[collectd] [PATCH 2/2] Add ceph plugin

Sage Weil sage at inktank.com
Sat Jan 19 02:17:19 CET 2013


This plugin will read from the socket associated with a Ceph daemon and
gather the performance metrics exposed there.  It will first issue a
'get schema' command to discover what metrics are available, and will then
slurp them up at regular intervals.

Most of the original code was written by Colin Patrick McCabe
<cmccabe at alumni.cmu.edu>, and then modified by <sage at inktank.com>.

Signed-off-by: Sage Weil <sage at inktank.com>
---
 configure.in         |    8 +
 src/Makefile.am      |    9 +
 src/ceph.c           |  810 ++++++++++++++++++++++++++++++++++++++++++++++++++
 src/collectd.conf.in |    1 +
 4 files changed, 828 insertions(+), 0 deletions(-)
 create mode 100644 src/ceph.c

diff --git a/configure.in b/configure.in
index 6d92bef..40a2575 100644
--- a/configure.in
+++ b/configure.in
@@ -4608,6 +4608,7 @@ dependency_error="no"
 plugin_ascent="no"
 plugin_battery="no"
 plugin_bind="no"
+plugin_ceph="no"
 plugin_conntrack="no"
 plugin_contextswitch="no"
 plugin_cpu="no"
@@ -4768,6 +4769,11 @@ then
 	plugin_curl_xml="yes"
 fi
 
+if test "x$with_libjson" = "xyes"
+then
+	plugin_ceph="yes"
+fi
+
 if test "x$have_processor_info" = "xyes"
 then
 	plugin_cpu="yes"
@@ -4925,6 +4931,7 @@ AC_PLUGIN([apple_sensors], [$with_libiokit],   [Apple's hardware sensors])
 AC_PLUGIN([ascent],      [$plugin_ascent],     [AscentEmu player statistics])
 AC_PLUGIN([battery],     [$plugin_battery],    [Battery statistics])
 AC_PLUGIN([bind],        [$plugin_bind],       [ISC Bind nameserver statistics])
+AC_PLUGIN([ceph],        [$plugin_ceph],       [Ceph daemon statistics])
 AC_PLUGIN([conntrack],   [$plugin_conntrack],  [nf_conntrack statistics])
 AC_PLUGIN([contextswitch], [$plugin_contextswitch], [context switch statistics])
 AC_PLUGIN([cpufreq],     [$plugin_cpufreq],    [CPU frequency statistics])
@@ -5260,6 +5267,7 @@ Configuration:
     ascent  . . . . . . . $enable_ascent
     battery . . . . . . . $enable_battery
     bind  . . . . . . . . $enable_bind
+    ceph  . . . . . . . . $enable_ceph
     conntrack . . . . . . $enable_conntrack
     contextswitch . . . . $enable_contextswitch
     cpu . . . . . . . . . $enable_cpu
diff --git a/src/Makefile.am b/src/Makefile.am
index 73e2df3..7aaf7e2 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -226,6 +226,15 @@ collectd_LDADD += "-dlopen" bind.la
 collectd_DEPENDENCIES += bind.la
 endif
 
+if BUILD_PLUGIN_CEPH
+pkglib_LTLIBRARIES += ceph.la
+ceph_la_SOURCES = ceph.c
+ceph_la_LDFLAGS = -module -avoid-version
+ceph_la_LIBADD = -ljson
+collectd_LDADD += "-dlopen" ceph.la
+collectd_DEPENDENCIES += ceph.la
+endif
+
 if BUILD_PLUGIN_CONNTRACK
 pkglib_LTLIBRARIES += conntrack.la
 conntrack_la_SOURCES = conntrack.c
diff --git a/src/ceph.c b/src/ceph.c
new file mode 100644
index 0000000..59d9f12
--- /dev/null
+++ b/src/ceph.c
@@ -0,0 +1,810 @@
+/**
+ * collectd - src/ceph.c
+ * Copyright (C) 2011  New Dream Network
+ *
+ * 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
+ *
+ * Authors:
