added propagating internal credential capability in CDF router

cdap-security/src/main/java/io/cdap/cdap/security/auth/ProxyUserIdentityExtractor.java

@@ -19,6 +19,8 @@
 import com.google.inject.Inject;
 import io.cdap.cdap.common.conf.CConfiguration;
 import io.cdap.cdap.common.conf.Constants;
+import io.cdap.cdap.proto.security.Credential;
+import io.cdap.cdap.security.auth.UserIdentity.IdentifierType;
 import io.netty.handler.codec.http.HttpHeaderNames;
 import io.netty.handler.codec.http.HttpRequest;
 import java.util.LinkedHashSet;
@@ -68,19 +70,29 @@ public UserIdentityExtractionResponse extract(HttpRequest request)
     UserIdentity identity = new UserIdentity(userIdentity, UserIdentity.IdentifierType.EXTERNAL,
         new LinkedHashSet<>(), now, now + EXPIRATION_SECS);
 
-    // Parse the access token from authorization header. The header will be in "Bearer" form.
+    // Parse the access token from authorization header. The header will be in "Bearer" form, if external
+    // or "CDAP-Internal" if internal
     String auth = request.headers().get(HttpHeaderNames.AUTHORIZATION);
     LOG.trace("Extracted user identity header '{}' and authorization header length '{}'",
         userIdentity,
         auth == null ? "NULL" : String.valueOf(auth.length()));
     String userCredential = null;
+    String prefix = "";
     if (auth != null) {
       int idx = auth.trim().indexOf(' ');
       if (idx < 0) {
         return new UserIdentityExtractionResponse(new UserIdentityPair(null, identity));
       }
+      prefix = auth.substring(0, idx).trim();
       userCredential = auth.substring(idx + 1).trim();
     }
+
+    if(Credential.CREDENTIAL_TYPE_INTERNAL.equalsIgnoreCase(prefix)){
+      UserIdentity internalIdentity = new UserIdentity(userIdentity, IdentifierType.INTERNAL,
+          new LinkedHashSet<>(), now, now + EXPIRATION_SECS);
+      return new UserIdentityExtractionResponse(new UserIdentityPair(userCredential, internalIdentity));
+    }
+
     return new UserIdentityExtractionResponse(new UserIdentityPair(userCredential, identity));
   }
 }