Refactoring around _manage_ca_certs() (#570)

charmhelpers/contrib/openstack/cert_utils.py

@@ -47,7 +47,7 @@
 )
 
 from charmhelpers.core.host import (
-    CA_CERT_DIR,
+    ca_cert_absolute_path,
     install_ca_cert,
     mkdir,
     write_file,
@@ -307,6 +307,26 @@ def install_certs(ssl_dir, certs, chain=None, user='root', group='root'):
             content=bundle['key'], perms=0o640)
 
 
+def get_cert_relation_ca_name(cert_relation_id=None):
+    """Determine CA certificate name as provided by relation.
+
+    The filename on disk depends on the name chosen for the application on the
+    providing end of the certificates relation.
+
+    :param cert_relation_id: (Optional) Relation id providing the certs
+    :type cert_relation_id: str
+    :returns: CA certificate filename without path nor extension
+    :rtype: str
+    """
+    if cert_relation_id is None:
+        try:
+            cert_relation_id = relation_ids('certificates')[0]
+        except IndexError:
+            return ''
+    return '{}_juju_ca_cert'.format(
+        remote_service_name(relid=cert_relation_id))
+
+
 def _manage_ca_certs(ca, cert_relation_id):
     """Manage CA certs.
 
@@ -316,7 +336,7 @@ def _manage_ca_certs(ca, cert_relation_id):
     :type cert_relation_id: str
     """
     config_ssl_ca = config('ssl_ca')
-    config_cert_file = '{}/{}.crt'.format(CA_CERT_DIR, CONFIG_CA_CERT_FILE)
+    config_cert_file = ca_cert_absolute_path(CONFIG_CA_CERT_FILE)
     if config_ssl_ca:
         log("Installing CA certificate from charm ssl_ca config to {}".format(
             config_cert_file), INFO)
@@ -329,8 +349,7 @@ def _manage_ca_certs(ca, cert_relation_id):
     log("Installing CA certificate from certificate relation", INFO)
     install_ca_cert(
         ca.encode(),
-        name='{}_juju_ca_cert'.format(
-            remote_service_name(relid=cert_relation_id)))
+        name=get_cert_relation_ca_name(cert_relation_id))
 
 
 def process_certificates(service_name, relation_id, unit,

charmhelpers/core/host.py

@@ -1068,6 +1068,17 @@ def modulo_distribution(modulo=3, wait=30, non_zero_wait=False):
         return calculated_wait_time
 
 
+def ca_cert_absolute_path(basename_without_extension):
+    """Returns absolute path to CA certificate.
+
+    :param basename_without_extension: Filename without extension
+    :type basename_without_extension: str
+    :returns: Absolute full path
+    :rtype: str
+    """
+    return '{}/{}.crt'.format(CA_CERT_DIR, basename_without_extension)
+
+
 def install_ca_cert(ca_cert, name=None):
     """
     Install the given cert as a trusted CA.
@@ -1083,7 +1094,7 @@ def install_ca_cert(ca_cert, name=None):
         ca_cert = ca_cert.encode('utf8')
     if not name:
         name = 'juju-{}'.format(charm_name())
-    cert_file = '{}/{}.crt'.format(CA_CERT_DIR, name)
+    cert_file = ca_cert_absolute_path(name)
     new_hash = hashlib.md5(ca_cert).hexdigest()
     if file_hash(cert_file) == new_hash:
         return

tests/contrib/openstack/test_cert_utils.py

@@ -481,6 +481,29 @@ def test_process_certificates_bindings(
             custom_hostname_link='funky-name',
             bindings=['mybinding', 'internal', 'admin', 'public'])
 
+    @mock.patch.object(cert_utils, 'remote_service_name')
+    @mock.patch.object(cert_utils, 'relation_ids')
+    def test_get_cert_relation_ca_name(self, relation_ids, remote_service_name):
+        remote_service_name.return_value = 'vault'
+
+        # Test with argument:
+        self.assertEqual(cert_utils.get_cert_relation_ca_name('certificates:1'),
+                         'vault_juju_ca_cert')
+        remote_service_name.assert_called_once_with(relid='certificates:1')
+        remote_service_name.reset_mock()
+
+        # Test without argument:
+        relation_ids.return_value = ['certificates:2']
+        self.assertEqual(cert_utils.get_cert_relation_ca_name(),
+                         'vault_juju_ca_cert')
+        remote_service_name.assert_called_once_with(relid='certificates:2')
+        remote_service_name.reset_mock()
+
+        # Test without argument nor 'certificates' relation:
+        relation_ids.return_value = []
+        self.assertEqual(cert_utils.get_cert_relation_ca_name(), '')
+        remote_service_name.assert_not_called()
+
     @mock.patch.object(cert_utils, 'remote_service_name')
     @mock.patch.object(cert_utils.os, 'remove')
     @mock.patch.object(cert_utils.os.path, 'exists')