+ *   Colin McCabe <cmccabe at alumni.cmu.edu>
+ **/
+
+#define _BSD_SOURCE
+
+#include "collectd.h"
+#include "common.h"
+#include "plugin.h"
+
+#include <arpa/inet.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <json/json.h>
+#include <json/json_object_private.h> /* need for struct json_object_iter */
+#include <limits.h>
+#include <poll.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <strings.h>
+#include <sys/socket.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <sys/un.h>
+#include <unistd.h>
+
+#define RETRY_ON_EINTR(ret, expr) \
+	while(1) { \
+		ret = expr; \
+		if (ret >= 0) \
+			break; \
+		ret = -errno; \
+		if (ret != -EINTR) \
+			break; \
+	}
+
+/** Timeout interval in seconds */
+#define CEPH_TIMEOUT_INTERVAL 1
+
+/** Maximum path length for a UNIX domain socket on this system */
+#define UNIX_DOMAIN_SOCK_PATH_MAX (sizeof(((struct sockaddr_un*)0)->sun_path))
+
+
+
+static void submit_values(const char *plugin_instance,
+			  const char *type, const char *type_instance,
+			  value_t *values, int num)
+{
+	value_list_t vl = VALUE_LIST_INIT;
+
+	DEBUG("submit_values %s/%s/%s num=%d)",
+	      plugin_instance, type, type_instance, num);
+	vl.values = values;
+	vl.values_len = num;
+	sstrncpy (vl.host, hostname_g, sizeof (vl.host));
+	sstrncpy (vl.plugin, "ceph", sizeof (vl.plugin));
+	if (plugin_instance != NULL)
+		sstrncpy (vl.plugin_instance, plugin_instance,
+				sizeof (vl.plugin_instance));
+	sstrncpy (vl.type, type, sizeof (vl.type));
+	if (type_instance != NULL)
+		sstrncpy (vl.type_instance, type_instance,
+				sizeof (vl.type_instance));
+
+	plugin_dispatch_values (&vl);
+}
+
+
+/******* ceph_daemon *******/
+struct ceph_daemon
+{
+	/** Version of the admin_socket interface */
+	uint32_t version;
+
+	/** Path to the socket that we use to talk to the ceph daemon */
+	char asok_path[UNIX_DOMAIN_SOCK_PATH_MAX];
+
+	/** instance name **/
+	char name[DATA_MAX_NAME_LEN];
+
+	/** our types **/
+	int num_types;
+	struct data_set_s *dsets;
+	int *pc_types;
+};
+
+enum perfcounter_type_d {
+	PERFCOUNTER_LONGRUNAVG = 0x4,
+	PERFCOUNTER_COUNTER = 0x8,
+};
+
+/** Array of daemons to monitor */
+static struct ceph_daemon **g_daemons = NULL;
+
+/** Number of elements in g_daemons */
+static int g_num_daemons = 0;
+
+static void ceph_daemon_print(const struct ceph_daemon *d)
+{
+	DEBUG("name=%s, asok_path=%s", d->name, d->asok_path);
+}
+
+static void ceph_daemons_print(void)
+{
+	int i;
+	for (i = 0; i < g_num_daemons; ++i) {
+		ceph_daemon_print(g_daemons[i]);
+	}
+}
+
+static void ceph_daemon_free(struct ceph_daemon *d)
+{
+	int i;
+
+	for (i = 0; i < d->num_types; i++)
+		plugin_unregister_data_set(d->dsets[i].type);
+	sfree(d->dsets);
+	sfree(d->pc_types);
+	sfree(d);
+}
+
+static int ceph_daemon_add_ds_entry(struct ceph_daemon *d,
+				    const char *group, const char *rawkey,
+				    int pc_type)
+{
+	struct data_set_s *dset;
+	int idx;
+	int ret;
+
+	if (strlen(rawkey) + 6 > DATA_MAX_NAME_LEN)
+		return -ENAMETOOLONG;
+
+	idx = d->num_types++;
+	d->dsets = realloc(d->dsets, sizeof(*d->dsets) * d->num_types);
+	if (!d->dsets)
