path: root/src/main/java/org/openecomp/restclient/client/RestClient.java

/**
 * ============LICENSE_START=======================================================
 * RestClient
 * ================================================================================
 * Copyright © 2017 AT&T Intellectual Property.
 * Copyright © 2017 Amdocs
 * 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.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * ============LICENSE_END=========================================================
 *
 * ECOMP and OpenECOMP are trademarks
 * and service marks of AT&T Intellectual Property.
 */
package org.openecomp.restclient.client;

import com.sun.jersey.api.client.Client;
import com.sun.jersey.api.client.ClientResponse;
import com.sun.jersey.api.client.WebResource;
import com.sun.jersey.api.client.WebResource.Builder;
import com.sun.jersey.core.util.MultivaluedMapImpl;

import org.openecomp.cl.api.LogFields;
import org.openecomp.cl.api.LogLine;
import org.openecomp.cl.api.Logger;
import org.openecomp.cl.eelf.LoggerFactory;
import org.openecomp.cl.mdc.MdcContext;
import org.openecomp.cl.mdc.MdcOverride;
import org.openecomp.restclient.logging.RestClientMsgs;
import org.openecomp.restclient.rest.RestClientBuilder;

import java.io.ByteArrayOutputStream;
import java.text.SimpleDateFormat;
import java.util.Arrays;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.UUID;

import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.MultivaluedMap;
import javax.ws.rs.core.Response;


/**
 * This class provides a general client implementation that micro services can use for communicating
 * with the endpoints via their exposed REST interfaces.
 */
public class RestClient {

  /**
   * This is a generic builder that is used for constructing the REST client that we will use to
   * communicate with the REST endpoint.
   */
  private RestClientBuilder clientBuilder;

  /**
   * The low level instance of the REST client that will be used to communicate with the endpoint.
   */
  private Client restClient = null;

  /** Standard logger for producing log statements. */
  private Logger logger = LoggerFactory.getInstance().getLogger("AAIRESTClient");

  /** Standard logger for producing metric statements. */
  private Logger metricsLogger = LoggerFactory.getInstance().getMetricsLogger("AAIRESTClient");

  private SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSSXXX");

  /** Reusable function call for GET REST operations. */
  private final RestOperation getOp = new GetRestOperation();

  /** Reusable function call for PUT REST operations. */
  private final RestOperation putOp = new PutRestOperation();

  /** Reusable function call for POST REST operations. */
  private final RestOperation postOp = new PostRestOperation();

  /** Reusable function call for DELETE REST operations. */
  private final RestOperation deleteOp = new DeleteRestOperation();

  /**
   * Creates a new instance of the {@link RestClient}.
   */
  public RestClient() {
    clientBuilder = new RestClientBuilder();
  }


  /**
   * Creates a new instance of the {@link RestClient} using the supplied {@link RestClientBuilder}.
   *
   * @param rcBuilder - The REST client builder that this instance of the {@link RestClient} should
   *        use.
   */
  public RestClient(RestClientBuilder rcBuilder) {
    clientBuilder = rcBuilder;
  }


  /**
   * Sets the flag to indicate whether or not validation should be performed against the host name
   * of the server we are trying to communicate with.
   *
   * @parameter validate - Set to true to enable validation, false to disable
   *
   * @return The AAIRESTClient instance. This is useful for chaining parameter assignments.
   */
  public RestClient validateServerHostname(boolean validate) {
    logger.debug("Set validate server hostname = " + validate);
    clientBuilder.setValidateServerHostname(validate);
    return this;
  }


  /**
   * Sets the flag to indicate whether or not validation should be performed against the certificate
   * chain.
   *
   * @parameter validate - Set to true to enable validation, false to disable.
   *
   * @return The AAIRESTClient instance. This is useful for chaining parameter assignments.
   */
  public RestClient validateServerCertChain(boolean validate) {
    logger.debug("Set validate server certificate chain = " + validate);
    clientBuilder.setValidateServerCertChain(validate);
    return this;
  }


  /**
   * Assigns the client certificate file to use.
   *
   * @param filename - The name of the certificate file.
   *
   * @return The AAIRESTClient instance. This is useful for chaining parameter assignments.
   */
  public RestClient clientCertFile(String filename) {
    logger.debug("Set client certificate filename = " + filename);
    clientBuilder.setClientCertFileName(filename);
    return this;
  }


