bin/xapian-replicate.cc

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/* Copyright (C) 2008,2011 Olly Betts
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301
 * USA
 */

#include <config.h>

#include "replicatetcpclient.h"

#include <xapian.h>

#include "gnu_getopt.h"
#include "stringutils.h"
#include "safeunistd.h"

#include <iostream>

using namespace std;

#define PROG_NAME "xapian-replicate"
#define PROG_DESC "Replicate a database from a master server to a local copy"

#define OPT_HELP 1
#define OPT_VERSION 2

// Wait DEFAULT_INTERVAL seconds between updates unless --interval is passed.
#define DEFAULT_INTERVAL 60

// Number of seconds before we assume that a reader will be closed.
#define READER_CLOSE_TIME 30

static void show_usage() {
    cout << "Usage: "PROG_NAME" [OPTIONS] DATABASE\n\n"
"Options:\n"
"  -h, --host=HOST     host to connect to (required)\n"
"  -p, --port=PORT     port to connect to (required)\n"
"  -m, --master=DB     replicate database DB from the master (default: DATABASE)\n"
"  -i, --interval=N    wait N seconds between each connection to the master\n"
"                      (default: "STRINGIZE(DEFAULT_INTERVAL)")\n"
"  -r, --reader-time=N wait N seconds to allow readers time to close before\n"
"                      applying repeated changesets (default: "STRINGIZE(READER_CLOSE_TIME)")\n"
"  -o, --one-shot      replicate only once and then exit\n"
"  -v, --verbose       be more verbose\n"
"  --help              display this help and exit\n"
"  --version           output version information and exit" << endl;
}

int
main(int argc, char **argv)
{
    const char * opts = "h:p:m:i:r:ov";
    const struct option long_opts[] = {
        {"host",        required_argument,      0, 'h'},
        {"port",        required_argument,      0, 'p'},
        {"master",      required_argument,      0, 'm'},
        {"interval",    required_argument,      0, 'i'},
        {"reader-time", required_argument,      0, 'r'},
        {"one-shot",    no_argument,            0, 'o'},
        {"verbose",     no_argument,            0, 'v'},
        {"help",        no_argument, 0, OPT_HELP},
        {"version",     no_argument, 0, OPT_VERSION},
        {NULL,          0, 0, 0}
    };

    string host;
    int port = 0;
    string masterdb;
    int interval = DEFAULT_INTERVAL;
    bool one_shot = false;
    bool verbose = false;
    int reader_close_time = READER_CLOSE_TIME;

    int c;
    while ((c = gnu_getopt_long(argc, argv, opts, long_opts, 0)) != -1) {
        switch (c) {
            case 'h':
                host.assign(optarg);
                break;
            case 'p':
                port = atoi(optarg);
                break;
            case 'm':
                masterdb.assign(optarg);
                break;
            case 'i':
                interval = atoi(optarg);
                break;
            case 'r':
                reader_close_time = atoi(optarg);
                break;
            case 'o':
                one_shot = true;
                break;
            case 'v':
                verbose = true;
                break;
            case OPT_HELP:
                cout << PROG_NAME" - "PROG_DESC"\n\n";
                show_usage();
                exit(0);
            case OPT_VERSION:
                cout << PROG_NAME" - "PACKAGE_STRING << endl;
                exit(0);
            default:
                show_usage();
                exit(1);
        }
    }

    if (argc - optind != 1) {
        show_usage();
        exit(1);
    }

    if (host.empty()) {
        cout << "Host required - specify with --host=HOST\n\n";
        show_usage();
        exit(1);
    }

    if (port == 0) {
        cout << "Port required - specify with --port=PORT\n\n";
        show_usage();
        exit(1);
    }

    // Path to the database to create/update.
    string dbpath(argv[optind]);

    if (masterdb.empty())
        masterdb = dbpath;

    while (true) {
        try {
            if (verbose) {
                cout << "Connecting to " << host << ":" << port << endl;
            }
            ReplicateTcpClient client(host, port, 10000);
            if (verbose) {
                cout << "Getting update for " << dbpath << " from "
                     << masterdb << endl;
            }
            Xapian::ReplicationInfo info;
            client.update_from_master(dbpath, masterdb, info,
                                      reader_close_time);
            if (verbose) {
                cout << "Update complete: " <<
                        info.fullcopy_count << " copies, " <<
                        info.changeset_count << " changesets, " <<
                        (info.changed ? "new live database" : "no changes to live database") <<
                        endl;
                if (info.fullcopy_count > 0 && !info.changed) {
                    cout <<
"Replication using a full copy failed. This is usually due to changes being\n"
"made at remote end too frequently. Ensure that sufficient changesets are\n"
"present at remote end by setting XAPIAN_MAX_CHANGESETS" << endl;
                }
            }
        } catch (const Xapian::NetworkError &error) {
            // Don't stop running if there's a network error - just log to
            // stderr and retry at next timeout.  This should make the client
            // robust against temporary network failures.
            cerr << argv[0] << ": " << error.get_description() << endl;

            // If we were running as a one-shot client though, we're going to
            // exit anyway, so let's make the return value reflect that there
            // was a failure.
            if (one_shot)
                exit(1);
        } catch (const Xapian::Error &error) {
            cerr << argv[0] << ": " << error.get_description() << endl;
            exit(1);
        } catch (const exception &e) {
            cerr << "Caught standard exception: " << e.what() << endl;
            exit(1);
        } catch (...) {
            cerr << "Caught unknown exception" << endl;
            exit(1);
        }
        if (one_shot) break;
        sleep(interval);
    }
}

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