+		return -ENOMEM;
+	d->pc_types = realloc(d->pc_types, sizeof(*d->pc_types) * d->num_types);
+	if (!d->pc_types)
+		return -ENOMEM;
+
+	dset = &d->dsets[idx];
+	d->pc_types[idx] = pc_type;
+	snprintf(dset->type, sizeof(dset->type), "ceph_%s", rawkey);
+
+	if (pc_type & PERFCOUNTER_LONGRUNAVG) {
+		dset->ds_num = 2;
+		dset->ds = malloc(sizeof(*dset->ds) * dset->ds_num);
+		if (!dset->ds)
+			return -ENOMEM;
+		dset->ds[0].type = DS_TYPE_COUNTER;
+		strncpy(dset->ds[0].name, "sum", sizeof(dset->ds[0].name));
+		dset->ds[0].min = NAN;
+		dset->ds[0].max = NAN;
+		dset->ds[1].type = DS_TYPE_COUNTER;
+		strncpy(dset->ds[1].name, "count", sizeof(dset->ds[0].name));
+		dset->ds[1].min = NAN;
+		dset->ds[1].max = NAN;
+	}
+	else {
+		dset->ds_num = 1;
+		dset->ds = malloc(sizeof(*dset->ds) * dset->ds_num);
+		if (!dset->ds)
+			return -ENOMEM;
+		if (pc_type & PERFCOUNTER_COUNTER)
+			dset->ds[0].type = DS_TYPE_COUNTER;
+		else
+			dset->ds[0].type = DS_TYPE_GAUGE;
+		strncpy(dset->ds[0].name, "value", sizeof(dset->ds[0].name));
+		dset->ds[0].min = NAN;
+		dset->ds[0].max = NAN;
+	}
+
+	ret = plugin_unregister_data_set(dset->type);
+	ret = plugin_register_data_set(dset);
+	DEBUG("plugin_register_data_set %s type %d ds_num %d returned %d",
+	      rawkey, pc_type, dset->ds_num, ret);
+	return ret;
+}
+
+/******* ceph_config *******/
+static int cc_handle_str(struct oconfig_item_s *item, char *dest, int dest_len)
+{
+	const char *val;
+	if (item->values_num != 1) {
+		return -ENOTSUP; 
+	}
+	if (item->values[0].type != OCONFIG_TYPE_STRING) {
+		return -ENOTSUP; 
+	}
+	val = item->values[0].value.string;
+	if (snprintf(dest, dest_len, "%s", val) > (dest_len - 1)) {
+		ERROR("ceph plugin: configuration parameter '%s' is too long.\n",
+		      item->key);
+		return -ENAMETOOLONG;
+	}
+	return 0;
+}
+
+static int ceph_config(oconfig_item_t *ci)
+{
+	int ret, i;
+	struct ceph_daemon *array, *nd, cd;
+	memset(&cd, 0, sizeof(struct ceph_daemon));
+
+	for (i = 0; i < ci->children_num; ++i) {
+		oconfig_item_t *child = ci->children + i;
+		if (strcasecmp("Name", child->key) == 0) {
+			ret = cc_handle_str(child, cd.name, DATA_MAX_NAME_LEN);
+			if (ret)
+				return ret;
+		}
+		else if (strcasecmp("SocketPath", child->key) == 0) {
+			ret = cc_handle_str(child, cd.asok_path,
+					    sizeof(cd.asok_path));
+			if (ret)
+				return ret;
+		}
+		else {
+			WARNING("ceph plugin: ignoring unknown option %s",
+				child->key);
+		}
+	}
+	if (cd.name[0] == '\0') {
+		ERROR("ceph plugin: you must configure a daemon name.\n");
+		return -EINVAL;
+	}
+	else if (cd.asok_path[0] == '\0') {
+		ERROR("ceph plugin(name=%s): you must configure an administrative "
+		      "socket path.\n", cd.name);
+		return -EINVAL;
+	}
+	else if (!((cd.asok_path[0] == '/') ||
+	      (cd.asok_path[0] == '.' && cd.asok_path[1] == '/'))) {
+		ERROR("ceph plugin(name=%s): administrative socket paths must begin with "
+		      "'/' or './' Can't parse: '%s'\n",
+		      cd.name, cd.asok_path);
+		return -EINVAL;
+	}
+
+	/* . -> _ in name */
+	for (i = 0; cd.name[i]; ++i)
+		if (cd.name[i] == '.')
