[FLINK-2703] Prepare Flink for being used with Logback.

This closes apache#1194

docs/apis/best_practices.md

@@ -269,3 +269,132 @@ For Google Protobuf you need the following Maven dependency:
 
 
 Please adjust the versions of both libraries as needed.
+
+
+## Using Logback instead of Log4j
+
+**Note: This tutorial is applicable starting from Flink 0.10**
+
+Apache Flink is using [slf4j](http:https://www.slf4j.org/) as the logging abstraction in the code. Users are advised to use sfl4j as well in their user functions.
+
+Sfl4j is a compile-time logging interface that can use different logging implementations at runtime, such as [log4j](http:https://logging.apache.org/log4j/2.x/) or [Logback](http:https://logback.qos.ch/).
+
+Flink is depending on Log4j by default. This page describes how to use Flink with Logback.
+
+To get a logger instance in the code, use the following code:
+
+
+{% highlight java %}
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class MyClass implements MapFunction {
+ private static final Logger LOG = LoggerFactory.getLogger(MyClass.class);
+ // ...
+{% endhighlight %}
+
+
+### Use Logback when running Flink out of the IDE / from a Java application
+
+
+In all cases were classes are executed with a classpath created by a dependency manager such as Maven, Flink will pull log4j into the classpath.
+
+Therefore, you will need to exclude log4j from Flink's dependencies. The following description will assume a Maven project created from a [Flink quickstart](../quickstart/java_api_quickstart.html).
+
+Change your projects `pom.xml` file like this:
+
+{% highlight xml %}
+<dependencies>
+ <!-- Add the two required logback dependencies -->
+ <dependency>
+  <groupId>ch.qos.logback</groupId>
+  <artifactId>logback-core</artifactId>
+  <version>1.1.3</version>
+ </dependency>
+ <dependency>
+  <groupId>ch.qos.logback</groupId>
+  <artifactId>logback-classic</artifactId>
+  <version>1.1.3</version>
+ </dependency>
+
+ <!-- Add the log4j -> sfl4j (-> logback) bridge into the classpath
+  Hadoop is logging to log4j! -->
+ <dependency>
+  <groupId>org.slf4j</groupId>
+  <artifactId>log4j-over-slf4j</artifactId>
+  <version>1.7.7</version>
+ </dependency>
+
+ <dependency>
+  <groupId>org.apache.flink</groupId>
+  <artifactId>flink-java</artifactId>
+  <version>0.10-SNAPSHOT</version>
+  <exclusions>
+  <exclusion>
+  <groupId>log4j</groupId>
+  <artifactId>*</artifactId>
+  </exclusion>
+  <exclusion>
+  <groupId>org.slf4j</groupId>
+  <artifactId>slf4j-log4j12</artifactId>
+  </exclusion>
+  </exclusions>
+ </dependency>
+ <dependency>
+  <groupId>org.apache.flink</groupId>
+  <artifactId>flink-streaming-core</artifactId>
+  <version>0.10-SNAPSHOT</version>
+  <exclusions>
+  <exclusion>
+  <groupId>log4j</groupId>
+  <artifactId>*</artifactId>
+  </exclusion>
+  <exclusion>
+  <groupId>org.slf4j</groupId>
+  <artifactId>slf4j-log4j12</artifactId>
+  </exclusion>
+  </exclusions>
+ </dependency>
+ <dependency>
+  <groupId>org.apache.flink</groupId>
+  <artifactId>flink-clients</artifactId>
+  <version>0.10-SNAPSHOT</version>
+  <exclusions>
+  <exclusion>
+  <groupId>log4j</groupId>
+  <artifactId>*</artifactId>
+  </exclusion>
+  <exclusion>
+  <groupId>org.slf4j</groupId>
+  <artifactId>slf4j-log4j12</artifactId>
+  </exclusion>
+  </exclusions>
+ </dependency>
+</dependencies>
+{% endhighlight %}
+
+The following changes were done in the `<dependencies>` section:
+
+ * Exclude all `log4j` dependencies from all Flink dependencies: This causes Maven to ignore Flink's transitive dependencies to log4j.
+ * Exclude the `slf4j-log4j12` artifact from Flink's dependencies: Since we are going to use the slf4j to logback binding, we have to remove the slf4j to log4j binding.
+ * Add the Logback dependencies: `logback-core` and `logback-classic`
+ * Add dependencies for `log4j-over-slf4j`. `log4j-over-slf4j` is a tool which allows legacy applications which are directly using the Log4j APIs to use the Slf4j interface. Flink depends on Hadoop which is directly using Log4j for logging. Therefore, we need to redirect all logger calls from Log4j to Slf4j which is in turn logging to Logback.
+
+Please note that you need to manually add the exclusions to all new Flink dependencies you are adding to the pom file.
+
+You may also need to check if other dependencies (non Flink) are pulling in log4j bindings. You can analyze the dependencies of your project with `mvn dependency:tree`.
+
+
+
+### Use Logback when running Flink on a cluster
+
+This tutorial is applicable when running Flink on YARN or as a standalone cluster.
+
+In order to use Logback instead of Log4j with Flink, you need to remove the `log4j-1.2.xx.jar` and `sfl4j-log4j12-xxx.jar` from the `lib/` directory.
+
+Next, you need to put the following jar files into the `lib/` folder:
+
+ * `logback-classic.jar`
+ * `logback-core.jar`
+ * `log4j-over-slf4j.jar`: This bridge needs to be present in the classpath for redirecting logging calls from Hadoop (which is using Log4j) to Slf4j.
+

