Change guard pdp rest to new api

The guard PDP REST call must be changed to support the new api.

Needed to clean out quite a bit of unnecessary code. In addition,
there never should be an Indeterminate response coming back anymore.

Issue-ID: POLICY-1730
Change-Id: I14b3ad39a803646cfffaba9b77cc2aac79e79bdf
Signed-off-by: Pamela Dragosh <pdragosh@research.att.com>

3 files changed, 68 insertions, 392 deletions

diff --git a/controlloop/common/guard/src/main/java/org/onap/policy/guard/CallGuardTask.java b/controlloop/common/guard/src/main/java/org/onap/policy/guard/CallGuardTask.java
index 046b7cfd6..22fce1999 100644
--- a/controlloop/common/guard/src/main/java/org/onap/policy/guard/CallGuardTask.java
+++ b/controlloop/common/guard/src/main/java/org/onap/policy/guard/CallGuardTask.java
@@ -7,9 +7,9 @@
  * 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.
@@ -20,12 +20,11 @@
 
 package org.onap.policy.guard;
 
-import com.att.research.xacml.api.DataTypeException;
-import com.att.research.xacml.std.annotations.RequestParser;
 import java.util.HashSet;
 import java.util.Set;
 import java.util.UUID;
 import java.util.function.Supplier;
+
 import org.drools.core.WorkingMemory;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -69,7 +68,7 @@ public class CallGuardTask implements Runnable {
     /**
      * Guard url is grabbed from PolicyEngine.manager properties
      */
-    public CallGuardTask(WorkingMemory wm, String cl, String act, 
+    public CallGuardTask(WorkingMemory wm, String cl, String act,
             String rec, String tar, String reqId, Supplier<Integer> vfcnt) {
         workingMemory = wm;
         clname = cl;
@@ -108,22 +107,14 @@ public class CallGuardTask implements Runnable {
             workingMemory.insert(guardResponse);
             return;
         }
-        
+
         final long startTime = System.nanoTime();
-        com.att.research.xacml.api.Request request = null;
 
         PolicyGuardXacmlRequestAttributes xacmlReq =
                         new PolicyGuardXacmlRequestAttributes(clname, actor, recipe, target, requestId, vfCount);
 
-        try {
-            request = RequestParser.parseRequest(xacmlReq);
-        } catch (IllegalArgumentException | IllegalAccessException | DataTypeException e) {
-            logger.error("CallGuardTask.run threw: {}", e);
-        }
-
-
         logger.debug("\n********** XACML REQUEST START ********");
-        logger.debug("{}", request);
+        logger.debug("{}", xacmlReq);
         logger.debug("********** XACML REQUEST END ********\n");
 
         String guardDecision = null;
@@ -147,7 +138,6 @@ public class CallGuardTask implements Runnable {
 
         guardResponse = new PolicyGuardResponse(guardDecision, UUID.fromString(this.requestId), this.recipe);
 
-
         //
         // Create an artificial Guard response in case we didn't get a clear Permit or Deny
         //
diff --git a/controlloop/common/guard/src/main/java/org/onap/policy/guard/PolicyGuardXacmlHelper.java b/controlloop/common/guard/src/main/java/org/onap/policy/guard/PolicyGuardXacmlHelper.java
index 6d1fd315e..2d43c885e 100644
--- a/controlloop/common/guard/src/main/java/org/onap/policy/guard/PolicyGuardXacmlHelper.java
+++ b/controlloop/common/guard/src/main/java/org/onap/policy/guard/PolicyGuardXacmlHelper.java
@@ -21,31 +21,20 @@
 
 package org.onap.policy.guard;
 
-import com.att.research.xacml.api.Attribute;
-import com.att.research.xacml.api.AttributeCategory;
-import com.att.research.xacml.api.AttributeValue;
-import com.att.research.xacml.api.Result;
-
-import java.io.ByteArrayInputStream;
-import java.io.IOException;
-import java.io.InputStream;
-import java.io.OutputStream;
-import java.io.Serializable;
-import java.net.HttpURLConnection;
-import java.net.URL;
-import java.util.ArrayList;
-import java.util.Base64;
-import java.util.Iterator;
-import java.util.Properties;
+import java.util.HashMap;
+import java.util.Map;
 import java.util.UUID;
 
