This emerged from discussions about NDS-573. The motivating case is Dataverse or Hydra with Solr. Solr doesn't offer an easy mechanism to customize it's schema – this is generally done by copying a file (schema.xml) to a directory on the filesystem. Both Dataverse and Hydra have custom schemas that need to be added to Solr. In the original Dataverse implementation, this was done by having a Dataverse-specific image. Mike suggested a nice alternative – put the config in the image git repo and set the repo path as a config option on Solr. However, we need Dataverse/Hydra to set this value on the Solr service without requiring user intervention.

Solution: Add a "setTo" option on the config object – basically the inverse of useFrom. Something like:

    "name": "CONFIG_REPO",

    "label" : "Solr Config Repo",

    "value" : "https://github.com/nds-org/ndslabs-hydra/trunk/solr/conf",

    "setTo" : "solr6.CONFIG_REPO",

    "isPassword" : false,

    "canOverride": true