  /**
   * Assigns the client certificate password to use.
   *
   * @param password - The certificate password.
   *
   * @return The AAIRESTClient instance. This is useful for chaining parameter assignments.
   */
  public RestClient clientCertPassword(String password) {
    logger.debug("Set client certificate password = " + password);
    clientBuilder.setClientCertPassword(password);
    return this;
  }


  /**
   * Assigns the name of the trust store file to use.
   *
   * @param filename - the name of the trust store file.
   *
   * @return The AAIRESTClient instance. This is useful for chaining parameter assignments.
   */
  public RestClient trustStore(String filename) {
    logger.debug("Set trust store filename = " + filename);
    clientBuilder.setTruststoreFilename(filename);
    return this;
  }


  /**
   * Assigns the connection timeout (in ms) to use when connecting to the target server.
   *
   * @param timeout - The length of time to wait in ms before timing out.
   *
   * @return The AAIRESTClient instance. This is useful for chaining parameter assignments.
   */
  public RestClient connectTimeoutMs(int timeout) {
    logger.debug("Set connection timeout = " + timeout + " ms");
    clientBuilder.setConnectTimeoutInMs(timeout);
    return this;
  }


  /**
   * Assigns the read timeout (in ms) to use when communicating with the target server.
   *
   * @param timeout The read timeout in milliseconds.
   *
   * @return The AAIRESTClient instance. This is useful for chaining parameter assignments.
   */
  public RestClient readTimeoutMs(int timeout) {
    logger.debug("Set read timeout = " + timeout + " ms");
    clientBuilder.setReadTimeoutInMs(timeout);
    return this;
  }

  /**
   * This method operates on a REST endpoint by submitting an HTTP operation request against the
   * supplied URL.    
   * This variant of the method will perform a requested number of retries in the event that the
   * first request is unsuccessful.
   *
   * @param operation - the REST operation type to send to the url
   * @param url - The REST endpoint to submit the REST request to.
   * @param payload - They payload to provide in the REST request, if applicable
   * @param headers - The headers that should be passed in the request
   * @param contentType - The content type of the payload
   * @param responseType - The expected format of the response.
   * 
   * @return The result of the REST request.
   */
  protected OperationResult processRequest(RestOperation operation, String url, String payload,
      Map<String, List<String>> headers, MediaType contentType, MediaType responseType,
      int numRetries) {


    OperationResult result = null;

    long startTimeInMs = System.currentTimeMillis();
    for (int retryCount = 0; retryCount < numRetries; retryCount++) {

      logger.info(RestClientMsgs.HTTP_REQUEST_WITH_RETRIES, url, Integer.toString(retryCount + 1));

      // Submit our query to the AAI.
      result = processRequest(operation, url, payload, headers, contentType, responseType);

      // If the submission was successful then we're done.
      if (Integer.toString(result.getResultCode()).charAt(0) == '2') {
        logger.info(RestClientMsgs.HTTP_REQUEST_TIME_WITH_RETRIES,
            Long.toString(System.currentTimeMillis() - startTimeInMs), url,
            Integer.toString(retryCount));
        return result;
      }

      // Our submission was unsuccessful...
      try {
        // Sleep between re-tries to be nice to the target system.
        Thread.sleep(500);

      } catch (InterruptedException e) {
        logger.error(RestClientMsgs.HTTP_REQUEST_INTERRUPTED, url, e.getLocalizedMessage());
        break;
      }
    }

    // If we've gotten this far, then we failed all of our retries.
    result.setResultCode(504);
    result.setFailureCause(
        "Failed to get a successful result " + "after multiple retries to target server");

    return result;
  }

  /**
   * This method operates on a REST endpoint by submitting an HTTP operation request against the
   * supplied URL.
   *
   * @param operation - the REST operation type to send to the url
   * @param url - The REST endpoint to submit the REST request to.
   * @param payload - They payload to provide in the REST request, if applicable
   * @param headers - The headers that should be passed in the request
   * @param contentType - The content type of the payload
   * @param responseType - The expected format of the response.
   *
   * @return The result of the REST request.
   */
  protected OperationResult processRequest(RestOperation operation, String url, String payload,
      Map<String, List<String>> headers, MediaType contentType, MediaType responseType) {

    ClientResponse clientResponse = null;
    OperationResult operationResult = new OperationResult();
    ByteArrayOutputStream baos = new ByteArrayOutputStream();

    String requestType = operation.getRequestType().name();

