Support Dropwizard applications without logback

dropwizard-core/src/main/java/io/dropwizard/Application.java

@@ -23,8 +23,7 @@
  */
 public abstract class Application<T extends Configuration> {
     protected Application() {
-        // make sure spinning up Hibernate Validator doesn't yell at us
-        BootstrapLogging.bootstrap(bootstrapLogLevel());
+        bootstrapLogging();
     }
 
     /**
@@ -34,6 +33,11 @@ protected Level bootstrapLogLevel() {
         return Level.WARN;
     }
 
+    protected void bootstrapLogging() {
+        // make sure spinning up Hibernate Validator doesn't yell at us
+        BootstrapLogging.bootstrap(bootstrapLogLevel());
+    }
+
     /**
      * Returns the {@link Class} of the configuration class type parameter.
      *

dropwizard-core/src/main/java/io/dropwizard/Configuration.java

@@ -65,8 +65,7 @@ public class Configuration {
     private ServerFactory server = new DefaultServerFactory();
 
     @Valid
-    @NotNull
-    private LoggingFactory logging = new DefaultLoggingFactory();
+    private LoggingFactory logging;
 
     @Valid
     @NotNull
@@ -96,15 +95,19 @@ public void setServerFactory(ServerFactory factory) {
      * @return logging-specific configuration parameters
      */
     @JsonProperty("logging")
-    public LoggingFactory getLoggingFactory() {
+    public synchronized LoggingFactory getLoggingFactory() {
+        if (logging == null) {
+            // Lazy init to avoid a hard dependency to logback
+            logging = new DefaultLoggingFactory();
+        }
         return logging;
     }
 
     /**
      * Sets the logging-specific section of the configuration file.
      */
     @JsonProperty("logging")
-    public void setLoggingFactory(LoggingFactory factory) {
+    public synchronized void setLoggingFactory(LoggingFactory factory) {
         this.logging = factory;
     }
 
@@ -121,9 +124,9 @@ public void setMetricsFactory(MetricsFactory metrics) {
     @Override
     public String toString() {
         return MoreObjects.toStringHelper(this)
-                .add("server", server)
-                .add("logging", logging)
-                .add("metrics", metrics)
-                .toString();
+            .add("server", server)
+            .add("logging", logging)
+            .add("metrics", metrics)
+            .toString();
     }
 }

dropwizard-core/src/main/java/io/dropwizard/server/AbstractServerFactory.java

@@ -205,8 +205,7 @@ public abstract class AbstractServerFactory implements ServerFactory {
     private static final Pattern WINDOWS_NEWLINE = Pattern.compile("\\r\\n?");
 
     @Valid
-    @NotNull
-    private RequestLogFactory requestLog = new LogbackAccessRequestLogFactory();
+    private RequestLogFactory requestLog;
 
     @Valid
     @NotNull
@@ -263,12 +262,16 @@ public boolean isThreadPoolSizedCorrectly() {
     }
 
     @JsonProperty("requestLog")
-    public RequestLogFactory getRequestLogFactory() {
+    public synchronized RequestLogFactory getRequestLogFactory() {
+        if (requestLog == null) {
+            // Lazy init to avoid a hard dependency to logback
+            requestLog = new LogbackAccessRequestLogFactory();
+        }
         return requestLog;
     }
 
     @JsonProperty("requestLog")
-    public void setRequestLogFactory(RequestLogFactory requestLog) {
+    public synchronized void setRequestLogFactory(RequestLogFactory requestLog) {
         this.requestLog = requestLog;
     }
 
@@ -576,9 +579,9 @@ protected SetUIDListener buildSetUIDListener() {
     }
 
     protected Handler addRequestLog(Server server, Handler handler, String name) {
-        if (requestLog.isEnabled()) {
+        if (getRequestLogFactory().isEnabled()) {
             final RequestLogHandler requestLogHandler = new RequestLogHandler();
-            requestLogHandler.setRequestLog(requestLog.build(name));
+            requestLogHandler.setRequestLog(getRequestLogFactory().build(name));
             // server should own the request log's lifecycle since it's already started,
             // the handler might not become managed in case of an error which would leave
             // the request log stranded

