Make zookeeper hosts configurable, consumerIds random and a few more improvements

Slowly moving towards the OfftopicClient to hold state and configuration around
websocket connections

Fixes #4
Fixes #3

build.gradle

@@ -39,6 +39,7 @@ dependencies {
     compile 'org.apache.kafka:kafka_2.10:0.8.1.1+'
 
     testCompile 'org.spockframework:spock-core:0.7-groovy-2.0'
+    testCompile 'cglib:cglib-nodep:2.2.+'
 }
 ////////////////////////////////////////////////////////////////////////////////
 

src/main/groovy/offtopic/Configuration.groovy

@@ -0,0 +1,18 @@
+package offtopic
+
+/**
+ * class for wrapping our system configuration
+ */
+@Singleton
+class Configuration extends Properties {
+    /**
+     * Load defaults, starting in the current working directory, searching for
+     * 'offtopic.properties'
+     */
+    public boolean loadDefaults() {
+        File cwdConfiguration = new File('offtopic.properties')
+        if (cwdConfiguration.exists()) {
+            this.load(new FileInputStream(cwdConfiguration))
+        }
+    }
+}

src/main/groovy/offtopic/KafkaSubscriber.groovy

@@ -14,9 +14,13 @@ class KafkaSubscriber {
     String topic
     private Closure callback
     private ConsumerConnector consumer
+    private String zookeepers
+    private String consumerId
 
-    public KafkaSubscriber(String topicName) {
+    public KafkaSubscriber(String zks, String topicName, String consumerId) {
         this.topic = topicName
+        this.zookeepers = zks
+        this.consumerId = consumerId
     }
 
     public void setCallback(Closure theCallback) {
@@ -25,7 +29,7 @@ class KafkaSubscriber {
 
     public void connect() {
         this.consumer = kafka.consumer.Consumer.createJavaConsumerConnector(
-                        createConsumerConfig('localhost:2181', 'offtopic-spock-test'))
+                        createConsumerConfig(this.zookeepers, this.consumerId))
     }
 
     public void shutdown() {
@@ -45,7 +49,7 @@ class KafkaSubscriber {
         consumerMap.get(this.topic).each { stream ->
             def iterator = stream.iterator()
             while (iterator.hasNext()) {
-                this.callback.call(iterator.next().message())
+                this.callback.call(iterator.next())
             }
         }
     }

src/main/groovy/offtopic/OfftopicClient.groovy

@@ -0,0 +1,9 @@
+package offtopic
+
+class OfftopicClient {
+    int clientId = 0
+
+    public OfftopicClient() {
+        this.clientId = new Random().nextInt()
+    }
+}

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

@@ -2,10 +2,22 @@ package offtopic.curator
 
 import org.apache.commons.pool2.impl.GenericObjectPool
 
-@Singleton(strict=false)
 class CuratorPool extends GenericObjectPool<CuratorClient>{
-    private CuratorPool() {
-        /** XXX: Figure out how to get ZK from settings */
-        super(new CuratorClientObjectFactory('localhost:2181'))
+    private static CuratorPool instance = null
+
+    public static void prepare(String zookeepers) {
+        this.instance = new CuratorPool(zookeepers)
+    }
+
+    public static CuratorPool getInstance() {
+        if (this.instance == null) {
+            throw new Exception("Cannot access CuratorPool before prepare() has been called")
+        }
+        return this.instance
+    }
+
+    private CuratorPool(String zookeepers) {
+        super(new CuratorClientObjectFactory(zookeepers))
+        println "CREATING WITH ${zookeepers}"
     }
 }

src/ratpack/offtopic.properties

@@ -0,0 +1 @@
+zookeepers=localhost:2181

src/ratpack/public/js/ws.js

@@ -18,7 +18,7 @@ function watchTopic(name) {
                 var el = "<div id='" + el_id + "' class='list-group-item'>" + data.raw + "<br/><div id='" +  el_id + "_b64' style='display:none;'><pre>" + data.b64 + "</pre></div>";
                 messages.prepend(el);
                 $("#" + el_id).click(function(ev) {
-                    $("#"+el_id+'_b64').show();
+                    $("#"+el_id+'_b64').toggle();
                 });
 
                 // Let's only keep the last 25

src/ratpack/ratpack.groovy

@@ -8,9 +8,13 @@ import static ratpack.websocket.WebSockets.websocket
 
 import offtopic.KafkaService
 import offtopic.KafkaSubscriber
+import offtopic.Configuration
+import offtopic.OfftopicClient
 
 ratpack {
     bindings {
+        offtopic.Configuration.instance.loadDefaults()
+        offtopic.curator.CuratorPool.prepare(Configuration.instance.zookeepers)
         add new HandlebarsModule()
         add new JacksonModule()
     }
@@ -32,6 +36,7 @@ ratpack {
         }
 
         get('topics/:name') {
+            println offtopic.Configuration.instance['offtopic.zookeepers']
             render "Fetching info for ${pathTokens.name}"
         }
 
@@ -40,7 +45,10 @@ ratpack {
         }
 
         get('topics/:name/websocket') { ctx ->
-            subscriber = new KafkaSubscriber(pathTokens.name)
+            client = new OfftopicClient()
+            subscriber = new KafkaSubscriber(Configuration.instance.zookeepers,
+                                             pathTokens.name,
+                                             "offtopic-${client.clientId}")
             runner = new Thread({
                 subscriber.connect()
                 println "subscriber connected"
@@ -52,8 +60,10 @@ ratpack {
                 println "Connected ${ws} ${subscriber}"
                 subscriber.callback = { msg ->
                     println "called back with: ${msg}"
-                    ws.send(groovy.json.JsonOutput.toJson(['raw' : new String(msg),
-                            'b64' : msg.encodeBase64().toString()]))
+                    ws.send(groovy.json.JsonOutput.toJson(['raw' : new String(msg.message()),
+                            'b64' : msg.message().encodeBase64().toString(),
+                            'topic' : msg.topic(),
+                            'tstamp' : System.currentTimeMillis()]))
                     println "sent message"
                 }
                 runner.start()

src/test/groovy/offtopic/ConfigurationSpec.groovy

@@ -0,0 +1,6 @@
+package offtopic
+
+import spock.lang.Specification
+
+class ConfigurationSpec extends Specification {
+}

src/test/groovy/offtopic/KafkaSubscriberSpec.groovy

@@ -5,7 +5,7 @@ import spock.lang.Specification
 class KafkaSubscriberSpec extends Specification {
     def "initializing"() {
         when:
-        def subscriber = new KafkaSubscriber('spock')
+        def subscriber = new KafkaSubscriber(null, 'spock', null)
 
         then:
         subscriber instanceof KafkaSubscriber

src/test/groovy/offtopic/OfftopicClientSpec.groovy

@@ -0,0 +1,13 @@
+package offtopic
+
+import spock.lang.Specification
+
+class OfftopicClientSpec extends Specification {
+    def "initialization should create a clientId"() {
+        when:
+        def client = new OfftopicClient()
+
+        then:
+        client.clientId != 0
+    }
+}

src/test/groovy/offtopic/curator/CuratorPoolSpec.groovy

@@ -4,7 +4,10 @@ import spock.lang.Specification
 
 class CuratorPoolSpec extends Specification {
     def "an instance should be an instance"() {
-        expect:
-        CuratorPool.instance instanceof CuratorPool
+        when:
+        CuratorPool.instance
+
+        then:
+        thrown(Exception)
     }
 }