    // Grab the current time so that we can log how long the
    // query took once we are done.
    long startTimeInMs = System.currentTimeMillis();
    MdcOverride override = new MdcOverride();
    override.addAttribute(MdcContext.MDC_START_TIME, formatter.format(startTimeInMs));

    logger.info(RestClientMsgs.HTTP_REQUEST, requestType, url);

    try {

      // Get a REST client instance for our request.
      Client client = getClient();

      // Debug log the request
      debugRequest(url, payload, headers, responseType);

      // Get a client request builder, and submit our GET request.
      Builder builder = getClientBuilder(client, url, payload, headers, contentType, responseType);
      clientResponse = operation.processOperation(builder);

      populateOperationResult(clientResponse, operationResult);

      // Debug log the response
      debugResponse(operationResult, clientResponse.getHeaders());

    } catch (Exception ex) {

      logger.error(RestClientMsgs.HTTP_REQUEST_ERROR, requestType, url, ex.getLocalizedMessage());
      operationResult.setResultCode(500);
      operationResult.setFailureCause(
          "Error during GET operation to AAI with message = " + ex.getLocalizedMessage());

    } finally {

      if (logger.isDebugEnabled()) {
        logger.debug(baos.toString());
      }

      // Not every valid response code is actually represented by the Response.Status
      // object, so we need to guard against missing codes, otherwise we throw null
      // pointer exceptions when we try to generate our metrics logs...
      Response.Status responseStatus =
          Response.Status.fromStatusCode(operationResult.getResultCode());
      String responseStatusCodeString = "";
      if (responseStatus != null) {
        responseStatusCodeString = responseStatus.toString();
      }

      metricsLogger.info(RestClientMsgs.HTTP_REQUEST_TIME,
          new LogFields().setField(LogLine.DefinedFields.STATUS_CODE, responseStatusCodeString)
              .setField(LogLine.DefinedFields.RESPONSE_CODE, operationResult.getResultCode())
              .setField(LogLine.DefinedFields.RESPONSE_DESCRIPTION, operationResult.getResult()),
          override, requestType, Long.toString(System.currentTimeMillis() - startTimeInMs), url);
      logger.info(RestClientMsgs.HTTP_REQUEST_TIME, requestType,
          Long.toString(System.currentTimeMillis() - startTimeInMs), url);
      logger.info(RestClientMsgs.HTTP_RESPONSE, url,
          operationResult.getResultCode() + " " + responseStatusCodeString);
    }

    return operationResult;
  }

  /**
   * This method submits an HTTP PUT request against the supplied URL.
   *
   * @param url - The REST endpoint to submit the PUT request to.
   * @param payload - the payload to send to the supplied URL
   * @param headers - The headers that should be passed in the request
   * @param contentType - The content type of the payload
   * @param responseType - The expected format of the response.
   *
   * @return The result of the PUT request.
   */
  public OperationResult put(String url, String payload, Map<String, List<String>> headers,
      MediaType contentType, MediaType responseType) {
    return processRequest(putOp, url, payload, headers, contentType, responseType);
  }

  /**
   * This method submits an HTTP POST request against the supplied URL.
   *
   * @param url - The REST endpoint to submit the POST request to.
   * @param payload - the payload to send to the supplied URL
   * @param headers - The headers that should be passed in the request
   * @param contentType - The content type of the payload
   * @param responseType - The expected format of the response.
   *
   * @return The result of the POST request.
   */
  public OperationResult post(String url, String payload, Map<String, List<String>> headers,
      MediaType contentType, MediaType responseType) {
    return processRequest(postOp, url, payload, headers, contentType, responseType);
  }

  /**
   * This method submits an HTTP GET request against the supplied URL.
   *
   * @param url - The REST endpoint to submit the GET request to.
   * @param headers - The headers that should be passed in the request
   * @param responseType - The expected format of the response.
   *
   * @return The result of the GET request.
   */
  public OperationResult get(String url, Map<String, List<String>> headers,
      MediaType responseType) {
    return processRequest(getOp, url, null, headers, null, responseType);
  }

  /**
   * This method submits an HTTP GET request against the supplied URL. 
   * This variant of the method will perform a requested number of retries in the event that the
   * first request is unsuccessful.
   * 
   * @param url - The REST endpoint to submit the GET request to.
   * @param headers - The headers that should be passed in the request
   * @param responseType - The expected format of the response.
   * @param numRetries - The number of times to try resubmitting the request in the event of a
   *        failure.
   * 
   * @return The result of the GET request.
   */
  public OperationResult get(String url, Map<String, List<String>> headers, MediaType responseType,
      int numRetries) {
    return processRequest(getOp, url, null, headers, null, responseType, numRetries);
  }

