Fix issue 297: incompatibility with AWS Keyspaces (complement) (#308)

* Wait for databasechangeloglock table is ready in AWS keyspaces

Complementary fix for issue #297

* Fix SQL syntax for table status check in AWS and add logs in case of error

* Use lowercase table name to correctly match name in AWS system table

src/main/java/liquibase/ext/cassandra/lockservice/LockServiceCassandra.java

@@ -9,6 +9,7 @@
 import liquibase.exception.UnexpectedLiquibaseException;
 import liquibase.executor.Executor;
 import liquibase.executor.ExecutorService;
+import liquibase.executor.LoggingExecutor;
 import liquibase.ext.cassandra.database.CassandraDatabase;
 import liquibase.lockservice.StandardLockService;
 import liquibase.statement.core.LockDatabaseChangeLogStatement;
@@ -150,6 +151,15 @@ public boolean isDatabaseChangeLogLockTableInitialized(final boolean tableJustCr
         if (!isDatabaseChangeLogLockTableInitialized || forceRecheck) {
             Executor executor = Scope.getCurrentScope().getSingleton(ExecutorService.class).getExecutor("jdbc", database);
 
+            // For AWS Keyspaces, it could be necessary to wait the table is ready in all the nodes of the cluster
+            // before querying it.
+            if (isAwsKeyspacesCompatibilityModeEnabled()) {
+                if (!waitForDatabaseChangeLogLockTableReady(executor)) {
+                    throw new UnexpectedLiquibaseException(
+                            "Waiting for databaseChangeLogLock table ready failed or timed out");
+                }
+            }
+
             try {
                 isDatabaseChangeLogLockTableInitialized = executeCountQuery(executor,
                         "SELECT COUNT(*) FROM " + getChangeLogLockTableName()) > 0;
@@ -213,4 +223,50 @@ private int executeCountQuery(final Executor executor, final String query) throw
             return executor.queryForInt(new RawSqlStatement(query));
         }
     }
+
+    /**
+     * Execute a query on the AWS Keyspaces {@code tables} table to check if the database changelog lock table is
+     * ready for querying (status {@code ACTIVE}).
+     * <p>
+     *     See: <a href="https://docs.aws.amazon.com/keyspaces/latest/devguide/working-with-tables.html#tables-create">
+     *         AWS documentation about creating tables in Keyspaces</a>.
+     * </p>
+     *
+     * @param executor The query executor.
+     * @return {@code true} if the table is ready before reaching the maximal number of attempts, {@code false}
+     * otherwise.
+     */
+    private boolean waitForDatabaseChangeLogLockTableReady(final Executor executor) {
+        int maxAttempts = 20;
+        final String tableName = database.getDatabaseChangeLogLockTableName();
+        if (executor instanceof LoggingExecutor) {
+            return true;
+        }
+        boolean isTableActive;
+        try {
+            int attempt = 1;
+            do {
+                try {
+                    Thread.sleep(getChangeLogLockRecheckTime() * 2000);
+                } catch (InterruptedException e) {
+                    // Restore thread interrupt status
+                    Thread.currentThread().interrupt();
+                }
+                Scope.getCurrentScope().getLog(LockServiceCassandra.class)
+                        .fine("Checking the status of table " + tableName + " (attempt #" + attempt + ")...");
+                attempt ++;
+                // Note: the table name must be lowercase to match the name in the table 'system_schema_mcs.tables'
+                final String tableStatusSqlStatement = "SELECT status FROM system_schema_mcs.tables "
+                        + "WHERE keyspace_name = '" + database.getLiquibaseCatalogName() + "' "
+                        + "AND table_name = '" + tableName.toLowerCase() + "'";
+                String status = executor.queryForObject(new RawSqlStatement(tableStatusSqlStatement), String.class);
+                isTableActive = "ACTIVE".equalsIgnoreCase(status);
+            } while (!isTableActive && attempt <= maxAttempts);
+        } catch (final DatabaseException e) {
+            Scope.getCurrentScope().getLog(LockServiceCassandra.class)
+                .warning("Failed to check the status of table " + tableName + " in AWS Keyspaces", e);
+            return false;
+        }
+        return isTableActive;
+    }
 }