-import org.apache.commons.io.IOUtils;
-import org.apache.http.entity.ContentType;
-import org.json.JSONObject;
 import org.onap.policy.common.endpoints.event.comm.Topic.CommInfrastructure;
 import org.onap.policy.common.endpoints.utils.NetLoggerUtil;
 import org.onap.policy.common.endpoints.utils.NetLoggerUtil.EventType;
+import org.onap.policy.common.utils.coder.CoderException;
+import org.onap.policy.common.utils.coder.StandardCoder;
 import org.onap.policy.drools.system.PolicyEngine;
+import org.onap.policy.models.decisions.concepts.DecisionRequest;
+import org.onap.policy.models.decisions.concepts.DecisionResponse;
+import org.onap.policy.rest.RestManager;
+import org.onap.policy.rest.RestManager.Pair;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -53,28 +42,17 @@ import org.slf4j.LoggerFactory;
 public class PolicyGuardXacmlHelper {
     private static final Logger logger = LoggerFactory.getLogger(PolicyGuardXacmlHelper.class);
 
-    private UrlEntry[] restUrls = null;
-    private int restUrlIndex = 0;
-
-    // REST timeout, initialized from 'pdpx.timeout' property
-    private int timeout = 20000;
+    private String url;
+    private String user;
+    private String pwd;
 
+    /**
+     *  Constructor.
+     */
     public PolicyGuardXacmlHelper() {
-        init(PolicyEngine.manager.getEnvironment());
-    }
-
-    // initialized from 'pdpx.url' property --
-    // Each entry in 'restUrls' contains a destination URL, and an optional
-    // 'Authorization' header entry. 'restUrlIndex' indicates the next
-    // entry to try -- after each failure, the index is advanced to the
-    // next entry (wrapping to the beginning, if needed).
-    private static class UrlEntry implements Serializable {
-        private static final long serialVersionUID = -8859237552195400518L;
-
-        URL restUrl;
-        String authorization = null;
-        String clientAuth = null;
-        String environment = null;
+        this.url = PolicyEngine.manager.getEnvironmentProperty("pdpx.host");
+        this.user = PolicyEngine.manager.getEnvironmentProperty("pdpx.username");
+        this.pwd = PolicyEngine.manager.getEnvironmentProperty("pdpx.password");
     }
 
     /**
@@ -85,357 +63,72 @@ public class PolicyGuardXacmlHelper {
      */
     public String callPdp(PolicyGuardXacmlRequestAttributes xacmlReq) {
         //
-        // Send it to the PDP
-        //
-        String response = null;
-
-        //
-        // Build the json request
+        // Create a request suitable for API
         //
-        JSONObject attributes = new JSONObject();
-        attributes.put("actor", xacmlReq.getActorId());
-        attributes.put("recipe", xacmlReq.getOperationId());
-        attributes.put("target", xacmlReq.getTargetId());
+        DecisionRequest decisionRequest = new DecisionRequest();
+        decisionRequest.setOnapName("Policy");
+        decisionRequest.setOnapComponent("Drools PDP");
+        decisionRequest.setOnapInstance("usecase template");
+        decisionRequest.setRequestId(UUID.randomUUID().toString());
+        decisionRequest.setAction("guard");
+        Map<String, String> guard = new HashMap<>();
+        guard.put("actor", xacmlReq.getActorId());
+        guard.put("recipe", xacmlReq.getOperationId());
+        guard.put("target", xacmlReq.getTargetId());
         if (xacmlReq.getClnameId() != null) {
-            attributes.put("clname", xacmlReq.getClnameId());
+            guard.put("clName", xacmlReq.getClnameId());
         }
         if (xacmlReq.getVfCount() != null) {
-            attributes.put("vfCount", xacmlReq.getVfCount());
+            guard.put("vfCount", Integer.toString(xacmlReq.getVfCount()));
         }
-        JSONObject jsonReq = new JSONObject();
-        jsonReq.put("decisionAttributes", attributes);
-        jsonReq.put("onapName", "PDPD");
-
+        Map<String, Object> resources = new HashMap<>();
+        resources.put("guard", guard);
+        decisionRequest.setResource(resources);
 