  /**
   * This method submits an HTTP DELETE request against the supplied URL.
   *
   * @param url - The REST endpoint to submit the DELETE request to.
   * @param headers - The headers that should be passed in the request
   * @param responseType - The expected format of the response.
   *
   * @return The result of the DELETE request.
   */
  public OperationResult delete(String url, Map<String, List<String>> headers,
      MediaType responseType) {
    return processRequest(deleteOp, url, null, headers, null, responseType);
  }

  /**
   * This method does a health check ("ping") against the supplied URL.
   *
   * @param url - The REST endpoint to attempt a health check.
   * @param srcAppName - The name of the application using this client.
   * @param destAppName - The name of the destination app.
   *
   * @return A boolean value. True if connection attempt was successful, false otherwise.
   *
   */
  public boolean healthCheck(String url, String srcAppName, String destAppName) {
    return healthCheck(url, srcAppName, destAppName, MediaType.TEXT_PLAIN_TYPE);

  }

  /**
   * This method does a health check ("ping") against the supplied URL.
   *
   * @param url - The REST endpoint to attempt a health check.
   * @param srcAppName - The name of the application using this client.
   * @param destAppName - The name of the destination app.
   * @param responseType - The response type.
   *
   * @return A boolean value. True if connection attempt was successful, false otherwise.
   *
   */
  public boolean healthCheck(String url, String srcAppName, String destAppName,
      MediaType responseType) {
    MultivaluedMap<String, String> headers = new MultivaluedMapImpl();
    headers.put(Headers.FROM_APP_ID, Arrays.asList(new String[] {srcAppName}));
    headers.put(Headers.TRANSACTION_ID, Arrays.asList(new String[] {UUID.randomUUID().toString()}));

    try {
      logger.info(RestClientMsgs.HEALTH_CHECK_ATTEMPT, destAppName, url);
      OperationResult result = get(url, headers, responseType);

      if (result != null && result.getFailureCause() == null) {
        logger.info(RestClientMsgs.HEALTH_CHECK_SUCCESS, destAppName, url);
        return true;
      } else {
        logger.error(RestClientMsgs.HEALTH_CHECK_FAILURE, destAppName, url,
            result.getFailureCause());
        return false;
      }
    } catch (Exception e) {
      logger.error(RestClientMsgs.HEALTH_CHECK_FAILURE, destAppName, url, e.getMessage());
      return false;
    }
  }

  /**
   * This method constructs a client request builder that can be used for submitting REST requests
   * to the supplied URL endpoint.
   *
   * @param client - The REST client we will be using to talk to the server.
   * @param url - The URL endpoint that our request will be submitted to.
   * @param headers - The headers that should be passed in the request
   * @param contentType - the content type of the payload
   * @param responseType - The expected format of the response.
   *
   * @return A client request builder.
   */
  private Builder getClientBuilder(Client client, String url, String payload,
      Map<String, List<String>> headers, MediaType contentType, MediaType responseType) {

    WebResource resource = client.resource(url);
    Builder builder = null;

    builder = resource.accept(responseType);

    if (contentType != null) {
      builder.type(contentType);
    }

    if (payload != null) {
      builder.entity(payload);
    }

    if (headers != null) {
      for (Entry<String, List<String>> header : headers.entrySet()) {
        builder.header(header.getKey(), header.getValue());
      }
    }

    return builder;
  }

  private void debugRequest(String url, String payload, Map<String, List<String>> headers,
      MediaType responseType) {
    if (logger.isDebugEnabled()) {
      StringBuilder debugRequest = new StringBuilder("REQUEST:\n");
      debugRequest.append("URL: ").append(url).append("\n");
      debugRequest.append("Payload: ").append(payload).append("\n");
      debugRequest.append("Response Type: ").append(responseType).append("\n");
      if (headers != null) {
        debugRequest.append("Headers: ");
        for (Entry<String, List<String>> header : headers.entrySet()) {
          debugRequest.append("\n\t").append(header.getKey()).append(":");
          for (String headerEntry : header.getValue()) {
            debugRequest.append("\"").append(headerEntry).append("\" ");
          }
        }
      }
      logger.debug(debugRequest.toString());
    }
  }

