4.     Applications, Data Sources, and Data files

Applications and their change history, and data sources, are stored in a very different format in a repository inside the <appdata>/.streams-repository/ folder. This is preparation for better versioning, content synchronization in a cluster and other things.

Before version 2020.2, all applications were stored as individual APP files in <appdata>/CEP/Applications. Every time an application was updated, a backup was placed in <appdata>/CEP/Archive. Data sources were stored as DSM files in <appdata>/CEP/Datasources.

If the new server starts and the <appdata>/.streams-repository/ folder doesn't exist, it will create one, and then look in the <appdata>/CEP/ folder. Any applications and data source files it finds in there, it will import into the newly created repository. After the import, the <appdata>/CEP/ folder is no longer used.

Optionally, you can also import all application backups from <appdata>/CEP/Archive/. If you do, they will be recorded as application edits in the new repository. While the web UI currently doesn't expose the change history, it may very well do so in the future.

NOTE	To opt out, set repository.import.archived.applications to false in Streams.properties.

 

You can repeat this migration as many times as you like: stop the new server, delete the entire <new_appdata>/.streams-repository/ folder, then start the new server. This provides a convenient way to keep the new server in sync with changes on the old server, assuming the old server is still in use. Please note that this process will lose all changes made on the new server only, as they are stored in the repository.

Data sources that use data files (e.g., CSV, JSON, XML) with relative paths expect the path to be relative to the <appdata>/Data/ folder. You can simply copy the entire <old_appdata>/Data/ folder to <new_appdata>.