コード例 #1
0
ファイル: plugin_tc.c プロジェクト: firehol/netdata
void *tc_main(void *ptr) {
    netdata_thread_cleanup_push(tc_main_cleanup, ptr);

    struct rusage thread;

    char command[FILENAME_MAX + 1];
    char *words[PLUGINSD_MAX_WORDS] = { NULL };

    uint32_t BEGIN_HASH = simple_hash("BEGIN");
    uint32_t END_HASH = simple_hash("END");
    uint32_t QDISC_HASH = simple_hash("qdisc");
    uint32_t CLASS_HASH = simple_hash("class");
    uint32_t SENT_HASH = simple_hash("Sent");
    uint32_t LENDED_HASH = simple_hash("lended:");
    uint32_t TOKENS_HASH = simple_hash("tokens:");
    uint32_t SETDEVICENAME_HASH = simple_hash("SETDEVICENAME");
    uint32_t SETDEVICEGROUP_HASH = simple_hash("SETDEVICEGROUP");
    uint32_t SETCLASSNAME_HASH = simple_hash("SETCLASSNAME");
    uint32_t WORKTIME_HASH = simple_hash("WORKTIME");
#ifdef DETACH_PLUGINS_FROM_NETDATA
    uint32_t MYPID_HASH = simple_hash("MYPID");
#endif
    uint32_t first_hash;

    snprintfz(command, TC_LINE_MAX, "%s/tc-qos-helper.sh", netdata_configured_primary_plugins_dir);
    char *tc_script = config_get("plugin:tc", "script to run to get tc values", command);

    while(!netdata_exit) {
        FILE *fp;
        struct tc_device *device = NULL;
        struct tc_class *class = NULL;

        snprintfz(command, TC_LINE_MAX, "exec %s %d", tc_script, localhost->rrd_update_every);
        debug(D_TC_LOOP, "executing '%s'", command);

        fp = mypopen(command, (pid_t *)&tc_child_pid);
        if(unlikely(!fp)) {
            error("TC: Cannot popen(\"%s\", \"r\").", command);
            goto cleanup;
        }

        char buffer[TC_LINE_MAX+1] = "";
        while(fgets(buffer, TC_LINE_MAX, fp) != NULL) {
            if(unlikely(netdata_exit)) break;

            buffer[TC_LINE_MAX] = '\0';
            // debug(D_TC_LOOP, "TC: read '%s'", buffer);

            tc_split_words(buffer, words, PLUGINSD_MAX_WORDS);

            if(unlikely(!words[0] || !*words[0])) {
                // debug(D_TC_LOOP, "empty line");
                continue;
            }
            // else debug(D_TC_LOOP, "First word is '%s'", words[0]);

            first_hash = simple_hash(words[0]);

            if(unlikely(device && ((first_hash == CLASS_HASH && strcmp(words[0], "class") == 0) ||  (first_hash == QDISC_HASH && strcmp(words[0], "qdisc") == 0)))) {
                // debug(D_TC_LOOP, "CLASS line on class id='%s', parent='%s', parentid='%s', leaf='%s', leafid='%s'", words[2], words[3], words[4], words[5], words[6]);

                char *type     = words[1];  // the class/qdisc type: htb, fq_codel, etc
                char *id       = words[2];  // the class/qdisc major:minor
                char *parent   = words[3];  // the word 'parent' or 'root'
                char *parentid = words[4];  // parentid
                char *leaf     = words[5];  // the word 'leaf'
                char *leafid   = words[6];  // leafid

                int parent_is_root = 0;
                int parent_is_parent = 0;
                if(likely(parent)) {
                    parent_is_parent = !strcmp(parent, "parent");

                    if(!parent_is_parent)
                        parent_is_root = !strcmp(parent, "root");
                }

                if(likely(type && id && (parent_is_root || parent_is_parent))) {
                    char qdisc = 0;

                    if(first_hash == QDISC_HASH) {
                        qdisc = 1;

                        if(!strcmp(type, "ingress")) {
                            // we don't want to get the ingress qdisc
                            // there should be an IFB interface for this

