/**
 * collectd - src/write_tsdb.c
 * Copyright (C) 2012       Pierre-Yves Ritschard
 * Copyright (C) 2011       Scott Sanders
 * Copyright (C) 2009       Paul Sadauskas
 * Copyright (C) 2009       Doug MacEachern
 * Copyright (C) 2007-2012  Florian octo Forster
 * Copyright (C) 2013-2014  Limelight Networks, Inc.
 * 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; only version 2 of the License is applicable.
 *
 * 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
 *
 * Based on the write_graphite plugin. Authors:
 *   Florian octo Forster <octo at collectd.org>
 *   Doug MacEachern <dougm at hyperic.com>
 *   Paul Sadauskas <psadauskas at gmail.com>
 *   Scott Sanders <scott at jssjr.com>
 *   Pierre-Yves Ritschard <pyr at spootnik.org>
 * write_tsdb Authors:
 *   Brett Hawn <bhawn at llnw.com>
 *   Kevin Bowling <kbowling@llnw.com>
 **/

/* write_tsdb plugin configuation example
 *
 * <Plugin write_tsdb>
 *   <Node>
 *     Host "localhost"
 *     Port "4242"
 *     HostTags "status=production deviceclass=www"
 *   </Node>
 * </Plugin>
 */

#include "collectd.h"
#include "common.h"
#include "plugin.h"
#include "configfile.h"

#include "utils_cache.h"

#include <pthread.h>
#include <sys/socket.h>
#include <netdb.h>

#ifndef WT_DEFAULT_NODE
# define WT_DEFAULT_NODE "localhost"
#endif

#ifndef WT_DEFAULT_SERVICE
# define WT_DEFAULT_SERVICE "4242"
#endif

#ifndef WT_DEFAULT_ESCAPE
# define WT_DEFAULT_ESCAPE '.'
#endif

/* Ethernet - (IPv6 + TCP) = 1500 - (40 + 32) = 1428 */
#ifndef WT_SEND_BUF_SIZE
# define WT_SEND_BUF_SIZE 1428
#endif

/*
 * Private variables
 */
struct wt_callback
{
    int      sock_fd;

    char     *node;
    char     *service;
    char     *host_tags;

    _Bool    store_rates;
    _Bool    always_append_ds;

    char     send_buf[WT_SEND_BUF_SIZE];
    size_t   send_buf_free;
    size_t   send_buf_fill;
    cdtime_t send_buf_init_time;

    pthread_mutex_t send_lock;
};


/*
 * Functions
 */
static void wt_reset_buffer(struct wt_callback *cb)
{
    memset(cb->send_buf, 0, sizeof(cb->send_buf));
    cb->send_buf_free = sizeof(cb->send_buf);
    cb->send_buf_fill = 0;
    cb->send_buf_init_time = cdtime();
}

static int wt_send_buffer(struct wt_callback *cb)
{
    ssize_t status = 0;

    status = swrite(cb->sock_fd, cb->send_buf, strlen(cb->send_buf));
    if (status < 0)
    {
        char errbuf[1024];
        ERROR("write_tsdb plugin: send failed with status %zi (%s)",
              status, sstrerror (errno, errbuf, sizeof (errbuf)));

        close (cb->sock_fd);
        cb->sock_fd = -1;

        return -1;
    }

    return 0;
}

/* NOTE: You must hold cb->send_lock when calling this function! */
static int wt_flush_nolock(cdtime_t timeout, struct wt_callback *cb)
{
    int status;

    DEBUG("write_tsdb plugin: wt_flush_nolock: timeout = %.3f; "
          "send_buf_fill = %zu;",
          (double)timeout,
          cb->send_buf_fill);

    /* timeout == 0  => flush unconditionally */
    if (timeout > 0)
    {
        cdtime_t now;

        now = cdtime();
        if ((cb->send_buf_init_time + timeout) > now)
            return 0;
    }

    if (cb->send_buf_fill <= 0)
    {
        cb->send_buf_init_time = cdtime();
        return 0;
    }

    status = wt_send_buffer(cb);
    wt_reset_buffer(cb);

    return status;
}

static int wt_callback_init(struct wt_callback *cb)
{
    struct addrinfo ai_hints;
    struct addrinfo *ai_list;
    struct addrinfo *ai_ptr;
    int status;

    const char *node = cb->node ? cb->node : WT_DEFAULT_NODE;
    const char *service = cb->service ? cb->service : WT_DEFAULT_SERVICE;

    if (cb->sock_fd > 0)
        return 0;

    memset(&ai_hints, 0, sizeof(ai_hints));
#ifdef AI_ADDRCONFIG
    ai_hints.ai_flags    |= AI_ADDRCONFIG;
#endif
    ai_hints.ai_family   = AF_UNSPEC;
    ai_hints.ai_socktype = SOCK_STREAM;

