Requester-Pays bucket support. (#3406)

* Requester-Pays bucket support.

Code and integration test.

To use this feature, set the "userProject" setting in the
CloudStorageConfiguration.

Optionally, set autoDetectRequesterPays to avoid automatically
unset userProject if the bucket isn't requester-pays.

* linter fixes

* minor linter fixes

* reviewer comments

* apply all codacy recommendations

* Put defaults back, remove unused import.

Author: jean-philippe-martin

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

@@ -17,9 +17,11 @@
 package com.google.cloud.storage.contrib.nio;
 
 import static com.google.common.base.Preconditions.checkArgument;
+import static com.google.common.base.Preconditions.checkNotNull;
 
 import com.google.auto.value.AutoValue;
 
+import javax.annotation.Nullable;
 import java.util.Map;
 
 /**
@@ -65,6 +67,25 @@ public abstract class CloudStorageConfiguration {
    */
   public abstract int maxChannelReopens();
 
+  /**
+   * Returns the project to be billed when accessing buckets. Leave empty for normal semantics,
+   * set to bill that project (project you own) for all accesses. This is required for accessing
+   * requester-pays buckets. This value cannot be null.
+   */
+  public abstract @Nullable String userProject();
+
+  /**
+   * Returns whether userProject will be cleared for non-requester-pays buckets. That is,
+   * if false (the default value), setting userProject causes that project to be billed
+   * regardless of whether the bucket is requester-pays or not. If true, setting
+   * userProject will only cause that project to be billed when the project is requester-pays.
+   *
+   * Setting this will cause the bucket to be accessed when the CloudStorageFileSystem object
+   * is created.
+   */
+  public abstract boolean useUserProjectOnlyForRequesterPaysBuckets();
+
+
   /**
    * Creates a new builder, initialized with the following settings:
    *
@@ -90,6 +111,9 @@ public static final class Builder {
     private boolean usePseudoDirectories = true;
     private int blockSize = CloudStorageFileSystem.BLOCK_SIZE_DEFAULT;
     private int maxChannelReopens = 0;
+    private @Nullable String userProject = null;
+    // This of this as "clear userProject if not RequesterPays"
+    private boolean useUserProjectOnlyForRequesterPaysBuckets = false;
 
     /**
      * Changes current working directory for new filesystem. This defaults to the root directory.
@@ -99,6 +123,7 @@ public static final class Builder {
      * @throws IllegalArgumentException if {@code path} is not absolute.
      */
     public Builder workingDirectory(String path) {
+      checkNotNull(path);
       checkArgument(UnixPath.getPath(false, path).isAbsolute(), "not absolute: %s", path);
       workingDirectory = path;
       return this;
@@ -147,6 +172,16 @@ public Builder maxChannelReopens(int value) {
       return this;
     }
 
+    public Builder userProject(String value) {
+      userProject = value;
+      return this;
+    }
+
+    public Builder autoDetectRequesterPays(boolean value) {
+      useUserProjectOnlyForRequesterPaysBuckets = value;
+      return this;
+    }
+
     /**
      * Creates new instance without destroying builder.
      */
@@ -157,7 +192,9 @@ public CloudStorageConfiguration build() {
           stripPrefixSlash,
           usePseudoDirectories,
           blockSize,
-          maxChannelReopens);
+          maxChannelReopens,
+          userProject,
+          useUserProjectOnlyForRequesterPaysBuckets);
     }
 
     Builder(CloudStorageConfiguration toModify) {
@@ -167,6 +204,8 @@ public CloudStorageConfiguration build() {
       usePseudoDirectories = toModify.usePseudoDirectories();
       blockSize = toModify.blockSize();
       maxChannelReopens = toModify.maxChannelReopens();
+      userProject = toModify.userProject();
+      useUserProjectOnlyForRequesterPaysBuckets = toModify.useUserProjectOnlyForRequesterPaysBuckets();
     }
 
     Builder() {}
@@ -201,6 +240,12 @@ static private CloudStorageConfiguration fromMap(Builder builder, Map<String, ?>
         case "maxChannelReopens":
           builder.maxChannelReopens((Integer) entry.getValue());
           break;
+        case "userProject":
+          builder.userProject((String) entry.getValue());
+          break;
+        case "useUserProjectOnlyForRequesterPaysBuckets":
+          builder.autoDetectRequesterPays((Boolean) entry.getValue());
+          break;
         default:
           throw new IllegalArgumentException(entry.getKey());
       }

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

@@ -20,6 +20,7 @@
 import static com.google.common.base.Preconditions.checkNotNull;
 
 import com.google.cloud.storage.StorageOptions;
+import com.google.common.base.Strings;
 import com.google.common.collect.ImmutableSet;
 
 import java.io.IOException;
@@ -33,6 +34,7 @@
 import java.nio.file.WatchService;
 import java.nio.file.attribute.FileTime;
 import java.nio.file.attribute.UserPrincipalLookupService;
+import java.util.HashMap;
 import java.util.Objects;
 import java.util.Set;
 
@@ -112,8 +114,9 @@ public static CloudStorageFileSystem forBucket(String bucket) {
   public static CloudStorageFileSystem forBucket(String bucket, CloudStorageConfiguration config) {
     checkArgument(
         !bucket.startsWith(URI_SCHEME + ":"), "Bucket name must not have schema: %s", bucket);
+    checkNotNull(config);
     return new CloudStorageFileSystem(
-        new CloudStorageFileSystemProvider(), bucket, checkNotNull(config));
+        new CloudStorageFileSystemProvider(config.userProject()), bucket, config);
   }
 
   /**
@@ -136,15 +139,29 @@ public static CloudStorageFileSystem forBucket(String bucket, CloudStorageConfig
       @Nullable StorageOptions storageOptions) {
     checkArgument(!bucket.startsWith(URI_SCHEME + ":"),
         "Bucket name must not have schema: %s", bucket);
-    return new CloudStorageFileSystem(new CloudStorageFileSystemProvider(storageOptions),
+    return new CloudStorageFileSystem(new CloudStorageFileSystemProvider(config.userProject(), storageOptions),
         bucket, checkNotNull(config));
   }
 
   CloudStorageFileSystem(
       CloudStorageFileSystemProvider provider, String bucket, CloudStorageConfiguration config) {
     checkArgument(!bucket.isEmpty(), "bucket");
-    this.provider = provider;
     this.bucket = bucket;
+    if (config.useUserProjectOnlyForRequesterPaysBuckets()) {
+      if (Strings.isNullOrEmpty(config.userProject())) {
+        throw new IllegalArgumentException("If useUserProjectOnlyForRequesterPaysBuckets is set, then userProject must be set too.");
+      }
+      // detect whether we want to pay for these accesses or not.
+      if (!provider.requesterPays(bucket)) {
+        // update config (just to ease debugging, we're not actually using config.userProject later.
+        HashMap<String, String> disableUserProject = new HashMap<>();
+        disableUserProject.put("userProject", "");
+        config = CloudStorageConfiguration.fromMap(config, disableUserProject);
+        // update the provider (this is the most important bit)
+        provider = provider.withNoUserProject();
+      }
+    }
+    this.provider = provider;
     this.config = config;
   }