On 10/09/2013, at 5:32 AM, Daz DeBoer <darrell.deb...@gradleware.com> wrote:
> On Sun, Sep 8, 2013 at 3:34 PM, Adam Murdoch <adam.murd...@gradleware.com> > wrote: > > On 09/09/2013, at 5:21 AM, Daz DeBoer <darrell.deb...@gradleware.com> wrote: > >> G'day >> Since we're currently changing the way we manage locks in the Gradle cache, >> it would be great if we could separate the 'filestore' part of the cache >> (that hasn't changed in structure since 1.0) from the binary metadata part >> (which changes quite frequently). >> >> What this means is that we'd have these in separate directories: >> ~/.gradle/caches/metadata-1 >> ~/.gradle/caches/filestore-1 >> >> The 'filestore' would simply contain the content that is currently in >> caches/artifacts-n/filestore. >> >> The benefit of this change is that the actual downloaded files would not >> need to be copied into a new location every time we change the metadata file >> format. >> >> The only complication I see is that we'd need a separate (cross-version) >> lock for the filestore since it would be shared by different Gradle >> versions. We'd need to bump the filestore version whenever the locking >> mechanism changes, rather than every time the metadata store format changes. > > I think having two locks would make it easy to deadlock when there are 2 > processes (or threads) resolving concurrently. We could address this by > enforcing a certain lock order (eg always lock the files if you need to lock > the metadata). > > Another option would be to have a single lock for both the files and > metadata, versioned on the locking protocol, something like: > > ~/.gradle/caches/files-1 > ~/.gradle/caches/files-1/store-1 > ~/.gradle/caches/files-1/metadata-1 > > > It could even look at bit more intentional if we used eg: > > caches/modules-1 > caches/modules-1/artifacts-1.0 > caches/modules-1/metadata-1.3 This isn't really going to work. If a format change is backwards compatible, then we should not change the directory name, otherwise we have two sets of processes that are using different stores even though they can share them. So we wouldn't use the minor version in file names, only major versions. > > This would be a cosmetic difference, but I think it would look clearer to > users. > > Either way, any chance we can slip this into the cache locking changes that > are currently in progress? Or add it as a story to be done soon? It's a separate story, but we can try to do it soon. I was waiting for the next meta-data format change. -- Adam Murdoch Gradle Co-founder http://www.gradle.org VP of Engineering, Gradleware Inc. - Gradle Training, Support, Consulting http://www.gradleware.com Join us at the Gradle eXchange 2013, Oct 28th in London, UK: http://skillsmatter.com/event/java-jee/gradle-exchange-2013
