Add logback as a dependency and gut the printlns from the codebase

build.gradle

@@ -55,6 +55,9 @@ dependencies {
 
     compile 'com.timgroup:java-statsd-client:3.0.1+'
 
+    /* Logback is to be used for logging through the app */
+    compile 'ch.qos.logback:logback-classic:1.1.2+'
+
     testCompile 'org.spockframework:spock-core:0.7-groovy-2.0'
     testCompile 'cglib:cglib-nodep:2.2.+'
 }

src/main/groovy/com/github/lookout/verspaetung/KafkaPoller.groovy

@@ -2,6 +2,10 @@ package com.github.lookout.verspaetung
 
 import groovy.transform.TypeChecked
 
+import java.util.concurrent.ConcurrentHashMap
+import org.slf4j.Logger
+import org.slf4j.LoggerFactory
+
 import kafka.cluster.Broker
 import kafka.client.ClientUtils
 import kafka.consumer.SimpleConsumer
@@ -18,10 +22,11 @@ class KafkaPoller extends Thread {
     private final String KAFKA_CLIENT_ID = 'VerspaetungClient'
     private final Integer KAFKA_TIMEOUT = (5 * 1000)
     private final Integer KAFKA_BUFFER = (100 * 1024)
+    private final Logger logger = LoggerFactory.getLogger(KafkaPoller.class)
 
     private Boolean keepRunning = true
     private Boolean shouldReconnect = false
-    private HashMap<Integer, SimpleConsumer> brokerConsumerMap = [:]
+    private ConcurrentHashMap<Integer, SimpleConsumer> brokerConsumerMap = [:]
     private List<Broker> brokers = []
     private AbstractMap<TopicPartition, List<zk.ConsumerOffset>> consumersMap
     private List<Closure> onDelta = []
@@ -31,8 +36,9 @@ class KafkaPoller extends Thread {
     }
 
     void run() {
+        logger.info("Starting wait loop")
         while (keepRunning) {
-            println 'kafka poll'
+            logger.debug("poll loop")
 
             if (shouldReconnect) {
                 reconnect()
@@ -46,8 +52,10 @@ class KafkaPoller extends Thread {
         }
     }
 
+    synchronized
     void dumpMetadata() {
-        println 'dumping'
+        logger.debug("dumping meta-data")
+
         def topics = this.consumersMap.keySet().collect { TopicPartition k -> k.topic }
         def metadata = ClientUtils.fetchTopicMetadata(toScalaSet(new HashSet(topics)),
                                                       brokersSeq,
@@ -71,7 +79,7 @@ class KafkaPoller extends Thread {
             }
         }
 
-        println 'dumped'
+        logger.debug("finished dumping meta-data")
     }
 
 
@@ -90,7 +98,7 @@ class KafkaPoller extends Thread {
      * Blocking reconnect to the Kafka brokers
      */
     void reconnect() {
-        println "reconnecting"
+        logger.info("Creating SimpleConsumer connections for brokers")
         this.brokers.each { Broker b ->
             SimpleConsumer consumer = new SimpleConsumer(b.host,
                                                          b.port,

src/main/groovy/com/github/lookout/verspaetung/Main.groovy

@@ -7,19 +7,22 @@ import java.util.concurrent.ConcurrentHashMap
 import groovy.transform.TypeChecked
 
 import com.timgroup.statsd.StatsDClient
-import com.timgroup.statsd.NonBlockingStatsDClient
+import com.timgroup.statsd.NonBlockingDogStatsDClient
 
 import org.apache.curator.retry.ExponentialBackoffRetry
 import org.apache.curator.framework.CuratorFrameworkFactory
 import org.apache.curator.framework.CuratorFramework
 import org.apache.curator.framework.recipes.cache.TreeCache
+import org.slf4j.Logger
+import org.slf4j.LoggerFactory
 
 //@TypeChecked
 class Main {
-    private static final StatsDClient statsd = new NonBlockingStatsDClient('verspaetung', 'localhost', 8125)
+    private static final StatsDClient statsd = new NonBlockingDogStatsDClient('verspaetung', '10.32.2.211', 8125)
+    private static final Logger logger = LoggerFactory.getLogger(Main.class)
 
     static void main(String[] args) {
-        println "Running ${args}"
+        logger.info("Running with: ${args}")
 
