cpp/src/qpid/ha/StatusCheck.cpp

/*
 *
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.
 *
 */
#include "StatusCheck.h"
#include "qpid/log/Statement.h"
#include "qpid/messaging/Address.h"
#include "qpid/messaging/Connection.h"
#include "qpid/messaging/Message.h"
#include "qpid/messaging/Receiver.h"
#include "qpid/messaging/Sender.h"
#include "qpid/messaging/Session.h"
#include "qpid/types/Variant.h"

namespace qpid {
namespace ha {

using namespace qpid::messaging;
using namespace qpid::types;
using namespace std;
using namespace sys;

const string HA_BROKER = "org.apache.qpid.ha:habroker:ha-broker";

class StatusCheckThread : public sys::Runnable {
  public:
    StatusCheckThread(StatusCheck& sc, const qpid::Address& addr, const BrokerInfo& self)
        : url(addr), statusCheck(sc), brokerInfo(self) {}
    void run();
  private:
    Url url;
    StatusCheck& statusCheck;
    uint16_t linkHeartbeatInterval;
    BrokerInfo brokerInfo;
};

void StatusCheckThread::run() {
    QPID_LOG(debug, statusCheck.logPrefix << "Checking status of " << url);
    Variant::Map options, clientProperties;
    clientProperties = brokerInfo.asMap(); // Detect self connections.
    clientProperties["qpid.ha-admin"] = 1; // Allow connection to backups.

    options["client-properties"] = clientProperties;
    options["heartbeat"] = statusCheck.linkHeartbeatInterval;
    Connection c(url.str(), options);

    try {
        c.open();
        Session session = c.createSession();
        messaging::Address responses("#;{create:always,node:{x-declare:{exclusive:True,auto-delete:True,arguments:{'qpid.replicate':none}}}}");
        Receiver r = session.createReceiver(responses);
        Sender s = session.createSender("qmf.default.direct/broker");
        Message request;
        request.setReplyTo(responses);
        request.setContentType("amqp/map");
        request.setProperty("x-amqp-0-10.app-id", "qmf2");
        request.setProperty("qmf.opcode", "_query_request");
        Variant::Map oid;
        oid["_object_name"] = HA_BROKER;
        Variant::Map content;
        content["_what"] = "OBJECT";
        content["_object_id"] = oid;
        encode(content, request);
        s.send(request);
        Message response = r.fetch(statusCheck.linkHeartbeatInterval*Duration::SECOND);
        session.acknowledge();
        Variant::List contentIn;
        decode(response, contentIn);
        if (contentIn.size() == 1) {
            Variant::Map details = contentIn.front().asMap()["_values"].asMap();
            string status = details["status"].getString();
            if (status != "joining") {
                statusCheck.setPromote(false);
                QPID_LOG(info, statusCheck.logPrefix << "Status of " << url << " is "
                         << status << ", this broker will refuse promotion.");
            }
            QPID_LOG(debug, statusCheck.logPrefix << "Status of " << url << ": " << status);
        }
    } catch(const exception& error) {
        QPID_LOG(info, "Checking status of " << url <<  ": " << error.what());
    }
    delete this;
}

StatusCheck::StatusCheck(const string& lp, uint16_t lh, const BrokerInfo& self)
    : logPrefix(lp), promote(true), linkHeartbeatInterval(lh), brokerInfo(self)
{}

StatusCheck::~StatusCheck() {
    // Join any leftovers
    for (size_t i = 0; i < threads.size(); ++i) threads[i].join();
}

void StatusCheck::setUrl(const Url& url) {
    Mutex::ScopedLock l(lock);
    for (size_t i = 0; i < url.size(); ++i)
        threads.push_back(Thread(new StatusCheckThread(*this, url[i], brokerInfo)));
}

bool StatusCheck::canPromote() {
    Mutex::ScopedLock l(lock);
    while (!threads.empty()) {
        Thread t = threads.back();
        threads.pop_back();
        Mutex::ScopedUnlock u(lock);
        t.join();
    }
    return promote;
}

void StatusCheck::setPromote(bool p) {
    Mutex::ScopedLock l(lock);
    promote = p;
}

}} // namespace qpid::ha