    ai_list = NULL;

    status = getaddrinfo(node, service, &ai_hints, &ai_list);
    if (status != 0)
    {
        ERROR("write_tsdb plugin: getaddrinfo (%s, %s) failed: %s",
              node, service, gai_strerror (status));
        return -1;
    }

    assert (ai_list != NULL);
    for (ai_ptr = ai_list; ai_ptr != NULL; ai_ptr = ai_ptr->ai_next)
    {
        cb->sock_fd = socket(ai_ptr->ai_family, ai_ptr->ai_socktype,
                             ai_ptr->ai_protocol);
        if (cb->sock_fd < 0)
            continue;

        status = connect(cb->sock_fd, ai_ptr->ai_addr, ai_ptr->ai_addrlen);
        if (status != 0)
        {
            close(cb->sock_fd);
            cb->sock_fd = -1;
            continue;
        }

        break;
    }

    freeaddrinfo(ai_list);

    if (cb->sock_fd < 0)
    {
        char errbuf[1024];
        ERROR("write_tsdb plugin: Connecting to %s:%s failed. "
              "The last error was: %s", node, service,
              sstrerror (errno, errbuf, sizeof(errbuf)));
        close(cb->sock_fd);
        return -1;
    }

    wt_reset_buffer(cb);

    return 0;
}

static void wt_callback_free(void *data)
{
    struct wt_callback *cb;

    if (data == NULL)
        return;

    cb = data;

    pthread_mutex_lock(&cb->send_lock);

    wt_flush_nolock(0, cb);

    close(cb->sock_fd);
    cb->sock_fd = -1;

    sfree(cb->node);
    sfree(cb->service);
    sfree(cb->host_tags);

    pthread_mutex_destroy(&cb->send_lock);

    sfree(cb);
}

static int wt_flush(cdtime_t timeout,
                    const char *identifier __attribute__((unused)),
                    user_data_t *user_data)
{
    struct wt_callback *cb;
    int status;

    if (user_data == NULL)
        return -EINVAL;

    cb = user_data->data;

    pthread_mutex_lock(&cb->send_lock);

    if (cb->sock_fd < 0)
    {
        status = wt_callback_init(cb);
        if (status != 0)
        {
            ERROR("write_tsdb plugin: wt_callback_init failed.");
            pthread_mutex_unlock(&cb->send_lock);
            return -1;
        }
    }

    status = wt_flush_nolock(timeout, cb);
    pthread_mutex_unlock(&cb->send_lock);

    return status;
}

static int wt_format_values(char *ret, size_t ret_len,
                            int ds_num, const data_set_t *ds,
                            const value_list_t *vl,
                            _Bool store_rates)
{
    size_t offset = 0;
    int status;
    gauge_t *rates = NULL;

    assert(0 == strcmp (ds->type, vl->type));

    memset(ret, 0, ret_len);

#define BUFFER_ADD(...) do { \
        status = ssnprintf (ret + offset, ret_len - offset, \
                            __VA_ARGS__); \
        if (status < 1) \
        { \
            sfree(rates); \
            return -1; \
        } \
        else if (((size_t) status) >= (ret_len - offset)) \
        { \
            sfree(rates); \
            return -1; \
        } \
        else \
            offset += ((size_t) status); \
} while (0)

    if (ds->ds[ds_num].type == DS_TYPE_GAUGE)
        BUFFER_ADD(GAUGE_FORMAT, vl->values[ds_num].gauge);
    else if (store_rates)
    {
        if (rates == NULL)
            rates = uc_get_rate (ds, vl);
        if (rates == NULL)
        {
            WARNING("format_values: "
                    "uc_get_rate failed.");
            return -1;
        }
        BUFFER_ADD(GAUGE_FORMAT, rates[ds_num]);
    }
    else if (ds->ds[ds_num].type == DS_TYPE_COUNTER)
        BUFFER_ADD("%llu", vl->values[ds_num].counter);
    else if (ds->ds[ds_num].type == DS_TYPE_DERIVE)
        BUFFER_ADD("%" PRIi64, vl->values[ds_num].derive);
    else if (ds->ds[ds_num].type == DS_TYPE_ABSOLUTE)
        BUFFER_ADD("%" PRIu64, vl->values[ds_num].absolute);
    else
    {
        ERROR("format_values plugin: Unknown data source type: %i",
              ds->ds[ds_num].type);
        sfree(rates);
        return -1;
    }