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

@@ -0,0 +1,22 @@
+package io.dropwizard.logging;
+
+import com.codahale.metrics.MetricRegistry;
+import com.fasterxml.jackson.annotation.JsonTypeName;
+
+/**
+ * A logging factory which does configure a logging infrastructure.
+ * Useful when the users doesn't want to use the Dropwizard logging configuration abilities.
+ */
+@JsonTypeName("external")
+public class ExternalLoggingFactory implements LoggingFactory {
+
+    @Override
+    public void configure(MetricRegistry metricRegistry, String name) {
+
+    }
+
+    @Override
+    public void stop() {
+
+    }
+}

dropwizard-logging/src/main/resources/META-INF/services/io.dropwizard.logging.LoggingFactory

@@ -1 +1,2 @@
 io.dropwizard.logging.DefaultLoggingFactory
+io.dropwizard.logging.ExternalLoggingFactory

dropwizard-request-logging/src/main/java/io/dropwizard/request/logging/ExternalRequestLogFactory.java

@@ -0,0 +1,33 @@
+package io.dropwizard.request.logging;
+
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonTypeName;
+import org.eclipse.jetty.server.RequestLog;
+import org.eclipse.jetty.server.Slf4jRequestLog;
+
+/**
+ * A request log factory which writes request logs via Slf4j and doesn't configure
+ * any logging infrastructure.
+ * Useful when the user doesn't want to configure request logging via Dropwizard configuration.
+ */
+@JsonTypeName("external")
+public class ExternalRequestLogFactory implements RequestLogFactory {
+
+    private boolean enabled = true;
+
+    @JsonProperty
+    public void setEnabled(boolean enabled) {
+        this.enabled = enabled;
+    }
+
+    @Override
+    @JsonProperty
+    public boolean isEnabled() {
+        return enabled;
+    }
+
+    @Override
+    public RequestLog build(String name) {
+        return new Slf4jRequestLog();
+    }
+}

dropwizard-request-logging/src/main/resources/META-INF/services/io.dropwizard.request.logging.RequestLogFactory

@@ -1,2 +1,3 @@
 io.dropwizard.request.logging.LogbackAccessRequestLogFactory
 io.dropwizard.request.logging.old.LogbackClassicRequestLogFactory
+io.dropwizard.request.logging.ExternalRequestLogFactory

dropwizard-servlets/src/main/java/io/dropwizard/servlets/tasks/LogConfigurationTask.java

@@ -3,6 +3,7 @@
 import ch.qos.logback.classic.Level;
 import ch.qos.logback.classic.LoggerContext;
 import com.google.common.collect.ImmutableMultimap;
+import org.slf4j.ILoggerFactory;
 import org.slf4j.LoggerFactory;
 
 import java.io.PrintWriter;
@@ -30,34 +31,33 @@
  */
 public class LogConfigurationTask extends Task {
 
-    private final LoggerContext loggerContext;
+    private final ILoggerFactory loggerContext;
 
     /**
      * Creates a new LogConfigurationTask.
      */
     public LogConfigurationTask() {
-        this((LoggerContext) LoggerFactory.getILoggerFactory());
+        this(LoggerFactory.getILoggerFactory());
     }
 
     /**
-     * Creates a new LogConfigurationTask with the given {@link ch.qos.logback.classic.LoggerContext} instance.
+     * Creates a new LogConfigurationTask with the given {@link ILoggerFactory} instance.
      * <p/>
      * <b>Use {@link LogConfigurationTask#LogConfigurationTask()} instead.</b>
      *
-     * @param loggerContext a {@link ch.qos.logback.classic.LoggerContext} instance
+     * @param loggerContext a {@link ILoggerFactory} instance
      */
-    public LogConfigurationTask(LoggerContext loggerContext) {
+    public LogConfigurationTask(ILoggerFactory loggerContext) {
         super("log-level");
         this.loggerContext = loggerContext;
     }
 
-    @Override
     public void execute(ImmutableMultimap<String, String> parameters, PrintWriter output) throws Exception {
         final List<String> loggerNames = getLoggerNames(parameters);
         final Level loggerLevel = getLoggerLevel(parameters);
 
         for (String loggerName : loggerNames) {
-            loggerContext.getLogger(loggerName).setLevel(loggerLevel);
+            ((LoggerContext) loggerContext).getLogger(loggerName).setLevel(loggerLevel);
             output.println(String.format("Configured logging level for %s to %s", loggerName, loggerLevel));
             output.flush();
         }