         try {
             //
             // Call RESTful PDP
             //
-            UrlEntry urlEntry = restUrls[restUrlIndex];
-            String jsonRequestString = jsonReq.toString();
-            NetLoggerUtil.log(EventType.OUT, CommInfrastructure.REST, urlEntry.restUrl.toString(), jsonRequestString);
-            response = callRestfulPdp(new ByteArrayInputStream(jsonReq.toString().getBytes()), urlEntry.restUrl,
-                    urlEntry.authorization, urlEntry.clientAuth, urlEntry.environment);
-            NetLoggerUtil.log(EventType.IN, CommInfrastructure.REST, urlEntry.restUrl.toString(), response);
+            NetLoggerUtil.log(EventType.OUT, CommInfrastructure.REST, this.url, decisionRequest.toString());
+            String response = callRestfulPdp(decisionRequest);
+            NetLoggerUtil.log(EventType.IN, CommInfrastructure.REST, this.url, response);
+
+            return response;
         } catch (Exception e) {
             logger.error("Error in sending RESTful request: ", e);
         }
 
-        return response;
+        return Util.DENY;
     }
 
     /**
      * This makes an HTTP POST call to a running PDP RESTful servlet to get a decision.
      *
-     * @param is the InputStream
-     * @param authorization the Authorization
-     * @param clientauth the ClientAuth
-     * @param environment the Environment
+     * @param decisionRequest The Decision request
      * @return response from guard which contains "Permit" or "Deny"
+     * @throws CoderException Exception when converting to/from JSON the message body
      */
-    private String callRestfulPdp(InputStream is, URL restUrl, String authorization, String clientauth,
-            String environment) {
-        HttpURLConnection connection = null;
-
-        try {
-            //
-            // Open up the connection
-            //
-            connection = (HttpURLConnection) restUrl.openConnection();
-            connection.setRequestProperty("Content-Type", "application/json");
-            //
-            // Setup our method and headers
-            //
-            connection.setRequestProperty("Accept", "application/json");
-            if (authorization != null) {
-                connection.setRequestProperty("Authorization", authorization);
-            }
-            if (clientauth != null) {
-                connection.setRequestProperty("ClientAuth", clientauth);
-            }
-            if (environment != null) {
-                connection.setRequestProperty("Environment", environment);
-            }
-            connection.setConnectTimeout(timeout);
-            connection.setReadTimeout(timeout);
-            connection.setRequestMethod("POST");
-            connection.setUseCaches(false);
-            //
-            // Adding this in. It seems the HttpUrlConnection class does NOT
-            // properly forward our headers for POST re-direction. It does so
-            // for a GET re-direction.
-            //
-            // So we need to handle this ourselves.
-            //
-            connection.setInstanceFollowRedirects(false);
-            connection.setDoOutput(true);
-            connection.setDoInput(true);
-            //
-            // Send the request
-            //
-            try (OutputStream os = connection.getOutputStream()) {
-                IOUtils.copy(is, os);
-            }
-
-            //
-            // Do the connect
-            //
-            connection.connect();
-
-            if (connection.getResponseCode() != 200) {
-                logger.error(connection.getResponseCode() + " " + connection.getResponseMessage());
-                return Util.INDETERMINATE;
-            }
-        } catch (Exception e) {
-            logger.error("Exception in 'PolicyGuardXacmlHelper.callRESTfulPDP'", e);
-            return Util.INDETERMINATE;
-        }
-
-        //
-        // Read the response
-        //
-        try {
-            ContentType contentType = ContentType.parse(connection.getContentType());
-
-            if (contentType.getMimeType().equalsIgnoreCase(ContentType.APPLICATION_JSON.getMimeType())) {
-                InputStream inputStream = connection.getInputStream();
-                int contentLength = connection.getContentLength();
-
-                return readResponseFromStream(inputStream, contentLength);
-            } else {
-                logger.error("unknown content-type: {}", contentType);
-                return Util.INDETERMINATE;
-            }
-
-        } catch (Exception e) {
-            String message = "Parsing Content-Type: " + connection.getContentType();
-            logger.error(message, e);
-            return Util.INDETERMINATE;
-        }
-    }
-
-    /**
-     * Parse XACML PDP response.
-     *
-     * @param xacmlResponse the XACML response
-     * @return the PolicyGuardResponse
-     */
-    public static PolicyGuardResponse parseXacmlPdpResponse(com.att.research.xacml.api.Response xacmlResponse) {
-        if (xacmlResponse == null) {
-            //
-            // In case the actual XACML response was null, create an empty
-            // response object with decision "Indeterminate"
-            //
-            return new PolicyGuardResponse("Indeterminate", null, "");
-        }
-
-        Iterator<Result> itRes = xacmlResponse.getResults().iterator();
-
-        Result res = itRes.next();
-        String decisionFromXacmlResponse = res.getDecision().toString();
-        Iterator<AttributeCategory> itAttrCat = res.getAttributes().iterator();
-        UUID reqIdFromXacmlResponse = null;
-        String operationFromXacmlResponse = "";
+    private String callRestfulPdp(DecisionRequest decisionRequest) throws CoderException {
+        StandardCoder coder = new StandardCoder();
 