#undef BUFFER_ADD

    sfree(rates);
    return 0;
}

static int wt_format_name(char *ret, int ret_len,
                          const value_list_t *vl,
                          const struct wt_callback *cb,
                          const char *ds_name)
{
    int status;
    char *temp = NULL;
    char *prefix = "";
    const char *meta_prefix = "tsdb_prefix";

    if (vl->meta) {
        status = meta_data_get_string(vl->meta, meta_prefix, &temp);
        if (status == -ENOENT) {
            /* defaults to empty string */
        } else if (status < 0) {
            sfree(temp);
            return status;
        } else {
            prefix = temp;
        }
    }

    if (ds_name != NULL) {
        if (vl->plugin_instance[0] == '\0') {
            if (vl->type_instance[0] == '\0') {
                ssnprintf(ret, ret_len, "%s%s.%s.%s", prefix, vl->plugin,
                        vl->type, ds_name);
            } else {
                ssnprintf(ret, ret_len, "%s%s.%s.%s.%s", prefix, vl->plugin,
                        vl->type, vl->type_instance, ds_name);
            }
        } else { /* vl->plugin_instance != "" */
            if (vl->type_instance[0] == '\0') {
                ssnprintf(ret, ret_len, "%s%s.%s.%s.%s", prefix, vl->plugin,
                        vl->plugin_instance, vl->type, ds_name);
            } else {
                ssnprintf(ret, ret_len, "%s%s.%s.%s.%s.%s", prefix,
                        vl->plugin, vl->plugin_instance, vl->type,
                        vl->type_instance, ds_name);
            }
        }
    } else { /* ds_name == NULL */
        if (vl->plugin_instance[0] == '\0') {
            if (vl->type_instance[0] == '\0') {
                ssnprintf(ret, ret_len, "%s%s.%s", prefix, vl->plugin,
                        vl->type);
            } else {
                ssnprintf(ret, ret_len, "%s%s.%s.%s", prefix, vl->plugin,
                        vl->type_instance, vl->type);
            }
        } else { /* vl->plugin_instance != "" */
            if (vl->type_instance[0] == '\0') {
                ssnprintf(ret, ret_len, "%s%s.%s.%s", prefix, vl->plugin,
                        vl->plugin_instance, vl->type);
            } else {
                ssnprintf(ret, ret_len, "%s%s.%s.%s.%s", prefix, vl->plugin,
                        vl->plugin_instance, vl->type, vl->type_instance);
            }
        }
    }

    sfree(temp);
    return 0;
}

static int wt_send_message (const char* key, const char* value,
                            cdtime_t time, struct wt_callback *cb,
                            const char* host, meta_data_t *md)
{
    int status;
    int message_len;
    char *temp = NULL;
    char *tags = "";
    char message[1024];
    char *host_tags = cb->host_tags ? cb->host_tags : "";
    const char *meta_tsdb = "tsdb_tags";

    /* skip if value is NaN */
    if (value[0] == 'n')
        return 0;

    if (md) {
        status = meta_data_get_string(md, meta_tsdb, &temp);
        if (status == -ENOENT) {
            /* defaults to empty string */
        } else if (status < 0) {
            ERROR("write_tsdb plugin: tags metadata get failure");
            sfree(temp);
            pthread_mutex_unlock(&cb->send_lock);
            return status;
        } else {
            tags = temp;
        }
    }

    message_len = ssnprintf (message,
                             sizeof(message),
                             "put %s %.0f %s fqdn=%s %s %s\r\n",
                             key,
                             CDTIME_T_TO_DOUBLE(time),
                             value,
                             host,
                             tags,
                             host_tags);

    sfree(temp);

    if (message_len >= sizeof(message)) {
        ERROR("write_tsdb plugin: message buffer too small: "
              "Need %d bytes.", message_len + 1);
        return -1;
    }

    pthread_mutex_lock(&cb->send_lock);

    if (cb->sock_fd < 0)
    {
        status = wt_callback_init(cb);
        if (status != 0)
        {
            ERROR("write_tsdb plugin: wt_callback_init failed.");
            pthread_mutex_unlock(&cb->send_lock);
            return -1;
        }
    }

    if (message_len >= cb->send_buf_free)
    {
        status = wt_flush_nolock(0, cb);
        if (status != 0)
        {
            pthread_mutex_unlock(&cb->send_lock);
            return status;
        }
    }

    /* Assert that we have enough space for this message. */
    assert(message_len < cb->send_buf_free);

    /* `message_len + 1' because `message_len' does not include the
     * trailing null byte. Neither does `send_buffer_fill'. */
    memcpy(cb->send_buf + cb->send_buf_fill,
            message, message_len + 1);
    cb->send_buf_fill += message_len;
    cb->send_buf_free -= message_len;

