Fixed #194 - Implementing system/df API call

Author: Boris Kuzmic

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

@@ -0,0 +1,34 @@
+package com.amihaiemil.docker;
+
+/**
+ * Info about Docker disk space usage in bytes.
+ * @author Boris Kuzmic (boris.kuzmic@gmail.com)
+ * @since 0.0.6
+ */
+public interface DiskSpaceInfo {
+
+    /**
+     * Images disk usage.
+     * @return Disk usage for images in bytes
+     */
+    Long images();
+
+    /**
+     * Containers disk usage.
+     * @return Disk usage for containers in bytes
+     */
+    Long containers();
+
+    /**
+     * Volumes disk usage.
+     * @return Disk usage for volumes in bytes
+     */
+    Long volumes();
+
+    /**
+     * Total disk usage.
+     * @return Total disk usage in bytes
+     */
+    Long totalSpace();
+
+}

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

@@ -82,6 +82,12 @@ public interface Docker {
      */
     Swarm swarm();
 
+    /**
+     * Entry point for the DockerSystem API.
+     * @return DockerSystem.
+     */
+    DockerSystem system();
+
     /**
      * The underlying, immutable, Apache HttpClient.<br><br>
      *

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

@@ -0,0 +1,23 @@
+package com.amihaiemil.docker;
+
+import java.io.IOException;
+
+/**
+ * Docker System API entry point.
+ * @author Boris Kuzmic (boris.kuzmic@gmail.com)
+ * @see <a href="https://docs.docker.com/engine/reference/commandline/system/">Docker DockerSystem API</a>
+ * @since 0.0.6
+ */
+public interface DockerSystem {
+
+    /**
+     * Show docker disk usage.
+     * @return The created {@link DiskSpaceInfo}.
+     * @throws IOException If an I/O error occurs.
+     * @throws UnexpectedResponseException If the API responds with an
+     *  unexpected status.
+     */
+    DiskSpaceInfo diskUsage()
+            throws IOException, UnexpectedResponseException;
+
+}

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

@@ -120,6 +120,15 @@ public final Swarm swarm() {
         );
     }
 
+    @Override
+    public DockerSystem system() {
+        return new RtDockerSystem(
+            this.client,
+            URI.create(this.baseUri.toString().concat("/system")),
+            this
+        );
+    }
+
     @Override
     public HttpClient httpClient() {
         return this.client;

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

@@ -0,0 +1,66 @@
+package com.amihaiemil.docker;
+
+import org.apache.http.HttpStatus;
+import org.apache.http.client.HttpClient;
+import org.apache.http.client.methods.HttpGet;
+
+import java.io.IOException;
+import java.net.URI;
+
+/**
+ * System API.
+ *
+ * @author Boris Kuzmic (boris.kuzmic@gmail.com)
+ * @since 0.0.6
+ */
+public final class RtDockerSystem implements DockerSystem {
+
+    /**
+     * Apache HttpClient which sends the requests.
+     */
+    private final HttpClient client;
+
+    /**
+     * Base URI.
+     */
+    private final URI baseUri;
+
+    /**
+     * Docker engine.
+     */
+    private Docker docker;
+
+    /**
+     * Ctor.
+     *
+     * @param client Given HTTP Client.
+     * @param baseUri Base URI, ending with /system.
+     * @param dkr The Docker engine.
+     */
+    RtDockerSystem(final HttpClient client, final URI baseUri,
+                   final Docker dkr) {
+        this.client = client;
+        this.baseUri = baseUri;
+        this.docker = dkr;
+    }
+
+    @Override
+    public DiskSpaceInfo diskUsage() throws IOException,
+            UnexpectedResponseException {
+        final HttpGet init = new HttpGet(this.baseUri.toString() + "/df");
+        try {
+            return new SystemDiskSpaceInfo(this.client.execute(
+                    init,
+                    new ReadJsonObject(
+                            new MatchStatus(
+                                    init.getURI(),
+                                    HttpStatus.SC_OK
+                            )
+                    )
+            ));
+        } finally {
+            init.releaseConnection();
+        }
+    }
+
+}

