From 921588a2447d2dc932e1165f6326150b365d56da Mon Sep 17 00:00:00 2001
From: Artem Prigoda <arteamon@gmail.com>
Date: Thu, 8 Feb 2018 13:31:46 +0100
Subject: [PATCH] Add support for providing a custom layout during logging
 bootstrap

Dropwizard users have the ability to configure their application to
use JSON as the logging format. Unfortunately, the default logging
bootstrap mechanism which kicks off before Dropwizard logging
configuration, uses the default logging layout. As a result, some
internal logging messages (Jetty, Hibernate initialization) are
produced in a not recognized format.

This change add possibility to specify a layout factory during
the bootstrap process. Users can override the bootstrap method of
`Application` and provide an own layout format. For example,

```
BootstrapLogging.bootstrap(Level.INFO, (loggerContext, timeZone) ->
    new EventJsonLayoutBaseFactory().build(loggerContext, timeZone));
```

As a result, the all applications logs will produced in the JSON format.
---
 .../logging/json/LayoutIntegrationTests.java   |  3 ++-
 .../dropwizard/logging/BootstrapLogging.java   | 18 +++++++++++++++---
 2 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/dropwizard-json-logging/src/test/java/io/dropwizard/logging/json/LayoutIntegrationTests.java b/dropwizard-json-logging/src/test/java/io/dropwizard/logging/json/LayoutIntegrationTests.java
index 9a17d81885b..5ccd14505ee 100644
--- a/dropwizard-json-logging/src/test/java/io/dropwizard/logging/json/LayoutIntegrationTests.java
+++ b/dropwizard-json-logging/src/test/java/io/dropwizard/logging/json/LayoutIntegrationTests.java
@@ -40,7 +40,8 @@
 public class LayoutIntegrationTests {
 
     static {
-        BootstrapLogging.bootstrap(Level.INFO);
+        BootstrapLogging.bootstrap(Level.INFO, (loggerContext, timeZone) ->
+            new EventJsonLayoutBaseFactory().build(loggerContext, timeZone));
     }
 
     private final ObjectMapper objectMapper = Jackson.newObjectMapper();
diff --git a/dropwizard-logging/src/main/java/io/dropwizard/logging/BootstrapLogging.java b/dropwizard-logging/src/main/java/io/dropwizard/logging/BootstrapLogging.java
index a6ed7a6cd1f..fe1c079b218 100644
--- a/dropwizard-logging/src/main/java/io/dropwizard/logging/BootstrapLogging.java
+++ b/dropwizard-logging/src/main/java/io/dropwizard/logging/BootstrapLogging.java
@@ -2,9 +2,11 @@
 
 import ch.qos.logback.classic.Level;
 import ch.qos.logback.classic.Logger;
+import ch.qos.logback.classic.LoggerContext;
 import ch.qos.logback.classic.filter.ThresholdFilter;
 import ch.qos.logback.classic.spi.ILoggingEvent;
 import ch.qos.logback.core.ConsoleAppender;
+import ch.qos.logback.core.Layout;
 import ch.qos.logback.core.encoder.LayoutWrappingEncoder;
 
 import javax.annotation.concurrent.GuardedBy;
@@ -35,6 +37,10 @@ public static void bootstrap() {
     }
 
     public static void bootstrap(Level level) {
+        bootstrap(level, DropwizardLayout::new);
+    }
+
+    public static void bootstrap(Level level, LayoutFactory layoutFactory) {
         LoggingUtil.hijackJDKLogging();
 
         BOOTSTRAPPING_LOCK.lock();
@@ -45,8 +51,8 @@ public static void bootstrap(Level level) {
             final Logger root = LoggingUtil.getLoggerContext().getLogger(org.slf4j.Logger.ROOT_LOGGER_NAME);
             root.detachAndStopAllAppenders();
 
-            final DropwizardLayout formatter = new DropwizardLayout(root.getLoggerContext(), TimeZone.getDefault());
-            formatter.start();
+            final Layout<ILoggingEvent> layout = layoutFactory.create(root.getLoggerContext(), TimeZone.getDefault());
+            layout.start();
 
             final ThresholdFilter filter = new ThresholdFilter();
             filter.setLevel(level.toString());
@@ -57,7 +63,7 @@ public static void bootstrap(Level level) {
             appender.setContext(root.getLoggerContext());
 
             final LayoutWrappingEncoder<ILoggingEvent> layoutEncoder = new LayoutWrappingEncoder<>();
-            layoutEncoder.setLayout(formatter);
+            layoutEncoder.setLayout(layout);
             appender.setEncoder(layoutEncoder);
             appender.start();
 
@@ -67,4 +73,10 @@ public static void bootstrap(Level level) {
             BOOTSTRAPPING_LOCK.unlock();
         }
     }
+
+    @FunctionalInterface
+    public interface LayoutFactory {
+
+        Layout<ILoggingEvent> create(LoggerContext loggerContext, TimeZone timeZone);
+    }
 }