Migrate Log4j 2.x Layout to logback-classic equivalents

org.openrewrite.java.logging.logback.Log4jLayoutToLogback

Migrates custom Log4j 2.x Layout components to logback-classic. This recipe operates on the following assumptions: 1. A logback-classic layout must extend the LayoutBase<ILoggingEvent> class. 2. log4j's format() is renamed to doLayout() in a logback-classic layout. 3. LoggingEvent getRenderedMessage() is converted to LoggingEvent getMessage(). 4. The log4j ignoresThrowable() method is not needed and has no equivalent in logback-classic. 5. The activateOptions() method merits further discussion. In log4j, a layout will have its activateOptions() method invoked by log4j configurators, that is PropertyConfigurator or DOMConfigurator just after all the options of the layout have been set. Thus, the layout will have an opportunity to check that its options are coherent and if so, proceed to fully initialize itself. 6. In logback-classic, layouts must implement the LifeCycle interface which includes a method called start(). The start() method is the equivalent of log4j's activateOptions() method. For more details, see this page from logback: Migration from log4j.

Recipe source

GitHub, Issue Tracker, Maven Central

• groupId: org.openrewrite.recipe

• artifactId: rewrite-logging-frameworks

• version: 2.6.0

Usage

This recipe has no required configuration options. It can be activated by adding a dependency on org.openrewrite.recipe:rewrite-logging-frameworks:2.6.0 in your build file or by running a shell command (in which case no build changes are needed):

Gradle

1. Add the following to your build.gradle file:

build.gradle

plugins {
    id("org.openrewrite.rewrite") version("6.12.0")
}

rewrite {
    activeRecipe("org.openrewrite.java.logging.logback.Log4jLayoutToLogback")
}

repositories {
    mavenCentral()
}

dependencies {
    rewrite("org.openrewrite.recipe:rewrite-logging-frameworks:2.6.0")
}

2. Run gradle rewriteRun to run the recipe.

Gradle init script

1. Create a file named init.gradle in the root of your project.

init.gradle

initscript {
    repositories {
        maven { url "https://plugins.gradle.org/m2" }
    }
    dependencies { classpath("org.openrewrite:plugin:6.12.0") }
}
rootProject {
    plugins.apply(org.openrewrite.gradle.RewritePlugin)
    dependencies {
        rewrite("org.openrewrite.recipe:rewrite-logging-frameworks:2.6.0")
    }
    rewrite {
        activeRecipe("org.openrewrite.java.logging.logback.Log4jLayoutToLogback")
    }
    afterEvaluate {
        if (repositories.isEmpty()) {
            repositories {
                mavenCentral()
            }
        }
    }
}

2. Run gradle --init-script init.gradle rewriteRun to run the recipe.

Maven POM

1. Add the following to your pom.xml file:

pom.xml

<project>
  <build>
    <plugins>
      <plugin>
        <groupId>org.openrewrite.maven</groupId>
        <artifactId>rewrite-maven-plugin</artifactId>
        <version>5.29.0</version>
        <configuration>
          <activeRecipes>
            <recipe>org.openrewrite.java.logging.logback.Log4jLayoutToLogback</recipe>
          </activeRecipes>
        </configuration>
        <dependencies>
          <dependency>
            <groupId>org.openrewrite.recipe</groupId>
            <artifactId>rewrite-logging-frameworks</artifactId>
            <version>2.6.0</version>
          </dependency>
        </dependencies>
      </plugin>
    </plugins>
  </build>
</project>

2. Run mvn rewrite:run to run the recipe.

Maven Command Line

shell

mvn -U org.openrewrite.maven:rewrite-maven-plugin:run -Drewrite.recipeArtifactCoordinates=org.openrewrite.recipe:rewrite-logging-frameworks:RELEASE -Drewrite.activeRecipes=org.openrewrite.java.logging.logback.Log4jLayoutToLogback

Moderne CLI

You will need to have configured the Moderne CLI on your machine before you can run the following command.

shell

mod run . --recipe Log4jLayoutToLogback

See how this recipe works across multiple open-source repositories

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Contributors

Aaron Gershman, Jonathan Schneider, Knut Wannheden, Patrick Way