Merge pull request #14 from irstevenson/doc-updates-fileconfig-test

Added test for `StartupSettings` and documentation of use - in `README.md`

README.md

@@ -40,6 +40,46 @@ Later we can check that the nodes discover each other
   }
 ```
 
+Usage with Settings File
+-----
+
+For a very simple client setup with a settings file you first need a JSON file such as:
+
+```json
+[{
+  "id":"419af818-0114-4c7b-8fdb-952915335ce4",
+  "port":50001,
+  "gossip_interval":1000,
+  "cleanup_interval":10000,
+  "members":[
+    {"host":"127.0.0.1", "port":50000}
+  ]
+}]
+```
+
+where:
+
+* `id` - is a unique id for this node (you can use any string, but above we use a UUID)
+* `port` - the port to use on the default adapter on the node's machine
+* `gossip_interval` - how often (in milliseconds) to gossip list of members to other node(s)
+* `cleanup_interval` - when to remove 'dead' nodes (in milliseconds)
+* `members` - initial seed nodes
+
+Then starting a local node is as simple as:
+
+```java
+GossipService gossipService = new GossipService(
+  StartupSettings.fromJSONFile( "node_settings.json" )
+);
+gossipService.start();
+```
+
+And then when all is done, shutdown with:
+
+```java
+gossipService.shutdown();
+```
+
 Event Listener
 ------
 
@@ -50,6 +90,9 @@ The status can be polled using the getters that return immutable lists.
    public List<LocalGossipMember> getDeadList()
 ```
 