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

@@ -0,0 +1,60 @@
+package com.amihaiemil.docker;
+
+import javax.json.JsonArray;
+import javax.json.JsonObject;
+
+/**
+ * Docker disk space usage information.
+ * @author Boris Kuzmic (boris.kuzmic@gmail.com)
+ * @since 0.0.6
+ */
+public final class SystemDiskSpaceInfo implements DiskSpaceInfo {
+
+    /**
+     * Response Json object from system/df call.
+     */
+    private final JsonObject json;
+
+    /**
+     * Ctor.
+     * @param jsonObject Response Json from system/df call
+     */
+    SystemDiskSpaceInfo(final JsonObject jsonObject) {
+        this.json = jsonObject;
+    }
+
+    @Override
+    public Long images() {
+        return this.json.getJsonNumber("LayersSize").longValue();
+    }
+
+    @Override
+    public Long containers() {
+        Long totalContainersSpace = 0L;
+        JsonArray containers = this.json.getJsonArray("Containers");
+        for (int i=0; i<containers.size(); i++) {
+            JsonObject container = containers.getJsonObject(i);
+            totalContainersSpace +=
+                    container.getJsonNumber("SizeRootFs").longValue();
+        }
+        return totalContainersSpace;
+    }
+
+    @Override
+    public Long volumes() {
+        Long totalVolumesSpace = 0L;
+        JsonArray volumes = this.json.getJsonArray("Volumes");
+        for (int i=0; i<volumes.size(); i++) {
+            JsonObject volume = volumes.getJsonObject(i);
+            totalVolumesSpace +=
+                    volume.getJsonObject("UsageData")
+                            .getJsonNumber("Size").longValue();
+        }
+        return totalVolumesSpace;
+    }
+
+    @Override
+    public Long totalSpace() {
+        return this.images() + this.containers() + this.volumes();
+    }
+}

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

@@ -0,0 +1,33 @@
+package com.amihaiemil.docker;
+
+import org.hamcrest.MatcherAssert;
+import org.hamcrest.Matchers;
+import org.junit.Test;
+
+import java.io.File;
+
+/**
+ * Integration tests for RtDockerSystem.
+ *
+ * @author Boris Kuzmic (boris.kuzmic@gmail.com)
+ * @since 0.0.6
+ */
+public final class RtDockerSystemITCase {
+
+    /**
+     * Show Docker disk space info.
+     * @throws Exception If something goes wrong.
+     */
+    @Test
+    public void showDiskSpaceInfo() throws Exception {
+        final Docker docker = new LocalDocker(
+                new File("/var/run/docker.sock")
+        );
+
+        DiskSpaceInfo info = docker.system().diskUsage();
+
+        MatcherAssert.assertThat(info.totalSpace(),
+                Matchers.greaterThanOrEqualTo(0L));
+    }
+
+}

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

@@ -0,0 +1,61 @@
+package com.amihaiemil.docker;
+
+import com.amihaiemil.docker.mock.AssertRequest;
+import com.amihaiemil.docker.mock.Response;
+import org.apache.http.HttpStatus;
+import org.hamcrest.MatcherAssert;
+import org.hamcrest.Matchers;
+import org.junit.Test;
+import org.mockito.Mockito;
+
+import javax.json.Json;
+import java.net.URI;
+
+/**
+ * Unit tests for RtDockerSystem.
+ *
+ * @author Boris Kuzmic (boris.kuzmic@gmail.com)
+ * @since 0.0.6
+ * @checkstyle MethodName (500 lines)
+ */
+public final class RtDockerSystemTestCase {
+
+    /**
+     * Must return the same disk space usage for images, containers and
+     * volumes as in json array returned by the service.
+     *
+     * @throws Exception If an error occurs.
+     */
+    @Test
+    public void returnsDiskSpaceUsage() throws Exception {
+        long totalSpace = new RtDockerSystem(
+                new AssertRequest(
+                    new Response(
+                        HttpStatus.SC_OK,
+                        Json.createObjectBuilder()
+                            .add("LayersSize", 250)
+                            .add("Containers",
+                                Json.createArrayBuilder()
+                                    .add(Json.createObjectBuilder()
+                                        .add("SizeRootFs", 50))
+                            ).add("Volumes",
+                            Json.createArrayBuilder()
+                                    .add(
+                                        Json.createObjectBuilder()
+                                            .add("UsageData",
+                                                Json.createObjectBuilder()
+                                                    .add("Size", 200)))
+                        ).build().toString()
+                    )
+                ),
+                URI.create("http://localhost/system"),
+                Mockito.mock(Docker.class)
+                ).diskUsage().totalSpace();
+        MatcherAssert.assertThat(
+                totalSpace,
+                Matchers.is(500L)
+        );
+    }
+
+
+}

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

@@ -28,15 +28,16 @@
 import com.amihaiemil.docker.mock.AssertRequest;
 import com.amihaiemil.docker.mock.Condition;
 import com.amihaiemil.docker.mock.Response;
-import java.net.URI;
-import java.util.concurrent.atomic.AtomicInteger;
-import javax.json.Json;
 import org.apache.http.HttpStatus;
 import org.hamcrest.MatcherAssert;
 import org.hamcrest.Matchers;
 import org.junit.Test;
 import org.mockito.Mockito;
 
+import javax.json.Json;
+import java.net.URI;
+import java.util.concurrent.atomic.AtomicInteger;
+
 /**
  * Unit tests for {@link RtImages}.
  * @author George Aristy (george.aristy@gmail.com)