-        while (itAttrCat.hasNext()) {
-            Iterator<Attribute> itAttr = itAttrCat.next().getAttributes().iterator();
-            while (itAttr.hasNext()) {
-                Attribute currentAttr = itAttr.next();
-                String attributeId = currentAttr.getAttributeId().stringValue();
-                if ("urn:org:onap:guard:request:request-id".equals(attributeId)) {
-                    Iterator<AttributeValue<?>> itValues = currentAttr.getValues().iterator();
-                    reqIdFromXacmlResponse = UUID.fromString(itValues.next().getValue().toString());
-                }
-                if ("urn:org:onap:guard:operation:operation-id".equals(attributeId)) {
-                    Iterator<AttributeValue<?>> itValues = currentAttr.getValues().iterator();
-                    operationFromXacmlResponse = itValues.next().getValue().toString();
-                }
-            }
-        }
-
-        return new PolicyGuardResponse(decisionFromXacmlResponse, reqIdFromXacmlResponse, operationFromXacmlResponse);
-
-    }
-
-    private void init(Properties properties) {
-        // used to store error messages
-        StringBuilder sb = new StringBuilder();
-
-        // fetch these parameters, if they exist
-        String timeoutString = properties.getProperty("pdpx.timeout");
-        String disabledString = properties.getProperty("guard.disabled");
-
-        if (disabledString != null && Boolean.parseBoolean(disabledString)) {
-            return;
-        }
-
-        ArrayList<UrlEntry> entries = initEntries(properties, sb);
-
-        if (entries.isEmpty()) {
-            sb.append("'pdpx.*' -- no URLs specified, ");
-        } else {
-            restUrls = entries.toArray(new UrlEntry[0]);
-        }
-
-        if (timeoutString != null) {
-            try {
-                // decode optional 'pdpx.timeout' parameter
-                timeout = Integer.valueOf(timeoutString);
-            } catch (NumberFormatException e) {
-                sb.append("'pdpx.timeout': " + e + ", ");
-                logger.trace(e.getLocalizedMessage());
-            }
-        }
-
-
-        // if there are any errors, update 'errorMessage' & disable guard
-        // queries
-        if (sb.length() != 0) {
-            // remove the terminating ", ", and extract resulting error message
-            sb.setLength(sb.length() - 2);
-            String errorMessage = sb.toString();
-            logger.error("Initialization failure: {}", errorMessage);
-        }
-    }
-
-    private ArrayList<UrlEntry> initEntries(Properties properties, StringBuilder sb) {
-        // now, see which numeric entries (1-9) exist
-        ArrayList<UrlEntry> entries = new ArrayList<>();
-
-        for (int index = 0; index < 10; index += 1) {
-            String urlPrefix = "guard.";
-            if (index != 0) {
-                urlPrefix = urlPrefix + index + ".";
-            }
-
-            // see if the associated URL exists
-            String restUrllist = properties.getProperty(urlPrefix + "url");
-            if (nullOrEmpty(restUrllist)) {
-                // no entry for this index
-                continue;
-            }
-
-            // support a list of entries separated by semicolons. Each entry
-            // can be:
-            // URL
-            // URL,user
-            // URL,user,password
-            for (String restUrl : restUrllist.split("\\s*;\\s*")) {
-                UrlEntry entry = initRestUrl(properties, sb, restUrl);
-                // include this URLEntry in the list
-                if (entry != null) {
-                    entries.add(entry);
-                }
-            }
-        }
-
-        return entries;
-    }
+        String jsonBody = coder.encode(decisionRequest);
+        RestManager restManager = new RestManager();
 