+			cd.name[i] = '_';
+
+	array = realloc(g_daemons,
+			sizeof(struct ceph_daemon *) * (g_num_daemons + 1));
+	if (array == NULL) {
+		/* The positive return value here indicates that this is a
+		 * runtime error, not a configuration error.  */
+		return ENOMEM;
+	}
+	g_daemons = (struct ceph_daemon**)array;
+	nd = malloc(sizeof(struct ceph_daemon));
+	if (!nd)
+		return ENOMEM;
+	memcpy(nd, &cd, sizeof(struct ceph_daemon));
+	g_daemons[g_num_daemons++] = nd;
+	return 0;
+}
+
+/******* JSON parsing *******/
+typedef int (*node_handler_t)(void*, const char *, const char*, json_object*);
+
+static int traverse_json(const char *json,
+			 node_handler_t handler, void *handler_arg)
+{
+	struct json_object_iter ia, ib;
+	json_object *root;
+	int ret;
+
+	root = json_tokener_parse(json);
+
+	ret = -EDOM;
+	if (!root)
+		goto out;
+	if (json_object_get_type(root) != json_type_object)
+		goto out;
+
+	json_object_object_foreachC(root, ia) {
+		json_object_object_foreachC(ia.val, ib) {
+			ret = handler(handler_arg, ia.key, ib.key, ib.val);
+			if (ret < 0)
+				goto out;
+		}
+	}
+	ret = 0;
+
+out:
+	json_object_put(root);
+	return ret;
+}
+
+static int node_handler_define_schema(void *arg, 
+				      const char *group, const char *key,
+				      json_object *jo)
+{
+	struct json_object_iter iter;
+	struct ceph_daemon *d = (struct ceph_daemon *)arg;
+	int pc_type;
+
+	if (json_object_get_type(jo) != json_type_object)
+		return -EDOM;
+
+	json_object_object_foreachC(jo, iter) {
+		if (strcmp(iter.key, "type"))
+			return -EDOM;
+		if (json_object_get_type(iter.val) != json_type_int)
+			return -EDOM;
+		pc_type = json_object_get_int(iter.val);
+		DEBUG(" got type d=%s group=%s key=%s pc_type=%04x",
+		      d->name, group, key, pc_type);
+		return ceph_daemon_add_ds_entry(d, group, key, pc_type);
+	}
+	return -EDOM;
+}
+
+static int node_handler_fetch_data(void *arg, 
+				   const char *group, const char *rawkey,
+				   json_object *jo)
+{
+	struct ceph_daemon *d = (struct ceph_daemon *)arg;
+	char key[80];
+	int idx;
+	value_t v[2];
+
+	snprintf(key, sizeof(key), "ceph_%s", rawkey);
+	DEBUG("fetch_data %s/%s", group, key);
+
+	for (idx = 0; idx < d->num_types; ++idx)
+		if (strcmp(d->dsets[idx].type, key) == 0)
+			break;
+	if (idx == d->num_types) {
+		DEBUG("couldn't find '%s'", key);
+		return 0;
+	}
+
+	if (d->pc_types[idx] & PERFCOUNTER_LONGRUNAVG) {
+		json_object *avgcount, *sum; 
+		if (json_object_get_type(jo) != json_type_object)
+			return -EINVAL;
+		avgcount = json_object_object_get(jo, "avgcount");
+		sum = json_object_object_get(jo, "sum");
+		if ((!avgcount) || (!sum))
+			return -EINVAL;
+		v[0].counter = json_object_get_int(sum);
+		v[1].counter = json_object_get_int(avgcount);
+		submit_values(group, key, d->name, v, 2);
+	}
+	else if (d->pc_types[idx] & PERFCOUNTER_COUNTER) {
+		/* We use json_object_get_double here because anything > 32 
+		 * bits may get truncated by json_object_get_int */
+		v[0].counter = json_object_get_double(jo);
+		submit_values(group, key, d->name, v, 1);
+	}
+	else {
+		v[0].gauge = json_object_get_double(jo);
+		submit_values(group, key, d->name, v, 1);
+	}
+	return 0;
+}
+
+
+
+/******* network I/O *******/
+enum cstate_t {
+	CSTATE_UNCONNECTED = 0,
+	CSTATE_WRITE_REQUEST,
+	CSTATE_READ_VERSION,
+	CSTATE_READ_AMT,
+	CSTATE_READ_JSON,
+};
+
