ncbi_dispd.c

ncbi源码

    if (s_IsUpdateNeeded(data) && !s_Resolve(iter))
        return 0;
    assert(data->n_node != 0);

    for (i = 0; i < data->n_node; i++) {
        info = data->s_node[i].info;
        status = info->rate;
        assert(status != 0.0);

        if (info->host == iter->preferred_host) {
            if (info->coef <= 0.0 || iter->preference) {
                status *= SERV_DISPD_LOCAL_SVC_BONUS;
                if (access < status &&
                    (iter->preference || info->coef < 0.0)) {
                    access =  status;
                    point  =  total + status; /* Latch this local server */
                    p      = -info->coef;
                    assert(point > 0.0);
                }
            } else
                status *= info->coef;
        }
        total                 += status;
        data->s_node[i].status = total;
    }

    if (point > 0.0 && iter->preference) {
        if (total != access) {
            p = SERV_Preference(iter->preference, access/total, data->n_node);
            status = total*p;
            p = total*(1.0 - p)/(total - access);
            for (i = 0; i < data->n_node; i++) {
                data->s_node[i].status *= p;
                if (p*point <= data->s_node[i].status)
                    data->s_node[i].status += status - p*access;
            }
        }
        point = -1.0;
    }
    /* We take pre-chosen local server only if its status is not less than
       p% of the average remaining status; otherwise, we ignore the server,
       and apply the generic procedure by seeding a random point. */
    if (point <= 0.0 || access*(data->n_node - 1) < p*0.01*(total - access))
        point = (total * rand()) / (double) RAND_MAX;
    for (i = 0; i < data->n_node; i++) {
        if (point <= data->s_node[i].status)
            break;
    }
    assert(i < data->n_node);

    info = data->s_node[i].info;
    info->rate = data->s_node[i].status - (i ? data->s_node[i-1].status : 0.0);
    if (i < --data->n_node) {
        memmove(data->s_node + i, data->s_node + i + 1,
                (data->n_node - i)*sizeof(*data->s_node));
    }
    if (host_info)
        *host_info = 0;

    return info;
}


static void s_Reset(SERV_ITER iter)
{
    SDISPD_Data* data = (SDISPD_Data*) iter->data;
    if (data && data->s_node) {
        size_t i;
        assert(data->n_max_node);
        for (i = 0; i < data->n_node; i++)
            free(data->s_node[i].info);
        data->n_node = 0;
    }
}


static void s_Close(SERV_ITER iter)
{
    SDISPD_Data* data = (SDISPD_Data*) iter->data;
    assert(data->n_node == 0); /* s_Reset() had to be called before */
    if (data->s_node)
        free(data->s_node);
    ConnNetInfo_Destroy(data->net_info);
    free(data);
    iter->data = 0;
}


/***********************************************************************
 *  EXTERNAL
 ***********************************************************************/

/*ARGSUSED*/
const SSERV_VTable* SERV_DISPD_Open(SERV_ITER iter,
                                    const SConnNetInfo* net_info,
                                    SSERV_Info** info, HOST_INFO* u/*unused*/)
{
    SDISPD_Data* data;

    if (!(data = (SDISPD_Data*) calloc(1, sizeof(*data))))
        return 0;
    if (!s_RandomSeed) {
        s_RandomSeed = (int) time(0) + (int) SOCK_gethostbyname(0);
        srand(s_RandomSeed);
    }
    data->net_info = ConnNetInfo_Clone(net_info); /*called with non-NULL*/
    if (iter->type & fSERV_StatelessOnly)
        data->net_info->stateless = 1/*true*/;
    if (iter->type & fSERV_Firewall)
        data->net_info->firewall = 1/*true*/;
    iter->data = data;

    iter->op = &s_op; /* SERV_Update() - from HTTP callback - expects this */
    if (!s_Resolve(iter)) {
        iter->op = 0;
        s_Reset(iter);
        s_Close(iter);
        return 0;
    }

    /* call GetNextInfo if info is needed */
    if (info)
        *info = 0;
    return &s_op;
}


void DISP_SetMessageHook(FDISP_MessageHook hook)
{
    if (hook) {
        if (hook != s_MessageHook)
            s_MessageIssued = s_MessageIssued ? -1 : -2;
    } else if (s_MessageIssued < -1)
        s_MessageIssued = 0;
    s_MessageHook = hook;
}


