Allow to start daemon database container (#360)

* Allow to start daemon database container
* Add documentation for TC_DAEMON parameter
* Add tests for TC_DAEMON parameter
* Update changelog

Author: inikolaev

CHANGELOG.md

@@ -1,6 +1,10 @@
 # Change Log
 All notable changes to this project will be documented in this file.
 
+## UNRELEASED
+### Changed
+- Added `TC_DAEMON` JDBC URL flag to prevent `ContainerDatabaseDriver` from shutting down containers at the time all connections are closed. (#359, #360)
+
 ## [1.3.0] - 2017-06-05
 ### Fixed
 - Improved container cleanup if startup failed (#336, #335)

docs/usage/database_containers.md

@@ -97,6 +97,14 @@ public class JDBCDriverTest {
     ...
 ```
 
+#### Running container in daemon mode
+
+By default database container is being stopped as soon as last connection is closed. There are cases when you might need to start container and keep it running till you stop it explicitly or JVM is shutdown. To do this, add `TC_DAEMON` parameter to the URL as follows:
+
+ `jdbc:tc:mysql://hostname/databasename?TC_DAEMON=true`
+
+With this parameter database container will keep running even when there're no open connections.
+
 #### Overriding MySQL my.cnf settings
 
 For MySQL databases, it is possible to override configuration settings using resources on the classpath. Assuming `somepath/mysql_conf_override`

modules/jdbc-test/src/test/java/org/testcontainers/jdbc/DatabaseDriverShutdownTest.java

@@ -0,0 +1,50 @@
+package org.testcontainers.jdbc;
+
+import org.junit.AfterClass;
+import org.junit.Test;
+import org.testcontainers.containers.JdbcDatabaseContainer;
+
+import java.sql.Connection;
+import java.sql.DriverManager;
+import java.sql.SQLException;
+
+import static org.rnorth.visibleassertions.VisibleAssertions.assertNotNull;
+import static org.rnorth.visibleassertions.VisibleAssertions.assertNull;
+import static org.rnorth.visibleassertions.VisibleAssertions.assertTrue;
+
+/**
+ * Created by inikolaev on 08/06/2017.
+ */
+public class DatabaseDriverShutdownTest {
+    @AfterClass
+    public static void testCleanup() {
+        ContainerDatabaseDriver.killContainers();
+    }
+
+    @Test
+    public void shouldStopContainerWhenAllConnectionsClosed() throws SQLException {
+        final String jdbcUrl = "jdbc:tc:postgresql://hostname/databasename";
+
+        getConnectionAndClose(jdbcUrl);
+
+        JdbcDatabaseContainer<?> container = ContainerDatabaseDriver.getContainer(jdbcUrl);
+        assertNull("Database container instance is null as expected", container);
+    }
+
+    @Test
+    public void shouldNotStopDaemonContainerWhenAllConnectionsClosed() throws SQLException {
+        final String jdbcUrl = "jdbc:tc:postgresql://hostname/databasename?TC_DAEMON=true";
+
+        getConnectionAndClose(jdbcUrl);
+
+        JdbcDatabaseContainer<?> container = ContainerDatabaseDriver.getContainer(jdbcUrl);
+        assertNotNull("Database container instance is not null as expected", container);
+        assertTrue("Database container is running as expected", container.isRunning());
+    }
+
+    private void getConnectionAndClose(String jdbcUrl) throws SQLException {
+        try (Connection connection = DriverManager.getConnection(jdbcUrl)) {
+            assertNotNull("Obtained connection as expected", connection);
+        }
+    }
+}

modules/jdbc/src/main/java/org/testcontainers/jdbc/ContainerDatabaseDriver.java

@@ -1,5 +1,6 @@
 package org.testcontainers.jdbc;
 
+import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.Charsets;
 import com.google.common.io.Resources;
 import org.slf4j.LoggerFactory;
@@ -37,6 +38,7 @@
 public class ContainerDatabaseDriver implements Driver {
 
     private static final Pattern URL_MATCHING_PATTERN = Pattern.compile("jdbc:tc:([a-z]+)(:([^:]+))?://[^\\?]+(\\?.*)?");
+    private static final Pattern DAEMON_MATCHING_PATTERN = Pattern.compile(".*([\\?&]?)TC_DAEMON=([^\\?&]+).*");
     private static final Pattern INITSCRIPT_MATCHING_PATTERN = Pattern.compile(".*([\\?&]?)TC_INITSCRIPT=([^\\?&]+).*");
     private static final Pattern INITFUNCTION_MATCHING_PATTERN = Pattern.compile(".*([\\?&]?)TC_INITFUNCTION=" +
             "((\\p{javaJavaIdentifierStart}\\p{javaJavaIdentifierPart}*\\.)*\\p{javaJavaIdentifierStart}\\p{javaJavaIdentifierPart}*)" +
@@ -186,6 +188,9 @@ private Map<String, String> getContainerParameters(String url) {
      * @return the connection, wrapped
      */
     private Connection wrapConnection(final Connection connection, final JdbcDatabaseContainer container, final String url) {
+        final Matcher matcher = DAEMON_MATCHING_PATTERN.matcher(url);
+        final boolean isDaemon = matcher.matches() ? Boolean.parseBoolean(matcher.group(2)) : false;
+
         Set<Connection> connections = containerConnections.get(container.getContainerId());
 
         if (connections == null) {
@@ -199,7 +204,7 @@ private Connection wrapConnection(final Connection connection, final JdbcDatabas
 
         return new ConnectionWrapper(connection, () -> {
             finalConnections.remove(connection);
-            if (finalConnections.isEmpty()) {
+            if (!isDaemon && finalConnections.isEmpty()) {
                 container.stop();
                 jdbcUrlContainerCache.remove(url);
             }
@@ -313,4 +318,16 @@ public static void killContainer(String jdbcUrl) {
             }
         }
     }
+
+    /**
+     * Utility method to get an instance of a database container given its JDBC URL.
+     * @param jdbcUrl the JDBC URL of the container instance to get
+     * @return an instance of database container or <code>null</code> if no container associated with JDBC URL
+     */
+    @VisibleForTesting
+    static JdbcDatabaseContainer getContainer(String jdbcUrl) {
+        synchronized (jdbcUrlContainerCache) {
+            return jdbcUrlContainerCache.get(jdbcUrl);
+        }
+    }
 }