/**
 * collectd - src/memcached.c, based on src/hddtemp.c
 * Copyright (C) 2007       Antony Dovgal
 * Copyright (C) 2007-2009  Florian Forster
 * Copyright (C) 2009       Doug MacEachern
 * Copyright (C) 2009       Franck Lombardi
 *
 * 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
 *
 * Authors:
 *   Antony Dovgal <tony at daylessday dot org>
 *   Florian octo Forster <octo at verplant.org>
 *   Doug MacEachern <dougm at hyperic.com>
 *   Franck Lombardi
 **/

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

# include <poll.h>
# include <netdb.h>
# include <sys/socket.h>
# include <sys/un.h>
# include <netinet/in.h>
# include <netinet/tcp.h>

#define MEMCACHED_DEF_HOST "127.0.0.1"
#define MEMCACHED_DEF_PORT "11211"

#define MEMCACHED_RETRY_COUNT 100

static const char *config_keys[] =
{
	"Socket",
	"Host",
	"Port"
};
static int config_keys_num = STATIC_ARRAY_SIZE (config_keys);

static char *memcached_socket = NULL;
static char *memcached_host = NULL;
static char memcached_port[16];

static int memcached_query_daemon (char *buffer, int buffer_size) /* {{{ */
{
	int fd;
	ssize_t status;
	int buffer_fill;
	int i = 0;

	if (memcached_socket != NULL) {
		struct sockaddr_un serv_addr;

		memset (&serv_addr, 0, sizeof (serv_addr));
		serv_addr.sun_family = AF_UNIX;
		sstrncpy (serv_addr.sun_path, memcached_socket,
				sizeof (serv_addr.sun_path));

		/* create our socket descriptor */
		fd = socket (AF_UNIX, SOCK_STREAM, 0);
		if (fd < 0) {
			char errbuf[1024];
			ERROR ("memcached: unix socket: %s", sstrerror (errno, errbuf,
						sizeof (errbuf)));
			return -1;
		}

		/* connect to the memcached daemon */
		status = (ssize_t) connect (fd, (struct sockaddr *) &serv_addr,
				sizeof (serv_addr));
		if (status != 0) {
			shutdown (fd, SHUT_RDWR);
			close (fd);
			fd = -1;
		}
	}
	else { /* if (memcached_socket == NULL) */
		const char *host;
		const char *port;

		struct addrinfo  ai_hints;
		struct addrinfo *ai_list, *ai_ptr;
		int              ai_return = 0;

		memset (&ai_hints, '\0', sizeof (ai_hints));
		ai_hints.ai_flags    = 0;
#ifdef AI_ADDRCONFIG
		/*	ai_hints.ai_flags   |= AI_ADDRCONFIG; */
#endif
		ai_hints.ai_family   = AF_INET;
		ai_hints.ai_socktype = SOCK_STREAM;
		ai_hints.ai_protocol = 0;

		host = memcached_host;
		if (host == NULL) {
			host = MEMCACHED_DEF_HOST;
		}

		port = memcached_port;
		if (strlen (port) == 0) {
			port = MEMCACHED_DEF_PORT;
		}

		if ((ai_return = getaddrinfo (host, port, NULL, &ai_list)) != 0) {
			char errbuf[1024];
			ERROR ("memcached: getaddrinfo (%s, %s): %s",
					host, port,
					(ai_return == EAI_SYSTEM)
					? sstrerror (errno, errbuf, sizeof (errbuf))
					: gai_strerror (ai_return));
			return -1;
		}

		fd = -1;
		for (ai_ptr = ai_list; ai_ptr != NULL; ai_ptr = ai_ptr->ai_next) {
			/* create our socket descriptor */
			fd = socket (ai_ptr->ai_family, ai_ptr->ai_socktype, ai_ptr->ai_protocol);
			if (fd < 0) {
				char errbuf[1024];
				ERROR ("memcached: socket: %s", sstrerror (errno, errbuf, sizeof (errbuf)));
				continue;
			}