/*
 * --------------------------------------------------------------------------
 * $Log: ncbi_dispd.c,v $
 * Revision 1000.0  2003/10/29 16:36:28  gouriano
 * PRODUCTION: IMPORTED [ORIGINAL] Dev-tree R6.61
 *
 * Revision 6.61  2003/10/14 14:40:07  lavr
 * Fix to avoid resolving empty client's host name
 *
 * Revision 6.60  2003/10/10 19:33:24  lavr
 * Do not generate address CGI parameter if host address is unknown
 *
 * Revision 6.59  2003/08/11 19:07:03  lavr
 * +DISP_SetMessageHook() and implementation of message delivery
 *
 * Revision 6.58  2003/05/31 05:14:38  lavr
 * Add ARGSUSED where args are meant to be unused
 *
 * Revision 6.57  2003/05/22 20:31:40  lavr
 * Comment change
 *
 * Revision 6.56  2003/05/14 15:43:31  lavr
 * Add host address in dispatcher's CGI query
 *
 * Revision 6.55  2003/02/13 21:38:22  lavr
 * Comply with new SERV_Preference() prototype
 *
 * Revision 6.54  2003/02/06 17:35:36  lavr
 * Move reset of disp_fail to correct place in s_Resolve()
 *
 * Revision 6.53  2003/02/04 22:02:44  lavr
 * Introduce adjustment routine and disp_fail member to avoid MAX_TRY retrying
 *
 * Revision 6.52  2003/01/31 21:17:37  lavr
 * Implementation of perference for preferred host
 *
 * Revision 6.51  2002/12/10 22:11:50  lavr
 * Stamp HTTP packets with "User-Agent:" header tag and DISP_PROTOCOL_VERSION
 *
 * Revision 6.50  2002/11/19 19:21:40  lavr
 * Use client_host from net_info instead of obtaining it explicitly
 *
 * Revision 6.49  2002/11/01 20:14:07  lavr
 * Expand hostname buffers to hold up to 256 chars
 *
 * Revision 6.48  2002/10/28 20:12:56  lavr
 * Module renamed and host info API included
 *
 * Revision 6.47  2002/10/28 15:46:21  lavr
 * Use "ncbi_ansi_ext.h" privately
 *
 * Revision 6.46  2002/10/21 18:32:35  lavr
 * Append service arguments "address" and "platform" in dispatcher requests
 *
 * Revision 6.45  2002/10/11 19:55:20  lavr
 * Append dispatcher request query with address and platform information
 * (as the old dispatcher used to do). Also, take advantage of various new
 * ConnNetInfo_*UserHeader() routines when preparing aux HTTP request.
 *
 * Revision 6.44  2002/09/24 15:08:50  lavr
 * Change non-zero rate assertion into more readable (info->rate != 0.0)
 *
 * Revision 6.43  2002/09/18 16:31:38  lavr
 * Temporary fix for precision loss removed & replaced with assert()
 *
 * Revision 6.42  2002/09/06 17:45:40  lavr
 * Include <connect/ncbi_priv.h> unconditionally (reported by J.Kans)
 *
 * Revision 6.41  2002/09/06 15:44:19  lavr
 * Use fHCC_SureFlush and CONN_Flush() instead of dummy read
 *
 * Revision 6.40  2002/08/12 15:13:50  lavr
 * Temporary fix for precision loss in transmission of SERV_Info as text
 *
 * Revision 6.39  2002/08/07 16:33:43  lavr
 * Changed EIO_ReadMethod enums accordingly; log moved to end
 *
 * Revision 6.38  2002/05/07 15:31:50  lavr
 * +#include <stdio.h>: noticed by J.Kans
 *
 * Revision 6.37  2002/05/06 19:18:12  lavr
 * Few changes to comply with the rest of API
 *
 * Revision 6.36  2002/04/13 06:40:05  lavr
 * Few tweaks to reduce the number of syscalls made
 *
 * Revision 6.35  2002/03/11 22:01:47  lavr
 * Threshold for choosing a local server explained better
 *
 * Revision 6.34  2001/12/04 15:57:05  lavr
 * Change log correction
 *
 * Revision 6.33  2001/10/01 19:53:39  lavr
 * -s_FreeData(), -s_ResetData() - do everything in s_Close()/s_Reset() instead
 *
 * Revision 6.32  2001/09/29 19:33:04  lavr
