Add setDefaultCloudStorageConfiguration

google-cloud-contrib/google-cloud-nio/src/main/java/com/google/cloud/storage/contrib/nio/CloudStorageConfiguration.java

@@ -72,6 +72,7 @@ public abstract class CloudStorageConfiguration {
    * <li>Performing I/O on paths with extra slashes, e.g. {@code a//b} will throw an error.
    * <li>The prefix slash on absolute paths will be removed when converting to an object name.
    * <li>Pseudo-directories are enabled, so any path with a trailing slash is a fake directory.
+   * <li>Channel re-opens are disabled.
    * </ul>
    */
   public static Builder builder() {
@@ -159,11 +160,27 @@ public CloudStorageConfiguration build() {
           maxChannelReopens);
     }
 
+    Builder(CloudStorageConfiguration toModify) {
+      workingDirectory = toModify.workingDirectory();
+      permitEmptyPathComponents = toModify.permitEmptyPathComponents();
+      stripPrefixSlash = toModify.stripPrefixSlash();
+      usePseudoDirectories = toModify.usePseudoDirectories();
+      blockSize = toModify.blockSize();
+      maxChannelReopens = toModify.maxChannelReopens();
+    }
+
     Builder() {}
   }
 
   static CloudStorageConfiguration fromMap(Map<String, ?> env) {
-    Builder builder = builder();
+    return fromMap(builder(), env);
+  }
+
+  static CloudStorageConfiguration fromMap(CloudStorageConfiguration defaultValues, Map<String, ?> env) {
+    return fromMap(new Builder(defaultValues), env);
+  }
+
+  static private CloudStorageConfiguration fromMap(Builder builder, Map<String, ?> env) {
     for (Map.Entry<String, ?> entry : env.entrySet()) {
       switch (entry.getKey()) {
         case "workingDirectory":

google-cloud-contrib/google-cloud-nio/src/main/java/com/google/cloud/storage/contrib/nio/CloudStorageFileSystem.java

@@ -62,6 +62,27 @@ public final class CloudStorageFileSystem extends FileSystem {
   private final String bucket;
   private final CloudStorageConfiguration config;
 
+  // Users can change this: then this affects every filesystem object created
+  // later, including via SPI. This is meant to be done only once, at the beginning
+  // of some main program, in order to force all libraries to use some settings we like.
+  // Libraries should never call this. It'll cause surprise to the writers of the main
+  // program and they'll be unhappy. Instead, create your own filesystem object with the
+  // right configuration and pass it along.
+  private static CloudStorageConfiguration userSpecifiedDefault = CloudStorageConfiguration.DEFAULT;
+
+  // Don't call this one, call the one in CloudStorageFileSystemProvider.
+  static void setDefaultCloudStorageConfiguration(CloudStorageConfiguration config) {
+    if (null == config) {
+      userSpecifiedDefault = CloudStorageConfiguration.DEFAULT;
+    } else {
+      userSpecifiedDefault = config;
+    }
+  }
+
+  static CloudStorageConfiguration getDefaultCloudStorageConfiguration() {
+    return userSpecifiedDefault;
+  }
+
   /**
    * Returns Google Cloud Storage {@link FileSystem} object for {@code bucket}.
    *
@@ -79,7 +100,7 @@ public final class CloudStorageFileSystem extends FileSystem {
    */
   @CheckReturnValue
   public static CloudStorageFileSystem forBucket(String bucket) {
-    return forBucket(bucket, CloudStorageConfiguration.DEFAULT);
+    return forBucket(bucket, userSpecifiedDefault);
   }
 
   /**

google-cloud-contrib/google-cloud-nio/src/main/java/com/google/cloud/storage/contrib/nio/CloudStorageFileSystemProvider.java

@@ -129,6 +129,30 @@ public static void setStorageOptions(StorageOptions newStorageOptions) {
     futureStorageOptions = newStorageOptions;
   }
 
+  /**
+   * Changes the default configuration for every filesystem object created
+   * from here on, including via SPI. If null then future filesystem objects
+   * will have the factory default configuration.
+   *
+   * <p>If options are specified later then they override the defaults.
+   * Methods that take a whole CloudStorageConfiguration (eg.
+   * CloudStorageFileSystem.forBucket) will completely override the defaults.
+   * Methods that take individual options (eg.
+   * CloudStorageFileSystemProvier.newFileSystem) will override only these options;
+   * the rest will be taken from the defaults specified here.
+   *
+   * <p>This is meant to be done only once, at the beginning of some main program,
+   * in order to force all libraries to use some settings we like.
+   *
+   * <p>Libraries should never call this. If you're a library then, instead, create your own
+   * filesystem object with the right configuration and pass it along.
+   *
+   * @param newDefault new default CloudStorageConfiguration
+   */
+  public static void setDefaultCloudStorageConfiguration(CloudStorageConfiguration newDefault) {
+    CloudStorageFileSystem.setDefaultCloudStorageConfiguration(newDefault);
+  }
+
   /**
    * Default constructor which should only be called by Java SPI.
    *
@@ -200,7 +224,11 @@ && isNullOrEmpty(uri.getUserInfo()),
         uri);
     CloudStorageUtil.checkBucket(uri.getHost());
     initStorage();
-    return new CloudStorageFileSystem(this, uri.getHost(), CloudStorageConfiguration.fromMap(env));
+    return new CloudStorageFileSystem(
+        this,
+        uri.getHost(),
+        CloudStorageConfiguration.fromMap(
+            CloudStorageFileSystem.getDefaultCloudStorageConfiguration(), env));
   }
 
