The Grouper change log consists of three tables. The change log temp table is where every Grouper process writes events. The change log temp to change log processes these events, gives them a sequential numeric id, calculates point in time calculations, and moves the data to the change log table. Change log consumers read from the change log table and keep a pointer to their progress in the change log consumer table.
Grouper can integrate with or provision data to external systems in real-time. This is done using Grouper Notifications, which are based on the Grouper Change Log. Approaches include:
- Use the Provisioning Service Provider (PSP). The PSP is able to incrementally provision one or more target LDAP directories (including Active Directory) based on the Change log. It can also provision SPML targets.
- Use the Grouper ESB Connector or XMPP to implement notifications from the Change log.
- Implement your own custom change log consumer in Java. This provides additional flexibility since you can get direct access to all the information for each change, but does require custom code. This is most useful if you are provisioning a target that cannot be provisioned by the other methods.
Change Log Events
As of Grouper 2.0, the following change log events are supported. Note that Grouper 2.1 no longer has notifications on flattened permissions due to performance concerns. Instead, whenever anything related to a permission changes (including memberships and all the hierarchies that could be involved in forming a permission), change log events are added for all the roles involved. The action name for the change log entry is permissionChangeOnRole.
This diagram shows the Change Log and Notifications in the Grouper Architecture.
Here are some change log events, you should look in source for your version of Grouper to get the full list. See ChangeLogTypeBuiltin.java or the GROUPER_CHANGE_LOG_TYPE table.
Change Log Category
permissionChangeOnRole (Grouper 2.1+)
Implementing a consumer
Note: you should implement an EsbEventListener (layer on top), not a change log consumer
There is a friendly SQL view: grouper_change_log_entry_v which will be more friendly to query if you are debugging something than the grouper_change_log_entry table
- Add retry timeouts and max retries (currently it will just keep retrying every cycle of loader (every minute?) if there is an exception in target system. It should sleep for progressively longer and longer until hitting a max
- Add filters so that all systems are not notified on all change log entries
- Add hook on change log entry (pre/post insert/update/delete
- Add import/export to xml
Design / FAQ
- The change log is transactional. If a rollback or failure occurs in Grouper, the change log will be in sync.
- If the destination is unreachable, it will retry next time with the same record
- You can query the change log directly with the API through the DAO
- Change log entries are ordered so that they notify in an order that will work (i.e. create a group before adding members)
- There is a unique id (sequential sequence) for each row in change log
- The timestamp is in micros, and will never be the same on the same jvm as another record
- No database triggers are user, it's an all Java solution
- There are 12 columns to stash data in the change log entry
- Grouper keeps track of progress of consumers run in the loader