Detecting Log Statements in Source Code

Note: This project is work in progress and currently not stable.

DeLoS is a Scala Compiler Plugin that extracts log statements from provided source code. The tool is intended for research purposes in the area of analysing and improving log statements.

Features

• Basic detection of log statements in Scala code
• Provide support for testing inspectors
• Simplify usage so that build.sbt does not need to be changed manually
• Improve output of results (support custom location, formatting, ...)
• Support more log libraries
  • SLF4J/scala-logging
  • Journal
  • Java logging libraries
• Provide statistics about log statement characteristics
  • Uniqueness
  • Average number of variables
  • Average number of strings
  • ...

Usage

To use the plugin, the following needs to be added to build.sbt:

addCompilerPlugin("net.scholtzan" %% "delos" % "0.0.1")

Supporting more log libraries

Currently only log statements of SLF4J are detected. To add support for more libraries a new Inspector class can be added to the log package. This class needs to extend LogStatementInspector and override the inspect method which traverses the abstract syntax tree (AST) of the source code files. Using Scalas pattern matching the AST is traversed and log statements are detected (see Scala Reflection). SLF4JInspector provides an exemplary implementation of a log statement inspector.

To test the compiler plugin, for each inspector a InspectorSpec can be added to test. These specs extend the trait LogInspectorSpec which takes care of running the compiler plugin against provided code and checks if the results are as expected. SLF4JInspectorSpec provides some examples for such tests.