Apply Logback system properties and not just common properties to context

Closes gh-24894

Author: wilkinsona

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/logging/logback/LogbackLoggingSystem.java

@@ -148,7 +148,7 @@ protected void loadDefaults(LoggingInitializationContext initializationContext,
 		}
 		Environment environment = initializationContext.getEnvironment();
 		// Apply system properties directly in case the same JVM runs multiple apps
-		new LoggingSystemProperties(environment, context::putProperty).apply(logFile);
+		new LogbackLoggingSystemProperties(environment, context::putProperty).apply(logFile);
 		LogbackConfigurator configurator = debug ? new DebugLogbackConfigurator(context)
 				: new LogbackConfigurator(context);
 		new DefaultLogbackConfiguration(initializationContext, logFile).apply(configurator);

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/logging/logback/LogbackLoggingSystemProperties.java

@@ -17,6 +17,7 @@
 package org.springframework.boot.logging.logback;
 
 import java.nio.charset.Charset;
+import java.util.function.BiConsumer;
 
 import ch.qos.logback.core.util.FileSize;
 
@@ -66,6 +67,16 @@ public LogbackLoggingSystemProperties(Environment environment) {
 		super(environment);
 	}
 
+	/**
+	 * Create a new {@link LogbackLoggingSystemProperties} instance.
+	 * @param environment the source environment
+	 * @param setter setter used to apply the property
+	 * @since 2.4.3
+	 */
+	public LogbackLoggingSystemProperties(Environment environment, BiConsumer<String, String> setter) {
+		super(environment, setter);
+	}
+
 	@Override
 	protected Charset getDefaultCharset() {
 		return Charset.defaultCharset();

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/logging/logback/LogbackLoggingSystemTests.java

@@ -17,11 +17,15 @@
 package org.springframework.boot.logging.logback;
 
 import java.io.File;
+import java.lang.reflect.Field;
+import java.lang.reflect.Modifier;
+import java.nio.charset.Charset;
 import java.nio.charset.StandardCharsets;
 import java.util.Arrays;
 import java.util.EnumSet;
 import java.util.HashSet;
 import java.util.List;
+import java.util.Map;
 import java.util.Set;
 import java.util.logging.Handler;
 import java.util.logging.LogManager;
@@ -57,6 +61,7 @@
 import org.springframework.core.env.ConfigurableEnvironment;
 import org.springframework.mock.env.MockEnvironment;
 import org.springframework.test.util.ReflectionTestUtils;
+import org.springframework.util.ReflectionUtils;
 import org.springframework.util.StringUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;
@@ -501,6 +506,30 @@ void initializeShouldSetSystemProperty() {
 		assertThat(System.getProperty(LoggingSystemProperties.LOG_FILE)).endsWith("example.log");
 	}
 
+	@Test
+	void initializeShouldApplyLogbackSystemPropertiesToTheContext() {
+		this.environment.setProperty("logging.logback.rollingpolicy.file-name-pattern", "file-name-pattern");
+		this.environment.setProperty("logging.logback.rollingpolicy.clean-history-on-start", "true");
+		this.environment.setProperty("logging.logback.rollingpolicy.max-file-size", "10MB");
+		this.environment.setProperty("logging.logback.rollingpolicy.total-size-cap", "100MB");
+		this.environment.setProperty("logging.logback.rollingpolicy.max-history", "20");
+		this.loggingSystem.beforeInitialize();
+		initialize(this.initializationContext, null, null);
+		LoggerContext loggerContext = (LoggerContext) StaticLoggerBinder.getSingleton().getLoggerFactory();
+		Map<String, String> properties = loggerContext.getCopyOfPropertyMap();
+		Set<String> expectedProperties = new HashSet<String>();
+		ReflectionUtils.doWithFields(LogbackLoggingSystemProperties.class,
+				(field) -> expectedProperties.add((String) field.get(null)), this::isPublicStaticFinal);
+		expectedProperties.removeAll(Arrays.asList("LOG_FILE", "LOG_PATH"));
+		assertThat(properties).containsOnlyKeys(expectedProperties);
+		assertThat(properties).containsEntry("CONSOLE_LOG_CHARSET", Charset.defaultCharset().name());
+	}
+
+	private boolean isPublicStaticFinal(Field field) {
+		int modifiers = field.getModifiers();
+		return Modifier.isPublic(modifiers) && Modifier.isStatic(modifiers) && Modifier.isFinal(modifiers);
+	}
+
 	@Test
 	void initializationIsOnlyPerformedOnceUntilCleanedUp() {
 		LoggerContext loggerContext = (LoggerContext) StaticLoggerBinder.getSingleton().getLoggerFactory();