    DEBUG("write_tsdb plugin: [%s]:%s buf %zu/%zu (%.1f %%) \"%s\"",
          cb->node,
          cb->service,
          cb->send_buf_fill, sizeof(cb->send_buf),
          100.0 * ((double) cb->send_buf_fill) /
          ((double) sizeof(cb->send_buf)),
          message);

    pthread_mutex_unlock(&cb->send_lock);

    return 0;
}

static int wt_write_messages(const data_set_t *ds, const value_list_t *vl,
                             struct wt_callback *cb)
{
    char key[10*DATA_MAX_NAME_LEN];
    char values[512];

    int status, i;

    if (0 != strcmp(ds->type, vl->type))
    {
        ERROR("write_tsdb plugin: DS type does not match "
              "value list type");
        return -1;
    }

    for (i = 0; i < ds->ds_num; i++)
    {
        const char *ds_name = NULL;

        if (cb->always_append_ds || (ds->ds_num > 1))
            ds_name = ds->ds[i].name;

        /* Copy the identifier to 'key' and escape it. */
        status = wt_format_name(key, sizeof(key), vl, cb, ds_name);
        if (status != 0)
        {
            ERROR("write_tsdb plugin: error with format_name");
            return status;
        }

        escape_string(key, sizeof(key));
        /* Convert the values to an ASCII representation and put that into
         * 'values'. */
        status = wt_format_values(values, sizeof(values), i, ds, vl,
                                  cb->store_rates);
        if (status != 0)
        {
            ERROR("write_tsdb plugin: error with "
                  "wt_format_values");
            return status;
        }

        /* Send the message to tsdb */
        status = wt_send_message(key, values, vl->time, cb, vl->host, vl->meta);
        if (status != 0)
        {
            ERROR("write_tsdb plugin: error with "
                  "wt_send_message");
            return status;
        }
    }

    return 0;
}

static int wt_write(const data_set_t *ds, const value_list_t *vl,
                    user_data_t *user_data)
{
    struct wt_callback *cb;
    int status;

    if (user_data == NULL)
        return EINVAL;

    cb = user_data->data;

    status = wt_write_messages(ds, vl, cb);

    return status;
}

static int wt_config_tsd(oconfig_item_t *ci)
{
    struct wt_callback *cb;
    user_data_t user_data;
    char callback_name[DATA_MAX_NAME_LEN];
    int i;

    cb = malloc(sizeof(*cb));
    if (cb == NULL)
    {
        ERROR("write_tsdb plugin: malloc failed.");
        return -1;
    }
    memset(cb, 0, sizeof(*cb));
    cb->sock_fd = -1;
    cb->node = NULL;
    cb->service = NULL;
    cb->host_tags = NULL;
    cb->store_rates = 0;

    pthread_mutex_init (&cb->send_lock, NULL);

    for (i = 0; i < ci->children_num; i++)
    {
        oconfig_item_t *child = ci->children + i;

        if (strcasecmp("Host", child->key) == 0)
            cf_util_get_string(child, &cb->node);
        else if (strcasecmp("Port", child->key) == 0)
            cf_util_get_service(child, &cb->service);
        else if (strcasecmp("HostTags", child->key) == 0)
            cf_util_get_string(child, &cb->host_tags);
        else if (strcasecmp("StoreRates", child->key) == 0)
            cf_util_get_boolean(child, &cb->store_rates);
        else if (strcasecmp("AlwaysAppendDS", child->key) == 0)
            cf_util_get_boolean(child, &cb->always_append_ds);
        else
        {
            ERROR("write_tsdb plugin: Invalid configuration "
                  "option: %s.", child->key);
        }
    }

    ssnprintf(callback_name, sizeof(callback_name), "write_tsdb/%s/%s",
              cb->node != NULL ? cb->node : WT_DEFAULT_NODE,
              cb->service != NULL ? cb->service : WT_DEFAULT_SERVICE);

    memset(&user_data, 0, sizeof(user_data));
    user_data.data = cb;
    user_data.free_func = wt_callback_free;
    plugin_register_write(callback_name, wt_write, &user_data);

    user_data.free_func = NULL;
    plugin_register_flush(callback_name, wt_flush, &user_data);

    return 0;
}

static int wt_config(oconfig_item_t *ci)
{
    int i;

    for (i = 0; i < ci->children_num; i++)
    {
        oconfig_item_t *child = ci->children + i;

        if (strcasecmp("Node", child->key) == 0)
            wt_config_tsd(child);
        else
        {
            ERROR("write_tsdb plugin: Invalid configuration "
                  "option: %s.", child->key);
        }
    }

    return 0;
}

void module_register(void)
{
    plugin_register_complex_config("write_tsdb", wt_config);
}

/* vim: set sw=4 ts=4 sts=4 tw=78 et : */
