HDFS-11394. Support for getting erasure coding policy through WebHDFS#FileStatus.

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/web/JsonUtil.java

@@ -134,6 +134,9 @@ private static Map<String, Object> toJsonMap(HdfsFileStatus status) {
     }
     if (status.isErasureCoded()) {
       m.put("ecBit", true);
+      if (status.getErasureCodingPolicy() != null) {
+        m.put("ecPolicy", status.getErasureCodingPolicy().getName());
+      }
     }
     if (status.isSnapshotEnabled()) {
       m.put("snapshotEnabled", status.isSnapshotEnabled());

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/web/TestWebHDFS.java

@@ -44,6 +44,7 @@
 import java.net.URI;
 import java.net.URISyntaxException;
 import java.net.URL;
+import java.nio.charset.StandardCharsets;
 import java.security.PrivilegedExceptionAction;
 import java.util.Arrays;
 import java.util.Random;
@@ -81,6 +82,7 @@
 import org.apache.hadoop.hdfs.TestFileCreation;
 import org.apache.hadoop.hdfs.client.HdfsClientConfigKeys;
 import org.apache.hadoop.hdfs.protocol.BlockStoragePolicy;
+import org.apache.hadoop.hdfs.protocol.ErasureCodingPolicy;
 import org.apache.hadoop.hdfs.protocol.SystemErasureCodingPolicies;
 import org.apache.hadoop.hdfs.protocol.HdfsConstants;
 import org.apache.hadoop.hdfs.protocol.SnapshotDiffReport;
@@ -109,6 +111,7 @@
 import org.apache.hadoop.test.GenericTestUtils;
 import org.apache.hadoop.util.DataChecksum;
 import org.apache.log4j.Level;
+import org.codehaus.jettison.json.JSONArray;
 import org.codehaus.jettison.json.JSONException;
 import org.codehaus.jettison.json.JSONObject;
 import org.junit.Assert;
@@ -1578,6 +1581,114 @@ public void testExceptionPropogationInAbstractRunner() throws Exception{
     }
   }
 
+  /**
+   * Tests that the LISTSTATUS ang GETFILESTATUS WebHDFS calls return the
+   * ecPolicy for EC files.
+   */
+  @Test(timeout=300000)
+  public void testECPolicyInFileStatus() throws Exception {
+    final Configuration conf = WebHdfsTestUtil.createConf();
+    final ErasureCodingPolicy ecPolicy = SystemErasureCodingPolicies
+        .getByID(SystemErasureCodingPolicies.RS_3_2_POLICY_ID);
+    final String ecPolicyName = ecPolicy.getName();
+    MiniDFSCluster cluster = new MiniDFSCluster.Builder(conf)
+        .numDataNodes(5)
+        .build();
+    cluster.waitActive();
+    final DistributedFileSystem fs = cluster.getFileSystem();
+
+    // Create an EC dir and write a test file in it
+    final Path ecDir = new Path("/ec");
+    Path ecFile = new Path(ecDir, "ec_file.txt");
+    Path nonEcFile = new Path(ecDir, "non_ec_file.txt");
+    fs.mkdirs(ecDir);
+
+    // Create a non-EC file before enabling ec policy
+    DFSTestUtil.createFile(fs, nonEcFile, 1024, (short) 1, 0);
+
+    fs.enableErasureCodingPolicy(ecPolicyName);
+    fs.setErasureCodingPolicy(ecDir, ecPolicyName);
+
+    // Create a EC file
+    DFSTestUtil.createFile(fs, ecFile, 1024, (short) 1, 0);
+
+    // Query webhdfs REST API to list statuses of files/directories in ecDir
+    InetSocketAddress addr = cluster.getNameNode().getHttpAddress();
+    URL listStatusUrl = new URL("http", addr.getHostString(), addr.getPort(),
+        WebHdfsFileSystem.PATH_PREFIX + ecDir.toString() + "?op=LISTSTATUS");
+
+    HttpURLConnection conn = (HttpURLConnection) listStatusUrl.openConnection();
+    conn.setRequestMethod("GET");
+    conn.setInstanceFollowRedirects(false);
+    String listStatusResponse = IOUtils.toString(conn.getInputStream(),
+        StandardCharsets.UTF_8);
+    Assert.assertEquals("Response wasn't " + HttpURLConnection.HTTP_OK,
+        HttpURLConnection.HTTP_OK, conn.getResponseCode());
+
+    // Verify that ecPolicy is set in the ListStatus response for ec file
+    String ecpolicyForECfile = getECPolicyFromFileStatusJson(
+        getFileStatusJson(listStatusResponse, ecFile.getName()));
+    assertEquals("EC policy for ecFile should match the set EC policy",
+        ecpolicyForECfile, ecPolicyName);
+
+    // Verify that ecPolicy is not set in the ListStatus response for non-ec
+    // file
+    String ecPolicyForNonECfile = getECPolicyFromFileStatusJson(
+        getFileStatusJson(listStatusResponse, nonEcFile.getName()));
+    assertEquals("EC policy for nonEcFile should be null (not set)",
+        ecPolicyForNonECfile, null);
+
+    // Query webhdfs REST API to get fileStatus for ecFile
+    URL getFileStatusUrl = new URL("http", addr.getHostString(), addr.getPort(),
+        WebHdfsFileSystem.PATH_PREFIX + ecFile.toString() +
+            "?op=GETFILESTATUS");
+
+    conn = (HttpURLConnection) getFileStatusUrl.openConnection();
+    conn.setRequestMethod("GET");
+    conn.setInstanceFollowRedirects(false);
+    String getFileStatusResponse = IOUtils.toString(conn.getInputStream(),
+        StandardCharsets.UTF_8);
+    Assert.assertEquals("Response wasn't " + HttpURLConnection.HTTP_OK,
+        HttpURLConnection.HTTP_OK, conn.getResponseCode());
+
+    // Verify that ecPolicy is set in getFileStatus response for ecFile
+    JSONObject fileStatusObject = new JSONObject(getFileStatusResponse)
+        .getJSONObject("FileStatus");
+    ecpolicyForECfile = getECPolicyFromFileStatusJson(fileStatusObject);
+    assertEquals("EC policy for ecFile should match the set EC policy",
+        ecpolicyForECfile, ecPolicyName);
+  }
+
+  /**
+   * Get FileStatus JSONObject from ListStatus response.
+   */
+  private JSONObject getFileStatusJson(String response, String fileName)
+      throws JSONException {
+    JSONObject listStatusResponseJson = new JSONObject(response);
+    JSONArray fileStatusArray = listStatusResponseJson
+        .getJSONObject("FileStatuses")
+        .getJSONArray("FileStatus");
+    for (int i = 0; i < fileStatusArray.length(); i++) {
+      JSONObject fileStatusJsonObject = fileStatusArray.getJSONObject(i);
+      if (fileName.equals(fileStatusJsonObject.get("pathSuffix"))) {
+        return fileStatusJsonObject;
+      }
+    }
+    return null;
+  }
+
+  /**
+   * Get ECPolicy name from FileStatus JSONObject.
+   */
+  private String getECPolicyFromFileStatusJson(JSONObject fileStatusJsonObject)
+      throws JSONException {
+    if (fileStatusJsonObject.has("ecPolicy")) {
+      return fileStatusJsonObject.getString("ecPolicy");
+    } else {
+      return null;
+    }
+  }
+
   final static class DummyThrowable extends Throwable {
   }
 }