+enum request_type_t {
+	ASOK_REQ_VERSION = 0,
+	ASOK_REQ_DATA = 1,
+	ASOK_REQ_SCHEMA = 2,
+	ASOK_REQ_NONE = 1000,
+};
+
+struct cconn
+{
+	/** The Ceph daemon that we're talking to */
+	struct ceph_daemon *d;
+
+	/** Request type */
+	uint32_t request_type;
+
+	/** The connection state */
+	enum cstate_t state;
+
+	/** The socket we use to talk to this daemon */ 
+	int asok;
+
+	/** The amount of data remaining to read / write. */
+	uint32_t amt;
+
+	/** Length of the JSON to read */
+	uint32_t json_len;
+
+	/** Buffer containing JSON data */
+	char *json;
+};
+
+static int cconn_connect(struct cconn *io)
+{
+	struct sockaddr_un address;
+	int flags, fd, err;
+	if (io->state != CSTATE_UNCONNECTED) {
+		ERROR("cconn_connect: io->state != CSTATE_UNCONNECTED");
+		return -EDOM;
+	}
+	fd = socket(PF_UNIX, SOCK_STREAM, 0);
+	if (fd < 0) {
+		int err = -errno;
+		ERROR("cconn_connect: socket(PF_UNIX, SOCK_STREAM, 0) failed: "
+		      "error %d", err);
+		return err;
+	}
+	memset(&address, 0, sizeof(struct sockaddr_un));
+	address.sun_family = AF_UNIX;
+	snprintf(address.sun_path, sizeof(address.sun_path),
+		 "%s", io->d->asok_path);
+	RETRY_ON_EINTR(err, connect(fd, (struct sockaddr *) &address, 
+			sizeof(struct sockaddr_un)));
+	if (err < 0) {
+		ERROR("cconn_connect: connect(%d) failed: error %d", fd, err);
+		return err;
+	}
+
+	flags = fcntl(fd, F_GETFL, 0);
+	if (fcntl(fd, F_SETFL, flags | O_NONBLOCK) != 0) {
+		err = -errno;
+		ERROR("cconn_connect: fcntl(%d, O_NONBLOCK) error %d", fd, err);
+		return err;
+	}
+	io->asok = fd;
+	io->state = CSTATE_WRITE_REQUEST;
+	io->amt = 0;
+	io->json_len = 0;
+	io->json = NULL;
+	return 0;
+}
+
+static void cconn_close(struct cconn *io)
+{
+	io->state = CSTATE_UNCONNECTED;
+	if (io->asok != -1) {
+		int res;
+		RETRY_ON_EINTR(res, close(io->asok));
+	}
+	io->asok = -1;
+	io->amt = 0;
+	io->json_len = 0;
+	sfree(io->json);
+	io->json = NULL;
+}
+
+/* Process incoming JSON counter data */
+static int cconn_process_json(struct cconn *io)
+{
+	switch (io->request_type) {
+	case ASOK_REQ_DATA:
+		return traverse_json(io->json, node_handler_fetch_data, io->d);
+	case ASOK_REQ_SCHEMA:
+		return traverse_json(io->json, node_handler_define_schema,
+				     io->d);
+	default:
+		return -EDOM;
+	}
+}
+
+static int cconn_validate_revents(struct cconn *io, int revents)
+{
+	if (revents & POLLERR) {
+		ERROR("cconn_validate_revents(name=%s): got POLLERR",
+		      io->d->name);
+		return -EIO;
+	}
+	switch (io->state) {
+	case CSTATE_WRITE_REQUEST:
+		return (revents & POLLOUT) ? 0 : -EINVAL;
+	case CSTATE_READ_VERSION:
+	case CSTATE_READ_AMT:
+	case CSTATE_READ_JSON:
+		return (revents & POLLIN) ? 0 : -EINVAL;
+		return (revents & POLLIN) ? 0 : -EINVAL;
+	default:
+		ERROR("cconn_validate_revents(name=%s) got to illegal state on line %d",
+		      io->d->name, __LINE__);
+		return -EDOM;
+	}
+}
+
+/** Handle a network event for a connection */
+static int cconn_handle_event(struct cconn *io)
+{
+	int ret;
+	switch (io->state) {
+	case CSTATE_UNCONNECTED:
+		ERROR("cconn_handle_event(name=%s) got to illegal state on line %d",
+		      io->d->name, __LINE__);
+		return -EDOM;
+	case CSTATE_WRITE_REQUEST: {
+		uint32_t cmd = htonl(io->request_type);
+		RETRY_ON_EINTR(ret, write(io->asok, ((char*)&cmd) + io->amt,
+					       sizeof(cmd) - io->amt));
