io.hops.hopsworks.api.admin.llap.LlapMonitorProxyServlet.java Source code

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/*
 * Changes to this file committed after and not including commit-id: ccc0d2c5f9a5ac661e60e6eaf138de7889928b8b
 * are released under the following license:
 *
 * This file is part of Hopsworks
 * Copyright (C) 2018, Logical Clocks AB. All rights reserved
 *
 * Hopsworks is free software: you can redistribute it and/or modify it under the terms of
 * the GNU Affero General Public License as published by the Free Software Foundation,
 * either version 3 of the License, or (at your option) any later version.
 *
 * Hopsworks is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
 * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
 * PURPOSE.  See the GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License along with this program.
 * If not, see <https://www.gnu.org/licenses/>.
 *
 * Changes to this file committed before and including commit-id: ccc0d2c5f9a5ac661e60e6eaf138de7889928b8b
 * are released under the following license:
 *
 * Copyright (C) 2013 - 2018, Logical Clocks AB and RISE SICS AB. All rights reserved
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of this
 * software and associated documentation files (the "Software"), to deal in the Software
 * without restriction, including without limitation the rights to use, copy, modify, merge,
 * publish, distribute, sublicense, and/or sell copies of the Software, and to permit
 * persons to whom the Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all copies or
 * substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS  OR IMPLIED, INCLUDING
 * BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL  THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
 * DAMAGES OR  OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

package io.hops.hopsworks.api.admin.llap;

import io.hops.hopsworks.api.kibana.ProxyServlet;
import org.apache.http.client.utils.URIUtils;

import javax.ejb.Stateless;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.ws.rs.core.Response;
import java.io.IOException;
import java.net.URI;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

@Stateless
public class LlapMonitorProxyServlet extends ProxyServlet {

    protected static final Pattern TEMPLATE_PATTERN = Pattern.compile("\\{(.+?)\\}");
    private static final String ATTR_QUERY_STRING = LlapMonitorProxyServlet.class.getSimpleName() + ".queryString";

    protected String targetUriTemplate;//has {name} parts

    @Override
    protected void initTarget() throws ServletException {
        targetUriTemplate = getConfigParam(P_TARGET_URI);
        if (targetUriTemplate == null)
            throw new ServletException(P_TARGET_URI + " is required.");

        //leave this.target* null to prevent accidental mis-use
    }

    @Override
    protected void service(HttpServletRequest servletRequest, HttpServletResponse servletResponse)
            throws ServletException, IOException {

        // Check if the user is logged in
        if (servletRequest.getUserPrincipal() == null) {
            servletResponse.sendError(403, "User is not logged in");
            return;
        }

        // Check that the user is an admin
        boolean isAdmin = servletRequest.isUserInRole("HOPS_ADMIN");
        if (!isAdmin) {
            servletResponse.sendError(Response.Status.BAD_REQUEST.getStatusCode(),
                    "You don't have the access right for this application");
            return;
        }

        // The path we will receive is [host]/llapmonitor/llaphost/
        // We need to extract the llaphost to redirect the request
        String[] pathInfoSplits = servletRequest.getPathInfo().split("/");
        String llapHost = pathInfoSplits[1];

        //Now rewrite the URL
        StringBuffer urlBuf = new StringBuffer();//note: StringBuilder isn't supported by Matcher
        Matcher matcher = TEMPLATE_PATTERN.matcher(targetUriTemplate);
        if (matcher.find()) {
            matcher.appendReplacement(urlBuf, llapHost);
        }

        matcher.appendTail(urlBuf);
        String newTargetUri = urlBuf.toString();
        servletRequest.setAttribute(ATTR_TARGET_URI, newTargetUri);
        URI targetUriObj;
        try {
            targetUriObj = new URI(newTargetUri);
        } catch (Exception e) {
            throw new ServletException("Rewritten targetUri is invalid: " + newTargetUri, e);
        }
        servletRequest.setAttribute(ATTR_TARGET_HOST, URIUtils.extractHost(targetUriObj));

        super.service(servletRequest, servletResponse);
    }

    @Override
    protected String rewriteQueryStringFromRequest(HttpServletRequest servletRequest, String queryString) {
        return (String) servletRequest.getAttribute(ATTR_QUERY_STRING);
    }

    /**
    * Reads the request URI from {@code servletRequest} and rewrites it,
    * considering targetUri.
    * It's used to make the new request.
    *
    * The servlet name ends with llapmonitor/. This means that the llaphost will be
    * forwarded to with the request as part of the pathInfo.
    * We need to remove the llaphost from the info
    */
    @Override
    protected String rewriteUrlFromRequest(HttpServletRequest servletRequest) {
        StringBuilder uri = new StringBuilder(500);
        String targetUri = getTargetUri(servletRequest);
        uri.append(targetUri);
        // Handle the path given to the servlet

        String[] pathInfoSplits = servletRequest.getPathInfo().split("/");
        // Concatenate pathInfo without the llaphost
        StringBuilder newPathInfo = new StringBuilder();
        for (int i = 2; i < pathInfoSplits.length; i++) {
            newPathInfo.append('/').append(pathInfoSplits[i]);
        }
        uri.append(encodeUriQuery(newPathInfo.toString()));

        // Handle the query string & fragment
        //ex:(following '?'): name=value&foo=bar#fragment
        String queryString = servletRequest.getQueryString();
        String fragment = null;
        //split off fragment from queryString, updating queryString if found
        if (queryString != null) {
            int fragIdx = queryString.indexOf('#');
            if (fragIdx >= 0) {
                fragment = queryString.substring(fragIdx + 2); // '#!', not '#'
                //        fragment = queryString.substring(fragIdx + 1);
                queryString = queryString.substring(0, fragIdx);
            }
        }

        queryString = rewriteQueryStringFromRequest(servletRequest, queryString);
        if (queryString != null && queryString.length() > 0) {
            uri.append('?');
            uri.append(encodeUriQuery(queryString));
        }

        if (doSendUrlFragment && fragment != null) {
            uri.append('#');
            uri.append(encodeUriQuery(fragment));
        }
        return uri.toString();
    }
}