-    private UrlEntry initRestUrl(Properties properties, StringBuilder sb, String restUrl) {
-        String urlPrefix = "guard.";
-        String pdpxPrefix = "pdpx.";
+        Map<String, String> headers = new HashMap<>();
+        headers.put("Accepts", "application/json");
 
-        String[] segments = restUrl.split("\\s*,\\s*");
-        String user = null;
-        String password = null;
+        Pair<Integer, String> httpDetails = restManager.post(url, user, pwd, headers, "application/json", jsonBody);
 
-        if (segments.length >= 2) {
-            // user id is provided
-            restUrl = segments[0];
-            user = segments[1];
-            if (segments.length >= 3) {
-                // password is also provided
-                password = segments[2];
-            }
+        if (httpDetails == null) {
+            return Util.DENY;
         }
 
-        // URL does exist -- create the entry
-        UrlEntry urlEntry = new UrlEntry();
-        try {
-            urlEntry.restUrl = new URL(restUrl);
-        } catch (java.net.MalformedURLException e) {
-            // if we don't have a URL,
-            // don't bother with the rest on this one
-            sb.append("'").append(urlPrefix).append("url' '").append(restUrl).append("': ").append(e).append(",");
-            return null;
-        }
-
-        if (nullOrEmpty(user)) {
-            // user id was not provided on '*.url' line --
-            // extract it from a separate property
-            user = properties.getProperty(pdpxPrefix + "username", properties.getProperty("pdpx.username"));
-        }
-        if (nullOrEmpty(password)) {
-            // password was not provided on '*.url' line --
-            // extract it from a separate property
-            password = properties.getProperty(pdpxPrefix + "password", properties.getProperty("pdpx.password"));
-        }
-
-        // see if 'user' and 'password' entries both exist
-        if (!nullOrEmpty(user) && !nullOrEmpty(password)) {
-            urlEntry.authorization = "Basic " + Base64.getEncoder().encodeToString((user + ":" + password).getBytes());
+        if (httpDetails.first == 200) {
+            DecisionResponse decision = coder.decode(httpDetails.second, DecisionResponse.class);
+            return decision.getStatus();
         }
 
-        // see if 'client.user' and 'client.password' entries both exist
-        String clientUser =
-                properties.getProperty(pdpxPrefix + "client.username", properties.getProperty("pdpx.client.username"));
-        String clientPassword =
-                properties.getProperty(pdpxPrefix + "client.password", properties.getProperty("pdpx.client.password"));
-        if (!nullOrEmpty(clientUser) && !nullOrEmpty(clientPassword)) {
-            urlEntry.clientAuth =
-                    "Basic " + Base64.getEncoder().encodeToString((clientUser + ":" + clientPassword).getBytes());
-        }
-
-        // see if there is an 'environment' entry
-        String environment =
-                properties.getProperty(pdpxPrefix + "environment", properties.getProperty("pdpx.environment"));
-        if (!nullOrEmpty(environment)) {
-            urlEntry.environment = environment;
-        }
-
-        return urlEntry;
-    }
-
-    /**
-     * Check if a string is null or an empty string.
-     *
-     * @param value the string to be tested
-     * @return 'true' if the string is 'null' or has a length of 0, 'false' otherwise
-     */
-    private static boolean nullOrEmpty(String value) {
-        return (value == null || value.isEmpty());
+        return Util.DENY;
     }
 