flink-dist/pom.xml

@@ -334,6 +334,8 @@ under the License.
  <exclude>org.apache.flink:flink-scala-examples</exclude>
  <exclude>org.apache.flink:flink-streaming-examples</exclude>
  <exclude>org.apache.flink:flink-python</exclude>
+ <exclude>org.slf4j:slf4j-log4j12</exclude>
+ <exclude>log4j:log4j</exclude>
  </excludes>
  </artifactSet>
  <transformers>

flink-dist/src/main/assemblies/bin.xml

@@ -40,6 +40,8 @@ under the License.
 
  <includes>
  <include>org.apache.flink:flink-python</include>
+ <include>org.slf4j:slf4j-log4j12</include>
+ <include>log4j:log4j</include>
  </includes>
  </dependencySet>
  </dependencySets>

flink-shaded-hadoop/pom.xml

@@ -85,7 +85,14 @@ under the License.
  <filter>
  <artifact>org.slf4j:*</artifact>
  <excludes>
- <exclude>org/slf4j/impl/StaticLoggerBinder*</exclude>
+ <exclude>org/slf4j/impl/**</exclude>
+ </excludes>
+ </filter>
+ <!-- Exclude Hadoop's log4j. Hadoop can use Flink's log4j dependency -->
+ <filter>
+ <artifact>log4j:*</artifact>
+ <excludes>
+ <exclude>org/apache/log4j/**</exclude>
  </excludes>
  </filter>
  </filters>

flink-yarn-tests/src/main/java/org/apache/flink/yarn/YARNSessionCapacitySchedulerITCase.java

@@ -54,7 +54,7 @@ public static void setup() {
  @Test
  public void testClientStartup() {
  LOG.info("Starting testClientStartup()");
- runWithArgs(new String[]{"-j", flinkUberjar.getAbsolutePath(),
+ runWithArgs(new String[]{"-j", flinkUberjar.getAbsolutePath(), "-t", flinkLibFolder.getAbsolutePath(),
  "-n", "1",
  "-jm", "768",
  "-tm", "1024", "-qu", "qa-team"},
@@ -72,6 +72,7 @@ public void testNonexistingQueue() {
  LOG.info("Starting testNonexistingQueue()");
  addTestAppender(FlinkYarnClient.class, Level.WARN);
  runWithArgs(new String[]{"-j", flinkUberjar.getAbsolutePath(),
+ "-t", flinkLibFolder.getAbsolutePath(),
  "-n", "1",
  "-jm", "768",
  "-tm", "1024",

