Addendum for HADOOP-10670.

hadoop-common-project/hadoop-auth/src/main/java/org/apache/hadoop/security/authentication/util/FileSignerSecretProvider.java

@@ -0,0 +1,84 @@
+/**
+ * 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. See accompanying LICENSE file.
+ */
+package org.apache.hadoop.security.authentication.util;
+
+import com.google.common.base.Charsets;
+import org.apache.hadoop.classification.InterfaceAudience;
+import org.apache.hadoop.classification.InterfaceStability;
+import org.apache.hadoop.security.authentication.server.AuthenticationFilter;
+import org.apache.hadoop.security.authentication.util.SignerSecretProvider;
+
+import javax.servlet.ServletContext;
+import java.io.*;
+import java.nio.charset.Charset;
+import java.util.Properties;
+
+/**
+ * A SignerSecretProvider that simply loads a secret from a specified file.
+ */
+@InterfaceStability.Unstable
+@InterfaceAudience.Private
+public class FileSignerSecretProvider extends SignerSecretProvider {
+
+  private byte[] secret;
+  private byte[][] secrets;
+
+  public FileSignerSecretProvider() {}
+
+  @Override
+  public void init(Properties config, ServletContext servletContext,
+                   long tokenValidity) throws Exception {
+
+    String signatureSecretFile = config.getProperty(
+        AuthenticationFilter.SIGNATURE_SECRET_FILE, null);
+
+    Reader reader = null;
+    if (signatureSecretFile != null) {
+      try {
+        StringBuilder sb = new StringBuilder();
+        reader = new InputStreamReader(
+            new FileInputStream(signatureSecretFile), Charsets.UTF_8);
+        int c = reader.read();
+        while (c > -1) {
+          sb.append((char) c);
+          c = reader.read();
+        }
+        secret = sb.toString().getBytes(Charset.forName("UTF-8"));
+      } catch (IOException ex) {
+        throw new RuntimeException("Could not read signature secret file: " +
+            signatureSecretFile);
+      } finally {
+        if (reader != null) {
+          try {
+            reader.close();
+          } catch (IOException e) {
+            // nothing to do
+          }
+        }
+      }
+    }
+
+    secrets = new byte[][]{secret};
+  }
+
+  @Override
+  public byte[] getCurrentSecret() {
+    return secret;
+  }
+
+  @Override
+  public byte[][] getAllSecrets() {
+    return secrets;
+  }
+}

hadoop-common-project/hadoop-auth/src/test/java/org/apache/hadoop/security/authentication/util/TestFileSignerSecretProvider.java

@@ -0,0 +1,51 @@
+/**
+ * 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. See accompanying LICENSE file.
+ */
+package org.apache.hadoop.security.authentication.util;
+
+import org.apache.hadoop.security.authentication.server.AuthenticationFilter;
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.io.File;
+import java.io.FileWriter;
+import java.io.Writer;
+import java.util.Properties;
+
+public class TestFileSignerSecretProvider {
+
+  @Test
+  public void testGetSecrets() throws Exception {
+    File testDir = new File(System.getProperty("test.build.data",
+        "target/test-dir"));
+    testDir.mkdirs();
+    String secretValue = "hadoop";
+    File secretFile = new File(testDir, "http-secret.txt");
+    Writer writer = new FileWriter(secretFile);
+    writer.write(secretValue);
+    writer.close();
+
+    FileSignerSecretProvider secretProvider
+            = new FileSignerSecretProvider();
+    Properties secretProviderProps = new Properties();
+    secretProviderProps.setProperty(
+            AuthenticationFilter.SIGNATURE_SECRET_FILE,
+        secretFile.getAbsolutePath());
+    secretProvider.init(secretProviderProps, null, -1);
+    Assert.assertArrayEquals(secretValue.getBytes(),
+        secretProvider.getCurrentSecret());
+    byte[][] allSecrets = secretProvider.getAllSecrets();
+    Assert.assertEquals(1, allSecrets.length);
+    Assert.assertArrayEquals(secretValue.getBytes(), allSecrets[0]);
+  }
+}