-    private static String readResponseFromStream(InputStream inputStream, int contentLength) throws IOException {
-        // if content length is -1, response is chunked, and
-        // TCP connection will be dropped at the end
-        byte[] buf = new byte[contentLength < 0 ? 1024 : contentLength];
-        int offset = 0;
-        do {
-            int size = inputStream.read(buf, offset, buf.length - offset);
-            if (size < 0) {
-                // In a chunked response a dropped connection is expected, but not if the response
-                // is not chunked
-                if (contentLength > 0) {
-                    logger.error("partial input stream");
-                }
-                break;
-            }
-            offset += size;
-        }
-        while (offset != contentLength);
-
-        String response = new String(buf, 0, offset);
-
-        //
-        // Connection may have failed or not been 200 OK, return Indeterminate
-        //
-        if (response.isEmpty()) {
-            return Util.INDETERMINATE;
-        }
-
-        return new JSONObject(response).getString("decision");
-
-    }
 }
diff --git a/controlloop/common/guard/src/main/java/org/onap/policy/guard/Util.java b/controlloop/common/guard/src/main/java/org/onap/policy/guard/Util.java
index 6298774bb..e378b61c9 100644
--- a/controlloop/common/guard/src/main/java/org/onap/policy/guard/Util.java
+++ b/controlloop/common/guard/src/main/java/org/onap/policy/guard/Util.java
@@ -2,14 +2,14 @@
  * ============LICENSE_START=======================================================
  * guard
  * ================================================================================
- * Copyright (C) 2017-2018 AT&T Intellectual Property. All rights reserved.
+ * Copyright (C) 2017-2019 AT&T Intellectual Property. All rights reserved.
  * ================================================================================
  * 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.
@@ -39,12 +39,9 @@ public final class Util {
     /*
      * Keys for guard properties
      */
-    public static final String PROP_GUARD_URL = "guard.url";
+    public static final String PROP_GUARD_URL = "pdpx.host";
     public static final String PROP_GUARD_USER = "pdpx.username";
     public static final String PROP_GUARD_PASS = "pdpx.password";
-    public static final String PROP_GUARD_CLIENT_USER = "pdpx.client.username";
-    public static final String PROP_GUARD_CLIENT_PASS = "pdpx.client.password";
-    public static final String PROP_GUARD_ENV = "pdpx.environment";
     public static final String PROP_GUARD_DISABLED = "guard.disabled";
 
     /*
@@ -89,7 +86,7 @@ public final class Util {
 
     /**
      * Load a Yaml file.
-     * 
+     *
      * @param testFile the Yaml file
      * @return the policies
      */
@@ -113,7 +110,7 @@ public final class Util {
 
     /**
      * Load a Yaml guard.
-     * 
+     *
      * @param testFile the Yaml file
      * @return the guard
      */
@@ -134,17 +131,13 @@ public final class Util {
 
     /**
      * Sets Guard Properties.
-     * 
+     *
      * <p>see /guard/src/test/java/org/onap/policy/guard/UtilTest.java for setting test properties
      */
-    public static void setGuardEnvProps(String url, String username, String password, String clientName,
-            String clientPassword, String environment) {
+    public static void setGuardEnvProps(String url, String username, String password) {
         PolicyEngine.manager.setEnvironmentProperty(org.onap.policy.guard.Util.PROP_GUARD_URL, url);
         PolicyEngine.manager.setEnvironmentProperty(org.onap.policy.guard.Util.PROP_GUARD_USER, username);
         PolicyEngine.manager.setEnvironmentProperty(org.onap.policy.guard.Util.PROP_GUARD_PASS, password);
-        PolicyEngine.manager.setEnvironmentProperty(org.onap.policy.guard.Util.PROP_GUARD_CLIENT_USER, clientName);
-        PolicyEngine.manager.setEnvironmentProperty(org.onap.policy.guard.Util.PROP_GUARD_CLIENT_PASS, clientPassword);
-        PolicyEngine.manager.setEnvironmentProperty(org.onap.policy.guard.Util.PROP_GUARD_ENV, environment);
     }
 
     public static void setGuardEnvProp(String key, String value) {