The ELisA Facility – RESTful API and Client Libraries

The ATLAS experiment at the LHC (CERN) comprises a large and geographically distributed community of over three thousand scientists from all over the world. Data acquisition is supervised by a shift crew of about 10 people running the experiment 24/7. Information concerning the experiment operation, configuration and behavior has to be reported, gathered and shared with the whole community. To provide such functionality, a logbook facility tool, known as ELisA, has been developed to offer an user-friendly web interface to browse activity logs and an effective way for shifters and experts to report on system operations.\nRecently, the ELisA facility has been extended by providing the ability to expose a programmatic API to the logbook functionality, to be used by tools and services of the data acquisition infrastructure. This paper presents the development of the ELisA RESTful API, which provides an HTTP-based interface to access, modify and create activity logs, and of the client libraries which bind such interface to Python, Java and C++. The advantage of the REST approach is to clearly decouple the server side logic with the client implementation details. In addition, a set of command line utilities has also been developed on top of the python library.\nThe description of the REST interface definition and implementation, the client-server interaction and consolidation and libraries development are presented in the paper.