         ExponentialBackoffRetry retry = new ExponentialBackoffRetry(1000, 3)
         CuratorFramework client = CuratorFrameworkFactory.newClient(args[0], retry)
@@ -32,7 +35,7 @@ class Main {
         KafkaPoller poller = new KafkaPoller(consumers)
         StandardTreeWatcher consumerWatcher = new StandardTreeWatcher(consumers)
         consumerWatcher.onInitComplete << {
-            println "standard consumers initialized to ${consumers.size()} (topic, partition) tuples"
+            logger.info("standard consumers initialized to ${consumers.size()} (topic, partition) tuples")
         }
 
         BrokerTreeWatcher brokerWatcher = new BrokerTreeWatcher(client)
@@ -43,17 +46,22 @@ class Main {
         cache.listenable.addListener(consumerWatcher)
 
         poller.onDelta << { String groupName, TopicPartition tp, Long delta ->
-            statsd.recordGaugeValue("${tp.topic}.${tp.partition}.${groupName}", delta)
+            statsd.recordGaugeValue(tp.topic, delta, [
+                                                        'topic' : tp.topic,
+                                                        'partition' : tp.partition,
+                                                        'consumer-group' : groupName
+                ])
         }
 
         poller.start()
         brokerWatcher.start()
         cache.start()
-        println 'started..'
+
+        logger.info("Started wait loop...")
 
         while (true) { Thread.sleep(1000) }
 
-        println 'exiting..'
+        logger.info("exiting..")
         poller.die()
         poller.join()
         return

src/main/groovy/com/github/lookout/verspaetung/zk/AbstractTreeWatcher.groovy

@@ -8,6 +8,8 @@ import org.apache.curator.framework.CuratorFramework
 import org.apache.curator.framework.recipes.cache.ChildData
 import org.apache.curator.framework.recipes.cache.TreeCacheListener
 import org.apache.curator.framework.recipes.cache.TreeCacheEvent
+import org.slf4j.Logger
+import org.slf4j.LoggerFactory
 
 /**
  * AbstractTreeWatcher defines the contract and base components for the various
@@ -19,10 +21,12 @@ import org.apache.curator.framework.recipes.cache.TreeCacheEvent
 abstract class AbstractTreeWatcher implements TreeCacheListener {
     protected AbstractMap<TopicPartition, List<ConsumerOffset>> consumersMap
     protected List<Closure> onInitComplete
+    protected Logger logger
 
     AbstractTreeWatcher(AbstractMap consumers) {
         this.consumersMap = consumers
         this.onInitComplete = []
+        this.logger = LoggerFactory.getLogger(this.class)
     }
 
     /**

src/main/groovy/com/github/lookout/verspaetung/zk/BrokerTreeWatcher.groovy

@@ -11,6 +11,8 @@ import org.apache.curator.framework.recipes.cache.ChildData
 import org.apache.curator.framework.recipes.cache.TreeCache
 import org.apache.curator.framework.recipes.cache.TreeCacheListener
 import org.apache.curator.framework.recipes.cache.TreeCacheEvent
+import org.slf4j.Logger
+import org.slf4j.LoggerFactory
 
 /**
  * The BrokerTreeWatcher is a kind of watcher whose sole purpose is
@@ -21,6 +23,7 @@ import org.apache.curator.framework.recipes.cache.TreeCacheEvent
 class BrokerTreeWatcher implements TreeCacheListener {
     static final Integer INVALID_BROKER_ID = -1
 
+    private final Logger logger = LoggerFactory.getLogger(BrokerTreeWatcher.class)
     private JsonSlurper json
     private TreeCache cache
     private final String BROKERS_PATH = '/brokers/ids'
@@ -61,7 +64,6 @@ class BrokerTreeWatcher implements TreeCacheListener {
         }
 
         if (event.type != TreeCacheEvent.Type.NODE_ADDED) {
-            println event
             return
         }
 

src/main/resources/logback.groovy

@@ -0,0 +1,14 @@
+scan()
+
+import ch.qos.logback.classic.encoder.PatternLayoutEncoder
+import ch.qos.logback.core.ConsoleAppender
+
+import static ch.qos.logback.classic.Level.*
+
+appender("STDOUT", ConsoleAppender) {
+  encoder(PatternLayoutEncoder) {
+    pattern = "%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n"
+  }
+}
+root(INFO, ["STDOUT"])
+