                            class = NULL;
                            continue;
                        }

                        if(parent_is_parent && parentid) {
                            // eliminate the minor number from parentid
                            // why: parentid is the id of the parent class
                            // but major: is also the id of the parent qdisc

                            char *s = parentid;
                            while(*s && *s != ':') s++;
                            if(*s == ':') s[1] = '\0';
                        }
                    }

                    if(parent_is_root) {
                        parentid = NULL;
                        leafid = NULL;
                    }
                    else if(!leaf || strcmp(leaf, "leaf") != 0)
                        leafid = NULL;

                    char leafbuf[20 + 1] = "";
                    if(leafid && leafid[strlen(leafid) - 1] == ':') {
                        strncpyz(leafbuf, leafid, 20 - 1);
                        strcat(leafbuf, "1");
                        leafid = leafbuf;
                    }

                    class = tc_class_add(device, id, qdisc, parentid, leafid);
                }
                else {
コード例 #2
0
void *socket_listen_main_single_threaded(void *ptr) {
    netdata_thread_cleanup_push(socket_listen_main_single_threaded_cleanup, ptr);
    web_server_mode = WEB_SERVER_MODE_SINGLE_THREADED;
    web_server_is_multithreaded = 0;

    struct web_client *w;

    if(!api_sockets.opened)
        fatal("LISTENER: no listen sockets available.");

    size_t i;
    for(i = 0; i < (size_t)FD_SETSIZE ; i++)
        single_threaded_clients[i] = NULL;

    fd_set ifds, ofds, efds, rifds, rofds, refds;
    FD_ZERO (&ifds);
    FD_ZERO (&ofds);
    FD_ZERO (&efds);
    int fdmax = 0;

    for(i = 0; i < api_sockets.opened ; i++) {
        if (api_sockets.fds[i] < 0 || api_sockets.fds[i] >= (int)FD_SETSIZE)
            fatal("LISTENER: Listen socket %d is not ready, or invalid.", api_sockets.fds[i]);

        info("Listening on '%s'", (api_sockets.fds_names[i])?api_sockets.fds_names[i]:"UNKNOWN");

        FD_SET(api_sockets.fds[i], &ifds);
        FD_SET(api_sockets.fds[i], &efds);
        if(fdmax < api_sockets.fds[i])
            fdmax = api_sockets.fds[i];
    }

    while(!netdata_exit) {
        debug(D_WEB_CLIENT_ACCESS, "LISTENER: single threaded web server waiting (fdmax = %d)...", fdmax);

        struct timeval tv = { .tv_sec = 1, .tv_usec = 0 };
        rifds = ifds;
        rofds = ofds;
        refds = efds;
        int retval = select(fdmax+1, &rifds, &rofds, &refds, &tv);

        if(unlikely(retval == -1)) {
            error("LISTENER: select() failed.");
            continue;
        }
        else if(likely(retval)) {
            debug(D_WEB_CLIENT_ACCESS, "LISTENER: got something.");

            for(i = 0; i < api_sockets.opened ; i++) {
                if (FD_ISSET(api_sockets.fds[i], &rifds)) {
                    debug(D_WEB_CLIENT_ACCESS, "LISTENER: new connection.");
                    w = web_client_create_on_listenfd(api_sockets.fds[i]);
                    if(unlikely(!w))
                        continue;

                    if(api_sockets.fds_families[i] == AF_UNIX)
                        web_client_set_unix(w);
                    else
                        web_client_set_tcp(w);

                    if (single_threaded_link_client(w, &ifds, &ofds, &ifds, &fdmax) != 0) {
                        web_client_release(w);
                    }
                }
            }

            for(i = 0 ; i <= (size_t)fdmax ; i++) {
                if(likely(!FD_ISSET(i, &rifds) && !FD_ISSET(i, &rofds) && !FD_ISSET(i, &refds)))
                    continue;

                w = single_threaded_clients[i];
                if(unlikely(!w)) {
                    // error("no client on slot %zu", i);
                    continue;
                }

                if(unlikely(single_threaded_unlink_client(w, &ifds, &ofds, &efds) != 0)) {
                    // error("failed to unlink client %zu", i);
                    web_client_release(w);
                    continue;
                }