  private void debugResponse(OperationResult operationResult,
      MultivaluedMap<String, String> headers) {
    if (logger.isDebugEnabled()) {
      StringBuilder debugResponse = new StringBuilder("RESPONSE:\n");
      debugResponse.append("Result: ").append(operationResult.getResultCode()).append("\n");
      debugResponse.append("Failure Cause: ").append(operationResult.getFailureCause())
          .append("\n");
      debugResponse.append("Payload: ").append(operationResult.getResult()).append("\n");
      if (headers != null) {
        debugResponse.append("Headers: ");
        for (Entry<String, List<String>> header : headers.entrySet()) {
          debugResponse.append("\n\t").append(header.getKey()).append(":");
          for (String headerEntry : header.getValue()) {
            debugResponse.append("\"").append(headerEntry).append("\" ");
          }
        }
      }
      logger.debug(debugResponse.toString());
    }
  }


  /**
   * This method creates an instance of the low level REST client to use for communicating with the
   * AAI, if one has not already been created, otherwise it returns the already created instance.
   *
   * @return A {@link Client} instance.
   */
  private synchronized Client getClient() throws Exception {

    if (restClient == null) {

      if (logger.isDebugEnabled()) {
        logger.debug("Instantiating REST client with following parameters:");
        logger.debug(
            "  validate server hostname          = " + clientBuilder.isValidateServerHostname());
        logger.debug(
            "  validate server certificate chain = " + clientBuilder.isValidateServerCertChain());
        logger.debug(
            "  client certificate filename       = " + clientBuilder.getClientCertFileName());
        logger.debug(
            "  client certificate password       = " + clientBuilder.getClientCertPassword());
        logger.debug(
            "  trust store filename              = " + clientBuilder.getTruststoreFilename());
        logger.debug("  connection timeout                = "
            + clientBuilder.getConnectTimeoutInMs() + " ms");
        logger.debug(
            "  read timeout                      = " + clientBuilder.getReadTimeoutInMs() + " ms");
      }

      restClient = clientBuilder.getClient();
    }

    return restClient;
  }


  /**
   * This method populates the fields of an {@link OperationResult} instance based on the contents
   * of a {@link ClientResponse} received in response to a REST request.
   */
  private void populateOperationResult(ClientResponse response, OperationResult opResult) {

    // If we got back a NULL response, then just produce a generic
    // error code and result indicating this.
    if (response == null) {
      opResult.setResultCode(500);
      opResult.setFailureCause("Client response was null");
      return;
    }

    int statusCode = response.getStatus();
    String payload = response.getEntity(String.class);

    opResult.setResultCode(statusCode);

    if ((statusCode < 200) || (statusCode > 299)) {
      opResult.setFailureCause(payload);
    } else {
      opResult.setResult(payload);
    }

    opResult.setHeaders(response.getHeaders());
  }

  private class GetRestOperation implements RestOperation {
    public ClientResponse processOperation(Builder builder) {
      return builder.get(ClientResponse.class);
    }

    public RequestType getRequestType() {
      return RequestType.GET;
    }
  }

  private class PutRestOperation implements RestOperation {
    public ClientResponse processOperation(Builder builder) {
      return builder.put(ClientResponse.class);
    }

    public RequestType getRequestType() {
      return RequestType.PUT;
    }
  }

  private class PostRestOperation implements RestOperation {
    public ClientResponse processOperation(Builder builder) {
      return builder.post(ClientResponse.class);
    }

    public RequestType getRequestType() {
      return RequestType.POST;
    }
  }

  private class DeleteRestOperation implements RestOperation {
    public ClientResponse processOperation(Builder builder) {
      return builder.delete(ClientResponse.class);
    }

    public RequestType getRequestType() {
      return RequestType.DELETE;
    }
  }

  /**
   * Interface used wrap a Jersey REST call using a functional interface.
   */
  private interface RestOperation {

    /**
     * Method used to wrap the functionality of making a REST call out to the endpoint.
     *
     * @param builder the Jersey builder used to make the request
     * @return the response from the REST endpoint
     */
    public ClientResponse processOperation(Builder builder);

    /**
     * Returns the REST request type.
     */
    public RequestType getRequestType();

    /**
     * The supported REST request types.
     */
    public enum RequestType {
      GET, PUT, POST, DELETE;
    }
  }
}