):
         if not sanity_check():
             return 0
         self.config = config()
-        if self.config['provider'] == 'bind':
-            bp = BindProvider()
-            bp.config_changed(self.config['domain'])
 
+        class_string = "{}.provider.Provider".format(self.config['provider'])
+        provider = load_class(class_string)
+        p = provider()
+        p.config_changed(self.config['domain'])
 
 if __name__ == '__main__':
     c = ConfigChanged()

hooks/programmable-multiple-relation-changed

@@ -2,14 +2,8 @@
 import os
 import sys
 # Add charmhelpers to the system path.
-try:
-    sys.path.insert(0, os.path.abspath(os.path.join(os.environ['CHARM_DIR'],
-                                                    'contrib')))
-except:
-    sys.path.insert(0, os.path.abspath(os.path.join('..', 'contrib')))
-
-
-from bind.provider import BindProvider
+sys.path.insert(0, os.path.abspath(os.path.join(os.environ['CHARM_DIR'],
+                'contrib')))
 
 from charmhelpers.core.hookenv import (
     config,
@@ -21,7 +15,7 @@ from charmhelpers.core.hookenv import (
 
 from common import trim_empty_array_elements as trim
 from common import resolve_hostname_to_ip as getip
-
+from common import load_class
 
 class ProgrammableChanged(object):
 
@@ -43,9 +37,10 @@ class ProgrammableChanged(object):
         if not domain:
             domain = config()['domain']
 
-        if self.config['provider'] == 'bind':
-            bp = BindProvider()
-            bp.add_record(resources, domain)
+        class_string = "{}.provider.Provider".format(self.config['provider'])
+        provider = load_class(class_string)
+        p = provider()
+        p.add_record(resources, domain)
 
 
 if __name__ == '__main__':

hooks/programmable-relation-changed

@@ -2,14 +2,8 @@
 import os
 import sys
 # Add charmhelpers to the system path.
-try:
-    sys.path.insert(0, os.path.abspath(os.path.join(os.environ['CHARM_DIR'],
+sys.path.insert(0, os.path.abspath(os.path.join(os.environ['CHARM_DIR'],
                                                     'contrib')))
-except:
-    sys.path.insert(0, os.path.abspath(os.path.join('..', 'contrib')))
-
-
-from bind.provider import BindProvider
 
 from charmhelpers.core.hookenv import (
     config,
@@ -19,6 +13,7 @@ from charmhelpers.core.hookenv import (
     relation_id,
 )
 from common import resolve_hostname_to_ip as getip
+from common import load_class
 
 
 class ProgrammableChanged(object):
@@ -41,9 +36,10 @@ class ProgrammableChanged(object):
 
         parsed = {'domain': domain, 'alias': alias, 'addr': addr, 'rr': rr}
 
-        if self.config['provider'] == 'bind':
-            bp = BindProvider()
-            bp.add_record(parsed, domain)
+        class_string = '{}.provider.Provider'.format(self.config['provider'])
+        provider = load_class(class_string)
+        p = provider()
+        p.add_record(parsed, domain)
 
 
 if __name__ == '__main__':

hooks/programmable-relation-departed

@@ -1,15 +1,11 @@
 #!/usr/bin/python
 import os
 import sys
-# Add charmhelpers to the system path.
-try:
-    sys.path.insert(0, os.path.abspath(os.path.join(os.environ['CHARM_DIR'],
-                                                    'contrib')))
-except:
-    sys.path.insert(0, os.path.abspath(os.path.join('..', 'contrib')))
 
+sys.path.insert(0, os.path.abspath(os.path.join(os.environ['CHARM_DIR'],
+                                                    'contrib')))
 
-from bind.provider import BindProvider
+#from bind.provider import BindProvider
 
 from charmhelpers.core.hookenv import (
     log,
@@ -18,6 +14,8 @@ from charmhelpers.core.hookenv import (
     relation_get,
 )
 
+from common import load_class
+
 class ProgrammableBroken(object):
 
     def __init__(self):
@@ -33,11 +31,10 @@ class ProgrammableBroken(object):
 
         parsed = {'domain': domain, 'alias': alias, 'addr': addr, 'rr': rr}
 
-        if self.config['provider'] == 'bind':
-            bp = BindProvider()
-            bp.remove_record(parsed, domain)
-
-
+        class_string = "{}.provider.Provider".format(self.config['provider'])
+        provider = load_class(class_string)
+        p = provider()
+        p.remove_record(parsed, domain)
 
 if __name__ == '__main__':
     c = ProgrammableBroken()