                if (unlikely(FD_ISSET(w->ifd, &refds) || FD_ISSET(w->ofd, &refds))) {
                    // error("no input on client %zu", i);
                    web_client_release(w);
                    continue;
                }

                if (unlikely(web_client_has_wait_receive(w) && FD_ISSET(w->ifd, &rifds))) {
                    if (unlikely(web_client_receive(w) < 0)) {
                        // error("cannot read from client %zu", i);
                        web_client_release(w);
                        continue;
                    }

                    if (w->mode != WEB_CLIENT_MODE_FILECOPY) {
                        debug(D_WEB_CLIENT, "%llu: Processing received data.", w->id);
                        web_client_process_request(w);
                    }
                }

                if (unlikely(web_client_has_wait_send(w) && FD_ISSET(w->ofd, &rofds))) {
                    if (unlikely(web_client_send(w) < 0)) {
                        // error("cannot send data to client %zu", i);
                        debug(D_WEB_CLIENT, "%llu: Cannot send data to client. Closing client.", w->id);
                        web_client_release(w);
                        continue;
                    }
                }

                if(unlikely(single_threaded_link_client(w, &ifds, &ofds, &efds, &fdmax) != 0)) {
                    // error("failed to link client %zu", i);
                    web_client_release(w);
                }
            }
        }
        else {
            debug(D_WEB_CLIENT_ACCESS, "LISTENER: single threaded web server timeout.");
        }
    }

    netdata_thread_cleanup_pop(1);
    return NULL;
}
コード例 #3
0
ファイル: plugin_proc_diskspace.c プロジェクト: cppmx/netdata
void *proc_diskspace_main(void *ptr) {
    netdata_thread_cleanup_push(diskspace_main_cleanup, ptr);

    int vdo_cpu_netdata = config_get_boolean("plugin:proc", "netdata server resources", 1);

    cleanup_mount_points = config_get_boolean(CONFIG_SECTION_DISKSPACE, "remove charts of unmounted disks" , cleanup_mount_points);

    int update_every = (int)config_get_number(CONFIG_SECTION_DISKSPACE, "update every", localhost->rrd_update_every);
    if(update_every < localhost->rrd_update_every)
        update_every = localhost->rrd_update_every;

    check_for_new_mountpoints_every = (int)config_get_number(CONFIG_SECTION_DISKSPACE, "check for new mount points every", check_for_new_mountpoints_every);
    if(check_for_new_mountpoints_every < update_every)
        check_for_new_mountpoints_every = update_every;

    struct rusage thread;

    usec_t duration = 0;
    usec_t step = update_every * USEC_PER_SEC;
    heartbeat_t hb;
    heartbeat_init(&hb);
    while(!netdata_exit) {
        duration = heartbeat_dt_usec(&hb);
        /* usec_t hb_dt = */ heartbeat_next(&hb, step);

        if(unlikely(netdata_exit)) break;


        // --------------------------------------------------------------------------
        // this is smart enough not to reload it every time

        mountinfo_reload(0);


        // --------------------------------------------------------------------------
        // disk space metrics

        struct mountinfo *mi;
        for(mi = disk_mountinfo_root; mi; mi = mi->next) {

            if(unlikely(mi->flags & (MOUNTINFO_IS_DUMMY | MOUNTINFO_IS_BIND)))
                continue;

            do_disk_space_stats(mi, update_every);
            if(unlikely(netdata_exit)) break;
        }

        if(unlikely(netdata_exit)) break;

        if(dict_mountpoints)
            dictionary_get_all(dict_mountpoints, mount_point_cleanup, NULL);

        if(vdo_cpu_netdata) {
            static RRDSET *stcpu_thread = NULL, *st_duration = NULL;
            static RRDDIM *rd_user = NULL, *rd_system = NULL, *rd_duration = NULL;