			/* connect to the memcached daemon */
			status = (ssize_t) connect (fd, (struct sockaddr *) ai_ptr->ai_addr, ai_ptr->ai_addrlen);
			if (status != 0) {
				shutdown (fd, SHUT_RDWR);
				close (fd);
				fd = -1;
				continue;
			}

			/* A socket could be opened and connecting succeeded. We're
			 * done. */
			break;
		}

		freeaddrinfo (ai_list);
	}

	if (fd < 0) {
		ERROR ("memcached: Could not connect to daemon.");
		return -1;
	}

	if (send(fd, "stats\r\n", sizeof("stats\r\n") - 1, MSG_DONTWAIT) != (sizeof("stats\r\n") - 1)) {
		ERROR ("memcached: Could not send command to the memcached daemon.");
		return -1;
	}

	{
		struct pollfd p;
		int status;

		memset (&p, 0, sizeof (p));
		p.fd = fd;
		p.events = POLLIN | POLLERR | POLLHUP;
		p.revents = 0;

		status = poll (&p, /* nfds = */ 1, /* timeout = */ 1000 * interval_g);
		if (status <= 0)
		{
			if (status == 0)
			{
				ERROR ("memcached: poll(2) timed out after %i seconds.", interval_g);
			}
			else
			{
				char errbuf[1024];
				ERROR ("memcached: poll(2) failed: %s",
						sstrerror (errno, errbuf, sizeof (errbuf)));
			}
			shutdown (fd, SHUT_RDWR);
			close (fd);
			return (-1);
		}
	}

	/* receive data from the memcached daemon */
	memset (buffer, '\0', buffer_size);

	buffer_fill = 0;
	while ((status = recv (fd, buffer + buffer_fill, buffer_size - buffer_fill, MSG_DONTWAIT)) != 0) {
		if (i > MEMCACHED_RETRY_COUNT) {
			ERROR("recv() timed out");
			break;
		}
		i++;

		if (status == -1) {
			char errbuf[1024];

			if (errno == EAGAIN) {
				continue;
			}

			ERROR ("memcached: Error reading from socket: %s",
					sstrerror (errno, errbuf, sizeof (errbuf)));
			shutdown(fd, SHUT_RDWR);
			close (fd);
			return -1;
		}
		buffer_fill += status;

		if (buffer_fill > 3 && buffer[buffer_fill-5] == 'E' && buffer[buffer_fill-4] == 'N' && buffer[buffer_fill-3] == 'D') {
			/* we got all the data */
			break;
		}
	}

	if (buffer_fill >= buffer_size) {
		buffer[buffer_size - 1] = '\0';
		WARNING ("memcached: Message from memcached has been truncated.");
	} else if (buffer_fill == 0) {
		WARNING ("memcached: Peer has unexpectedly shut down the socket. "
				"Buffer: `%s'", buffer);
		shutdown(fd, SHUT_RDWR);
		close(fd);
		return -1;
	}

	shutdown(fd, SHUT_RDWR);
	close(fd);
	return 0;
}
/* }}} */

static int memcached_config (const char *key, const char *value) /* {{{ */
{
	if (strcasecmp (key, "Socket") == 0) {
		if (memcached_socket != NULL) {
			free (memcached_socket);
		}
		memcached_socket = strdup (value);
	} else if (strcasecmp (key, "Host") == 0) {
		if (memcached_host != NULL) {
			free (memcached_host);
		}
		memcached_host = strdup (value);
	} else if (strcasecmp (key, "Port") == 0) {
		int port = (int) (atof (value));
		if ((port > 0) && (port <= 65535)) {
			ssnprintf (memcached_port, sizeof (memcached_port), "%i", port);
		} else {
			sstrncpy (memcached_port, value, sizeof (memcached_port));
		}
	} else {
		return -1;
	}

