Ensure get_requests_for_local_unit doesn't fail on incomplete relation

This is a rebuild/make sync for charms to pickup the fix in charmhelpers to fix
any inadvertant accesses of ['ca'] in the relation data before it is available
from vault in the certificates relation.  Fix in charmhelpers is in [1].

[1] juju/charm-helpers#824
Closes-Bug: #2028683

Change-Id: Ie197482fcba7cadd27ea74f22e2a6e2c97eaddac

charmhelpers/contrib/openstack/cert_utils.py

@@ -414,18 +414,27 @@ def get_requests_for_local_unit(relation_name=None):
         is_legacy_request = set(sent).intersection(legacy_keys)
         for unit in related_units(rid):
             data = relation_get(rid=rid, unit=unit)
-            if data.get(raw_certs_key):
-                bundles.append({
-                    'ca': data['ca'],
-                    'chain': data.get('chain'),
-                    'certs': json.loads(data[raw_certs_key])})
-            elif is_legacy_request:
-                bundles.append({
-                    'ca': data['ca'],
-                    'chain': data.get('chain'),
-                    'certs': {sent['common_name']:
-                              {'cert': data.get(local_name + '.server.cert'),
-                               'key': data.get(local_name + '.server.key')}}})
+            # Note: Bug#2028683 - data may not be available if the certificates
+            # relation hasn't been populated by the providing charm. If no 'ca'
+            # in the data then don't attempt the bundle at all.
+            if data.get('ca'):
+                if data.get(raw_certs_key):
+                    bundles.append({
+                        'ca': data['ca'],
+                        'chain': data.get('chain'),
+                        'certs': json.loads(data[raw_certs_key])
+                    })
+                elif is_legacy_request:
+                    bundles.append({
+                        'ca': data['ca'],
+                        'chain': data.get('chain'),
+                        'certs': {
+                            sent['common_name']: {
+                                'cert': data.get(local_name + '.server.cert'),
+                                'key': data.get(local_name + '.server.key')
+                            }
+                        }
+                    })
 
     return bundles
 

charmhelpers/core/unitdata.py

@@ -151,6 +151,7 @@ def config_changed():
 import datetime
 import itertools
 import json
+import logging
 import os
 import pprint
 import sqlite3
@@ -521,6 +522,41 @@ class DeltaSet(Record):
 
 def kv():
     global _KV
+
+    # If we are running unit tests, it is useful to go into memory-backed KV store to
+    # avoid concurrency issues when running multiple tests. This is not a
+    # problem when juju is running normally.
+
+    env_var = os.environ.get("CHARM_HELPERS_TESTMODE", "auto").lower()
+    if env_var not in ["auto", "no", "yes"]:
+        logging.warning(f"Unknown value for CHARM_HELPERS_TESTMODE '{env_var}', assuming 'no'")
+        env_var = "no"
+
+    if env_var == "no":
+        in_memory_db = False
+    elif env_var == "yes":
+        in_memory_db = True
+    elif env_var == "auto":
+        # If UNIT_STATE_DB is set, respect this request
+        if "UNIT_STATE_DB" in os.environ:
+            in_memory_db = False
+        # Autodetect normal juju execution by looking for juju variables
+        elif "JUJU_CHARM_DIR" in os.environ or "JUJU_UNIT_NAME" in os.environ:
+            in_memory_db = False
+        else:
+            # We are probably running in unit test mode
+            logging.warning("Auto-detected unit test environment for KV store.")
+            in_memory_db = True
+    else:
+        # Help the linter realise that in_memory_db is always set
+        raise Exception("Cannot reach this line")
+
     if _KV is None:
-        _KV = Storage()
+        if in_memory_db:
+            _KV = Storage(":memory:")
+        else:
+            _KV = Storage()
+    else:
+        if in_memory_db and _KV.db_path != ":memory:":
+            logging.warning("Running with in_memory_db and KV is not set to :memory:")
     return _KV