+		DEBUG("cconn_handle_event(name=%s,state=%d,amt=%d,ret=%d)",
+		      io->d->name, io->state, io->amt, ret);
+		if (ret < 0)
+			return ret;
+		io->amt += ret;
+		if (io->amt >= sizeof(cmd)) {
+			io->amt = 0;
+			switch (io->request_type) {
+			case ASOK_REQ_VERSION:
+				io->state = CSTATE_READ_VERSION;
+				break;
+			default:
+				io->state = CSTATE_READ_AMT;
+				break;
+			}
+		}
+		return 0;
+	}
+	case CSTATE_READ_VERSION: {
+		RETRY_ON_EINTR(ret, read(io->asok, 
+			((char*)(&io->d->version)) + io->amt,
+			sizeof(io->d->version) - io->amt));
+		DEBUG("cconn_handle_event(name=%s,state=%d,ret=%d)",
+		      io->d->name, io->state, ret);
+		if (ret < 0)
+			return ret;
+		io->amt += ret;
+		if (io->amt >= sizeof(io->d->version)) {
+			io->d->version = ntohl(io->d->version);
+			if (io->d->version != 1) {
+				ERROR("cconn_handle_event(name=%s) not "
+				      "expecting version %d!", 
+				      io->d->name, io->d->version);
+				return -ENOTSUP;
+			}
+			DEBUG("cconn_handle_event(name=%s): identified as "
+			      "version %d", io->d->name, io->d->version);
+			io->amt = 0;
+			cconn_close(io);
+			io->request_type = ASOK_REQ_SCHEMA;
+		}
+		return 0;
+	}
+	case CSTATE_READ_AMT: {
+		RETRY_ON_EINTR(ret, read(io->asok, 
+			((char*)(&io->json_len)) + io->amt,
+			sizeof(io->json_len) - io->amt));
+		DEBUG("cconn_handle_event(name=%s,state=%d,ret=%d)",
+		      io->d->name, io->state, ret);
+		if (ret < 0)
+			return ret;
+		io->amt += ret;
+		if (io->amt >= sizeof(io->json_len)) {
+			io->json_len = ntohl(io->json_len);
+			io->amt = 0;
+			io->state = CSTATE_READ_JSON;
+			io->json = calloc(1, io->json_len + 1);
+			if (!io->json)
+				return -ENOMEM;
+		}
+		return 0;
+	}
+	case CSTATE_READ_JSON: {
+		RETRY_ON_EINTR(ret, read(io->asok, io->json + io->amt,
+					      io->json_len - io->amt));
+		DEBUG("cconn_handle_event(name=%s,state=%d,ret=%d)",
+		      io->d->name, io->state, ret);
+		if (ret < 0)
+			return ret;
+		io->amt += ret;
+		if (io->amt >= io->json_len) {
+			DEBUG("raw ceph json is %s", io->json);
+			ret = cconn_process_json(io);
+			if (ret)
+				return ret;
+			cconn_close(io);
+			io->request_type = ASOK_REQ_NONE;
+		}
+		return 0;
+	}
+	default:
+		ERROR("cconn_handle_event(name=%s) got to illegal state on "
+		      "line %d", io->d->name, __LINE__);
+		return -EDOM;
+	}
+}
+
+static int cconn_prepare(struct cconn *io, struct pollfd* fds)
+{
+	int ret;
+	if (io->request_type == ASOK_REQ_NONE) {
+		/* The request has already been serviced. */
+		return 0;
+	}
+	else if ((io->request_type == ASOK_REQ_DATA) &&
+			 (io->d->num_types == 0)) {
+		/* If there are no counters to report on, don't bother
+		 * connecting */
+		return 0;
+	}
+
+	switch (io->state) {
+	case CSTATE_UNCONNECTED:
+		ret = cconn_connect(io);
+		if (ret > 0)
+			return -ret;
+		else if (ret < 0)
+			return ret;
+		fds->fd = io->asok;
+		fds->events = POLLOUT;
+		return 1;
+	case CSTATE_WRITE_REQUEST:
+		fds->fd = io->asok;
+		fds->events = POLLOUT;
+		return 1;
+	case CSTATE_READ_VERSION:
+	case CSTATE_READ_AMT:
+	case CSTATE_READ_JSON:
+		fds->fd = io->asok;
+		fds->events = POLLIN;
+		return 1;
+	default:
+		ERROR("cconn_prepare(name=%s) got to illegal state on line %d",
+		      io->d->name, __LINE__);
+		return -EDOM;
+	}
+}
+
+/** Returns the difference between two struct timevals in milliseconds.
