Whip your logs into shape!
Flogger is an AspectJ library that provides the ability to easily add information to the MDC.
Adding Flogger to a Spring Boot project is as simple as adding a dependency to flogger-spring-boot.
<dependency>
<groupId>com.jahnelgroup.flogger</groupId>
<artifactId>flogger-spring-boot</artifactId>
<version>2.0.0</version>
</dependency>
Flogger can also be used in plain Java projects using the aspectj-maven-plugin.
flogger-sample is an example project showing how to set it up.
To add method parameters to the MDC, annotate them with @BindParam.
To add the return value of a method to the MDC, annotate the method with @BindReturn.
The key in the MDC can be customized by the value field on both annotations.
You can expand an object before it gets added to the MDC by setting expand=true in the annotations.
This will add the object's field values and method return values (only methods that take 0 parameters)
to the MDC instead of calling .toString() on the object.
By default, every field and method on the object will be added to the MDC. This can be customized similar
to Lombok's @EqualsAndHashCode.
To exclude a field/method, annotate it with @BindExpand.Exclude.
You can specify exactly which fields/methods are to be added to the MDC by annotating the object's class with
@BindExpand(onlyExplicityIncluded=true) and then each method/field you wish to add with @BindExpand.Include.
The key in the MDC for expanded fields/methods can be customized by the value field on @BindExpand.Include.
public class Expanded {
private String field = "field"
private String method() {
return "method";
}
public String toString() {
return "expanded.toString()";
}
}
...
public void method(@BindParam(expand=?) Expanded expanded) {...}
When expand=false the MDC contains :
{expanded=expanded.toString()}
When expand=true the MDC contains:
{field=field, method=method, toString=expanded.toString()}