HDFS-13878. HttpFS: Implement GETSNAPSHOTTABLEDIRECTORYLIST. Contributed by Siyao Meng.

Signed-off-by: Wei-Chiu Chuang <weichiu@apache.org>

hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/fs/http/client/HttpFSFileSystem.java

@@ -46,6 +46,7 @@
 import org.apache.hadoop.hdfs.protocol.BlockStoragePolicy;
 import org.apache.hadoop.hdfs.protocol.FsPermissionExtension;
 import org.apache.hadoop.hdfs.protocol.SnapshotDiffReport;
+import org.apache.hadoop.hdfs.protocol.SnapshottableDirectoryStatus;
 import org.apache.hadoop.hdfs.web.JsonUtilClient;
 import org.apache.hadoop.lib.wsrs.EnumSetParam;
 import org.apache.hadoop.security.UserGroupInformation;
@@ -234,7 +235,8 @@ public enum Operation {
     SETSTORAGEPOLICY(HTTP_PUT), UNSETSTORAGEPOLICY(HTTP_POST),
     ALLOWSNAPSHOT(HTTP_PUT), DISALLOWSNAPSHOT(HTTP_PUT),
     CREATESNAPSHOT(HTTP_PUT), DELETESNAPSHOT(HTTP_DELETE),
-    RENAMESNAPSHOT(HTTP_PUT), GETSNAPSHOTDIFF(HTTP_GET);
+    RENAMESNAPSHOT(HTTP_PUT), GETSNAPSHOTDIFF(HTTP_GET),
+    GETSNAPSHOTTABLEDIRECTORYLIST(HTTP_GET);
 
     private String httpMethod;
 
@@ -1482,4 +1484,16 @@ public SnapshotDiffReport getSnapshotDiffReport(Path path,
     return JsonUtilClient.toSnapshotDiffReport(json);
   }
 
+  public SnapshottableDirectoryStatus[] getSnapshottableDirectoryList()
+      throws IOException {
+    Map<String, String> params = new HashMap<String, String>();
+    params.put(OP_PARAM, Operation.GETSNAPSHOTTABLEDIRECTORYLIST.toString());
+    HttpURLConnection conn = getConnection(
+        Operation.GETSNAPSHOTTABLEDIRECTORYLIST.getMethod(),
+        params, new Path(getUri().toString(), "/"), true);
+    HttpExceptionUtils.validateResponse(conn, HttpURLConnection.HTTP_OK);
+    JSONObject json = (JSONObject) HttpFSUtils.jsonParse(conn);
+    return JsonUtilClient.toSnapshottableDirectoryList(json);
+  }
+
 }

hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/fs/http/server/FSOperations.java

@@ -37,6 +37,7 @@
 import org.apache.hadoop.hdfs.DistributedFileSystem;
 import org.apache.hadoop.hdfs.protocol.BlockStoragePolicy;
 import org.apache.hadoop.hdfs.protocol.SnapshotDiffReport;
+import org.apache.hadoop.hdfs.protocol.SnapshottableDirectoryStatus;
 import org.apache.hadoop.hdfs.web.JsonUtil;
 import org.apache.hadoop.io.IOUtils;
 import org.apache.hadoop.lib.service.FileSystemAccess;
@@ -1701,4 +1702,38 @@ public String execute(FileSystem fs) throws IOException {
       }
     }
   }
+
+  /**
+   *  Executor that performs a getSnapshottableDirListing operation.
+   */
+  @InterfaceAudience.Private
+  public static class FSGetSnapshottableDirListing implements
+      FileSystemAccess.FileSystemExecutor<String> {
+
+    /**
+     * Creates a getSnapshottableDirListing executor.
+     */
+    public FSGetSnapshottableDirListing() {
+    }
+
+    /**
+     * Executes the filesystem operation.
+     * @param fs filesystem instance to use.
+     * @return A JSON string of all snapshottable directories.
+     * @throws IOException thrown if an IO error occurred.
+     */
+    @Override
+    public String execute(FileSystem fs) throws IOException {
+      SnapshottableDirectoryStatus[] sds = null;
+      if (fs instanceof DistributedFileSystem) {
+        DistributedFileSystem dfs = (DistributedFileSystem) fs;
+        sds = dfs.getSnapshottableDirListing();
+      } else {
+        throw new UnsupportedOperationException("getSnapshottableDirListing is "
+            + "not supported for HttpFs on " + fs.getClass()
+            + ". Please check your fs.defaultFS configuration");
+      }
+      return JsonUtil.toJsonString(sds);
+    }
+  }
 }

hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/fs/http/server/HttpFSParametersProvider.java

