Original approach was to upgrade one version of play at a time and keep all functionality. This turned out incredible difficult given all the interdependencies between libraries and scala version. See old branch: https://opensource.ncsa.illinois.edu/bitbucket/projects/CATS/repos/clowder/compare/commits?sourceBranch=refs%2Fheads%2F2.0&targetBranch=refs%2Fheads%2Fdevelop.

Currently working on this: Luigi Marini Rob Kooper Maxwell Burnette Todd Nicholson

New approach is as follows:

• Remove all unused and legacy code. This will be 2.0.
  • XML RDF export
  • Rabbitmq monitoring using manager API (Maxwell Burnette started on this)
  • Geostreams API
  • Deprecated endpoints
  • Every plugin should become a Guice Trait + Implementation (2.1?)
    • For services that are not implemented, provide an no-op implementation
    • Enabled/disabled, is it in the config? Is it a common trait and the ability to provide implementation class in config file?
  • ??? (Add by end of this week Nov. 1st)
• Elasticsearch upgrade?
• New MongoDB implementation. This will be 3.0+.
  • Replace Salat and Cashbah with Java Mongo Driver and keep the rest as is
    • Mongo drivers
      • http://mongodb.github.io/mongo-java-driver/ (this might be our safest bet)
      • http://mongodb.github.io/mongo-java-driver-reactivestreams/
      • https://mongodb.github.io/mongo-scala-driver/
  • Split services in two layers.
    • Top layer has the common code that calls the other services. For example when removing a dataset also remove files.
    • Bottom layer is traits to do CRUD operations on resources and requires multiple implementations.
• Modify code to be compatible with newer versions of Playframework. 4.0+
  • Should jump straight to 2.7 or 2.6. We need to figure out which one. 
  • Migrate authentication / authorization:
    
    • https://github.com/mohiva/play-silhouette
• How do tests factor in? can we start writing them before the refactoring? For example unit tests of services vs play scala tests of controllers actions.
• Enforce style as part of this process. Using IDE? We should look at what rules and style software to use.
  • http://www.scalastyle.org/
  • Pick our preferred rules

Play 2.6 Upgrade

• Upgrade Play 2.2.0 to 2.2.6
• https://www.playframework.com/documentation/2.5.x/Migration23
• https://www.playframework.com/documentation/2.5.x/Migration24
  • http://www.silhouette.rocks/ - Secure Social replacement
    • example: https://github.com/adrianhurt/play-silhouette-credentials-seed
• https://www.playframework.com/documentation/2.5.x/Migration25
• https://www.playframework.com/documentation/2.6.x/Migration26

Sbt migration: http://www.scala-sbt.org/0.13/docs/Migrating-from-sbt-012x.html