            // ----------------------------------------------------------------

            getrusage(RUSAGE_THREAD, &thread);

            if(unlikely(!stcpu_thread)) {
                stcpu_thread = rrdset_create_localhost(
                        "netdata"
                        , "plugin_diskspace"
                        , NULL
                        , "diskspace"
                        , NULL
                        , "NetData Disk Space Plugin CPU usage"
                        , "milliseconds/s"
                        , "diskspace"
                        , NULL
                        , 132020
                        , update_every
                        , RRDSET_TYPE_STACKED
                );

                rd_user   = rrddim_add(stcpu_thread, "user", NULL, 1, 1000, RRD_ALGORITHM_INCREMENTAL);
                rd_system = rrddim_add(stcpu_thread, "system", NULL, 1, 1000, RRD_ALGORITHM_INCREMENTAL);
            }
            else
                rrdset_next(stcpu_thread);

            rrddim_set_by_pointer(stcpu_thread, rd_user, thread.ru_utime.tv_sec * 1000000ULL + thread.ru_utime.tv_usec);
            rrddim_set_by_pointer(stcpu_thread, rd_system, thread.ru_stime.tv_sec * 1000000ULL + thread.ru_stime.tv_usec);
            rrdset_done(stcpu_thread);

            // ----------------------------------------------------------------

            if(unlikely(!st_duration)) {
                st_duration = rrdset_create_localhost(
                        "netdata"
                        , "plugin_diskspace_dt"
                        , NULL
                        , "diskspace"
                        , NULL
                        , "NetData Disk Space Plugin Duration"
                        , "milliseconds/run"
                        , "diskspace"
                        , NULL
                        , 132021
                        , update_every
                        , RRDSET_TYPE_AREA
                );

                rd_duration = rrddim_add(st_duration, "duration", NULL, 1, 1000, RRD_ALGORITHM_ABSOLUTE);
            }
            else
                rrdset_next(st_duration);

            rrddim_set_by_pointer(st_duration, rd_duration, duration);
            rrdset_done(st_duration);

            // ----------------------------------------------------------------

            if(unlikely(netdata_exit)) break;
        }
    }

    netdata_thread_cleanup_pop(1);
    return NULL;
}
コード例 #4
0
ファイル: backends.c プロジェクト: Peoplecantfly/netdata
void *backends_main(void *ptr) {
    netdata_thread_cleanup_push(backends_main_cleanup, ptr);

    int default_port = 0;
    int sock = -1;
    BUFFER *b = buffer_create(1), *response = buffer_create(1);
    int (*backend_request_formatter)(BUFFER *, const char *, RRDHOST *, const char *, RRDSET *, RRDDIM *, time_t, time_t, uint32_t) = NULL;
    int (*backend_response_checker)(BUFFER *) = NULL;

    // ------------------------------------------------------------------------
    // collect configuration options

    struct timeval timeout = {
            .tv_sec = 0,
            .tv_usec = 0
    };
    int enabled             = config_get_boolean(CONFIG_SECTION_BACKEND, "enabled", 0);
    const char *source      = config_get(CONFIG_SECTION_BACKEND, "data source", "average");
    const char *type        = config_get(CONFIG_SECTION_BACKEND, "type", "graphite");
    const char *destination = config_get(CONFIG_SECTION_BACKEND, "destination", "localhost");
    backend_prefix          = config_get(CONFIG_SECTION_BACKEND, "prefix", "netdata");
    const char *hostname    = config_get(CONFIG_SECTION_BACKEND, "hostname", localhost->hostname);
    backend_update_every    = (int)config_get_number(CONFIG_SECTION_BACKEND, "update every", backend_update_every);
    int buffer_on_failures  = (int)config_get_number(CONFIG_SECTION_BACKEND, "buffer on failures", 10);
    long timeoutms          = config_get_number(CONFIG_SECTION_BACKEND, "timeout ms", backend_update_every * 2 * 1000);
    backend_send_names      = config_get_boolean(CONFIG_SECTION_BACKEND, "send names instead of ids", backend_send_names);

    charts_pattern = simple_pattern_create(config_get(CONFIG_SECTION_BACKEND, "send charts matching", "*"), NULL, SIMPLE_PATTERN_EXACT);
    hosts_pattern = simple_pattern_create(config_get(CONFIG_SECTION_BACKEND, "send hosts matching", "localhost *"), NULL, SIMPLE_PATTERN_EXACT);


