# Merge Strategy

It's possible to load multiple config files. CasC can load YAML files from a directory.
And it's convenient to maintain if we split different parts of Jenkins into multiple files.

## Supported strategies

* [ErrorOnConflictMergeStrategy](../../plugin/src/main/java/io/jenkins/plugins/casc/yaml/ErrorOnConflictMergeStrategy.java) (default)
    * The strategy name is `errorOnConflict`.
    * Throws an exception if there's a conflict in multiple YAML files.
* [OverrideMergeStrategy](../../plugin/src/main/java/io/jenkins/plugins/casc/yaml/OverrideMergeStrategy.java)
    * The strategy name is `override`
    * Override the config files according to the loading order.
    
## Use cases

You can provide two YAML config files. They can be system and user config files. Then allow users to change their file and override the system configuration.

## How to

There are two ways to configure the strategy name.

* set the environment `CASC_MERGE_STRATEGY`
* set the system property `casc.merge.strategy`

The strategy name could be `errorOnConflict` or `override`.