Currently user can see only current logs of the instance. On fetch logs screen she can view log history and debug the issue when issue comes. For example, as a developer we receive issue something like on X date we faced Y issue. And devs face many problems in getting logs from Infra team, on using this screen devs can have access to logs from history and by passing the search string she can fetch/filter the logs they want to see.
For example, if user wants to see logs of xService then she can simply pass the xService in the search string and fetch it. If user wants to see logs of date '2016-05-30' then she can pass it as search string and extract the required logs.
For now I have added functionality to get the logs from OFBiz runtime/logs folder files. Later we can extend it to get logs from deployment location and from multiple virtual instance setup for load balancing.