    // ------------------------------------------------------------------------
    // validate configuration options
    // and prepare for sending data to our backend

    backend_options = backend_parse_data_source(source, backend_options);

    if(timeoutms < 1) {
        error("BACKEND: invalid timeout %ld ms given. Assuming %d ms.", timeoutms, backend_update_every * 2 * 1000);
        timeoutms = backend_update_every * 2 * 1000;
    }
    timeout.tv_sec  = (timeoutms * 1000) / 1000000;
    timeout.tv_usec = (timeoutms * 1000) % 1000000;

    if(!enabled || backend_update_every < 1)
        goto cleanup;

    // ------------------------------------------------------------------------
    // select the backend type

    if(!strcmp(type, "graphite") || !strcmp(type, "graphite:plaintext")) {

        default_port = 2003;
        backend_response_checker = process_graphite_response;

        if((backend_options & BACKEND_SOURCE_BITS) == BACKEND_SOURCE_DATA_AS_COLLECTED)
            backend_request_formatter = format_dimension_collected_graphite_plaintext;
        else
            backend_request_formatter = format_dimension_stored_graphite_plaintext;

    }
    else if(!strcmp(type, "opentsdb") || !strcmp(type, "opentsdb:telnet")) {

        default_port = 4242;
        backend_response_checker = process_opentsdb_response;

        if((backend_options & BACKEND_SOURCE_BITS) == BACKEND_SOURCE_DATA_AS_COLLECTED)
            backend_request_formatter = format_dimension_collected_opentsdb_telnet;
        else
            backend_request_formatter = format_dimension_stored_opentsdb_telnet;

    }
    else if (!strcmp(type, "json") || !strcmp(type, "json:plaintext")) {

        default_port = 5448;
        backend_response_checker = process_json_response;

        if ((backend_options & BACKEND_SOURCE_BITS) == BACKEND_SOURCE_DATA_AS_COLLECTED)
            backend_request_formatter = format_dimension_collected_json_plaintext;
        else
            backend_request_formatter = format_dimension_stored_json_plaintext;

    }
    else {
        error("BACKEND: Unknown backend type '%s'", type);
        goto cleanup;
    }

    if(backend_request_formatter == NULL || backend_response_checker == NULL) {
        error("BACKEND: backend is misconfigured - disabling it.");
        goto cleanup;
    }


    // ------------------------------------------------------------------------
    // prepare the charts for monitoring the backend operation

    struct rusage thread;

    collected_number
            chart_buffered_metrics = 0,
            chart_lost_metrics = 0,
            chart_sent_metrics = 0,
            chart_buffered_bytes = 0,
            chart_received_bytes = 0,
            chart_sent_bytes = 0,
            chart_receptions = 0,
            chart_transmission_successes = 0,
            chart_transmission_failures = 0,
            chart_data_lost_events = 0,
            chart_lost_bytes = 0,
            chart_backend_reconnects = 0,
            chart_backend_latency = 0;

    RRDSET *chart_metrics = rrdset_create_localhost("netdata", "backend_metrics", NULL, "backend", NULL, "Netdata Buffered Metrics", "metrics", "backends", NULL, 130600, backend_update_every, RRDSET_TYPE_LINE);
    rrddim_add(chart_metrics, "buffered", NULL,  1, 1, RRD_ALGORITHM_ABSOLUTE);
    rrddim_add(chart_metrics, "lost",     NULL,  1, 1, RRD_ALGORITHM_ABSOLUTE);
    rrddim_add(chart_metrics, "sent",     NULL,  1, 1, RRD_ALGORITHM_ABSOLUTE);

    RRDSET *chart_bytes = rrdset_create_localhost("netdata", "backend_bytes", NULL, "backend", NULL, "Netdata Backend Data Size", "KB", "backends", NULL, 130610, backend_update_every, RRDSET_TYPE_AREA);
    rrddim_add(chart_bytes, "buffered", NULL, 1, 1024, RRD_ALGORITHM_ABSOLUTE);
    rrddim_add(chart_bytes, "lost",     NULL, 1, 1024, RRD_ALGORITHM_ABSOLUTE);
    rrddim_add(chart_bytes, "sent",     NULL, 1, 1024, RRD_ALGORITHM_ABSOLUTE);
    rrddim_add(chart_bytes, "received", NULL, 1, 1024, RRD_ALGORITHM_ABSOLUTE);