@@ -113,6 +113,7 @@ public class HttpFSParametersProvider extends ParametersProvider {
     PARAMS_DEF.put(Operation.GETSNAPSHOTDIFF,
         new Class[] {OldSnapshotNameParam.class,
             SnapshotNameParam.class});
+    PARAMS_DEF.put(Operation.GETSNAPSHOTTABLEDIRECTORYLIST, new Class[] {});
   }
 
   public HttpFSParametersProvider() {

hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/fs/http/server/HttpFSServer.java

@@ -379,6 +379,14 @@ public InputStream run() throws Exception {
       response = Response.ok(js).type(MediaType.APPLICATION_JSON).build();
       break;
     }
+    case GETSNAPSHOTTABLEDIRECTORYLIST: {
+      FSOperations.FSGetSnapshottableDirListing command =
+          new FSOperations.FSGetSnapshottableDirListing();
+      String js = fsExecute(user, command);
+      AUDIT_LOG.info("[{}]", "/");
+      response = Response.ok(js).type(MediaType.APPLICATION_JSON).build();
+      break;
+    }
     default: {
       throw new IOException(
           MessageFormat.format("Invalid HTTP GET operation [{0}]", op.value()));

hadoop-hdfs-project/hadoop-hdfs-httpfs/src/test/java/org/apache/hadoop/fs/http/client/BaseTestHttpFSWith.java

@@ -41,6 +41,8 @@
 import org.apache.hadoop.hdfs.protocol.HdfsConstants;
 import org.apache.hadoop.hdfs.protocol.SnapshotDiffReport;
 import org.apache.hadoop.hdfs.protocol.SnapshotException;
+import org.apache.hadoop.hdfs.protocol.SnapshottableDirectoryStatus;
+import org.apache.hadoop.hdfs.web.JsonUtil;
 import org.apache.hadoop.hdfs.web.WebHdfsFileSystem;
 import org.apache.hadoop.ipc.RemoteException;
 import org.apache.hadoop.security.UserGroupInformation;
@@ -1071,7 +1073,7 @@ protected enum Operation {
     GETTRASHROOT, STORAGEPOLICY, ERASURE_CODING,
     CREATE_SNAPSHOT, RENAME_SNAPSHOT, DELETE_SNAPSHOT,
     ALLOW_SNAPSHOT, DISALLOW_SNAPSHOT, DISALLOW_SNAPSHOT_EXCEPTION,
-    FILE_STATUS_ATTR, GET_SNAPSHOT_DIFF
+    FILE_STATUS_ATTR, GET_SNAPSHOT_DIFF, GET_SNAPSHOTTABLE_DIRECTORY_LIST
   }
 
   private void operation(Operation op) throws Exception {
@@ -1185,6 +1187,9 @@ private void operation(Operation op) throws Exception {
       testGetSnapshotDiff();
       testGetSnapshotDiffIllegalParam();
       break;
+    case GET_SNAPSHOTTABLE_DIRECTORY_LIST:
+      testGetSnapshottableDirListing();
+      break;
     }
   }
 
@@ -1529,4 +1534,51 @@ private void testGetSnapshotDiffIllegalParam() throws Exception {
       fs.delete(path, true);
     }
   }
+
+  private void verifyGetSnapshottableDirListing(
+      FileSystem fs, DistributedFileSystem dfs) throws Exception {
+    // Get snapshottable directory list
+    SnapshottableDirectoryStatus[] sds = null;
+    if (fs instanceof HttpFSFileSystem) {
+      HttpFSFileSystem httpFS = (HttpFSFileSystem) fs;
+      sds = httpFS.getSnapshottableDirectoryList();
+    } else if (fs instanceof WebHdfsFileSystem) {
+      WebHdfsFileSystem webHdfsFileSystem = (WebHdfsFileSystem) fs;
+      sds = webHdfsFileSystem.getSnapshottableDirectoryList();
+    } else {
+      Assert.fail(fs.getClass().getSimpleName() +
+          " doesn't support getSnapshottableDirListing");
+    }
+    // Verify result with DFS
+    SnapshottableDirectoryStatus[] dfssds = dfs.getSnapshottableDirListing();
+    Assert.assertEquals(JsonUtil.toJsonString(sds),
+        JsonUtil.toJsonString(dfssds));
+  }
+
+  private void testGetSnapshottableDirListing() throws Exception {
+    if (!this.isLocalFS()) {
+      FileSystem fs = this.getHttpFSFileSystem();
+      // Create directories with snapshot allowed
+      Path path1 = new Path("/tmp/tmp-snap-dirlist-test-1");
+      DistributedFileSystem dfs = (DistributedFileSystem)
+          FileSystem.get(path1.toUri(), this.getProxiedFSConf());
+      // Verify response when there is no snapshottable directory
+      verifyGetSnapshottableDirListing(fs, dfs);
+      createSnapshotTestsPreconditions(path1);
+      Assert.assertTrue(fs.getFileStatus(path1).isSnapshotEnabled());
+      // Verify response when there is one snapshottable directory
+      verifyGetSnapshottableDirListing(fs, dfs);
+      Path path2 = new Path("/tmp/tmp-snap-dirlist-test-2");
+      createSnapshotTestsPreconditions(path2);
+      Assert.assertTrue(fs.getFileStatus(path2).isSnapshotEnabled());
+      // Verify response when there are two snapshottable directories
+      verifyGetSnapshottableDirListing(fs, dfs);
+
+      // Clean up and verify
+      fs.delete(path2, true);
+      verifyGetSnapshottableDirListing(fs, dfs);
+      fs.delete(path1, true);
+      verifyGetSnapshottableDirListing(fs, dfs);
+    }
+  }
 }

