Improve customization of Tomcat's access log

Add `directory`, `prefix` and `suffix` properties to further customize
how access logs are configured on Tomcat. Relocate all properties to the
`server.tomcat.accesslog` namespace.

`server.tomcat.accessLogPattern` and `server.tomcat.accessLogEnabled` are
deprecated and replaced by `server.tomcat.accesslog.pattern` and
`server.tomcat.accesslog.enabled` respectively.

Closes gh-2491

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/ServerProperties.java

@@ -467,14 +467,9 @@ public class ServerProperties implements EmbeddedServletContainerCustomizer, Ord
 	public static class Tomcat {
 
 		/**
-		 * Format pattern for access logs.
+		 * Access log configuration
 		 */
-		private String accessLogPattern;
-
-		/**
-		 * Enable access log.
-		 */
-		private boolean accessLogEnabled = false;
+		private final Accesslog accesslog = new Accesslog();
 
 		/**
 		 * Regular expression that matches proxies that are to be trusted.
@@ -550,12 +545,50 @@ public class ServerProperties implements EmbeddedServletContainerCustomizer, Ord
 			this.maxHttpHeaderSize = maxHttpHeaderSize;
 		}
 
+		public Accesslog getAccesslog() {
+			return this.accesslog;
+		}
+
+		/**
+		 * Specify if access log is enabled.
+		 * @return {@code true} if access log is enabled
+		 * @deprecated since 1.3.0 in favor of {@code server.tomcat.accesslog.enabled}
+		 */
+		@Deprecated
+		@DeprecatedConfigurationProperty(replacement = "server.tomcat.accesslog.enabled")
 		public boolean getAccessLogEnabled() {
-			return this.accessLogEnabled;
+			return this.accesslog.isEnabled();
 		}
 
+		/**
+		 * Set if access log is enabled.
+		 * @param accessLogEnabled the access log enable flag
+		 * @deprecated since 1.3.0 in favor of {@code server.tomcat.accesslog.enabled}
+		 */
+		@Deprecated
 		public void setAccessLogEnabled(boolean accessLogEnabled) {
-			this.accessLogEnabled = accessLogEnabled;
+			getAccesslog().setEnabled(accessLogEnabled);
+		}
+
+		/**
+		 * Get the format pattern for access logs.
+		 * @return the format pattern for access logs
+		 * @deprecated since 1.3.0 in favor of {@code server.tomcat.accesslog.pattern}
+		 */
+		@Deprecated
+		@DeprecatedConfigurationProperty(replacement = "server.tomcat.accesslog.pattern")
+		public String getAccessLogPattern() {
+			return this.accesslog.getPattern();
+		}
+
+		/**
+		 * Set the format pattern for access logs
+		 * @param accessLogPattern the pattern for access logs
+		 * @deprecated since 1.3.0 in favor of {@code server.tomcat.accesslog.pattern}
+		 */
+		@Deprecated
+		public void setAccessLogPattern(String accessLogPattern) {
+			this.accesslog.setPattern(accessLogPattern);
 		}
 
 		public int getBackgroundProcessorDelay() {
@@ -574,14 +607,6 @@ public class ServerProperties implements EmbeddedServletContainerCustomizer, Ord
 			this.basedir = basedir;
 		}
 
-		public String getAccessLogPattern() {
-			return this.accessLogPattern;
-		}
-
-		public void setAccessLogPattern(String accessLogPattern) {
-			this.accessLogPattern = accessLogPattern;
-		}
-
 		public String getInternalProxies() {
 			return this.internalProxies;
 		}
@@ -642,7 +667,7 @@ public class ServerProperties implements EmbeddedServletContainerCustomizer, Ord
 			if (this.maxHttpHeaderSize > 0) {
 				customizeMaxHttpHeaderSize(factory);
 			}
-			if (this.accessLogEnabled) {
+			if (this.accesslog.enabled) {
 				customizeAccessLog(factory);
 			}
 			if (getUriEncoding() != null) {
@@ -711,12 +736,87 @@ public class ServerProperties implements EmbeddedServletContainerCustomizer, Ord
 		}
 
