This PR enhances the failure message emitted to console when a test cluster node fails to come up.

When `./gradlew run` fails, we would frequently need to see the node's log (stored elsewhere on disk) to learn what went wrong, but it is common expectation that errors would show up in console with other gradle output. This can lead to a frustrating developer experience, so we should point to the log location for debugging next steps.

For the case of a cluster, the log message points to the log file of the first node. Hopefully, that is enough of a hint and the developer can pursue the logs of other nodes as needed.

Author: ankit--sethi

build-tools/src/main/java/org/elasticsearch/gradle/testclusters/ElasticsearchCluster.java

@@ -592,7 +592,14 @@ public void waitForAllConditions() {
         writeUnicastHostsFiles();
 
         LOGGER.info("Starting to wait for cluster to form");
-        waitForConditions(waitConditions, System.currentTimeMillis(), CLUSTER_UP_TIMEOUT, CLUSTER_UP_TIMEOUT_UNIT, this);
+        waitForConditions(
+            waitConditions,
+            getFirstNode().getLogsDir().toString(),
+            System.currentTimeMillis(),
+            CLUSTER_UP_TIMEOUT,
+            CLUSTER_UP_TIMEOUT_UNIT,
+            this
+        );
     }
 
     @Override

build-tools/src/main/java/org/elasticsearch/gradle/testclusters/ElasticsearchNode.java

@@ -421,6 +421,11 @@ public Path getConfigDir() {
         return configFile.getParent();
     }
 
+    @Internal
+    public Path getLogsDir() {
+        return confPathLogs;
+    }
+
     @Override
     @Input
     public boolean isPreserveDataDir() {
@@ -896,6 +901,7 @@ private void startElasticsearchProcess() {
             }
         }
         LOGGER.info("Running `{}` in `{}` for {} env: {}", command, workingDir, this, environment);
+        LOGGER.info("In case of node failure, check {} logs available at: {}", this.name, confPathLogs);
         Process esProcess;
         try {
             esProcess = processBuilder.start();
@@ -1621,12 +1627,19 @@ public boolean isProcessAlive() {
     }
 
     void waitForAllConditions() {
-        waitForConditions(waitConditions, System.currentTimeMillis(), NODE_UP_TIMEOUT_UNIT.toMillis(NODE_UP_TIMEOUT) +
-        // Installing plugins at config time and loading them when nods start requires additional time we need to
-        // account for
-            ADDITIONAL_CONFIG_TIMEOUT_UNIT.toMillis(
-                ADDITIONAL_CONFIG_TIMEOUT * (plugins.size() + keystoreFiles.size() + keystoreSettings.size() + credentials.size())
-            ), TimeUnit.MILLISECONDS, this);
+        waitForConditions(
+            waitConditions,
+            confPathLogs.toString(),
+            System.currentTimeMillis(),
+            NODE_UP_TIMEOUT_UNIT.toMillis(NODE_UP_TIMEOUT) +
+            // Installing plugins at config time and loading them when nods start requires additional time we need to
+            // account for
+                ADDITIONAL_CONFIG_TIMEOUT_UNIT.toMillis(
+                    ADDITIONAL_CONFIG_TIMEOUT * (plugins.size() + keystoreFiles.size() + keystoreSettings.size() + credentials.size())
+                ),
+            TimeUnit.MILLISECONDS,
+            this
+        );
     }
 
     @Override

build-tools/src/main/java/org/elasticsearch/gradle/testclusters/TestClusterConfiguration.java

@@ -130,6 +130,7 @@ public interface TestClusterConfiguration {
 
     default void waitForConditions(
         LinkedHashMap<String, Predicate<TestClusterConfiguration>> waitConditions,
+        String logsPath,
         long startedAtMillis,
         long nodeUpTimeout,
         TimeUnit nodeUpTimeoutUnit,
@@ -142,7 +143,9 @@ default void waitForConditions(
             Throwable lastException = null;
             while (System.currentTimeMillis() - startedAtMillis < TimeUnit.MILLISECONDS.convert(nodeUpTimeout, nodeUpTimeoutUnit)) {
                 if (context.isProcessAlive() == false) {
-                    throw new TestClustersException("process was found dead while waiting for " + description + ", " + this);
+                    throw new TestClustersException(
+                        "process was found dead while waiting for " + description + ", " + this + ". Node logs available at: " + logsPath
+                    );
                 }
 
                 try {