SMARTLOG: Place error log statement by deep understanding of log intention

Failure-diagnosis logs can dramatically reduce the system recovery time when software systems fail. Log automation tools can assist developers to write high quality log code. In traditional designs of log automation tools, they define log placement rules by extracting syntax features or summarizing code patterns. These approaches are, however, limited since the log placements are far beyond those rules but are according to the intention of software code. To overcome these limitations, we design and implement SmartLog, an intention-aware log automation tool. To describe the intention of log statements, we propose the Intention Description Model (IDM). SmartLog then explores the intention of existing logs and mines log rules from equivalent intentions. We conduct the experiments based on 6 real-world open-source projects. Experimental results show that SmartLog improves the accuracy of log placement by 43% and 16% compared with two state-of-the-art works. For 86 real-world patches aimed to add logs, 57% of them can be covered by SmartLog, while the overhead of all additional logs is less than 1%.