Logging foundation: structured LogEvent, JUL handler, Log API enhancements

apache-maven/pom.xml

@@ -78,13 +78,6 @@ under the License.
       <version>${slf4jVersion}</version>
       <scope>runtime</scope>
     </dependency>
-    <!-- bridge from java.util.logging (JUL) to SLF4J -->
-    <dependency>
-      <groupId>org.slf4j</groupId>
-      <artifactId>jul-to-slf4j</artifactId>
-      <version>${slf4jVersion}</version>
-      <scope>runtime</scope>
-    </dependency>
     <dependency>
       <groupId>org.apache.maven.resolver</groupId>
       <artifactId>maven-resolver-connector-basic</artifactId>

api/maven-api-core/src/main/java/org/apache/maven/api/build/report/LogEvent.java

@@ -0,0 +1,189 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.maven.api.build.report;
+
+import java.time.Instant;
+
+import org.apache.maven.api.annotations.Experimental;
+import org.apache.maven.api.annotations.Immutable;
+import org.apache.maven.api.annotations.Nonnull;
+import org.apache.maven.api.annotations.Nullable;
+
+/**
+ * A structured log event captured during the build.
+ * <p>
+ * Each event carries the log level, timestamp, message, and optionally
+ * the logger name and a stack trace. This replaces raw log line strings
+ * in the build report, enabling programmatic filtering by level and
+ * correlation by timestamp.
+ * <p>
+ * Events originating from the Maven Log API or from JUL
+ * ({@code java.util.logging}) carry additional source metadata: the
+ * source class name, source method name, and thread identifier.
+ * For Log API events the source class name is the mojo implementation
+ * FQCN; for JUL events it comes from {@code LogRecord}.  Events from
+ * direct SLF4J logging have these fields set to {@code null}.
+ *
+ * @since 4.1.0
+ */
+@Experimental
+@Immutable
+public interface LogEvent {
+
+    /**
+     * When this log event was produced (wall-clock time).
+     *
+     * @return the event instant, never {@code null}
+     */
+    @Nonnull
+    Instant timestamp();
+
+    /**
+     * The severity level of this log event.
+     *
+     * @return the log level, never {@code null}
+     */
+    @Nonnull
+    LogLevel level();
+
+    /**
+     * The log message, without level prefix or timestamp formatting.
+     *
+     * @return the log message, never {@code null}
+     */
+    @Nonnull
+    String message();
+
+    /**
+     * The name of the logger that produced this event
+     * (e.g. {@code "org.apache.maven.plugins.compiler.CompilerMojo"}).
+     *
+     * @return the logger name, or {@code null} if unavailable
+     */
+    @Nullable
+    String loggerName();
+
+    /**
+     * The stack trace associated with this event, if an exception was logged.
+     * <p>
+     * The trace is formatted as a multi-line string and may be truncated
+     * for very deep stack traces.
+     *
+     * @return the stack trace string, or {@code null} if no exception was logged
+     */
+    @Nullable
+    String stackTrace();
+
+    /**
+     * The fully formatted log line as rendered for console output, including
+     * the level prefix, timestamp, and any ANSI styling applied by the logger.
+     * <p>
+     * This is the string that would be printed to the terminal in verbose mode.
+     * Console renderers that just need pass-through output can use this directly,
+     * while renderers that apply custom formatting (e.g. rich mode) can use the
+     * structured fields ({@link #level()}, {@link #message()}) instead.
+     * <p>
+     * May be {@code null} if the event was created outside the SLF4J pipeline
+     * (e.g. in tests or by programmatic construction).
+     *
+     * @return the formatted log line, or {@code null}
+     */
+    @Nullable
+    String formattedMessage();
+
+    // ---- Source metadata (populated for Log API and JUL events) ----
+
+    /**
+     * The fully qualified class name of the source that issued the log call.
+     * <p>
+     * For Maven Log API events this is the mojo implementation class name.
+     * For JUL events it is the value from {@code LogRecord.getSourceClassName()}.
+     * For direct SLF4J logging it is {@code null}.
+     *
+     * @return the source class name, or {@code null}
+     */
+    @Nullable
+    default String sourceClassName() {
+        return null;
+    }
+
+    /**
+     * The method name of the source that issued the log call.
+     * <p>
+     * For Maven Log API events this is resolved via {@link StackWalker}.
+     * For JUL events it is the value from {@code LogRecord.getSourceMethodName()}.
+     * For direct SLF4J logging it is {@code null}.
+     *
+     * @return the source method name, or {@code null}
+     */
+    @Nullable
+    default String sourceMethodName() {
+        return null;
+    }
+
+    /**
+     * The thread identifier from which this log event originated.
+     * <p>
+     * Populated for both Log API and JUL events.  Returns {@code -1}
+     * if the thread ID is not available (i.e. for direct SLF4J events).
+     *
+     * @return the thread ID, or {@code -1} if unavailable
+     */
+    default long threadId() {
+        return -1;
+    }
+
+    /**
+     * A monotonically increasing sequence number for total ordering of
+     * log events, useful when multiple events share the same timestamp.
+     * <p>
+     * Assigned by the logging pipeline when the event is captured,
+     * providing a global ordering across all event sources (Log API,
+     * JUL, and direct SLF4J).
+     *
+     * @return the sequence number, or {@code -1} if unavailable
+     */
+    default long sequenceNumber() {
+        return -1;
+    }
+
+    /**
+     * The project this log event belongs to
+     * (e.g. {@code "org.apache.maven:maven-core:4.1.0-SNAPSHOT"}), or {@code null}
+     * if the event was not produced in the context of a specific project.
+     *
+     * @return the project identifier, or {@code null}
+     */
+    @Nullable
+    default String projectId() {
+        return null;
+    }
+
+    /**
+     * The mojo execution that produced this event
+     * (e.g. {@code "compiler:compile@default-compile"}), or {@code null}
+     * if the event was logged outside a mojo execution.
+     *
+     * @return the mojo execution identifier, or {@code null}
+     */
+    @Nullable
+    default String mojoId() {
+        return null;
+    }
+}

