Add setting system/default timezone in logging configuration

Users should have the ability to use the system timezone in the logging
configuration. It allows administrators to take advantage of the operation
system/JVM time zone management tools and use the same configuration
for Dropwizard applications in different time zones.

docs/source/manual/configuration.rst

@@ -614,6 +614,7 @@ discardingThreshold    51           When the blocking queue has only the capacit
                                     If no discarding threshold is specified, then a default of queueSize / 5 is used.
                                     To keep all events, set discardingThreshold to 0.
 timeZone               UTC          The time zone to which event timestamps will be converted.
+                                    To use the system/default time zone, set it to ``system``.
 target                 stdout       The name of the standard stream to which events will be written.
                                     Can be ``stdout`` or ``stderr``.
 logFormat              default      The Logback pattern with which events will be formatted. See

dropwizard-logging/src/main/java/io/dropwizard/logging/AbstractAppenderFactory.java

@@ -14,10 +14,12 @@
 import io.dropwizard.logging.async.AsyncAppenderFactory;
 import io.dropwizard.logging.filter.FilterFactory;
 import io.dropwizard.logging.layout.LayoutFactory;
+import org.slf4j.LoggerFactory;
 
 import javax.validation.constraints.Max;
 import javax.validation.constraints.Min;
 import javax.validation.constraints.NotNull;
+import java.util.Arrays;
 import java.util.List;
 import java.util.TimeZone;
 
@@ -100,7 +102,7 @@ public abstract class AbstractAppenderFactory<E extends DeferredProcessingAware>
     private boolean includeCallerData = false;
 
     private ImmutableList<FilterFactory<E>> filterFactories = ImmutableList.of();
-    
+
     private boolean neverBlock = false;
 
     @JsonProperty
@@ -148,6 +150,19 @@ public TimeZone getTimeZone() {
         return timeZone;
     }
 
+    @JsonProperty
+    public void setTimeZone(String zoneId) {
+        if (zoneId.equalsIgnoreCase("system")) {
+            this.timeZone = TimeZone.getDefault();
+        } else {
+            if (Arrays.asList(TimeZone.getAvailableIDs()).contains(zoneId)) {
+                this.timeZone = TimeZone.getTimeZone(zoneId);
+            } else {
+                LoggerFactory.getLogger(getClass()).warn("Unknown timezone '{}' provided, using UTC", zoneId);
+            }
+        }
+    }
+
     @JsonProperty
     public void setTimeZone(TimeZone timeZone) {
         this.timeZone = timeZone;
@@ -172,7 +187,7 @@ public ImmutableList<FilterFactory<E>> getFilterFactories() {
     public void setFilterFactories(List<FilterFactory<E>> appenders) {
         this.filterFactories = ImmutableList.copyOf(appenders);
     }
-    
+
     @JsonProperty
     public void setNeverBlock(boolean neverBlock) {
         this.neverBlock = neverBlock;

dropwizard-logging/src/test/java/io/dropwizard/logging/AppenderFactoryCustomTimeZone.java

@@ -0,0 +1,58 @@
+package io.dropwizard.logging;
+
+import com.google.common.io.Resources;
+import io.dropwizard.configuration.YamlConfigurationFactory;
+import io.dropwizard.jackson.Jackson;
+import io.dropwizard.validation.BaseValidator;
+import org.junit.Test;
+
+import java.io.File;
+import java.net.URISyntaxException;
+import java.util.TimeZone;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class AppenderFactoryCustomTimeZone {
+
+    static {
+        BootstrapLogging.bootstrap();
+    }
+
+    private final YamlConfigurationFactory<ConsoleAppenderFactory> factory = new YamlConfigurationFactory<>(
+        ConsoleAppenderFactory.class, BaseValidator.newValidator(), Jackson.newObjectMapper(), "dw");
+
+    private static File loadResource(String resourceName) throws URISyntaxException {
+        return new File(Resources.getResource(resourceName).toURI());
+    }
+
+    @Test
+    public void testLoadAppenderWithCustomTimeZone() throws Exception {
+        final ConsoleAppenderFactory appender = factory.build(loadResource("yaml/appender_with_custom_time_zone.yml"));
+        assertThat(appender.getTimeZone().getID()).isEqualTo("CET");
+    }
+
+    @Test
+    public void testLoadAppenderWithNoTimeZone() throws Exception {
+        final ConsoleAppenderFactory appender = factory.build(loadResource("yaml/appender_with_no_time_zone.yml"));
+        assertThat(appender.getTimeZone().getID()).isEqualTo("UTC");
+    }
+
+    @Test
+    public void testLoadAppenderWithUtcTimeZone() throws Exception {
+        final ConsoleAppenderFactory appender = factory.build(loadResource("yaml/appender_with_utc_time_zone.yml"));
+        assertThat(appender.getTimeZone().getID()).isEqualTo("UTC");
+    }
+
+    @Test
+    public void testLoadAppenderWithWrongTimeZone() throws Exception {
+        final ConsoleAppenderFactory appender = factory.build(loadResource("yaml/appender_with_wrong_time_zone.yml"));
+        assertThat(appender.getTimeZone().getID()).isEqualTo("UTC");
+    }
+
+    @Test
+    public void testLoadAppenderWithSystemTimeZone() throws Exception {
+        final ConsoleAppenderFactory appender = factory.build(loadResource("yaml/appender_with_system_time_zone.yml"));
+        assertThat(appender.getTimeZone()).isEqualTo(TimeZone.getDefault());
+    }
+
+}

dropwizard-logging/src/test/resources/yaml/appender_with_custom_time_zone.yml

@@ -0,0 +1,2 @@
+type: console
+timeZone: CET

dropwizard-logging/src/test/resources/yaml/appender_with_no_time_zone.yml

@@ -0,0 +1 @@
+type: console

dropwizard-logging/src/test/resources/yaml/appender_with_system_time_zone.yml

@@ -0,0 +1,2 @@
+type: console
+timeZone: system

dropwizard-logging/src/test/resources/yaml/appender_with_utc_time_zone.yml

@@ -0,0 +1,2 @@
+type: console
+timeZone: UTC

dropwizard-logging/src/test/resources/yaml/appender_with_wrong_time_zone.yml

@@ -0,0 +1,2 @@
+type: console
+timeZone: Narnia