HADOOP-11054. Add a KeyProvider instantiation based on a URI. (tucu)

hadoop-common-project/hadoop-common/CHANGES.txt

@@ -496,6 +496,8 @@ Release 2.6.0 - UNRELEASED
     HADOOP-10863. KMS should have a blacklist for decrypting EEKs. 
     (asuresh via tucu)
 
+    HADOOP-11054. Add a KeyProvider instantiation based on a URI. (tucu)
+
   OPTIMIZATIONS
 
     HADOOP-10838. Byte array native checksumming. (James Thomas via todd)

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/crypto/key/KeyProviderFactory.java

@@ -63,16 +63,10 @@ public abstract class KeyProviderFactory {
     for(String path: conf.getStringCollection(KEY_PROVIDER_PATH)) {
       try {
         URI uri = new URI(path);
-        boolean found = false;
+        KeyProvider kp = get(uri, conf);
-        for(KeyProviderFactory factory: serviceLoader) {
-          KeyProvider kp = factory.createProvider(uri, conf);
         if (kp != null) {
           result.add(kp);
-            found = true;
+        } else {
-            break;
-          }
-        }
-        if (!found) {
           throw new IOException("No KeyProviderFactory for " + uri + " in " +
               KEY_PROVIDER_PATH);
         }
@@ -83,4 +77,26 @@ public abstract class KeyProviderFactory {
     }
     return result;
   }
+
+  /**
+   * Create a KeyProvider based on a provided URI.
+   *
+   * @param uri key provider URI
+   * @param conf configuration to initialize the key provider
+   * @return the key provider for the specified URI, or <code>NULL</code> if
+   *         a provider for the specified URI scheme could not be found.
+   * @throws IOException thrown if the provider failed to initialize.
+   */
+  public static KeyProvider get(URI uri, Configuration conf)
+      throws IOException {
+    KeyProvider kp = null;
+    for (KeyProviderFactory factory : serviceLoader) {
+      kp = factory.createProvider(uri, conf);
+      if (kp != null) {
+        break;
+      }
+    }
+    return kp;
+  }
+
 }

hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/crypto/key/TestKeyProviderFactory.java

@@ -357,4 +357,17 @@ public class TestKeyProviderFactory {
     }
   }
 
+  @Test
+  public void testGetProviderViaURI() throws Exception {
+    Configuration conf = new Configuration(false);
+    URI uri = new URI(JavaKeyStoreProvider.SCHEME_NAME + "://file" + tmpDir +
+        "/test.jks");
+    KeyProvider kp = KeyProviderFactory.get(uri, conf);
+    Assert.assertNotNull(kp);
+    Assert.assertEquals(JavaKeyStoreProvider.class, kp.getClass());
+    uri = new URI("foo://bar");
+    kp = KeyProviderFactory.get(uri, conf);
+    Assert.assertNull(kp);
+
+  }
 }