[ADDED] Lame Duck Mode Notifications (#337)

[Added] Lame Duck Mode Notification

Co-authored-by: Rick Hightower <rick.hightower@aboutobjects.com>

CHANGELOG.md

@@ -1,7 +1,7 @@
 
 # Change Log
 
-## Version 2.7.0
+## Version 2.8.0
 
  - [ADDED] #323 Nats.connect v2 credentials (@olicuzo)
  - [CHANGED]  #320 Update MAINTAINERS.md (@gcolliso)

README.md

@@ -52,9 +52,9 @@ The java-nats client is provided in a single jar file, with a single external de
 
 ### Downloading the Jar
 
-You can download the latest jar at [https://search.maven.org/remotecontent?filepath=io/nats/jnats/2.7.0/jnats-2.7.0.jar](https://search.maven.org/remotecontent?filepath=io/nats/jnats/2.7.0/jnats-2.7.0.jar).
+You can download the latest jar at [https://search.maven.org/remotecontent?filepath=io/nats/jnats/2.8.0/jnats-2.8.0.jar](https://search.maven.org/remotecontent?filepath=io/nats/jnats/2.8.0/jnats-2.8.0.jar).
 
-The examples are available at [https://search.maven.org/remotecontent?filepath=io/nats/jnats/2.7.0/jnats-2.7.0-examples.jar](https://search.maven.org/remotecontent?filepath=io/nats/jnats/2.7.0/jnats-2.7.0-examples.jar).
+The examples are available at [https://search.maven.org/remotecontent?filepath=io/nats/jnats/2.8.0/jnats-2.8.0-examples.jar](https://search.maven.org/remotecontent?filepath=io/nats/jnats/2.8.0/jnats-2.8.0-examples.jar).
 
 To use NKeys, you will need the ed25519 library, which can be downloaded at [https://repo1.maven.org/maven2/net/i2p/crypto/eddsa/0.3.0/eddsa-0.3.0.jar](https://repo1.maven.org/maven2/net/i2p/crypto/eddsa/0.3.0/eddsa-0.3.0.jar).
 
@@ -64,7 +64,7 @@ The NATS client is available in the Maven central repository, and can be importe
 
 ```groovy
 dependencies {
-    implementation 'io.nats:jnats:2.7.0'
+    implementation 'io.nats:jnats:2.8.0'
 }
 ```
 