 * BUGFIX: SERV_Update() requires VT bound (was not the case in constructor)
 *
 * Revision 6.31  2001/09/29 18:41:03  lavr
 * "Server-Keyed-Info:" removed from protocol
 *
 * Revision 6.30  2001/09/28 20:52:16  lavr
 * Update VT method revised as now called on a per-line basis
 *
 * Revision 6.29  2001/09/24 20:30:01  lavr
 * Reset() VT method added and utilized
 *
 * Revision 6.28  2001/09/10 21:23:53  lavr
 * "Relay-Mode:" tag eliminated from the dispatcher protocol
 *
 * Revision 6.27  2001/07/24 18:02:02  lavr
 * Seed random generator at Open()
 *
 * Revision 6.26  2001/07/18 17:41:25  lavr
 * BUGFIX: In code for selecting services by preferred host
 *
 * Revision 6.25  2001/07/03 20:49:44  lavr
 * RAND_MAX included in the interval search
 *
 * Revision 6.24  2001/06/25 15:36:38  lavr
 * s_GetNextInfo now takes one additional argument for host environment
 *
 * Revision 6.23  2001/06/20 17:27:49  kans
 * include <time.h> for Mac compiler
 *
 * Revision 6.22  2001/06/19 19:12:01  lavr
 * Type change: size_t -> TNCBI_Size; time_t -> TNCBI_Time
 *
 * Revision 6.21  2001/05/17 15:02:51  lavr
 * Typos corrected
 *
 * Revision 6.20  2001/05/11 15:30:31  lavr
 * Protocol change: REQUEST_FAILED -> DISP_FAILURES
 *
 * Revision 6.19  2001/05/03 16:58:16  lavr
 * FIX: Percent is taken of local bonus coef instead of the value itself
 *
 * Revision 6.18  2001/05/03 16:35:53  lavr
 * Local bonus coefficient modified: meaning of negative value changed
 *
 * Revision 6.17  2001/04/26 20:20:01  lavr
 * Better way of choosing local server with a tiny (e.g. penalized) status
 *
 * Revision 6.16  2001/04/24 21:35:46  lavr
 * Treatment of new bonus coefficient for local servers
 *
 * Revision 6.15  2001/03/21 21:24:11  lavr
 * Type match (int) for %n in scanf
 *
 * Revision 6.14  2001/03/06 23:57:27  lavr
 * SERV_DISPD_LOCAL_SVC_BONUS used for services running locally
 *
 * Revision 6.13  2001/03/05 23:10:46  lavr
 * SERV_ReadInfo takes only one argument now
 *
 * Revision 6.12  2001/03/01 00:33:12  lavr
 * FIXES: Empty update does not generate parse error
 *        Dispathing error is only logged in debug mode; milder severity
 *
 * Revision 6.11  2001/02/09 17:36:48  lavr
 * Modified: fSERV_StatelessOnly overrides info->stateless
 *
 * Revision 6.10  2001/01/25 17:06:36  lavr
 * s_FreeData now calls ConnNetInfo_Destroy() unconditionally
 *
 * Revision 6.9  2001/01/12 23:51:40  lavr
 * Message logging modified for use LOG facility only
 *
 * Revision 6.8  2001/01/08 23:48:14  lavr
 * (unsigned char) conversion in isspace
 *
 * Revision 6.7  2001/01/08 22:40:23  lavr
 * Further development of service-mapping protocol: stateless/stateful
 * is now separated from firewall/direct mode (see also in few more files)
 *
 * Revision 6.6  2000/12/29 18:05:46  lavr
 * First working revision.
 *
 * Revision 6.5  2000/10/20 17:36:05  lavr
 * Partially working dispd dispatcher client (service mapping works)
 * Checkin for backup purposes; working code '#if 0'-ed out
 *
 * Revision 6.4  2000/10/05 22:43:30  lavr
 * Another dummy revision: still in development
 *
 * Revision 6.3  2000/10/05 22:34:23  lavr
 * Temporary (dummy) revision for compilation to go
 *
 * Revision 6.2  2000/05/22 16:53:12  lavr
 * Rename service_info -> server_info everywhere (including
 * file names) as the latter name is more relevant
 *
 * Revision 6.1  2000/05/12 18:43:59  lavr
 * Initial revision
 *
 * ==========================================================================
 */