(#70) Implemented Swarm.init()

src/main/java/com/amihaiemil/docker/RtSwarm.java

@@ -27,8 +27,15 @@
 
 import java.io.IOException;
 import java.net.URI;
+import javax.json.Json;
 import javax.json.JsonObject;
+import org.apache.http.HttpResponse;
+import org.apache.http.HttpStatus;
 import org.apache.http.client.HttpClient;
+import org.apache.http.client.methods.HttpPost;
+import org.apache.http.entity.ContentType;
+import org.apache.http.entity.StringEntity;
+import org.apache.http.util.EntityUtils;
 
 /**
  * Swarm API.
@@ -61,4 +68,36 @@ final class RtSwarm implements Swarm {
     public JsonObject inspect() throws IOException {
         return new Inspection(this.client, this.baseUri.toString());
     }
+
+    @Override
+    public String init(final String listenAddress) throws IOException {
+        return this.init(
+            Json.createObjectBuilder()
+                .add("ListenAddr", listenAddress)
+                .add("ForceNewCluster", false)
+                .build()
+        );
+    }
+
+    @Override
+    public String init(final JsonObject spec) throws IOException {
+        final HttpPost init = new HttpPost(this.baseUri.toString() + "/init");
+        try {
+            init.setEntity(
+                new StringEntity(
+                    spec.toString(), ContentType.APPLICATION_JSON
+                )
+            );
+            final HttpResponse response = this.client.execute(init);
+            final int status = response.getStatusLine().getStatusCode();
+            if (status == HttpStatus.SC_OK) {
+                return EntityUtils.toString(response.getEntity());
+            }
+            throw new UnexpectedResponseException(
+                init.getRequestLine().getUri(), status, HttpStatus.SC_OK
+            );
+        } finally {
+            init.releaseConnection();
+        }
+    }
 }

src/main/java/com/amihaiemil/docker/Swarm.java

@@ -37,7 +37,7 @@
  * @author George Aristy (george.aristy@gmail.com)
  * @version $Id$
  * @since 0.0.1
- * @todo #3:30min Implement all of the Swarm operations. See
+ * @todo #70:30min Continue implementing all of the Swarm operations. See
  *  https://docs.docker.com/engine/api/v1.35/#tag/Swarm for reference and also
  *  the roadmap laid out here:
  *  https://github.com/amihaiemil/docker-java-api/issues/3#issuecomment-375821822
@@ -52,4 +52,22 @@ public interface Swarm {
      * @throws IOException If something goes wrong.
      */
     JsonObject inspect() throws IOException;
+
+    /**
+     * Initialize a new swarm.
+     * @param listenAddress Listen address used for inter-manager communication.
+     *     This can either be in the form of '192.168.1.1:4567' or 'eth0:4567'
+     *     where the port number is optional in both cases.
+     * @return The swarm's token.
+     * @throws IOException If something goes wrong.
+     */
+    String init(String listenAddress) throws IOException;
+
+    /**
+     * Initialize a new swarm by providing a full specification.
+     * @param spec Full specification for the swarm.
+     * @return The swarm's token.
+     * @throws IOException If something goes wrong.
+     */
+    String init(JsonObject spec) throws IOException;
 }

src/test/java/com/amihaiemil/docker/RtSwarmTestCase.java

@@ -27,6 +27,7 @@
 
 import com.amihaiemil.docker.mock.AssertRequest;
 import com.amihaiemil.docker.mock.Condition;
+import com.amihaiemil.docker.mock.PayloadOf;
 import com.amihaiemil.docker.mock.Response;
 import java.net.URI;
 import org.apache.http.HttpStatus;
@@ -131,4 +132,76 @@ public void inspectThrowsErrorIfResponseIs503() throws Exception {
             ), URI.create("http://localhost")
         ).inspect();
     }
+
+    /**
+     * The init request should have correct URI, method, and also its JSON
+     * payload should have at least the 'ListenAddr' and 'ForceNewCluster'
+     * properties.
+     * @throws Exception If an error occurs.
+     */
+    @Test
+    public void initRequestWellformed() throws Exception {
+        final String listenAddress = "172.27.9.10";
+        new RtSwarm(
+            new AssertRequest(
+                new Response(HttpStatus.SC_OK, "sometoken123"),
+                new Condition(
+                    "Request method must be POST.",
+                    req -> "POST".equals(req.getRequestLine().getMethod())
+                ),
+                new Condition(
+                    "The 'ListenAddr' attribute is mandatory.",
+                    req -> new PayloadOf(req).containsKey("ListenAddr")
+                ),
+                new Condition(
+                    "The 'ListenAddr' value must be the same as the one given.",
+                    req -> listenAddress.equals(
+                        new PayloadOf(req).getString("ListenAddr")
+                    )
+                ),
+                new Condition(
+                    "The 'ForceNewCluster' attribute is mandatory.",
+                    req -> new PayloadOf(req).containsKey("ForceNewCluster")
+                ),
+                new Condition(
+                    "The 'ForceNewCluster' attribute cannot be empty.",
+                    req -> !new PayloadOf(req).isNull("ForceNewCluster")
+
+                )
+            ),
+            URI.create("http://docker/swarm")
+        ).init(listenAddress);
+    }
+
+    /**
+     * Must return the same token returned by Docker.
+     * @throws Exception If something goes wrong.
+     */
+    @Test
+    public void initReturnsSwarmToken() throws Exception {
+        MatcherAssert.assertThat(
+            new RtSwarm(
+                new AssertRequest(
+                    new Response(HttpStatus.SC_OK, "sometoken123")
+                ),
+                URI.create("http://docker")
+            ).init("123"),
+            Matchers.is("sometoken123")
+        );
+    }
+
+    /**
+     * Must throw {@link UnexpectedResponseException} if docker responds with
+     * a code different from 200.
+     * @throws Exception If an error occurs.
+     */
+    @Test(expected = UnexpectedResponseException.class)
+    public void initUnexpectedErrorIfResponseIsNot200() throws Exception {
+        new RtSwarm(
+            new AssertRequest(
+                new Response(HttpStatus.SC_BAD_REQUEST, "")
+            ),
+            URI.create("http://docker")
+        ).init("123");
+    }
 }