    RRDSET *chart_ops = rrdset_create_localhost("netdata", "backend_ops", NULL, "backend", NULL, "Netdata Backend Operations", "operations", "backends", NULL, 130630, backend_update_every, RRDSET_TYPE_LINE);
    rrddim_add(chart_ops, "write",     NULL, 1, 1, RRD_ALGORITHM_ABSOLUTE);
    rrddim_add(chart_ops, "discard",   NULL, 1, 1, RRD_ALGORITHM_ABSOLUTE);
    rrddim_add(chart_ops, "reconnect", NULL, 1, 1, RRD_ALGORITHM_ABSOLUTE);
    rrddim_add(chart_ops, "failure",   NULL, 1, 1, RRD_ALGORITHM_ABSOLUTE);
    rrddim_add(chart_ops, "read",      NULL, 1, 1, RRD_ALGORITHM_ABSOLUTE);

    /*
     * this is misleading - we can only measure the time we need to send data
     * this time is not related to the time required for the data to travel to
     * the backend database and the time that server needed to process them
     *
     * issue #1432 and https://www.softlab.ntua.gr/facilities/documentation/unix/unix-socket-faq/unix-socket-faq-2.html
     *
    RRDSET *chart_latency = rrdset_create_localhost("netdata", "backend_latency", NULL, "backend", NULL, "Netdata Backend Latency", "ms", "backends", NULL, 130620, backend_update_every, RRDSET_TYPE_AREA);
    rrddim_add(chart_latency, "latency",   NULL,  1, 1000, RRD_ALGORITHM_ABSOLUTE);
    */

    RRDSET *chart_rusage = rrdset_create_localhost("netdata", "backend_thread_cpu", NULL, "backend", NULL, "NetData Backend Thread CPU usage", "milliseconds/s", "backends", NULL, 130630, backend_update_every, RRDSET_TYPE_STACKED);
    rrddim_add(chart_rusage, "user",   NULL, 1, 1000, RRD_ALGORITHM_INCREMENTAL);
    rrddim_add(chart_rusage, "system", NULL, 1, 1000, RRD_ALGORITHM_INCREMENTAL);


    // ------------------------------------------------------------------------
    // prepare the backend main loop

    info("BACKEND: configured ('%s' on '%s' sending '%s' data, every %d seconds, as host '%s', with prefix '%s')", type, destination, source, backend_update_every, hostname, backend_prefix);

    usec_t step_ut = backend_update_every * USEC_PER_SEC;
    time_t after = now_realtime_sec();
    int failures = 0;
    heartbeat_t hb;
    heartbeat_init(&hb);

    while(!netdata_exit) {

        // ------------------------------------------------------------------------
        // Wait for the next iteration point.

        heartbeat_next(&hb, step_ut);
        time_t before = now_realtime_sec();
        debug(D_BACKEND, "BACKEND: preparing buffer for timeframe %lu to %lu", (unsigned long)after, (unsigned long)before);

        // ------------------------------------------------------------------------
        // add to the buffer the data we need to send to the backend

        netdata_thread_disable_cancelability();

        size_t count_hosts = 0;
        size_t count_charts_total = 0;
        size_t count_dims_total = 0;

        rrd_rdlock();
        RRDHOST *host;
        rrdhost_foreach_read(host) {
            if(unlikely(!rrdhost_flag_check(host, RRDHOST_FLAG_BACKEND_SEND|RRDHOST_FLAG_BACKEND_DONT_SEND))) {
                char *name = (host == localhost)?"localhost":host->hostname;
                if (!hosts_pattern || simple_pattern_matches(hosts_pattern, name)) {
                    rrdhost_flag_set(host, RRDHOST_FLAG_BACKEND_SEND);
                    info("enabled backend for host '%s'", name);
                }
                else {
                    rrdhost_flag_set(host, RRDHOST_FLAG_BACKEND_DONT_SEND);
                    info("disabled backend for host '%s'", name);
                }
            }

            if(unlikely(!rrdhost_flag_check(host, RRDHOST_FLAG_BACKEND_SEND)))
                continue;

            rrdhost_rdlock(host);

            count_hosts++;
            size_t count_charts = 0;
            size_t count_dims = 0;
            size_t count_dims_skipped = 0;

            const char *__hostname = (host == localhost)?hostname:host->hostname;