hadoop-hdfs-project/hadoop-hdfs-httpfs/src/test/java/org/apache/hadoop/fs/http/server/TestHttpFSServer.java

@@ -20,6 +20,7 @@
 import org.apache.hadoop.hdfs.DFSConfigKeys;
 import org.apache.hadoop.hdfs.DistributedFileSystem;
 import org.apache.hadoop.hdfs.protocol.SnapshotDiffReport;
+import org.apache.hadoop.hdfs.protocol.SnapshottableDirectoryStatus;
 import org.apache.hadoop.hdfs.web.JsonUtil;
 import org.apache.hadoop.security.authentication.util.SignerSecretProvider;
 import org.apache.hadoop.security.authentication.util.StringSignerSecretProviderCreator;
@@ -1400,4 +1401,56 @@ public void testGetSnapshotDiffIllegalParam() throws Exception {
     // Clean up
     dfs.delete(path, true);
   }
+
+  private void verifyGetSnapshottableDirectoryList(DistributedFileSystem dfs)
+      throws Exception {
+    // Send a request
+    HttpURLConnection conn = sendRequestToHttpFSServer("/",
+        "GETSNAPSHOTTABLEDIRECTORYLIST", "");
+    // Should return HTTP_OK
+    Assert.assertEquals(conn.getResponseCode(), HttpURLConnection.HTTP_OK);
+    // Verify the response
+    BufferedReader reader =
+        new BufferedReader(new InputStreamReader(conn.getInputStream()));
+    // The response should be a one-line JSON string.
+    String dirLst = reader.readLine();
+    // Verify the content of diff with DFS API.
+    SnapshottableDirectoryStatus[] dfsDirLst = dfs.getSnapshottableDirListing();
+    Assert.assertEquals(dirLst, JsonUtil.toJsonString(dfsDirLst));
+  }
+
+  @Test
+  @TestDir
+  @TestJetty
+  @TestHdfs
+  public void testGetSnapshottableDirectoryList() throws Exception {
+    createHttpFSServer(false, false);
+    // Create test directories
+    String pathStr1 = "/tmp/tmp-snap-dirlist-test-1";
+    createDirWithHttp(pathStr1, "700", null);
+    Path path1 = new Path(pathStr1);
+    String pathStr2 = "/tmp/tmp-snap-dirlist-test-2";
+    createDirWithHttp(pathStr2, "700", null);
+    Path path2 = new Path(pathStr2);
+    DistributedFileSystem dfs = (DistributedFileSystem) FileSystem.get(
+        path1.toUri(), TestHdfsHelper.getHdfsConf());
+    // Verify response when there is no snapshottable directory
+    verifyGetSnapshottableDirectoryList(dfs);
+    // Enable snapshot for path1
+    dfs.allowSnapshot(path1);
+    Assert.assertTrue(dfs.getFileStatus(path1).isSnapshotEnabled());
+    // Verify response when there is one snapshottable directory
+    verifyGetSnapshottableDirectoryList(dfs);
+    // Enable snapshot for path2
+    dfs.allowSnapshot(path2);
+    Assert.assertTrue(dfs.getFileStatus(path2).isSnapshotEnabled());
+    // Verify response when there are two snapshottable directories
+    verifyGetSnapshottableDirectoryList(dfs);
+
+    // Clean up and verify
+    dfs.delete(path2, true);
+    verifyGetSnapshottableDirectoryList(dfs);
+    dfs.delete(path1, true);
+    verifyGetSnapshottableDirectoryList(dfs);
+  }
 }