flink-yarn-tests/src/main/java/org/apache/flink/yarn/YARNSessionFIFOITCase.java

@@ -101,7 +101,7 @@ public void checkForProhibitedLogContents() {
  @Test
  public void testClientStartup() {
  LOG.info("Starting testClientStartup()");
- runWithArgs(new String[]{"-j", flinkUberjar.getAbsolutePath(),
+ runWithArgs(new String[]{"-j", flinkUberjar.getAbsolutePath(), "-t", flinkLibFolder.getAbsolutePath(),
  "-n", "1",
  "-jm", "768",
  "-tm", "1024",
@@ -119,6 +119,7 @@ public void testDetachedMode() {
  LOG.info("Starting testDetachedMode()");
  addTestAppender(FlinkYarnSessionCli.class, Level.INFO);
  Runner runner = startWithArgs(new String[]{"-j", flinkUberjar.getAbsolutePath(),
+ "-t", flinkLibFolder.getAbsolutePath(),
  "-n", "1",
  "-jm", "768",
  "-tm", "1024",
@@ -166,7 +167,7 @@ public void testDetachedMode() {
  @Test(timeout=100000) // timeout after 100 seconds
  public void testTaskManagerFailure() {
  LOG.info("Starting testTaskManagerFailure()");
- Runner runner = startWithArgs(new String[]{"-j", flinkUberjar.getAbsolutePath(),
+ Runner runner = startWithArgs(new String[]{"-j", flinkUberjar.getAbsolutePath(), "-t", flinkLibFolder.getAbsolutePath(),
  "-n", "1",
  "-jm", "768",
  "-tm", "1024",
@@ -338,6 +339,7 @@ public void testQueryCluster() {
  public void testNonexistingQueue() {
  LOG.info("Starting testNonexistingQueue()");
  runWithArgs(new String[]{"-j", flinkUberjar.getAbsolutePath(),
+ "-t", flinkLibFolder.getAbsolutePath(),
  "-n", "1",
  "-jm", "768",
  "-tm", "1024",
@@ -362,7 +364,7 @@ public void testNonexistingQueue() {
  public void testResourceComputation() {
  addTestAppender(FlinkYarnClient.class, Level.WARN);
  LOG.info("Starting testResourceComputation()");
- runWithArgs(new String[]{"-j", flinkUberjar.getAbsolutePath(),
+ runWithArgs(new String[]{"-j", flinkUberjar.getAbsolutePath(), "-t", flinkLibFolder.getAbsolutePath(),
  "-n", "5",
  "-jm", "256",
  "-tm", "1585"}, "Number of connected TaskManagers changed to", null, RunTypes.YARN_SESSION, 0);
@@ -390,7 +392,7 @@ public void testResourceComputation() {
  public void testfullAlloc() {
  addTestAppender(FlinkYarnClient.class, Level.WARN);
  LOG.info("Starting testfullAlloc()");
- runWithArgs(new String[]{"-j", flinkUberjar.getAbsolutePath(),
+ runWithArgs(new String[]{"-j", flinkUberjar.getAbsolutePath(), "-t", flinkLibFolder.getAbsolutePath(),
  "-n", "2",
  "-jm", "256",
  "-tm", "3840"}, "Number of connected TaskManagers changed to", null, RunTypes.YARN_SESSION, 0);
@@ -413,7 +415,7 @@ public void perJobYarnCluster() {
  File exampleJarLocation = YarnTestBase.findFile("..", new ContainsName(new String[] {"-WordCount.jar"} , "streaming")); // exclude streaming wordcount here.
  Assert.assertNotNull("Could not find wordcount jar", exampleJarLocation);
  runWithArgs(new String[]{"run", "-m", "yarn-cluster",
- "-yj", flinkUberjar.getAbsolutePath(),
+ "-yj", flinkUberjar.getAbsolutePath(), "-yt", flinkLibFolder.getAbsolutePath(),
  "-yn", "1",
  "-ys", "2", //test that the job is executed with a DOP of 2
  "-yjm", "768",
@@ -441,6 +443,7 @@ public void perJobYarnClusterWithParallelism() {
  "-p", "2", //test that the job is executed with a DOP of 2
  "-m", "yarn-cluster",
  "-yj", flinkUberjar.getAbsolutePath(),
+ "-yt", flinkLibFolder.getAbsolutePath(),
  "-yn", "1",
  "-yjm", "768",
  "-ytm", "1024", exampleJarLocation.getAbsolutePath()},
@@ -477,6 +480,7 @@ private void testDetachedPerJobYarnClusterInternal(String job) {
  }
 