	return 0;
}
/* }}} */

static void submit_counter (const char *type, const char *type_inst,
		counter_t value) /* {{{ */
{
	value_t values[1];
	value_list_t vl = VALUE_LIST_INIT;

	values[0].counter = value;

	vl.values = values;
	vl.values_len = 1;
	sstrncpy (vl.host, hostname_g, sizeof (vl.host));
	sstrncpy (vl.plugin, "memcached", sizeof (vl.plugin));
	sstrncpy (vl.type, type, sizeof (vl.type));
	if (type_inst != NULL)
		sstrncpy (vl.type_instance, type_inst, sizeof (vl.type_instance));

	plugin_dispatch_values (&vl);
} /* void memcached_submit_cmd */
/* }}} */

static void submit_counter2 (const char *type, const char *type_inst,
		counter_t value0, counter_t value1) /* {{{ */
{
	value_t values[2];
	value_list_t vl = VALUE_LIST_INIT;

	values[0].counter = value0;
	values[1].counter = value1;

	vl.values = values;
	vl.values_len = 2;
	vl.time = time (NULL);
	sstrncpy (vl.host, hostname_g, sizeof (vl.host));
	sstrncpy (vl.plugin, "memcached", sizeof (vl.plugin));
	sstrncpy (vl.type, type, sizeof (vl.type));
	if (type_inst != NULL)
		sstrncpy (vl.type_instance, type_inst, sizeof (vl.type_instance));

	plugin_dispatch_values (&vl);
} /* void memcached_submit_cmd */
/* }}} */

static void submit_gauge (const char *type, const char *type_inst,
		gauge_t value) /* {{{ */
{
	value_t values[1];
	value_list_t vl = VALUE_LIST_INIT;

	values[0].gauge = value;

	vl.values = values;
	vl.values_len = 1;
	vl.time = time (NULL);
	sstrncpy (vl.host, hostname_g, sizeof (vl.host));
	sstrncpy (vl.plugin, "memcached", sizeof (vl.plugin));
	sstrncpy (vl.type, type, sizeof (vl.type));
	if (type_inst != NULL)
		sstrncpy (vl.type_instance, type_inst, sizeof (vl.type_instance));

	plugin_dispatch_values (&vl);
}
/* }}} */

static void submit_gauge2 (const char *type, const char *type_inst,
		gauge_t value0, gauge_t value1) /* {{{ */
{
	value_t values[2];
	value_list_t vl = VALUE_LIST_INIT;

	values[0].gauge = value0;
	values[1].gauge = value1;

	vl.values = values;
	vl.values_len = 2;
	vl.time = time (NULL);
	sstrncpy (vl.host, hostname_g, sizeof (vl.host));
	sstrncpy (vl.plugin, "memcached", sizeof (vl.plugin));
	sstrncpy (vl.type, type, sizeof (vl.type));
	if (type_inst != NULL)
		sstrncpy (vl.type_instance, type_inst, sizeof (vl.type_instance));

	plugin_dispatch_values (&vl);
}
/* }}} */

static int memcached_read (void) /* {{{ */
{
	char buf[1024];
	char *fields[3];
	char *ptr;
	char *line;
	char *saveptr;
	int fields_num;

	gauge_t bytes_used = NAN;
	gauge_t bytes_total = NAN;
	gauge_t hits = NAN;
	gauge_t gets = NAN;
	counter_t rusage_user = 0;
	counter_t rusage_syst = 0;
	counter_t octets_rx = 0;
	counter_t octets_tx = 0;

	/* get data from daemon */
	if (memcached_query_daemon (buf, sizeof (buf)) < 0) {
		return -1;
	}

#define FIELD_IS(cnst) \
	(((sizeof(cnst) - 1) == name_len) && (strcmp (cnst, fields[1]) == 0))

	ptr = buf;
	saveptr = NULL;
	while ((line = strtok_r (ptr, "\n\r", &saveptr)) != NULL)
	{
		int name_len;

		ptr = NULL;

		fields_num = strsplit(line, fields, 3);
		if (fields_num != 3)
			continue;

		name_len = strlen(fields[1]);
		if (name_len == 0)
			continue;

