config: add error logging when fail to decrypt a encrypted global configuration

framework/config/src/main/java/org/apache/cloudstack/framework/config/dao/ConfigurationDaoImpl.java

@@ -174,7 +174,17 @@ public boolean update(String name, String category, String value) {
     @Override
     public String getValue(String name) {
         ConfigurationVO config = findByName(name);
-        return (config == null) ? null : config.getValue();
+        if (config == null) {
+            return null;
+        }
+        try {
+            return config.getValue();
+        } catch (CloudRuntimeException ex) {
+            logger.error("Unable to get global configuration {}: {}. " +
+                    "We expect the value of setting to be encrypted in the database with the Management Server's key, " +
+                    "but we were unable to decrypt it using this key", name, ex.getMessage());
+            throw ex;
+        }
     }
 
     @Override

framework/config/src/main/java/org/apache/cloudstack/framework/config/impl/ConfigDepotImpl.java

@@ -286,11 +286,7 @@ protected String getConfigStringValueInternal(Ternary<String, ConfigKey.Scope, L
             }
             return scopedConfigStorage.getConfigValue(scopeId, key);
         }
-        ConfigurationVO configurationVO = _configDao.findById(key);
-        if (configurationVO != null) {
-            return configurationVO.getValue();
-        }
-        return null;
+        return _configDao.getValue(key);
     }
 
     protected Ternary<String, ConfigKey.Scope, Long> getConfigCacheKey(String key, ConfigKey.Scope scope, Long scopeId) {

framework/config/src/main/java/org/apache/cloudstack/framework/config/impl/ConfigurationVO.java

@@ -155,7 +155,7 @@ public void setName(String name) {
 
     @Override
     public String getValue() {
-        if(isEncrypted()) {
+        if (isEncrypted()) {
             return DBEncryptionUtil.decrypt(value);
         } else {
             return value;

framework/config/src/test/java/org/apache/cloudstack/framework/config/impl/ConfigDepotImplTest.java

@@ -77,9 +77,7 @@ public void testIsNewConfig() {
     }
 
     private void runTestGetConfigStringValue(String key, String value) {
-        ConfigurationVO configurationVO = Mockito.mock(ConfigurationVO.class);
-        Mockito.when(configurationVO.getValue()).thenReturn(value);
-        Mockito.when(_configDao.findById(key)).thenReturn(configurationVO);
+        Mockito.when(_configDao.getValue(key)).thenReturn(value);
         String result = configDepotImpl.getConfigStringValue(key, ConfigKey.Scope.Global, null);
         Assert.assertEquals(value, result);
     }
@@ -106,7 +104,7 @@ private void runTestGetConfigStringValueExpiry(long wait, int configDBRetrieval)
         }
         String result = configDepotImpl.getConfigStringValue(key, ConfigKey.Scope.Global, null);
         Assert.assertEquals(value, result);
-        Mockito.verify(_configDao, Mockito.times(configDBRetrieval)).findById(key);
+        Mockito.verify(_configDao, Mockito.times(configDBRetrieval)).getValue(key);
     }
 
     @Test