Send response also when config generation is 0

Needed for returning empty sentinel config, since we cannot use a new generation
numbed. 0 is used as a special generation number that should allow response
to be given to client even if it is not higher than the current generation.

3 files changed, 67 insertions, 34 deletions

diff --git a/config-proxy/src/main/java/com/yahoo/vespa/config/proxy/ClientUpdater.java b/config-proxy/src/main/java/com/yahoo/vespa/config/proxy/ClientUpdater.java
index f20b45cbe45..e57758f3eec 100644
--- a/config-proxy/src/main/java/com/yahoo/vespa/config/proxy/ClientUpdater.java
+++ b/config-proxy/src/main/java/com/yahoo/vespa/config/proxy/ClientUpdater.java
@@ -49,7 +49,8 @@ class ClientUpdater {
         for (DelayedResponse response : responseDelayQueue.toArray(new DelayedResponse[0])) {
             JRTServerConfigRequest request = response.getRequest();
             if (request.getConfigKey().equals(config.getKey())
-                    && (config.getGeneration() >= request.getRequestGeneration())) {
+                    // Generation 0 is special, used when returning empty sentinel config
+                    && (config.getGeneration() >= request.getRequestGeneration() || config.getGeneration() == 0)) {
                 if (delayedResponses.remove(response)) {
                     found = true;
                     log.log(LogLevel.DEBUG, () -> "Call returnOkResponse for " + config.getKey() + "," + config.getGeneration());
diff --git a/config-proxy/src/test/java/com/yahoo/vespa/config/proxy/ClientUpdaterTest.java b/config-proxy/src/test/java/com/yahoo/vespa/config/proxy/ClientUpdaterTest.java
index fdf59a45841..25140afd4cc 100644
--- a/config-proxy/src/test/java/com/yahoo/vespa/config/proxy/ClientUpdaterTest.java
+++ b/config-proxy/src/test/java/com/yahoo/vespa/config/proxy/ClientUpdaterTest.java
@@ -10,14 +10,13 @@ import org.junit.Rule;
 import org.junit.Test;
 import org.junit.rules.TemporaryFolder;
 
-import static org.hamcrest.CoreMatchers.is;
 import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertThat;
 
 /**
  * @author hmusum
  */
 public class ClientUpdaterTest {
+
     private MockRpcServer rpcServer;
     private ConfigProxyStatistics statistics;
     private DelayedResponses delayedResponses;
@@ -37,53 +36,83 @@ public class ClientUpdaterTest {
 
     @Test
     public void basic() {
-        assertThat(rpcServer.responses, is(0L));
-
         final RawConfig fooConfig = ProxyServerTest.fooConfig;
-        clientUpdater.updateSubscribers(fooConfig);
-
-        // No delayed response, so not returned
-        assertEquals(0, rpcServer.responses);
+        configUpdatedSendResponse(fooConfig);
+        // Nobody asked for the config, so no response sent
+        assertSentResponses(0);
 
-        delayedResponses.add(new DelayedResponse(JRTServerConfigRequestV3.createFromRequest(JRTConfigRequestFactory.createFromRaw(fooConfig, -10L).getRequest())));
-        clientUpdater.updateSubscribers(fooConfig);
-        assertEquals(1, rpcServer.responses);
+        simulateClientRequestingConfig(fooConfig);
+        configUpdatedSendResponse(fooConfig);
+        assertSentResponses(1);
 
-        // Will not find bar config in delayed responses
+        // Nobody asked for 'bar' config
         RawConfig barConfig = new RawConfig(new ConfigKey<>("bar", "id", "namespace"), fooConfig.getDefMd5());
-        clientUpdater.updateSubscribers(barConfig);
-        assertEquals(1, rpcServer.responses);
+        configUpdatedSendResponse(barConfig);
+        assertSentResponses(1);
     }
 
     @Test
     public void errorResponse() {
-        assertThat(rpcServer.responses, is(0L));
-
-        clientUpdater.updateSubscribers(ProxyServerTest.errorConfig);
-        assertThat(rpcServer.responses, is(0L));
-        assertThat(statistics.errors(), is(1L));
+        configUpdatedSendResponse(ProxyServerTest.errorConfig);
+        assertSentResponses(0);
+        assertEquals(1, statistics.errors());
     }
 