		/*
		 * For an explanation on these fields please refer to
		 * <http://code.sixapart.com/svn/memcached/trunk/server/doc/protocol.txt>
		 */

		/*
		 * CPU time consumed by the memcached process
		 */
		if (FIELD_IS ("rusage_user"))
		{
			rusage_user = atoll (fields[2]);
		}
		else if (FIELD_IS ("rusage_system"))
		{
			rusage_syst = atoll(fields[2]);
		}

		/*
		 * Number of threads of this instance
		 */
		else if (FIELD_IS ("threads"))
		{
			submit_gauge2 ("ps_count", NULL, NAN, atof (fields[2]));
		}

		/*
		 * Number of items stored
		 */
		else if (FIELD_IS ("curr_items"))
		{
			submit_gauge ("memcached_items", "current", atof (fields[2]));
		}

		/*
		 * Number of bytes used and available (total - used)
		 */
		else if (FIELD_IS ("bytes"))
		{
			bytes_used = atof (fields[2]);
		}
		else if (FIELD_IS ("limit_maxbytes"))
		{
			bytes_total = atof(fields[2]);
		}

		/*
		 * Connections
		 */
		else if (FIELD_IS ("curr_connections"))
		{
			submit_gauge ("memcached_connections", "current", atof (fields[2]));
		}

		/*
		 * Commands
		 */
		else if ((name_len > 4) && (strncmp (fields[1], "cmd_", 4) == 0))
		{
			const char *name = fields[1] + 4;
			submit_counter ("memcached_command", name, atoll (fields[2]));
			if (strcmp (name, "get") == 0)
				gets = atof (fields[2]);
		}

		/*
		 * Operations on the cache, i. e. cache hits, cache misses and evictions of items
		 */
		else if (FIELD_IS ("get_hits"))
		{
			submit_counter ("memcached_ops", "hits", atoll (fields[2]));
			hits = atof (fields[2]);
		}
		else if (FIELD_IS ("get_misses"))
		{
			submit_counter ("memcached_ops", "misses", atoll (fields[2]));
		}
		else if (FIELD_IS ("evictions"))
		{
			submit_counter ("memcached_ops", "evictions", atoll (fields[2]));
		}

		/*
		 * Network traffic
		 */
		else if (FIELD_IS ("bytes_read"))
		{
			octets_rx = atoll (fields[2]);
		}
		else if (FIELD_IS ("bytes_written"))
		{
			octets_tx = atoll (fields[2]);
		}
	} /* while ((line = strtok_r (ptr, "\n\r", &saveptr)) != NULL) */

	if (!isnan (bytes_used) && !isnan (bytes_total) && (bytes_used <= bytes_total))
		submit_gauge2 ("df", "cache", bytes_used, bytes_total - bytes_used);

	if ((rusage_user != 0) || (rusage_syst != 0))
		submit_counter2 ("ps_cputime", NULL, rusage_user, rusage_syst);

	if ((octets_rx != 0) || (octets_tx != 0))
		submit_counter2 ("memcached_octets", NULL, octets_rx, octets_tx);

	if (!isnan (gets) && !isnan (hits))
	{
		gauge_t rate = NAN;

		if (gets != 0.0)
			rate = 100.0 * hits / gets;

		submit_gauge ("percent", "hitratio", rate);
	}

	return 0;
}
/* }}} */

void module_register (void) /* {{{ */
{
	plugin_register_config ("memcached", memcached_config, config_keys, config_keys_num);
	plugin_register_read ("memcached", memcached_read);
}
/* }}} */

/*
 * Local variables:
 * tab-width: 4
 * c-basic-offset: 4
 * End:
 * vim600: sw=4 ts=4 fdm=marker noexpandtab
 * vim<600: sw=4 ts=4 noexpandtab
 */