            RRDSET *st;
            rrdset_foreach_read(st, host) {
                if(likely(backends_can_send_rrdset(backend_options, st))) {
                    rrdset_rdlock(st);

                    count_charts++;

                    RRDDIM *rd;
                    rrddim_foreach_read(rd, st) {
                        if (likely(rd->last_collected_time.tv_sec >= after)) {
                            chart_buffered_metrics += backend_request_formatter(b, backend_prefix, host, __hostname, st, rd, after, before, backend_options);
                            count_dims++;
                        }
                        else {
                            debug(D_BACKEND, "BACKEND: not sending dimension '%s' of chart '%s' from host '%s', its last data collection (%lu) is not within our timeframe (%lu to %lu)", rd->id, st->id, __hostname, (unsigned long)rd->last_collected_time.tv_sec, (unsigned long)after, (unsigned long)before);
                            count_dims_skipped++;
                        }
                    }

                    rrdset_unlock(st);
                }
            }

            debug(D_BACKEND, "BACKEND: sending host '%s', metrics of %zu dimensions, of %zu charts. Skipped %zu dimensions.", __hostname, count_dims, count_charts, count_dims_skipped);
            count_charts_total += count_charts;
            count_dims_total += count_dims;

            rrdhost_unlock(host);
        }
        rrd_unlock();

        netdata_thread_enable_cancelability();

        debug(D_BACKEND, "BACKEND: buffer has %zu bytes, added metrics for %zu dimensions, of %zu charts, from %zu hosts", buffer_strlen(b), count_dims_total, count_charts_total, count_hosts);

        // ------------------------------------------------------------------------

        chart_buffered_bytes = (collected_number)buffer_strlen(b);

        // reset the monitoring chart counters
        chart_received_bytes =
        chart_sent_bytes =
        chart_sent_metrics =
        chart_lost_metrics =
        chart_transmission_successes =
        chart_transmission_failures =
        chart_data_lost_events =
        chart_lost_bytes =
        chart_backend_reconnects =
        chart_backend_latency = 0;

        if(unlikely(netdata_exit)) break;

        //fprintf(stderr, "\nBACKEND BEGIN:\n%s\nBACKEND END\n", buffer_tostring(b)); // FIXME
        //fprintf(stderr, "after = %lu, before = %lu\n", after, before);

        // prepare for the next iteration
        // to add incrementally data to buffer
        after = before;

        // ------------------------------------------------------------------------
        // if we are connected, receive a response, without blocking

        if(likely(sock != -1)) {
            errno = 0;

            // loop through to collect all data
            while(sock != -1 && errno != EWOULDBLOCK) {
                buffer_need_bytes(response, 4096);

                ssize_t r = recv(sock, &response->buffer[response->len], response->size - response->len, MSG_DONTWAIT);
                if(likely(r > 0)) {
                    // we received some data
                    response->len += r;
                    chart_received_bytes += r;
                    chart_receptions++;
                }
                else if(r == 0) {
                    error("BACKEND: '%s' closed the socket", destination);
                    close(sock);
                    sock = -1;
                }
                else {
                    // failed to receive data
                    if(errno != EAGAIN && errno != EWOULDBLOCK) {
                        error("BACKEND: cannot receive data from backend '%s'.", destination);
                    }
                }
            }

            // if we received data, process them
            if(buffer_strlen(response))
                backend_response_checker(response);
        }

        // ------------------------------------------------------------------------
        // if we are not connected, connect to a backend server

        if(unlikely(sock == -1)) {
            usec_t start_ut = now_monotonic_usec();
            size_t reconnects = 0;

            sock = connect_to_one_of(destination, default_port, &timeout, &reconnects, NULL, 0);

            chart_backend_reconnects += reconnects;
            chart_backend_latency += now_monotonic_usec() - start_ut;
        }

        if(unlikely(netdata_exit)) break;