     @Test
     public void it_does_not_send_old_config_in_response() {
-        assertThat(rpcServer.responses, is(0L));
+        RawConfig fooConfigOldGeneration = ProxyServerTest.fooConfig;
+
+        RawConfig fooConfig = createConfigWithNextConfigGeneration(fooConfigOldGeneration);
+        configUpdatedSendResponse(fooConfig);
+
+        // Nobody asked for the config
+        assertSentResponses(0);
+
+        simulateClientRequestingConfig(fooConfig);
+        configUpdatedSendResponse(fooConfig);
+        assertSentResponses(1);
+
+        simulateClientRequestingConfig(fooConfig);
+        configUpdatedSendResponse(fooConfigOldGeneration);
+        // Old config generation, so no response returned
+        assertSentResponses(1);
+    }
 
+    @Test
+    public void it_does_send_config_with_generation_0_in_response() {
         RawConfig fooConfigOldGeneration = ProxyServerTest.fooConfig;
 
-        final RawConfig fooConfig = ProxyServerTest.createConfigWithNextConfigGeneration(fooConfigOldGeneration, 0);
-        clientUpdater.updateSubscribers(fooConfig);
+        RawConfig fooConfig = createConfigWithNextConfigGeneration(fooConfigOldGeneration, 1);
+
+        simulateClientRequestingConfig(fooConfig);
+        configUpdatedSendResponse(fooConfig);
+        assertSentResponses(1);
+
+        RawConfig fooConfig2 = createConfigWithNextConfigGeneration(fooConfigOldGeneration, 0);
+        simulateClientRequestingConfig(fooConfig2);
+        configUpdatedSendResponse(fooConfig2);
+        assertSentResponses(2);
+    }
+
+    private void assertSentResponses(int expected) {
+        assertEquals(expected, rpcServer.responses);
+    }
 
-        // No delayed response, so not returned
-        assertEquals(0, rpcServer.responses);
+    private void simulateClientRequestingConfig(RawConfig config) {
+        delayedResponses.add(new DelayedResponse(JRTServerConfigRequestV3.createFromRequest(JRTConfigRequestFactory.createFromRaw(config, -10L).getRequest())));
+    }
 
-        delayedResponses.add(new DelayedResponse(JRTServerConfigRequestV3.createFromRequest(JRTConfigRequestFactory.createFromRaw(fooConfig, -10L).getRequest())));
-        clientUpdater.updateSubscribers(fooConfig);
-        assertEquals(1, rpcServer.responses);
+    private void configUpdatedSendResponse(RawConfig config) {
+        clientUpdater.updateSubscribers(config);
+    }
+
+    private RawConfig createConfigWithNextConfigGeneration(RawConfig config) {
+        return createConfigWithNextConfigGeneration(config, config.getGeneration() + 1);
+    }
 
-        delayedResponses.add(new DelayedResponse(JRTServerConfigRequestV3.createFromRequest(JRTConfigRequestFactory.createFromRaw(fooConfig, -10L).getRequest())));
-        clientUpdater.updateSubscribers(fooConfigOldGeneration);
-        // Old config generation, so not returned
-        assertEquals(1, rpcServer.responses);
+    private RawConfig createConfigWithNextConfigGeneration(RawConfig config, long newConfigGeneration) {
+        final int errorCode = 0;
+        return ProxyServerTest.createConfigWithNextConfigGeneration(config, errorCode, ProxyServerTest.fooConfig.getPayload(), newConfigGeneration);
     }
 
 }
diff --git a/config-proxy/src/test/java/com/yahoo/vespa/config/proxy/ProxyServerTest.java b/config-proxy/src/test/java/com/yahoo/vespa/config/proxy/ProxyServerTest.java
index 513a5caa08d..22488da7c80 100644
--- a/config-proxy/src/test/java/com/yahoo/vespa/config/proxy/ProxyServerTest.java
+++ b/config-proxy/src/test/java/com/yahoo/vespa/config/proxy/ProxyServerTest.java
@@ -1,7 +1,6 @@
 // Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.vespa.config.proxy;
 
-import com.yahoo.config.subscription.ConfigSourceSet;
 import com.yahoo.vespa.config.*;
 import com.yahoo.vespa.config.protocol.JRTServerConfigRequest;
 import com.yahoo.vespa.config.protocol.Payload;
@@ -220,9 +219,13 @@ public class ProxyServerTest {
     }
 
     private static RawConfig createConfigWithNextConfigGeneration(RawConfig config, int errorCode, Payload payload) {
+        return createConfigWithNextConfigGeneration(config, errorCode, payload, config.getGeneration() + 1);
+    }
+
+    static RawConfig createConfigWithNextConfigGeneration(RawConfig config, int errorCode, Payload payload, long configGeneration) {
         return new RawConfig(config.getKey(), config.getDefMd5(),
                              payload, config.getConfigMd5(),
-                             config.getGeneration() + 1, false,
+                             configGeneration, false,
                              errorCode, config.getDefContent(), Optional.empty());
     }