We are working together with the people from JFrog on improving the Ivy/Gradle dependency cache. There is a lot of cool stuff we want to add. In this posting I want to discuss a particular aspect. We are very interested in feedback and good use cases therefore I'm posting this to the user list and not to the dev list.
Current State: - Ivy dynamic revisions, like "junit:junit:4.+" can be used in Gradle. Ivy enables to set a time to live (ttl) for the cached dependency. During that time, Ivy does not check for newer versions of the dependency. We don’t expose this Ivy feature yet via Gradle. - Maven snapshots: Although Ivy can resolve from Maven repositories and understand Maven snapshots, it does not expose its ttl mechanism to Maven snapshots. Which means that with plain Ivy there is for each run of a build a remote check whether a newer version of the snapshot exists. The performance hit is extreme, specially if your repository is in the internet. Gradle provides therefore the possibility to configure the actual Maven resolver for how often to look for a newer version. - Offline: Neither Ivy nor Gradle does provide build-in offline support. The workaround is to add an additional offline resolver that is using the cache as a repository. Planned for milestone-2: 1. We want to add build-in offline support. 2. We want to have a better and more consistent model for dynamic revisions, including Maven snapshots. A simple solution would be to use offline support for this. We could just add a timer schema for offline builds. To make things fully flexible without making them complicated, we could also add a hook where you can add code that decides per dependency whether the offline cache should be used. 3. Alternatively we could add either to the cache or to all repositories a way to define ttl’s for dependencies. I’m not sure whether this should be a property of the cache or the resolver. In Maven it is a repository property, in Ivy a property of the cache. Although in Ivy to can even add a cache instance per resolver if you like. As we are not sure about all the use cases yet I favor approach No. 2. It is very simple and yet you can deal with all custom scenarios via the hook. I would guess that those custom scenarios are the exception and that for most users a ttl for the offline build is good enough. Hans -- Hans Dockter Founder, Gradle http://www.gradle.org, http://twitter.com/gradleware CEO, Gradleware - Gradle Training, Support, Consulting http://www.gradleware.com
