Add Log4j 1 to Log4j 2 configuration file conversion

build.gradle.kts

@@ -19,6 +19,12 @@ recipeDependencies {
     parserClasspath("org.projectlombok:lombok:1.18.+")
 }
 
+repositories {
+    mavenCentral()
+    mavenLocal()
+    maven("https://repository.apache.org/snapshots")
+}
+
 dependencies {
     compileOnly("org.projectlombok:lombok:latest.release")
     annotationProcessor("org.projectlombok:lombok:latest.release")
@@ -27,13 +33,15 @@ dependencies {
 
     implementation(platform("org.openrewrite:rewrite-bom:${rewriteVersion}"))
     implementation("org.openrewrite:rewrite-java")
+    implementation("org.openrewrite:rewrite-maven")
     implementation("org.openrewrite.recipe:rewrite-java-dependencies:${rewriteVersion}")
     implementation("org.openrewrite.recipe:rewrite-static-analysis:${rewriteVersion}")
     runtimeOnly("org.openrewrite:rewrite-java-17")
 
     implementation("log4j:log4j:1.+")
-    implementation("org.apache.logging.log4j:log4j-core:2.+")
+    implementation("org.apache.logging.log4j:log4j-core:2.24.3")
     implementation("org.slf4j:slf4j-api:2.+")
+    implementation("org.apache.logging.log4j:log4j-converter-config:0.3.0-SNAPSHOT")
 
     annotationProcessor("org.openrewrite:rewrite-templating:$rewriteVersion")
     implementation("org.openrewrite:rewrite-templating:$rewriteVersion")
@@ -46,7 +54,7 @@ dependencies {
     testRuntimeOnly("org.junit.jupiter:junit-jupiter-engine:latest.release")
 
     testImplementation("org.openrewrite:rewrite-kotlin:${rewriteVersion}")
-    testImplementation("org.openrewrite:rewrite-maven")
+    testImplementation("org.openrewrite:rewrite-properties:${rewriteVersion}")
     testImplementation("org.openrewrite:rewrite-test")
     testImplementation("org.openrewrite:rewrite-java-tck")
 

src/main/java/org/openrewrite/java/logging/ConvertConfiguration.java

@@ -0,0 +1,95 @@
+package org.openrewrite.java.logging;
+
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.nio.charset.StandardCharsets;
+import lombok.AllArgsConstructor;
+import org.apache.logging.converter.config.ConfigurationConverter;
+import org.jspecify.annotations.Nullable;
+import org.openrewrite.ExecutionContext;
+import org.openrewrite.FindSourceFiles;
+import org.openrewrite.NlsRewrite.Description;
+import org.openrewrite.NlsRewrite.DisplayName;
+import org.openrewrite.Option;
+import org.openrewrite.Preconditions;
+import org.openrewrite.Recipe;
+import org.openrewrite.SourceFile;
+import org.openrewrite.Tree;
+import org.openrewrite.TreeVisitor;
+import org.openrewrite.text.PlainText;
+
+/**
+ * Converts a logging configuration file from one format to another.
+ */
+@AllArgsConstructor
+public class ConvertConfiguration extends Recipe {
+
+    @Option(displayName = "Pattern for the files to convert",
+            description = "If set, only the files that match this pattern will be converted.",
+            required = false)
+    @Nullable
+    String filePattern;
+
+    @Option(displayName = "Input format", description = "The id of the input logging configuration format. See [Log4j documentation](https://logging.staged.apache.org/log4j/transform/log4j-converter-config.html#formats) for a list of supported formats.", example = "v1:properties")
+    String inputFormat;
+
+    @Option(displayName = "Output format", description = "The id of the output logging configuration format. See [Log4j documentation](https://logging.staged.apache.org/log4j/transform/log4j-converter-config.html#formats) for a list of supported formats.", example = "v2:xml")
+    String outputFormat;
+
+    private static final ConfigurationConverter converter = ConfigurationConverter.getInstance();
+
+    @Override
+    public @DisplayName String getDisplayName() {
+        return "Convert logging configuration";
+    }
+
+    @Override
+    public @Description String getDescription() {
+        return "Converts the configuration of a logging backend from one format to another. For example it can convert a Log4j 1 properties configuration file into a Log4j Core 2 XML configuration file.";
+    }
+
+    @Override
+    public int maxCycles() {
+        return 1;
+    }
+
+    @Override
+    public TreeVisitor<?, ExecutionContext> getVisitor() {
+        return
+                Preconditions.check(new FindSourceFiles(filePattern),
+                        new TreeVisitor<Tree, ExecutionContext>() {
+
+                            @Override
+                            public boolean isAcceptable(SourceFile sourceFile, ExecutionContext executionContext) {
+                                return super.isAcceptable(sourceFile, executionContext);
+                            }
+
+                            @Override
+                            public @Nullable Tree visit(@Nullable Tree tree, ExecutionContext executionContext) {
+                                if (tree instanceof SourceFile) {
+                                    SourceFile sourceFile = (SourceFile) tree;
+                                    ByteArrayInputStream inputStream = new ByteArrayInputStream(sourceFile.printAllAsBytes());
+                                    ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
+
+                                    converter.convert(inputStream, inputFormat, outputStream, outputFormat);
+
+                                    String utf8 = new String(outputStream.toByteArray(), StandardCharsets.UTF_8);
+                                    if (tree instanceof PlainText) {
+                                        return ((PlainText) tree).withText(utf8).withCharset(StandardCharsets.UTF_8);
+                                    }
+                                    return PlainText.builder()
+                                            .id(sourceFile.getId())
+                                            .charsetBomMarked(sourceFile.isCharsetBomMarked())
+                                            .charsetName(StandardCharsets.UTF_8.name())
+                                            .checksum(sourceFile.getChecksum())
+                                            .fileAttributes(sourceFile.getFileAttributes())
+                                            .markers(sourceFile.getMarkers())
+                                            .sourcePath(sourceFile.getSourcePath())
+                                            .text(utf8)
+                                            .build();
+                                }
+                                return super.visit(tree, executionContext);
+                            }
+                        });
+    }
+}