+These can be accessed from the `GossipManager` on your `GossipService`, e.g:
+`gossipService.get_gossipManager().getMemberList();`
+
 Users can also attach an event listener:
 
 ```java

src/main/java/com/google/code/gossip/GossipService.java

@@ -29,7 +29,7 @@ public class GossipService {
    */
   public GossipService(StartupSettings startupSettings) throws InterruptedException,
           UnknownHostException {
-    this(InetAddress.getLocalHost().getHostAddress(), startupSettings.getPort(), "",
+    this(InetAddress.getLocalHost().getHostAddress(), startupSettings.getPort(), startupSettings.getId(),
              startupSettings.getGossipMembers(), startupSettings
                     .getGossipSettings(), null);
   }

src/main/java/com/google/code/gossip/StartupSettings.java

@@ -8,6 +8,7 @@ import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
 
+import org.apache.log4j.Logger;
 import org.json.JSONArray;
 import org.json.JSONException;
 import org.json.JSONObject;
@@ -18,6 +19,10 @@ import org.json.JSONObject;
  * @author harmenw
  */
 public class StartupSettings {
+  private static final Logger log = Logger.getLogger(StartupSettings.class);
+
+  /** The id to use fo the service */
+  private String _id;
 
   /** The port to start the gossip service on. */
   private int _port;
@@ -31,25 +36,51 @@ public class StartupSettings {
   /**
    * Constructor.
    *
+   * @param id
+   *          The id to be used for this service
    * @param port
    *          The port to start the service on.
+   * @param logLevel
+   *          unused
    */
-  public StartupSettings(int port, int logLevel) {
+  public StartupSettings(String id, int port, int logLevel) {
-    this(port, new GossipSettings());
+    this(id, port, new GossipSettings());
   }
 
   /**
    * Constructor.
    *
+   * @param id
+   *          The id to be used for this service
    * @param port
    *          The port to start the service on.
    */
-  public StartupSettings(int port, GossipSettings gossipSettings) {
+  public StartupSettings(String id, int port, GossipSettings gossipSettings) {
+    _id = id;
     _port = port;
     _gossipSettings = gossipSettings;
     _gossipMembers = new ArrayList<>();
   }
 
+  /**
+   * Set the id to be used for this service.
+   *
+   * @param id
+   *          The id for this service.
+   */
+  public void setId( String id ) {
+    _id = id;
+  }
+
+  /**
+   * Get the id for this service.
+   *
+   * @return the service's id.
+   */
+  public String getId() {
+    return _id;
+  }
+
   /**
    * Set the port of the gossip service.
    *
@@ -126,6 +157,9 @@ public class StartupSettings {
     // Now get the port number.
     int port = jsonObject.getInt("port");
 
+    // Get the id to be used
+    String id = jsonObject.getString("id");
+
     // Get the gossip_interval from the config file.
     int gossipInterval = jsonObject.getInt("gossip_interval");
 
@@ -133,22 +167,22 @@ public class StartupSettings {
     int cleanupInterval = jsonObject.getInt("cleanup_interval");
 
     // Initiate the settings with the port number.
-    StartupSettings settings = new StartupSettings(port, new GossipSettings(
+    StartupSettings settings = new StartupSettings(id, port, new GossipSettings(
             gossipInterval, cleanupInterval));
 
     // Now iterate over the members from the config file and add them to the settings.
-    System.out.print("Config-members [");
+    String configMembersDetails = "Config-members [";
     JSONArray membersJSON = jsonObject.getJSONArray("members");
     for (int i = 0; i < membersJSON.length(); i++) {
       JSONObject memberJSON = membersJSON.getJSONObject(i);
       RemoteGossipMember member = new RemoteGossipMember(memberJSON.getString("host"),
               memberJSON.getInt("port"), "");
       settings.addGossipMember(member);
-      System.out.print(member.getAddress());
+      configMembersDetails += member.getAddress();
       if (i < (membersJSON.length() - 1))
-        System.out.print(", ");
+        configMembersDetails += ", ";
     }
-    System.out.println("]");
+    log.info( configMembersDetails + "]" );
 
     // Return the created settings object.
     return settings;

src/test/java/io/teknek/gossip/StartupSettingsTest.java

@@ -0,0 +1,79 @@
+package io.teknek.gossip;
+
+import com.google.code.gossip.GossipMember;
+import com.google.code.gossip.GossipService;
+import com.google.code.gossip.GossipSettings;
+import com.google.code.gossip.StartupSettings;
+import org.apache.log4j.Logger;
+import org.json.JSONException;
+import org.junit.Test;
+
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.UUID;
+import java.util.concurrent.TimeUnit;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+/**
+ * Tests support of using {@code StartupSettings} and thereby reading
+ * setup config from file.
+ */
+public class StartupSettingsTest {
+  private static final Logger log = Logger.getLogger( StartupSettingsTest.class );
+
+  @Test
+  public void testUsingSettingsFile() throws IOException, InterruptedException, JSONException {
+    File settingsFile = File.createTempFile("gossipTest",".json");
+    log.debug( "Using settings file: " + settingsFile.getAbsolutePath() );
+    settingsFile.deleteOnExit();
+    writeSettingsFile(settingsFile);
+
+    // Start the other simple node that the settings file points to
+    GossipService firstService = new GossipService(
+      "127.0.0.1", 50000, UUID.randomUUID().toString(),
+      new ArrayList<GossipMember>(), new GossipSettings(), null
+    );
+    firstService.start();
+
+    // Start a node with the settings file
+    GossipService serviceUnderTest = new GossipService(
+      StartupSettings.fromJSONFile( settingsFile )
+    );
+    serviceUnderTest.start();
+
+    // Let the sync up
+    TimeUnit.SECONDS.sleep(2);
+
+    // Check the results
+    assertEquals(1, firstService.get_gossipManager().getMemberList().size() );
+    assertEquals(1, serviceUnderTest.get_gossipManager().getMemberList().size() );
+    assertTrue(
+      firstService.get_gossipManager().getMemberList().size() ==
+      serviceUnderTest.get_gossipManager().getMemberList().size() );
+
+    firstService.shutdown();
+    serviceUnderTest.shutdown();
+  }
+
+  private void writeSettingsFile( File target ) throws IOException {
+    String settings =
+            "[{\n" + // It is odd that this is meant to be in an array, but oh well.
+            "  \"id\":\"" + UUID.randomUUID() + "\",\n" +
+            "  \"port\":50001,\n" +
+            "  \"gossip_interval\":1000,\n" +
+            "  \"cleanup_interval\":10000,\n" +
+            "  \"members\":[\n" +
+            "    {\"host\":\"127.0.0.1\", \"port\":50000}\n" +
+            "  ]\n" +
+            "}]";
+
+    log.info( "Using settings file with contents of:\n---\n" + settings + "\n---" );
+    FileOutputStream output = new FileOutputStream(target);
+    output.write( settings.getBytes() );
+    output.close();
+  }
+}

src/test/java/io/teknek/gossip/TenNodeThreeSeedTest.java

@@ -52,11 +52,12 @@ public class TenNodeThreeSeedTest {
               new GossipListener(){
         @Override
         public void gossipEvent(GossipMember member, GossipState state) {
-          System.out.println(member+" "+ state);
+          log.info(member+" "+ state);
         }
       });
       clients.add(gossipService);
       gossipService.start();
+      gossipService.get_gossipManager().getMemberList();
     }
     TUnit.assertThat(new Callable<Integer> (){
       public Integer call() throws Exception {