Add logback for logging

Fixes #15

build.gradle

@@ -44,6 +44,9 @@ dependencies {
     compile 'org.apache.curator:curator-framework:[2.7.1,2.8)'
     compile 'org.apache.commons:commons-pool2:[2.2,3.0)'
 
+    /* For logging at runtime */
+    compile 'ch.qos.logback:logback-parent:[1.1.3,2.0)'
+
     compile 'org.apache.kafka:kafka_2.11:0.8.2.1'
     // Forcing us up to ZK 3.5 to prevent wacky classpath errors when mixing
     // and matching dependencies

src/main/groovy/offtopic/Configuration.groovy

@@ -1,9 +1,12 @@
 package offtopic
 
+import groovy.util.logging.Slf4j
+
 /**
  * class for wrapping our system configuration
  */
 @Singleton
+@Slf4j
 class Configuration extends Properties {
     /**
      * Load defaults, starting in the current working directory, searching for
@@ -12,7 +15,11 @@ class Configuration extends Properties {
     public boolean loadDefaults() {
         File cwdConfiguration = new File('offtopic.properties')
         if (cwdConfiguration.exists()) {
+            log.info('Loading `offtopic.properties` for configuration')
             this.load(new FileInputStream(cwdConfiguration))
         }
+        else {
+            log.warn('Could not load configuration file {}', cwdConfiguration.absolutePath)
+        }
     }
 }

src/main/groovy/offtopic/KafkaService.groovy

@@ -1,36 +1,40 @@
 package offtopic
 
 import groovy.json.JsonSlurper
+import groovy.util.logging.Slf4j
 import offtopic.curator.CuratorPool
+import org.apache.curator.framework.CuratorFramework
 
 /**
  * KafkaService is a helper class to help expose data about Kafka to the
  * Ratpack app
  */
+@Slf4j
 class KafkaService {
     final static String BROKERS_PATH = "/brokers/ids"
     final static String TOPICS_PATH = "/brokers/topics"
 
-    public static ArrayList fetchBrokers() {
-        def brokers = new ArrayList()
-        def parser = new JsonSlurper()
+    public static List<String> fetchBrokers() {
+        JsonSlurper parser = new JsonSlurper()
+        List<String> brokers = []
 
-        CuratorPool.withCurator { c ->
-            c.getChildren().forPath(BROKERS_PATH).each { String id ->
+        CuratorPool.withCurator { CuratorFramework c ->
+            c.children.forPath(BROKERS_PATH).each { String id ->
                 // Pulling this into a String buffer since parse(byte[]) is
                 // throwing a stackoverflow error
-                String buffer = new String(c.getData().forPath("${BROKERS_PATH}/${id}"))
+                String buffer = new String(c.data.forPath("${BROKERS_PATH}/${id}"))
                 brokers.add(parser.parseText(buffer))
             }
         }
 
+        log.info('Fetched brokers from Zookeeper: {}', brokers)
         return brokers
     }
 
-    public static ArrayList fetchTopics() {
-        ArrayList brokers = null
+    public static List<String> fetchTopics() {
+        List brokers = []
         CuratorPool.withCurator { c ->
-            brokers = c.getChildren().forPath(TOPICS_PATH)
+            brokers = c.children.forPath(TOPICS_PATH)
         }
         return brokers
     }

src/main/groovy/offtopic/curator/CuratorClient.groovy

@@ -1,10 +1,11 @@
 package offtopic.curator
 
+import org.apache.curator.framework.CuratorFramework
 import org.apache.curator.retry.ExponentialBackoffRetry
 import org.apache.curator.framework.CuratorFrameworkFactory
 
 class CuratorClient {
-    def client = null
+    CuratorFramework client
 
     public CuratorClient(String zookeepers) {
         if (zookeepers?.length() <= 0) {

src/main/groovy/offtopic/curator/CuratorPool.groovy

@@ -21,7 +21,7 @@ class CuratorPool extends GenericObjectPool<CuratorClient>{
     }
 
     public static void withCurator(Closure closure) {
-        def curator = null
+        CuratorClient curator = null
         try {
             curator = CuratorPool.instance.borrowObject()
             closure.call(curator.client)

src/ratpack/ratpack.groovy

@@ -1,13 +1,16 @@
+import org.slf4j.Logger
+import org.slf4j.LoggerFactory
 import ratpack.handlebars.HandlebarsModule
 import ratpack.jackson.JacksonModule
 
+import java.util.logging.Level
+
 import static ratpack.handlebars.Template.handlebarsTemplate
 import static ratpack.jackson.Jackson.json
 import static ratpack.groovy.Groovy.*
 import static ratpack.websocket.WebSockets.websocket
 
 import offtopic.KafkaService
-import offtopic.KafkaSubscriber
 import offtopic.Configuration
 import offtopic.OfftopicClient
 
@@ -26,7 +29,6 @@ ratpack {
 
         get('topics') {
             topics = KafkaService.fetchTopics()
-            println topics
 
             if (request.headers.get('Content-Type') == 'application/json') {
                 render(json(topics))
@@ -45,19 +47,20 @@ ratpack {
         }
 
         get('topics/:name/websocket') { ctx ->
-            def client = new OfftopicClient(Configuration.instance)
-            def grepper = null
+            OfftopicClient client = new OfftopicClient(Configuration.instance)
+            String grepper = null
 
             websocket(ctx) { ws ->
-                println "Connected ${ws}"
+                Logger log = LoggerFactory.getLogger('WebSocket')
+                log.info('Connected client {}', ws)
                 client.onMessageCallback = { m ->
-                    println "called back with ${m} (grep: ${grepper})"
+                    log.debug('Callback with {] (grep: {})', m, grepper)
                     if ((grepper == null) || (m.raw =~ grepper)) {
                         ws.send(groovy.json.JsonOutput.toJson(m))
                     }
                 }
                 client.createSubscribersFor(pathTokens.name)
-                print "subscribers created for ${pathTokens.name}"
+                log.info('Subscribers created for {}', pathTokens.name)
                 client.startSubscribers()
             } connect { sock ->
                 sock.onClose {
@@ -80,18 +83,6 @@ ratpack {
             }
         }
 
-        /* set up a demo/dummy websocket listener */
-        get("ws") { context ->
-            websocket(context) { ws ->
-            } connect {
-                it.onClose {
-                    println "closing"
-                } onMessage {
-                    "client sent me ${it}"
-                }
-            }
-        }
-
         fileSystem "public", { f -> f.files() }
     }
 }