FOR IMMEDIATE RELEASE
April 29, 2014
Read it online: http://bit.ly/1koK2tg
On the Way to Beta: Fifth Alpha Release of Fedora 4
Winchester, MA The Fedora 4 team is proud to announce the fifth Alpha release
of Fedora 4. In the continuing effort to provide rapid access to the quickly
growing Fedora 4 feature set, this Alpha release is one of several leading up
to the feature-complete Fedora 4 Beta release.
Available from the GitHub release[1]
* Fedora 4 Alpha 5 "One-Click Run" [2]
* Fedora 4 Alpha 5 web application[3]
* Fedora 4 Alpha 5 web application with authorization[4]
* Fedora 4 Alpha 5 JMS indexer webapp[5]
* Features
Versioning
This release enhanced the object and datastream versioning capability[6] in two
fundamental ways. Specifically, whereas the creation of new versions was
previously supported, this release added the logical corollary capability of
rolling back to or reverting[7] to a previous version.
Also, the deletion[8] of previous versions is now supported.
Triplestore
While the internal search index within Fedora 4 natively supports the ability
to reindex on startup, the recommended pattern[9] for exposing a search
experience to repository users did not support the ability to reindex the
external Solr or triplestore indices prior to this release. This release
introduced an HTTP endpoint[10] for triggering the reindex of external indices
for:
* the entire repository
* a tree of resources within the repository, or
* a single repository resource
Beyond reindexing, this release also demonstrated the configuration[11] where
there are more than one Fedora 4 repositories all feeding events into a single
external triplestore.
Linked data
In the on-going effort to expose repository resources in a standardized,
linked-data friendly manner, Fedora 4 continues to keep in step with the
maturing Linked Data Platform (LDP) draft specification[12]. Support for
appropriate HTTP request headers which allow the user to indicate a preference
for the comprehensiveness of triples found in responses was added. Likewise,
appropriate HTTP response headers were added that specify paging[13]
information and relationships between parent and child resources in an LDP
fashion.
Performance
Tests were performed this release focused on the determination of whether there
is an impact on object creation speeds with the increase in the number of child
resources (object or datastream) under a single parent resource. These tests
were run with multiple backend storage configurations to additionally assess
what, if any, factor the storage backend plays into performance trends.
Thirty thousand objects (first with 1 KB datastreams, then with 2 MB
datastreams) were created at the top level of the repository and individually
timed using the following backends:
* LevelDB
* RAM
* File
Although a slight up-tick in per object slowdown was indicated during the 2-MB
tests, the trend was not absolutely conclusive. Further tests will be repeated
with a greater number of objects.
The test results can be found on the wiki[14].
Test Coverage
Having a comprehensive suite of unit and integration tests affords the Fedora 4
code-base with greater resilience to rippling bugs, demonstrations of expected
usage patterns of the APIs and components, as well as enables architectural
refactoring to occur with less risk. A focus of this release was to increase
our test coverage[15].
The following are the code coverage statistics at the end of this release.
* Unit tests: 73.1%
* Integration tests: 71.7%
* Overall coverage: 86.0%
Housekeeping
Several feature enhancements and bugs were addressed during this release. Bug
fixes and application polishing included:
* Added resource locking[16] for concurrent requests on same resource(s)
* Locking is available at single node and hierarchy tree levels
* Enhanced pluggability of external/internal identifier mappings
* Created a utility[17] for uploading a sample dataset to a running
Fedora 4 repository
* Updated jms-indexer-pluggable integration tests to deploy Fedora
webapp in addition to triplestore and indexer webapp
* Enhanced REST-API to return timestamp when creating objects and
datastreams
* Improved HTTP caching headers
* Corrected multiple HTTP response codes
* Fixed authorization bug which prevented users with both reader and
writer roles from reading a resource
* Fixed benchtool bug which prevented an equal number of HTTP client
threads from being created to support the "num threads" option
References
[1] https://github.com/futures/fcrepo4/releases/tag/fcrepo-4.0.0-alpha-5
[2]
https://github.com/futures/fcrepo4/releases/download/fcrepo-4.0.0-alpha-5/fcrepo-webapp-4.0.0-alpha-5-jetty-console.war
[3]
https://github.com/futures/fcrepo4/releases/download/fcrepo-4.0.0-alpha-5/fcrepo-webapp-4.0.0-alpha-5.war
[4]
https://github.com/futures/fcrepo4/releases/download/fcrepo-4.0.0-alpha-5/fcrepo-webapp-4.0.0-alpha-5-auth.war
[5]
https://github.com/futures/fcrepo-jms-indexer-pluggable/releases/download/fcrepo-jms-indexer-pluggable-4.0.0-alpha-5/fcrepo-jms-indexer-webapp-4.0.0-alpha-5.war
[6] https://wiki.duraspace.org/display/FF/Versioning
[7]
https://wiki.duraspace.org/display/FF/RESTful+HTTP+API+-+Versioning#RESTfulHTTPAPI-Versioning-revert
[8]
https://wiki.duraspace.org/display/FF/RESTful+HTTP+API+-+Versioning#RESTfulHTTPAPI-Versioning-delete
[9] https://wiki.duraspace.org/display/FF/External+Triplestore
[10]
https://wiki.duraspace.org/display/FF/Indexer+Configuration#IndexerConfiguration-reindex
[11]
https://wiki.duraspace.org/display/FF/Indexer+Configuration#IndexerConfiguration-multi
[12] http://www.w3.org/TR/2014/WD-ldp-20140311/
[13] https://dvcs.w3.org/hg/ldpwg/raw-file/default/ldp-paging.html
[14] https://wiki.duraspace.org/display/FF/Flat+Hierarchies+Testing
[15] http://sonar.fcrepo.org/dashboard/index/1
[16] https://wiki.duraspace.org/display/FF/Locking
[17] futures/fcrepo-sample-dataset
futures/fcrepo-sample-dataset
fcrepo-sample-dataset - This repository holds a sample Fedora dataset and the
tooling for uploading it into a Fedora repository.
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