src/main/resources/META-INF/rewrite/log4j.yml

@@ -17,8 +17,8 @@
 ---
 type: specs.openrewrite.org/v1beta/recipe
 name: org.openrewrite.java.logging.log4j.ParameterizedLogging
-displayName: Parameterize Log4j 2.x logging statements
-description: Use Log4j 2.x parameterized logging, which can significantly boost performance for messages that
+displayName: Parameterize Log4j API 2 logging statements
+description: Use Log4j API 2 parameterized logging, which can significantly boost performance for messages that
   otherwise would be assembled with String concatenation. Particularly impactful when the log level is not enabled, as
   no work is done to assemble the message.
 tags:
@@ -57,8 +57,22 @@ recipeList:
 ---
 type: specs.openrewrite.org/v1beta/recipe
 name: org.openrewrite.java.logging.log4j.Log4j1ToLog4j2
-displayName: Migrate Log4j 1.x to Log4j 2.x
-description: Migrates Log4j 1.x to Log4j 2.x.
+displayName: Migrate Log4j 1 to Log4j API/Log4j Core 2
+description: Transforms code written using Log4j 1 to use Log4j API 2
+  and switches the logging backend from Log4j 1 to Log4j Core 2.
+tags:
+  - logging
+  - log4j
+recipeList:
+  - org.openrewrite.java.logging.log4j.Log4j1ToLog4jApi
+  - org.openrewrite.java.logging.log4j.Log4j1ToLog4jCore2
+---
+type: specs.openrewrite.org/v1beta/recipe
+name: org.openrewrite.java.logging.log4j.Log4j1ToLog4jApi
+displayName: Migrate Log4j 1 to Log4j API 2
+description: "Transforms code written using Log4j 1 to use Log4j API 2.
+  Should be used together with a recipe that switches the logging implementation to a more modern one:
+  e.g. JBoss LogManager, Log4j Core 2 or Logback."
 tags:
   - logging
   - log4j
@@ -71,7 +85,6 @@ recipeList:
   - org.openrewrite.java.ChangeMethodTargetToStatic:
       methodPattern: org.apache.log4j.Logger getRootLogger()
       fullyQualifiedTargetTypeName: org.apache.logging.log4j.LogManager
-
   - org.openrewrite.java.logging.log4j.LoggerSetLevelToConfiguratorRecipe
   - org.openrewrite.java.ChangeMethodName:
       methodPattern: org.apache.log4j.Priority isGreaterOrEqual(org.apache.log4j.Priority)
@@ -80,7 +93,6 @@ recipeList:
   - org.openrewrite.java.ChangeType:
       oldFullyQualifiedTypeName: org.apache.log4j.Priority
       newFullyQualifiedTypeName: org.apache.logging.log4j.Level
-
   - org.openrewrite.java.ChangeMethodTargetToStatic:
       methodPattern: org.apache.log4j.Category getInstance(Class)
       fullyQualifiedTargetTypeName: org.apache.logging.log4j.LogManager
@@ -93,7 +105,6 @@ recipeList:
   - org.openrewrite.java.ChangeType:
       oldFullyQualifiedTypeName: org.apache.log4j.Category
       newFullyQualifiedTypeName: org.apache.logging.log4j.Logger
-
   - org.openrewrite.java.ChangePackage:
       oldPackageName: org.apache.log4j
       newPackageName: org.apache.logging.log4j
@@ -103,27 +114,41 @@ recipeList:
       artifactId: log4j-api
       version: 2.x
       onlyIfUsing: org.apache.log4j.*
+---
+type: specs.openrewrite.org/v1beta/recipe
+name: org.openrewrite.java.logging.log4j.Log4j1ToLog4jCore2
+displayName: Migrate Log4j 1 to Log4j Core 2
+description: Replaces Log4j 1 as logging implementation with Log4j Core 2.
+  This recipe does not replace code occurrences of Log4j 1 and should be only used if Log4j 1 is not used
+  directly as logging API.
+recipeList:
+  # Guarantees alignment between Log4j API and Log4j Core version, regardless of the Maven conflict resolution
+  # algorithm used.