  Runner runner = startWithArgs(new String[]{"run", "-m", "yarn-cluster", "-yj", flinkUberjar.getAbsolutePath(),
+ "-yt", flinkLibFolder.getAbsolutePath(),
  "-yn", "1",
  "-yjm", "768",
  "-yD", "yarn.heap-cutoff-ratio=0.5", // test if the cutoff is passed correctly
@@ -621,6 +625,7 @@ public void testJavaAPI() {
  flinkYarnClient.setJobManagerMemory(768);
  flinkYarnClient.setTaskManagerMemory(1024);
  flinkYarnClient.setLocalJarPath(new Path(flinkUberjar.getAbsolutePath()));
+ flinkYarnClient.setShipFiles(Arrays.asList(flinkLibFolder.listFiles()));
  String confDirPath = System.getenv("FLINK_CONF_DIR");
  flinkYarnClient.setConfigurationDirectory(confDirPath);
  flinkYarnClient.setFlinkConfigurationObject(GlobalConfiguration.getConfiguration());
@@ -632,9 +637,8 @@ public void testJavaAPI() {
  yarnCluster = flinkYarnClient.deploy();
  yarnCluster.connectToCluster();
  } catch (Exception e) {
- System.err.println("Error while deploying YARN cluster: "+e.getMessage());
  LOG.warn("Failing test", e);
- Assert.fail();
+ Assert.fail("Error while deploying YARN cluster: "+e.getMessage());
  }
  FlinkYarnClusterStatus expectedStatus = new FlinkYarnClusterStatus(1, 1);
  for(int second = 0; second < WAIT_TIME * 2; second++) { // run "forever"

flink-yarn-tests/src/main/java/org/apache/flink/yarn/YarnTestBase.java

@@ -98,10 +98,18 @@ public abstract class YarnTestBase extends TestLogger {
 
  protected static MiniYARNCluster yarnCluster = null;
 
+ /**
+ * Uberjar (fat jar) file of Flink
+ */
  protected static File flinkUberjar;
 
  protected static final Configuration yarnConfiguration;
 
+ /**
+ * lib/ folder of the flink distribution.
+ */
+ protected static File flinkLibFolder;
+
  static {
  yarnConfiguration = new YarnConfiguration();
  yarnConfiguration.setInt(YarnConfiguration.RM_SCHEDULER_MINIMUM_ALLOCATION_MB, 512);
@@ -329,6 +337,10 @@ public static void startYARNWithConfig(Configuration conf) {
  flinkUberjar = findFile(uberjarStartLoc, new RootDirFilenameFilter());
  Assert.assertNotNull("Flink uberjar not found", flinkUberjar);
  String flinkDistRootDir = flinkUberjar.getParentFile().getParent();
+ flinkLibFolder = flinkUberjar.getParentFile(); // the uberjar is located in lib/
+ Assert.assertNotNull("Flink flinkLibFolder not found", flinkLibFolder);
+ Assert.assertTrue("lib folder not found", flinkLibFolder.exists());
+ Assert.assertTrue("lib folder not found", flinkLibFolder.isDirectory());
 
  if (!flinkUberjar.exists()) {
  Assert.fail("Unable to locate yarn-uberjar.jar");

flink-yarn-tests/src/main/resources/log4j-test.properties

@@ -16,7 +16,7 @@
 # limitations under the License.
 ################################################################################
 
-log4j.rootLogger=FATAL, console
+log4j.rootLogger=INFO, console
 
 # Log all infos in the given file
 log4j.appender.console=org.apache.log4j.ConsoleAppender

flink-yarn/src/main/java/org/apache/flink/yarn/FlinkYarnClient.java

@@ -26,7 +26,6 @@
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.HashMap;
-import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
 
@@ -248,15 +247,14 @@ public int getTaskManagerCount() {
  @Override
  public void setShipFiles(List<File> shipFiles) {
  File shipFile;
- for(Iterator<File> it = shipFiles.iterator(); it.hasNext(); ) {
- shipFile = it.next();
+ for (File shipFile1 : shipFiles) {
+ shipFile = shipFile1;
  // remove uberjar from ship list (by default everything in the lib/ folder is added to
  // the list of files to ship, but we handle the uberjar separately.
- if(shipFile.getName().startsWith("flink-dist-") && shipFile.getName().endsWith("jar")) {
- it.remove();
+ if (!(shipFile.getName().startsWith("flink-dist-") && shipFile.getName().endsWith("jar"))) {
+ this.shipFiles.add(shipFile);
  }
  }
- this.shipFiles.addAll(shipFiles);
  }
 
  public void setDynamicPropertiesEncoded(String dynamicPropertiesEncoded) {