Debugging remote services developed on cloud systems

Cloud based development platforms are getting more widely used as the cloud services become more available and the performance of such platforms increase. One of the key issues in providing a cloud based development platform is to enable the developers to debug their code just as efficiently and effectively as they would perform in a desktop IDE development session. However, especially if the development of a remote service is being carried out, the debugging client and the server running the actual code is separated, disclosing many problems which are not present in a usual debugging session. This study proposes a record/replay approach to deal with the problems of remote debugging. The debugger saves all the variables values if the developer selects the full recording option.The debugger saves the inputs of the web services so the developer can select the erroneous execution from the list of previous calls then the developer can debug or replay the code. Debugging the code will execute the code line by line using the current situation of the database and web services. The developer can use breakpoints so if the continue buttton is pressed the debugger will continue executing line by line until reaching the first breakpoint. Developer can also use the replay button to show the old values of the variables and by doing so the developer can understand the previous error without a deep checking in the web service logs. To keep the communication overhead of the approach as small as possible, a new type of recording is proposed (the minimal recording), in the minimal recording the debugger saves the variable values only for external data access such as getting the data from a database query or a web service call. The debugger will not save extra data if the web service is working without errors. The debugger stores the related variable values regarding the recording type when the web service throws an exception allowing the debugger to execute the web service later line by line in the client's debugging session. The debugger contains the basic debugger features like step over, continue and step back buttons. The step back features works only with the full recording option. In this case we can name the debugging as TTD (Time Travel Debugging). The proposed approach is integrated to a real world cloud based development platform and the run-time overhead is measured on some case studies to demonstrate the usefulness of the approach.