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`](http://logback.qos.ch/manual/migrationFromLog4j.html).

Recipe source

GitHub, Issue Tracker, Maven Central

Usage

This recipe has no required configuration options. It can be activated by adding a dependency on org.openrewrite.recipe:rewrite-logging-frameworks 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("6.28.3")
}

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

repositories {
    mavenCentral()
}

dependencies {
    rewrite("org.openrewrite.recipe:rewrite-logging-frameworks:2.17.1")
}

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:6.28.3") }
}
rootProject {
    plugins.apply(org.openrewrite.gradle.RewritePlugin)
    dependencies {
        rewrite("org.openrewrite.recipe:rewrite-logging-frameworks:2.17.1")
    }
    rewrite {
        activeRecipe("org.openrewrite.java.logging.logback.Log4jLayoutToLogback")
        setExportDatatables(true)
    }
    afterEvaluate {
        if (repositories.isEmpty()) {
            repositories {
                mavenCentral()
            }
        }
    }
}

2. Run the recipe.

shell

gradle --init-script init.gradle rewriteRun

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>5.46.3</version>
        <configuration>
          <exportDatatables>true</exportDatatables>
          <activeRecipes>
            <recipe>org.openrewrite.java.logging.logback.Log4jLayoutToLogback</recipe>
          </activeRecipes>
        </configuration>
        <dependencies>
          <dependency>
            <groupId>org.openrewrite.recipe</groupId>
            <artifactId>rewrite-logging-frameworks</artifactId>
            <version>2.17.1</version>
          </dependency>
        </dependencies>
      </plugin>
    </plugins>
  </build>
</project>

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

Maven Command Line

You will need to have Maven installed on your machine before you can run the following command.

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 -Drewrite.exportDatatables=true

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

If the recipe is not available locally, then you can install it using:

mod config recipes jar install org.openrewrite.recipe:rewrite-logging-frameworks:2.17.1

See how this recipe works across multiple open-source repositories

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Data Tables

Source files that had results

org.openrewrite.table.SourcesFileResults

Source files that were modified by the recipe run.

Column Name	Description
Source path before the run	The source path of the file before the run. null when a source file was created during the run.
Source path after the run	A recipe may modify the source path. This is the path after the run. null when a source file was deleted during the run.
Parent of the recipe that made changes	In a hierarchical recipe, the parent of the recipe that made a change. Empty if this is the root of a hierarchy or if the recipe is not hierarchical at all.
Recipe that made changes	The specific recipe that made a change.
Estimated time saving	An estimated effort that a developer to fix manually instead of using this recipe, in unit of seconds.
Cycle	The recipe cycle in which the change was made.

Source files that errored on a recipe

org.openrewrite.table.SourcesFileErrors

The details of all errors produced by a recipe run.

Column Name	Description
Source path	The file that failed to parse.
Recipe that made changes	The specific recipe that made a change.
Stack trace	The stack trace of the failure.

Recipe performance

org.openrewrite.table.RecipeRunStats

Statistics used in analyzing the performance of recipes.

Column Name	Description
The recipe	The recipe whose stats are being measured both individually and cumulatively.
Source file count	The number of source files the recipe ran over.
Source file changed count	The number of source files which were changed in the recipe run. Includes files created, deleted, and edited.
Cumulative scanning time	The total time spent across the scanning phase of this recipe.
99th percentile scanning time	99 out of 100 scans completed in this amount of time.
Max scanning time	The max time scanning any one source file.
Cumulative edit time	The total time spent across the editing phase of this recipe.
99th percentile edit time	99 out of 100 edits completed in this amount of time.
Max edit time	The max time editing any one source file.

Contributors

Aaron Gershman, Jonathan Schneider, Knut Wannheden, Patrick Way