 		private void customizeAccessLog(TomcatEmbeddedServletContainerFactory factory) {
-			AccessLogValve valve = new AccessLogValve();
-			String accessLogPattern = getAccessLogPattern();
-			valve.setPattern(accessLogPattern == null ? "common" : accessLogPattern);
-			valve.setSuffix(".log");
-			factory.addContextValves(valve);
+			factory.addContextValves(this.accesslog.createAccessLogValve());
 		}
+
+		public static class Accesslog {
+
+			/**
+			 * Enable access log.
+			 */
+			private boolean enabled = false;
+
+			/**
+			 * Format pattern for access logs.
+			 */
+			private String pattern = "common";
+
+			/**
+			 * Directory in which log files are created. Can be relative to the tomcat
+			 * base dir or absolute.
+			 */
+			private String directory = "logs";
+
+			/**
+			 * Log file name prefix.
+			 */
+			protected String prefix = "access_log";
+
+			/**
+			 * Log file name suffix.
+			 */
+			private String suffix = ".log";
+
+			AccessLogValve createAccessLogValve() {
+				AccessLogValve valve = new AccessLogValve();
+				valve.setPattern(this.pattern);
+				valve.setDirectory(this.directory);
+				valve.setPrefix(this.prefix);
+				valve.setSuffix(this.suffix);
+				return valve;
+			}
+
+			public boolean isEnabled() {
+				return enabled;
+			}
+
+			public void setEnabled(boolean enabled) {
+				this.enabled = enabled;
+			}
+
+			public String getPattern() {
+				return pattern;
+			}
+
+			public void setPattern(String pattern) {
+				this.pattern = pattern;
+			}
+
+			public String getDirectory() {
+				return directory;
+			}
+
+			public void setDirectory(String directory) {
+				this.directory = directory;
+			}
+
+			public String getPrefix() {
+				return prefix;
+			}
+
+			public void setPrefix(String prefix) {
+				this.prefix = prefix;
+			}
+
+			public String getSuffix() {
+				return suffix;
+			}
+
+			public void setSuffix(String suffix) {
+				this.suffix = suffix;
+			}
+		}
+
 	}
 
 	public static class Undertow {

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/web/ServerPropertiesTests.java

@@ -110,18 +110,20 @@ public class ServerPropertiesTests {
 	@Test
 	public void testTomcatBinding() throws Exception {
 		Map<String, String> map = new HashMap<String, String>();
-		map.put("server.tomcat.access_log_pattern", "%h %t '%r' %s %b");
+		map.put("server.tomcat.accesslog.pattern", "%h %t '%r' %s %b");
+		map.put("server.tomcat.accesslog.prefix", "foo");
+		map.put("server.tomcat.accesslog.suffix", "-bar.log");
 		map.put("server.tomcat.protocol_header", "X-Forwarded-Protocol");
 		map.put("server.tomcat.remote_ip_header", "Remote-Ip");
 		map.put("server.tomcat.internal_proxies", "10\\.\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}");
 		bindProperties(map);
-		assertEquals("%h %t '%r' %s %b", this.properties.getTomcat()
-				.getAccessLogPattern());
-		assertEquals("Remote-Ip", this.properties.getTomcat().getRemoteIpHeader());
-		assertEquals("X-Forwarded-Protocol", this.properties.getTomcat()
-				.getProtocolHeader());
-		assertEquals("10\\.\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}", this.properties.getTomcat()
-				.getInternalProxies());
+		ServerProperties.Tomcat tomcat = this.properties.getTomcat();
+		assertEquals("%h %t '%r' %s %b", tomcat.getAccesslog().getPattern());
+		assertEquals("foo", tomcat.getAccesslog().getPrefix());
+		assertEquals("-bar.log", tomcat.getAccesslog().getSuffix());
+		assertEquals("Remote-Ip", tomcat.getRemoteIpHeader());
+		assertEquals("X-Forwarded-Protocol", tomcat.getProtocolHeader());
+		assertEquals("10\\.\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}", tomcat.getInternalProxies());
 	}
 
 	@Test

spring-boot-docs/src/main/asciidoc/appendix-application-properties.adoc

@@ -105,8 +105,11 @@ content into your application; rather pick only the properties that you need.
 	server.ssl.trust-store-password=
 	server.ssl.trust-store-provider=
 	server.ssl.trust-store-type=
-	server.tomcat.access-log-pattern= # log pattern of the access log
-	server.tomcat.access-log-enabled=false # is access logging enabled
+	server.tomcat.accesslog.directory=logs # directory in which log files are created
+	server.tomcat.accesslog.enabled=false # is access logging enabled
+	server.tomcat.accesslog.pattern= # log pattern of the access log
+	server.tomcat.accesslog.prefix=access_log # log file name prefix
+	server.tomcat.accesslog.suffix=.log # log file name suffix
 	server.tomcat.internal-proxies=10\\.\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}|\\
 			192\\.168\\.\\d{1,3}\\.\\d{1,3}|\\
 			169\\.254\\.\\d{1,3}\\.\\d{1,3}|\\