@@ -90,7 +90,7 @@ The NATS client is available on the Maven central repository, and can be importe
 <dependency>
     <groupId>io.nats</groupId>
     <artifactId>jnats</artifactId>
-    <version>2.7.0</version>
+    <version>2.8.0</version>
 </dependency>
 ```
 

build.gradle

@@ -15,10 +15,10 @@ plugins {
 // Update version here, repeated check-ins not into master will have snapshot on them
 // Be sure to update Nats.java with the latest version, the change log and the package-info.java
 def versionMajor = 2
-def versionMinor = 7
+def versionMinor = 8
 def versionPatch = 0
 def versionModifier = ""
-def jarVersion = "2.7.0"
+def jarVersion = "2.8.0"
 def branch = System.getenv("TRAVIS_BRANCH") != null ? System.getenv("TRAVIS_BRANCH") : "";
 def tag = System.getenv("TRAVIS_TAG") != null ? System.getenv("TRAVIS_TAG") : "";
 def useSigning = "master".equals(branch) || (!"".equals(tag) && tag.equals(branch)) // tag will be the branch on a tag event for travis

src/main/java/io/nats/client/ConnectionListener.java

@@ -30,7 +30,9 @@ public enum Events {
         /** The connection was reconnected and the server has been notified of all subscriptions. */
         RESUBSCRIBED("nats: subscriptions re-established"),
         /** The connection was told about new servers from, from the current server. */ 
-        DISCOVERED_SERVERS("nats: discovered servers");
+        DISCOVERED_SERVERS("nats: discovered servers"),
+        /** Server Sent a lame duck mode. */
+        LAME_DUCK("nats: lame duck mode");
 
         private String event;
 

src/main/java/io/nats/client/Nats.java

@@ -72,7 +72,7 @@ public class Nats {
     /**
      * Current version of the library - {@value #CLIENT_VERSION}
      */
-    public static final String CLIENT_VERSION = "2.7.0";
+    public static final String CLIENT_VERSION = "2.8.0";
 
     /**
      * Current language of the library - {@value #CLIENT_LANGUAGE}

src/main/java/io/nats/client/impl/NatsConnection.java

@@ -1344,6 +1344,10 @@ void handleInfo(String infoJson) {
         if (urls != null && urls.length > 0) {
             processConnectionEvent(Events.DISCOVERED_SERVERS);
         }
+
+        if (serverInfo.isLameDuckMode()) {
+            processConnectionEvent(Events.LAME_DUCK);
+        }
     }
 
     void queueOutgoing(NatsMessage msg) {

src/main/java/io/nats/client/impl/NatsServerInfo.java

@@ -31,6 +31,7 @@ class NatsServerInfo {
     static final String CONNECT_URLS = "connect_urls";
     static final String PROTOCOL_VERSION = "proto";
     static final String NONCE = "nonce";
+    static final String LAME_DUCK_MODE = "ldm";
 
     private String serverId;
     private String version;
@@ -44,12 +45,17 @@ class NatsServerInfo {
     private String rawInfoJson;
     private int protocolVersion;
     private byte[] nonce;
+    private boolean lameDuckMode;
 
     public NatsServerInfo(String json) {
         this.rawInfoJson = json;
         parseInfo(json);
     }
 
+    public boolean isLameDuckMode() {
+        return lameDuckMode;
+    }
+
     public String getServerId() {
         return this.serverId;
     }
@@ -106,6 +112,7 @@ public String getRawJson() {
     private static final String grabObject = "\\{(.+?)\\}";
 
     void parseInfo(String jsonString) {
+        Pattern lameDuckMode = Pattern.compile("\""+LAME_DUCK_MODE+"\":" + grabBoolean, Pattern.CASE_INSENSITIVE);
         Pattern serverIdRE = Pattern.compile("\""+SERVER_ID+"\":" + grabString, Pattern.CASE_INSENSITIVE);
         Pattern versionRE = Pattern.compile("\""+VERSION+"\":" + grabString, Pattern.CASE_INSENSITIVE);
         Pattern goRE = Pattern.compile("\""+GO+"\":" + grabString, Pattern.CASE_INSENSITIVE);
@@ -168,7 +175,13 @@ void parseInfo(String jsonString) {
         if (m.find()) {
             this.tlsRequired = Boolean.parseBoolean(m.group(1));
         }
-
+
+        m = lameDuckMode.matcher(jsonString);
+        if (m.find()) {
+            this.lameDuckMode = Boolean.parseBoolean(m.group(1));
+        }
+
+
         m = portRE.matcher(jsonString);
         if (m.find()) {
             this.port = Integer.parseInt(m.group(1));

src/test/java/io/nats/client/impl/InfoHandlerTests.java

@@ -13,18 +13,16 @@
 
 package io.nats.client.impl;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertTrue;
-
 import java.io.IOException;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.ExecutionException;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
 
+import io.nats.client.*;
 import org.junit.Test;
 
-import io.nats.client.Connection;
-import io.nats.client.NatsServerProtocolMock;
-import io.nats.client.Nats;
+import static org.junit.Assert.*;
 
 public class InfoHandlerTests {
     @Test
@@ -44,6 +42,8 @@ public void testInitialInfo() throws IOException, InterruptedException {
         }
     }
 
+
+
     @Test
     public void testUnsolicitedInfo() throws IOException, InterruptedException, ExecutionException {
         String customInfo = "{\"server_id\":\"myid\"}";
@@ -103,4 +103,79 @@ public void testUnsolicitedInfo() throws IOException, InterruptedException, Exec
             }
         }
     }
+
+
+
+    @Test
+    public void testLDM() throws IOException, InterruptedException, ExecutionException, TimeoutException {
+        String customInfo = "{\"server_id\":\"myid\", \"ldm\":true}";
+        CompletableFuture<Boolean> gotPong = new CompletableFuture<>();
+        CompletableFuture<Boolean> sendInfo = new CompletableFuture<>();
+        CompletableFuture<ConnectionListener.Events> connectLDM = new CompletableFuture<>();
+
+        NatsServerProtocolMock.Customizer infoCustomizer = (ts, r, w) -> {
+
+            // Wait for client to be ready.
+            try {
+                sendInfo.get();
+            } catch (Exception e) {
+                // return, we will fail the test
+                gotPong.cancel(true);
+                return;
+            }
+
+            System.out.println("*** Mock Server @" + ts.getPort() + " sending INFO ...");
+            w.write("INFO {\"server_id\":\"replacement\"}\r\n");
+            w.flush();
+
+            System.out.println("*** Mock Server @" + ts.getPort() + " sending PING ...");
+            w.write("PING\r\n");
+            w.flush();
+
+            String pong = "";
+
+            System.out.println("*** Mock Server @" + ts.getPort() + " waiting for PONG ...");
+            try {
+                pong = r.readLine();
+            } catch (Exception e) {
+                gotPong.cancel(true);
+                return;
+            }
+
+            if (pong != null && pong.startsWith("PONG")) {
+                System.out.println("*** Mock Server @" + ts.getPort() + " got PONG ...");
+                gotPong.complete(Boolean.TRUE);
+            } else {
+                System.out.println("*** Mock Server @" + ts.getPort() + " got something else... " + pong);
+                gotPong.complete(Boolean.FALSE);
+            }
+        };
+
+        try (NatsServerProtocolMock ts = new NatsServerProtocolMock(infoCustomizer, customInfo)) {
+
+            Options options = new Options.Builder().server(ts.getURI()).connectionListener(new ConnectionListener() {
+                @Override
+                public void connectionEvent(Connection conn, Events type) {
+                    if (type.equals(Events.LAME_DUCK)) connectLDM.complete(type);
+                }
+            }).build();
+
+            Connection nc = Nats.connect(options);
+            try {
+                assertTrue("Connected Status", Connection.Status.CONNECTED == nc.getStatus());
+                assertEquals("got custom info", "myid", ((NatsConnection) nc).getInfo().getServerId());
+                sendInfo.complete(Boolean.TRUE);
+
+                assertTrue("Got pong.", gotPong.get().booleanValue()); // Server round tripped so we should have new info
+                assertEquals("got replacement info", "replacement", ((NatsConnection) nc).getInfo().getServerId());
+            } finally {
+                nc.close();
+                assertTrue("Closed Status", Connection.Status.CLOSED == nc.getStatus());
+            }
+        }
+
+        ConnectionListener.Events event = connectLDM.get(5, TimeUnit.SECONDS);
+        assertEquals(event, ConnectionListener.Events.LAME_DUCK);
+        System.out.println(event);
+    }
 }