Adds SkaffoldDownloader. (#5)

Author: coollog

skaffold-plugins-core/src/integration-test/java/com/google/cloud/tools/skaffold/downloader/SkaffoldDownloaderIntegrationTest.java

@@ -0,0 +1,38 @@
+/*
+ * Copyright 2018 Google LLC. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package com.google.cloud.tools.skaffold.downloader;
+
+import java.io.IOException;
+import java.nio.file.Path;
+import org.junit.Assert;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.TemporaryFolder;
+
+/** Integration tests for {@link SkaffoldDownloader}. */
+public class SkaffoldDownloaderIntegrationTest {
+
+  @Rule public TemporaryFolder temporaryFolder = new TemporaryFolder();
+
+  @Test
+  public void testDownloadLatest() throws IOException, InterruptedException {
+    Path temporarySkaffoldExecutable = temporaryFolder.newFile().toPath();
+    SkaffoldDownloader.downloadLatest(temporarySkaffoldExecutable);
+    Process skaffoldProcess = new ProcessBuilder(temporarySkaffoldExecutable.toString()).start();
+    Assert.assertEquals(0, skaffoldProcess.waitFor());
+  }
+}

skaffold-plugins-core/src/main/java/com/google/cloud/tools/skaffold/downloader/SkaffoldDownloader.java

@@ -0,0 +1,107 @@
+/*
+ * Copyright 2018 Google LLC. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package com.google.cloud.tools.skaffold.downloader;
+
+import static java.nio.file.attribute.PosixFilePermission.GROUP_EXECUTE;
+import static java.nio.file.attribute.PosixFilePermission.OTHERS_EXECUTE;
+import static java.nio.file.attribute.PosixFilePermission.OWNER_EXECUTE;
+
+import com.google.cloud.tools.skaffold.filesystem.OperatingSystem;
+import com.google.common.annotations.VisibleForTesting;
+import java.io.IOException;
+import java.net.MalformedURLException;
+import java.net.URL;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.attribute.PosixFilePermission;
+import java.util.EnumSet;
+import java.util.Set;
+
+/**
+ * Downloads {@code skaffold} executable.
+ *
+ * @see <a
+ *     href="https://github.com/GoogleContainerTools/skaffold/blob/master/docs/published-artifacts.adoc">https://github.com/GoogleContainerTools/skaffold/blob/master/docs/published-artifacts.adoc</a>
+ */
+public class SkaffoldDownloader {
+
+  /**
+   * Downloads the latest {@code skaffold} release.
+   *
+   * @throws IOException if an I/O exception occurs during download
+   * @throws MalformedURLException if the URL to download from is malformed
+   */
+  public static void downloadLatest(Path destination) throws IOException {
+    // Skaffold publishes the latest release with version "latest".
+    download(new URL(getUrl("latest", OperatingSystem.resolve())), destination);
+  }
+
+  /**
+   * Downloads to the {@code destination}.
+   *
+   * @param destination the destination file to download {@code skaffold} to
+   * @throws IOException if an I/O exception occurs during download
+   */
+  @VisibleForTesting
+  static void download(URL url, Path destination) throws IOException {
+    if (Downloader.download(url, destination) == -1) {
+      throw new IOException("Could not get size of skaffold binary to download");
+    }
+
+    // Makes skaffold executable.
+    try {
+      Set<PosixFilePermission> executableFilePermissions =
+          Files.getPosixFilePermissions(destination);
+      executableFilePermissions.addAll(EnumSet.of(OWNER_EXECUTE, GROUP_EXECUTE, OTHERS_EXECUTE));
+      Files.setPosixFilePermissions(destination, executableFilePermissions);
+
+    } catch (UnsupportedOperationException ex) {
+      // File system does not support POSIX.
+    }
+  }
+
+  /**
+   * Resolves the correct URL to download {@code skaffold} from based on the version to download and
+   * the operating system.
+   *
+   * @param version the version to download (use {@code latest} for the latest version)
+   * @param operatingSystem the {@link OperatingSystem}
+   * @return the URL to download from
+   * @see <a
+   *     href="https://github.com/GoogleContainerTools/skaffold/releases">https://github.com/GoogleContainerTools/skaffold/releases</a>
+   */
+  @VisibleForTesting
+  static String getUrl(String version, OperatingSystem operatingSystem) {
+    String base = "https://storage.googleapis.com/skaffold/releases/" + version + "/";
+
+    switch (operatingSystem) {
+      case LINUX:
+        return base + "skaffold-linux-amd64";
+
+      case MAC_OS:
+        return base + "skaffold-darwin-amd64";
+
+      case WINDOWS:
+        return base + "skaffold-windows-amd64.exe";
+
+      default:
+        throw new IllegalStateException("unreachable");
+    }
+  }
+
+  private SkaffoldDownloader() {}
+}

skaffold-plugins-core/src/test/java/com/google/cloud/tools/skaffold/downloader/SkaffoldDownloaderTest.java

@@ -0,0 +1,38 @@
+/*
+ * Copyright 2018 Google LLC. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package com.google.cloud.tools.skaffold.downloader;
+
+import com.google.cloud.tools.skaffold.filesystem.OperatingSystem;
+import org.junit.Assert;
+import org.junit.Test;
+
+/** Test for {@link SkaffoldDownloader}. */
+public class SkaffoldDownloaderTest {
+
+  @Test
+  public void testGetUrl() {
+    Assert.assertEquals(
+        "https://storage.googleapis.com/skaffold/releases/version/skaffold-linux-amd64",
+        SkaffoldDownloader.getUrl("version", OperatingSystem.LINUX));
+    Assert.assertEquals(
+        "https://storage.googleapis.com/skaffold/releases/someversion/skaffold-darwin-amd64",
+        SkaffoldDownloader.getUrl("someversion", OperatingSystem.MAC_OS));
+    Assert.assertEquals(
+        "https://storage.googleapis.com/skaffold/releases/latest/skaffold-windows-amd64.exe",
+        SkaffoldDownloader.getUrl("latest", OperatingSystem.WINDOWS));
+  }
+}