+  - org.openrewrite.maven.AddManagedDependency:
+      groupId: org.apache.logging.log4j
+      artifactId: log4j-bom
+      version: 2.x
+      type: pom
+      scope: import
   - org.openrewrite.java.dependencies.AddDependency:
       groupId: org.apache.logging.log4j
       artifactId: log4j-core
       version: 2.x
-      onlyIfUsing: org.apache.log4j.*
+      scope: runtime
+  # Removes Log4j 1 and replacements
   - org.openrewrite.java.dependencies.RemoveDependency:
       groupId: log4j
       artifactId: log4j
+  - org.openrewrite.java.dependencies.RemoveDependency:
+      groupId: org.apache.logging.log4j
+      artifactId: log4j-1.2-api
+  - org.openrewrite.java.dependencies.RemoveDependency:
+      groupId: org.slf4j
+      artifactId: log4j-over-slf4j
   - org.openrewrite.java.dependencies.RemoveDependency:
       groupId: ch.qos.reload4j
       artifactId: reload4j
-  - org.openrewrite.java.dependencies.AddDependency:
-      groupId: org.apache.logging.log4j
-      artifactId: log4j-api
-      version: 2.x
-      onlyIfUsing: org.apache.logging.log4j.*
-  - org.openrewrite.java.dependencies.AddDependency:
-      groupId: org.apache.logging.log4j
-      artifactId: log4j-core
-      version: 2.x
-      onlyIfUsing: org.apache.logging.log4j.*
+  # Switch the target of SLF4J-to-X bridges
   - org.openrewrite.java.dependencies.ChangeDependency:
       oldGroupId: org.slf4j
       oldArtifactId: slf4j-log4j12
@@ -136,8 +161,47 @@ recipeList:
       newGroupId: org.apache.logging.log4j
       newArtifactId: log4j-slf4j-impl
       newVersion: 2.x
+  #
+  - org.openrewrite.java.dependencies.UpgradeDependencyVersion:
+      groupId: commons-logging
+      artifactId: commons-logging
+      newVersion: latest.release
   - org.openrewrite.java.logging.log4j.UpgradeLog4J2DependencyVersion
-
+  - org.openrewrite.java.logging.log4j.Log4j1ConfigurationToLog4jCore2
+---
+type: specs.openrewrite.org/v1beta/recipe
+name: org.openrewrite.java.logging.log4j.Log4j1ConfigurationToLog4jCore2
+displayName: Migrate Log4j 1 configuration to Log4j Core 2 format
+description: Migrates Log4j 1 configuration files to the Log4j Core 2 XML format.
+recipeList:
+  - org.openrewrite.java.logging.log4j.V1PropertiesToV2Xml
+  - org.openrewrite.java.logging.log4j.V1XmlToV2Xml
+---
+type: specs.openrewrite.org/v1beta/recipe
+name: org.openrewrite.java.logging.log4j.V1PropertiesToV2Xml
+displayName: Migrate `log4j.properties` files to `log4j2.xml` format
+description: Migrates `log4j.properties` files to the `log4j2.xml` format.
+recipeList:
+  - org.openrewrite.java.logging.ConvertConfiguration:
+      filePattern: "**/log4j.properties"
+      inputFormat: "v1:properties"
+      outputFormat: "v2:xml"
+  - org.openrewrite.RenameFile:
+      fileMatcher: "**/log4j.properties"
+      fileName: "log4j2.xml"
+---
+type: specs.openrewrite.org/v1beta/recipe
+name: org.openrewrite.java.logging.log4j.V1XmlToV2Xml
+displayName: Migrate `log4j.xml` files to `log4j2.xml` format
+description: Migrates `log4j.xml` files to the `log4j2.xml` format.
+recipeList:
+  - org.openrewrite.java.logging.ConvertConfiguration:
+      filePattern: "**/log4j.xml"
+      inputFormat: "v1:xml"
+      outputFormat: "v2:xml"
+  - org.openrewrite.RenameFile:
+      fileMatcher: "**/log4j.xml"
+      fileName: "log4j2.xml"
 ---
 type: specs.openrewrite.org/v1beta/recipe
 name: org.openrewrite.java.logging.log4j.UpgradeLog4J2DependencyVersion

