Add examples for port mapping

Closes #19

Author: nickkkccc

README.md

@@ -232,6 +232,13 @@ cartridge build at the image build stage.
 
 An example of how to set the `TARANTOOL_CLUSTER_COOKIE` parameter: https://github.com/tarantool/testcontainers-java-tarantool/blob/355d1e985bd10beca83bc7ca77f919a288709419/src/test/java/org/testcontainers/containers/TarantoolCartridgeBootstrapFromLuaWithFixedPortsTest.java#L57-L82
 
+##### Mapping ports
+
+Often there is a need to connect to a container through a specific port. To achieve this goal it is necessary
+to know the mapped port specified in the Java code. To get the mapped port, use the getMappedPort(...)` method of
+testcontainers API. See examples: https://github.com/tarantool/testcontainers-java-tarantool/blob/ae580cb59d4621d7c11e5f80c394ec141d4c92b3/src/test/java/org/testcontainers/containers/TarantoolCartridgePortMappingTest.java#L22-L98
+
+
 ## License
 
 See [LICENSE](LICENSE).

pom.xml

@@ -92,17 +92,25 @@
         </dependency>
 
         <!-- Test dependencies -->
+        <dependency>
+            <groupId>org.apache.httpcomponents</groupId>
+            <artifactId>httpclient</artifactId>
+            <version>4.5.1</version>
+            <scope>test</scope>
+        </dependency>
+
         <dependency>
             <groupId>ch.qos.logback</groupId>
             <artifactId>logback-classic</artifactId>
             <version>1.3.4</version>
             <scope>test</scope>
         </dependency>
+
         <dependency>
-          <groupId>org.junit.jupiter</groupId>
-          <artifactId>junit-jupiter</artifactId>
-          <version>5.8.1</version>
-          <scope>test</scope>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter</artifactId>
+            <version>5.8.1</version>
+            <scope>test</scope>
         </dependency>
         <dependency>
             <groupId>org.testcontainers</groupId>

src/test/java/org/testcontainers/containers/TarantoolCartridgePortMappingTest.java

@@ -0,0 +1,105 @@
+package org.testcontainers.containers;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.net.Socket;
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.time.Duration;
+import java.util.concurrent.ThreadLocalRandom;
+
+import org.apache.http.HttpResponse;
+import org.apache.http.client.methods.HttpGet;
+import org.apache.http.impl.client.CloseableHttpClient;
+import org.apache.http.impl.client.HttpClientBuilder;
+import org.junit.jupiter.api.Test;
+import org.slf4j.LoggerFactory;
+import org.testcontainers.containers.output.Slf4jLogConsumer;
+import org.testcontainers.junit.jupiter.Container;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+public class TarantoolCartridgePortMappingTest {
+
+    @Container
+    private final static TarantoolCartridgeContainer container = new TarantoolCartridgeContainer(
+            "Dockerfile",
+            "mapping-ports-container",
+            "cartridge/instances.yml",
+            "cartridge/replicasets.yml")
+            .withEnv(TarantoolCartridgeContainer.ENV_TARANTOOL_CLUSTER_COOKIE, "secret")
+            .withRouterUsername("admin")
+            .withRouterPassword("secret")
+            .withStartupTimeout(Duration.ofMinutes(5))
+            .withLogConsumer(new Slf4jLogConsumer(
+                    LoggerFactory.getLogger(TarantoolCartridgeBootstrapFromYamlTest.class)));
+
+    @Test
+    void portMappingTest() throws IOException, URISyntaxException {
+
+        final int httpPortToFirstRouter = 8081;
+        final int httpPortToSecondRouter = 8082;
+        final int portToFirstRouter = 3301;
+        final int portToSecondRouter = 3302;
+        final String host = "localhost";
+        final String schema = "http";
+
+        container.addExposedPorts(httpPortToFirstRouter, httpPortToSecondRouter, portToFirstRouter, portToSecondRouter);
+        container.start();
+
+        URI firstRouterConnectionURI = new URI(schema, null, host,
+                container.getMappedPort(httpPortToFirstRouter), null, null, null);
+
+        // send get request to first router via http
+        HttpResponse response = sendCurlToRouterHttpAPI(firstRouterConnectionURI);
+        assertEquals(200, response.getStatusLine().getStatusCode());
+
+        URI secondRouterConnectionURI = new URI(schema, null, host,
+                container.getMappedPort(httpPortToSecondRouter), null, null, null);
+        // send get request to second router via http
+        response = sendCurlToRouterHttpAPI(secondRouterConnectionURI);
+        assertEquals(200, response.getStatusLine().getStatusCode());
+
+        // connect to first router via socket
+        URI firstRouterConnectionURIViaSocket = new URI(null, null, host,
+                container.getMappedPort(portToFirstRouter), null, null, null);
+        String result = connectToRouterViaSocket(firstRouterConnectionURIViaSocket);
+        assertFalse(result.isEmpty());
+        assertTrue(result.contains("Tarantool"));
+
+        // connect to second router via socket
+        URI secondRouterConnectionURIViaSocket = new URI(null, null, host,
+                container.getMappedPort(portToSecondRouter), null, null, null);
+        result = connectToRouterViaSocket(secondRouterConnectionURIViaSocket);
+        assertFalse(result.isEmpty());
+        assertTrue(result.contains("Tarantool"));
+
+        // Connect to random port
+        URI randomPortConnectionURIViaSocket = new URI(null, null, host,
+                ThreadLocalRandom.current().nextInt(49152, 65535), null, null, null);
+        result = connectToRouterViaSocket(randomPortConnectionURIViaSocket);
+        assertTrue(result.isEmpty());
+    }
+
+    private HttpResponse sendCurlToRouterHttpAPI(URI uri) throws IOException {
+        try (CloseableHttpClient httpClient = HttpClientBuilder.create().build()) {
+            HttpGet httpGetRequest = new HttpGet(uri);
+            return httpClient.execute(httpGetRequest);
+        }
+    }
+
+    private String connectToRouterViaSocket(URI uri) {
+        final String returnedString;
+
+        try (Socket socket = new Socket(uri.getHost(), uri.getPort());
+             BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()))) {
+
+            returnedString = in.readLine();
+        } catch (IOException e) {
+            return "";
+        }
+        return returnedString;
+    }
+}