impl/maven-cli/src/main/java/org/apache/maven/cling/logging/impl/Log4j2Configuration.java → api/maven-api-core/src/main/java/org/apache/maven/api/build/report/LogLevel.java

@@ -16,29 +16,23 @@
  * specific language governing permissions and limitations
  * under the License.
  */
-package org.apache.maven.cling.logging.impl;
+package org.apache.maven.api.build.report;
 
-import org.apache.maven.cling.logging.BaseSlf4jConfiguration;
+import org.apache.maven.api.annotations.Experimental;
+import org.apache.maven.api.annotations.Immutable;
 
 /**
- * Configuration for slf4j-log4j2.
+ * Log severity levels, mirroring the standard SLF4J levels.
  *
- * @since 3.1.0
+ * @since 4.1.0
+ * @see LogEvent#level()
  */
-public class Log4j2Configuration extends BaseSlf4jConfiguration {
-    @Override
-    public void setRootLoggerLevel(Level level) {
-        String value =
-                switch (level) {
-                    case DEBUG -> "debug";
-                    case INFO -> "info";
-                    default -> "error";
-                };
-        System.setProperty("maven.logging.root.level", value);
-    }
-
-    @Override
-    public void activate() {
-        // no op
-    }
+@Experimental
+@Immutable
+public enum LogLevel {
+    TRACE,
+    DEBUG,
+    INFO,
+    WARN,
+    ERROR
 }

api/maven-api-core/src/main/java/org/apache/maven/api/build/report/package-info.java

@@ -0,0 +1,33 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/**
+ * Structured build report data model.
+ * <p>
+ * This package provides structured representations of build execution
+ * data, including log events and (in future) full build reports.
+ * {@link org.apache.maven.api.build.report.LogEvent} is the foundational
+ * type representing a single structured log entry captured during the build.
+ *
+ * @since 4.1.0
+ */
+@Experimental
+package org.apache.maven.api.build.report;
+
+import org.apache.maven.api.annotations.Experimental;

compat/maven-embedder/pom.xml

@@ -163,11 +163,6 @@ under the License.
       <artifactId>commons-cli</artifactId>
     </dependency>
 
-    <dependency>
-      <groupId>ch.qos.logback</groupId>
-      <artifactId>logback-classic</artifactId>
-      <optional>true</optional>
-    </dependency>
     <dependency>
       <groupId>org.jline</groupId>
       <artifactId>jansi-core</artifactId>

impl/maven-cli/pom.xml

@@ -195,19 +195,10 @@ under the License.
       <groupId>org.slf4j</groupId>
       <artifactId>slf4j-api</artifactId>
     </dependency>
-    <dependency>
-      <groupId>org.slf4j</groupId>
-      <artifactId>jul-to-slf4j</artifactId>
-    </dependency>
     <dependency>
       <groupId>commons-cli</groupId>
       <artifactId>commons-cli</artifactId>
     </dependency>
-    <dependency>
-      <groupId>ch.qos.logback</groupId>
-      <artifactId>logback-classic</artifactId>
-      <optional>true</optional>
-    </dependency>
 
     <dependency>
       <groupId>org.junit.jupiter</groupId>