src/main/resources/META-INF/rewrite/logback.yml

@@ -17,8 +17,10 @@
 ---
 type: specs.openrewrite.org/v1beta/recipe
 name: org.openrewrite.java.logging.logback.Log4jToLogback
-displayName: Migrate Log4j 2.x to Logback
-description: Migrates usage of Apache Log4j 2.x to using `logback` as an SLF4J implementation directly. Note, this currently does not modify `log4j.properties` files.
+displayName: Migrate Log4j API/Log4j Core 2 to SLF4J/Logback
+description: |
+  Migrates usage of Apache Log4j API with Log4j Core 2 implementation to SLF4J with Logback implementation.
+  Note, this currently does not modify the Log4j Core 2 configuration files.
 tags:
   - logging
   - log4j

src/test/java/org/openrewrite/java/logging/ConvertConfigurationTest.java

@@ -0,0 +1,62 @@
+package org.openrewrite.java.logging;
+
+import static org.openrewrite.test.SourceSpecs.text;
+
+import org.junit.jupiter.api.Test;
+import org.openrewrite.DocumentExample;
+import org.openrewrite.test.RewriteTest;
+
+class ConvertConfigurationTest implements RewriteTest {
+
+    @DocumentExample
+    @Test
+    void convertsLog4j1ToLog4j2Configuration() {
+        rewriteRun(spec -> spec.recipe(new ConvertConfiguration("file.txt", "v1:properties", "v2:xml")),
+                text("""
+                                # Console appender
+                                log4j.appender.CONSOLE = org.apache.log4j.ConsoleAppender
+                                log4j.appender.CONSOLE.Follow = true
+                                log4j.appender.CONSOLE.Target = System.err
+                                log4j.appender.CONSOLE.layout = org.apache.log4j.PatternLayout
+                                log4j.appender.CONSOLE.layout.ConversionPattern = %d [%t] %-5p %c - %m%n%ex
+                                # Rolling file appender
+                                log4j.appender.ROLLING = org.apache.log4j.RollingFileAppender
+                                log4j.appender.ROLLING.File = file.log
+                                log4j.appender.ROLLING.MaxBackupIndex = 30
+                                # Exactly 10 GiB
+                                log4j.appender.ROLLING.MaxFileSize = 10737418240
+                                log4j.appender.ROLLING.layout = org.apache.log4j.SimpleLayout
+
+                                # Loggers
+                                log4j.rootLogger = INFO, CONSOLE
+
+                                log4j.logger.org.openrewrite = DEBUG, CONSOLE, ROLLING
+                                log4j.additivity.org.openrewrite = false
+                                """,
+                        """
+                                <?xml version='1.0' encoding='UTF-8'?>
+                                <Configuration xmlns="https://logging.apache.org/xml/ns" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="https://logging.apache.org/xml/ns https://logging.apache.org/xml/ns/log4j-config-2.xsd">
+                                  <Properties/>
+                                  <Appenders>
+                                    <RollingFile append="true" bufferSize="8192" bufferedIo="false" fileName="file.log" filePattern="file.log.%i" immediateFlush="true" name="ROLLING">
+                                      <PatternLayout alwaysWriteExceptions="false" pattern="%p - %m%n"/>
+                                      <SizeBasedTriggeringPolicy size="10.00 GB"/>
+                                      <DefaultRolloverStrategy fileIndex="min" max="30"/>
+                                    </RollingFile>
+                                    <Console follow="true" immediateFlush="true" name="CONSOLE" target="SYSTEM_ERR">
+                                      <PatternLayout pattern="%d [%t] %-5p %c - %m%n%ex"/>
+                                    </Console>
+                                  </Appenders>
+                                  <Loggers>
+                                    <Root level="INFO">
+                                      <AppenderRef ref="CONSOLE"/>
+                                    </Root>
+                                    <Logger additivity="false" level="DEBUG" name="org.openrewrite">
+                                      <AppenderRef ref="CONSOLE"/>
+                                      <AppenderRef ref="ROLLING"/>
+                                    </Logger>
+                                  </Loggers>
+                                </Configuration>
+                                """));
+    }
+}