   @Override

google-cloud-contrib/google-cloud-nio/src/main/java/com/google/cloud/storage/contrib/nio/CloudStorageOptions.java

@@ -92,7 +92,7 @@ public static CloudStorageOption.OpenCopy withBlockSize(int size) {
   }
 
   /**
-   * Sets the max number of times that the channel can be reopen if reading
+   * Sets the max number of times that the channel can be reopened if reading
    * fails because the channel unexpectedly closes.
    *
    * <p>The default is 0.

google-cloud-contrib/google-cloud-nio/src/main/java/com/google/cloud/storage/contrib/nio/CloudStorageReadChannel.java

@@ -21,6 +21,7 @@
 import com.google.cloud.storage.BlobInfo;
 import com.google.cloud.storage.Storage;
 import com.google.cloud.storage.StorageException;
+import com.google.common.annotations.VisibleForTesting;
 
 import javax.annotation.CheckReturnValue;
 import javax.annotation.concurrent.ThreadSafe;
@@ -49,7 +50,8 @@ final class CloudStorageReadChannel implements SeekableByteChannel {
   private final Storage gcsStorage;
   private final BlobId file;
   // max # of times we may reopen the file
-  private final int maxChannelReopens;
+  @VisibleForTesting
+  final int maxChannelReopens;
   // how many times we re-opened the file
   private int reopens;
   private ReadChannel channel;

google-cloud-contrib/google-cloud-nio/src/test/java/com/google/cloud/storage/contrib/nio/CloudStorageFileSystemTest.java

@@ -33,6 +33,7 @@
 
 import java.io.IOException;
 import java.net.URI;
+import java.nio.channels.SeekableByteChannel;
 import java.nio.file.FileSystem;
 import java.nio.file.FileSystems;
 import java.nio.file.Files;
@@ -69,6 +70,57 @@ public void before() {
     CloudStorageFileSystemProvider.setStorageOptions(LocalStorageHelper.getOptions());
   }
 
+  @Test
+  public void checkDefaultOptions() throws IOException {
+    // 1. We get the normal default if we don't do anything special.
+    Path path = Paths.get(URI.create("gs://bucket/file"));
+    CloudStorageFileSystem gcs = (CloudStorageFileSystem)path.getFileSystem();
+    assertThat(gcs.config().maxChannelReopens()).isEqualTo(0);
+
+    // 2(a). Override the default, and see it reflected.
+    CloudStorageFileSystemProvider.setDefaultCloudStorageConfiguration(
+        CloudStorageConfiguration.builder()
+        .maxChannelReopens(123).build());
+    Path path2 = Paths.get(URI.create("gs://newbucket/file"));
+    CloudStorageFileSystem gcs2 = (CloudStorageFileSystem)path2.getFileSystem();
+    assertThat(gcs2.config().maxChannelReopens()).isEqualTo(123);
+
+    // 2(b) ...even reflected if we try to open a file.
+    try (FileSystem fs = CloudStorageFileSystem.forBucket("bucket")) {
+      CloudStorageFileSystem csfs = (CloudStorageFileSystem)fs;
+      assertThat(csfs.config().maxChannelReopens()).isEqualTo(123);
+      Files.write(fs.getPath("/angel"), ALONE.getBytes(UTF_8));
+      path2 = Paths.get(URI.create("gs://bucket/angel"));
+      try (SeekableByteChannel seekableByteChannel = Files.newByteChannel(path2)) {
+        CloudStorageReadChannel cloudChannel = (CloudStorageReadChannel) seekableByteChannel;
+        assertThat(cloudChannel.maxChannelReopens).isEqualTo(123);
+      }
+    }
+
+    // 4. Clean up.
+    CloudStorageFileSystemProvider.setDefaultCloudStorageConfiguration(null);
+    Path path3 = Paths.get(URI.create("gs://newbucket/file"));
+    CloudStorageFileSystem gcs3 = (CloudStorageFileSystem)path3.getFileSystem();
+    assertThat(gcs3.config().maxChannelReopens()).isEqualTo(0);
+  }
+
+  @Test
+  public void canOverrideDefaultOptions() throws IOException {
+    // Set a new default.
+    CloudStorageFileSystemProvider.setDefaultCloudStorageConfiguration(
+        CloudStorageConfiguration.builder()
+            .maxChannelReopens(123).build());
+
+    // This code wants its own value.
+    try (FileSystem fs = CloudStorageFileSystem.forBucket("bucket", CloudStorageConfiguration.builder().maxChannelReopens(7).build())) {
+      CloudStorageFileSystem csfs = (CloudStorageFileSystem)fs;
+      assertThat(csfs.config().maxChannelReopens()).isEqualTo(7);
+    }
+
+    // Clean up.
+    CloudStorageFileSystemProvider.setDefaultCloudStorageConfiguration(null);
+  }
+
   @Test
   public void testGetPath() throws IOException {
     try (FileSystem fs = CloudStorageFileSystem.forBucket("bucket")) {