Starting to clean up KafkaService so it's less dependent on a global CuratorPool

build.gradle

@@ -32,7 +32,7 @@ repositories {
 }
 
 dependencies {
-    compile 'org.codehaus.groovy:groovy-all:2.4.4'
+    compile 'org.codehaus.groovy:groovy-all:[2.4.4,2.5)'
 
     compile 'io.ratpack:ratpack-handlebars:[0.9.19,1.0)'
     compile 'io.ratpack:ratpack-jackson:[0.9.17,1.0)'

src/main/groovy/offtopic/KafkaService.groovy

@@ -2,7 +2,6 @@ package offtopic
 
 import groovy.json.JsonSlurper
 import groovy.util.logging.Slf4j
-import offtopic.curator.CuratorPool
 import org.apache.curator.framework.CuratorFramework
 
 /**
@@ -14,28 +13,28 @@ class KafkaService {
     final static String BROKERS_PATH = "/brokers/ids"
     final static String TOPICS_PATH = "/brokers/topics"
 
-    public static List<String> fetchBrokers() {
+    /**
+     * Fetch brokers based on their conventional location in Zookeeper (/brokers/ids)
+     * and return a list of maps for the various discovered broker metadata
+     *
+     * {"jmx_port":9999,"timestamp":"1428168559585","host":"kafka-stage1-1.lasangia.io","version":1,"port":6667}
+     *
+     * @return List of Map objects containing deserialized metadata
+     */
+    static List<Map> fetchBrokers(CuratorFramework curator) {
         JsonSlurper parser = new JsonSlurper()
-        List<String> brokers = []
+        List<Map> brokers = []
 
-        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.data.forPath("${BROKERS_PATH}/${id}"))
-                brokers.add(parser.parseText(buffer))
-            }
+        curator.children.forPath(BROKERS_PATH).each { String id ->
+            byte[] buffer = curator.data.forPath("${BROKERS_PATH}/${id}")
+            brokers.add(parser.parse(buffer) as Map)
         }
 
         log.info('Fetched brokers from Zookeeper: {}', brokers)
         return brokers
     }
 
-    public static List<String> fetchTopics() {
-        List brokers = []
-        CuratorPool.withCurator { c ->
-            brokers = c.children.forPath(TOPICS_PATH)
-        }
-        return brokers
+    static List<String> fetchTopics(CuratorFramework curator) {
+        return curator.children.forPath(TOPICS_PATH)
     }
 }

src/main/groovy/offtopic/KafkaSubscriber.groovy

@@ -11,33 +11,32 @@ import groovy.util.logging.Slf4j
  */
 @Slf4j
 class KafkaSubscriber {
-
     String topic
     private Closure callback
     private ConsumerConnector consumer
     private String zookeepers
     private String consumerId
 
-    public KafkaSubscriber(String zks, String topicName, String consumerId) {
+    KafkaSubscriber(String zks, String topicName, String consumerId) {
         this.topic = topicName
         this.zookeepers = zks
         this.consumerId = consumerId
     }
 
-    public void setCallback(Closure theCallback) {
-        this.callback = theCallback
+    void setCallback(Closure theCallback) {
+        callback = theCallback
     }
 
-    public void connect() {
-        this.consumer = kafka.consumer.Consumer.createJavaConsumerConnector(
-                        createConsumerConfig(this.zookeepers, this.consumerId))
+    void connect() {
+        consumer = kafka.consumer.Consumer.createJavaConsumerConnector(
+                        createConsumerConfig(zookeepers, consumerId))
     }
 
-    public void shutdown() {
+    void shutdown() {
         this.consumer?.shutdown()
     }
 
-    public void consume() {
+    void consume() {
         if (this.consumer == null) {
             log.warn "no consumer, gtfo"
             return

src/ratpack/ratpack.groovy

@@ -1,3 +1,5 @@
+import offtopic.curator.CuratorPool
+import org.apache.curator.framework.CuratorFramework
 import org.slf4j.Logger
 import org.slf4j.LoggerFactory
 import ratpack.handlebars.HandlebarsModule
@@ -28,7 +30,10 @@ ratpack {
         }
 
         get('topics') {
-            topics = KafkaService.fetchTopics()
+            List<String> topics
+            CuratorPool.withCurator { CuratorFramework cf ->
+                topics = KafkaService.fetchTopics(cf)
+            }
 
             if (request.headers.get('Content-Type') == 'application/json') {
                 render(json(topics))
@@ -73,7 +78,10 @@ ratpack {
         }
 
         get('brokers') {
-            brokers = KafkaService.fetchBrokers()
+            List<Map> brokers
+            CuratorPool.withCurator { CuratorFramework cf ->
+                brokers = KafkaService.fetchBrokers(cf)
+            }
 
             if (request.headers.get('Content-Type') == 'application/json') {
                 render(json(brokers))

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(null, 'spock', null)
+        KafkaSubscriber subscriber = new KafkaSubscriber(null, 'spock', null)
 
         then:
         subscriber instanceof KafkaSubscriber