        // ------------------------------------------------------------------------
        // if we are connected, send our buffer to the backend server

        if(likely(sock != -1)) {
            size_t len = buffer_strlen(b);
            usec_t start_ut = now_monotonic_usec();
            int flags = 0;
#ifdef MSG_NOSIGNAL
            flags += MSG_NOSIGNAL;
#endif

            ssize_t written = send(sock, buffer_tostring(b), len, flags);
            chart_backend_latency += now_monotonic_usec() - start_ut;
            if(written != -1 && (size_t)written == len) {
                // we sent the data successfully
                chart_transmission_successes++;
                chart_sent_bytes += written;
                chart_sent_metrics = chart_buffered_metrics;

                // reset the failures count
                failures = 0;

                // empty the buffer
                buffer_flush(b);
            }
            else {
                // oops! we couldn't send (all or some of the) data
                error("BACKEND: failed to write data to database backend '%s'. Willing to write %zu bytes, wrote %zd bytes. Will re-connect.", destination, len, written);
                chart_transmission_failures++;

                if(written != -1)
                    chart_sent_bytes += written;

                // increment the counter we check for data loss
                failures++;

                // close the socket - we will re-open it next time
                close(sock);
                sock = -1;
            }
        }
        else {
            error("BACKEND: failed to update database backend '%s'", destination);
            chart_transmission_failures++;

            // increment the counter we check for data loss
            failures++;
        }

        if(failures > buffer_on_failures) {
            // too bad! we are going to lose data
            chart_lost_bytes += buffer_strlen(b);
            error("BACKEND: reached %d backend failures. Flushing buffers to protect this host - this results in data loss on back-end server '%s'", failures, destination);
            buffer_flush(b);
            failures = 0;
            chart_data_lost_events++;
            chart_lost_metrics = chart_buffered_metrics;
        }

        if(unlikely(netdata_exit)) break;

        // ------------------------------------------------------------------------
        // update the monitoring charts

        if(likely(chart_ops->counter_done)) rrdset_next(chart_ops);
        rrddim_set(chart_ops, "read",         chart_receptions);
        rrddim_set(chart_ops, "write",        chart_transmission_successes);
        rrddim_set(chart_ops, "discard",      chart_data_lost_events);
        rrddim_set(chart_ops, "failure",      chart_transmission_failures);
        rrddim_set(chart_ops, "reconnect",    chart_backend_reconnects);
        rrdset_done(chart_ops);

        if(likely(chart_metrics->counter_done)) rrdset_next(chart_metrics);
        rrddim_set(chart_metrics, "buffered", chart_buffered_metrics);
        rrddim_set(chart_metrics, "lost",     chart_lost_metrics);
        rrddim_set(chart_metrics, "sent",     chart_sent_metrics);
        rrdset_done(chart_metrics);

        if(likely(chart_bytes->counter_done)) rrdset_next(chart_bytes);
        rrddim_set(chart_bytes, "buffered",   chart_buffered_bytes);
        rrddim_set(chart_bytes, "lost",       chart_lost_bytes);
        rrddim_set(chart_bytes, "sent",       chart_sent_bytes);
        rrddim_set(chart_bytes, "received",   chart_received_bytes);
        rrdset_done(chart_bytes);

        /*
        if(likely(chart_latency->counter_done)) rrdset_next(chart_latency);
        rrddim_set(chart_latency, "latency",  chart_backend_latency);
        rrdset_done(chart_latency);
        */

        getrusage(RUSAGE_THREAD, &thread);
        if(likely(chart_rusage->counter_done)) rrdset_next(chart_rusage);
        rrddim_set(chart_rusage, "user",   thread.ru_utime.tv_sec * 1000000ULL + thread.ru_utime.tv_usec);
        rrddim_set(chart_rusage, "system", thread.ru_stime.tv_sec * 1000000ULL + thread.ru_stime.tv_usec);
        rrdset_done(chart_rusage);

        if(likely(buffer_strlen(b) == 0))
            chart_buffered_metrics = 0;

        if(unlikely(netdata_exit)) break;
    }

cleanup:
    if(sock != -1)
        close(sock);

    buffer_free(b);
    buffer_free(response);

    netdata_thread_cleanup_pop(1);
    return NULL;
}