+ * On overflow, we return max/min int.
+ */
+static int milli_diff(const struct timeval *t1, const struct timeval *t2)
+{
+	int64_t ret;
+	int sec_diff = t1->tv_sec - t2->tv_sec;
+	int usec_diff = t1->tv_usec - t2->tv_usec;
+	ret = usec_diff / 1000;
+	ret += (sec_diff * 1000);
+	if (ret > INT_MAX)
+		return INT_MAX;
+	else if (ret < INT_MIN)
+		return INT_MIN;
+	return (int)ret;
+}
+
+/** This handles the actual network I/O to talk to the Ceph daemons.
+ */
+static int cconn_main_loop(uint32_t request_type)
+{
+	int i, ret, some_unreachable = 0;
+	struct timeval end_tv;
+	struct cconn io_array[g_num_daemons];
+
+	DEBUG("entering cconn_main_loop(request_type = %d)", request_type);
+
+	/* create cconn array */
+	memset(io_array, 0, sizeof(io_array));
+	for (i = 0; i < g_num_daemons; ++i) {
+		io_array[i].d = g_daemons[i];
+		io_array[i].request_type = request_type;
+		io_array[i].state = CSTATE_UNCONNECTED;
+	}
+
+	/** Calculate the time at which we should give up */
+	gettimeofday(&end_tv, NULL);
+	end_tv.tv_sec += CEPH_TIMEOUT_INTERVAL;
+
+	while (1) {
+		int nfds, diff;
+		struct timeval tv;
+		struct cconn *polled_io_array[g_num_daemons];
+		struct pollfd fds[g_num_daemons];
+		memset(fds, 0, sizeof(fds));
+		nfds = 0;
+		for (i = 0; i < g_num_daemons; ++i) {
+			struct cconn *io = io_array + i;
+			ret = cconn_prepare(io, fds + nfds);
+			if (ret < 0) {
+				WARNING("ERROR: cconn_prepare(name=%s,i=%d,st=%d)=%d",
+				      io->d->name, i, io->state, ret);
+				cconn_close(io);
+				io->request_type = ASOK_REQ_NONE;
+				some_unreachable = 1;
+			}
+			else if (ret == 1) {
+				DEBUG("did cconn_prepare(name=%s,i=%d,st=%d)",
+				      io->d->name, i, io->state);
+				polled_io_array[nfds++] = io_array + i;
+			}
+		}
+		if (nfds == 0) {
+			/* finished */
+			ret = 0;
+			DEBUG("cconn_main_loop: no more cconn to manage.");
+			goto done;
+		}
+		gettimeofday(&tv, NULL);
+		diff = milli_diff(&end_tv, &tv);
+		if (diff <= 0) {
+			/* Timed out */
+			ret = -ETIMEDOUT;
+			WARNING("ERROR: cconn_main_loop: timed out.\n");
+			goto done;
+		}
+		RETRY_ON_EINTR(ret, poll(fds, nfds, diff));
+		if (ret < 0) {
+			ERROR("poll(2) error: %d", ret);
+			goto done;
+		}
+		for (i = 0; i < nfds; ++i) {
+			struct cconn *io = polled_io_array[i];
+			int revents = fds[i].revents;
+			if (revents == 0) {
+				/* do nothing */
+			}
+			else if (cconn_validate_revents(io, revents)) {
+				WARNING("ERROR: cconn(name=%s,i=%d,st=%d): "
+					"revents validation error: "
+					"revents=0x%08x", io->d->name, i,
+					io->state, revents);
+				cconn_close(io);
+				io->request_type = ASOK_REQ_NONE;
+				some_unreachable = 1;
+			}
+			else {
+				int ret = cconn_handle_event(io);
+				if (ret) {
+					WARNING("ERROR: cconn_handle_event(name=%s,"
+						"i=%d,st=%d): error %d",
+						io->d->name, i,
+						io->state, ret);
+					cconn_close(io);
+					io->request_type = ASOK_REQ_NONE;
+					some_unreachable = 1;
+				}
+			}
+		}
+	}
+done:
+	for (i = 0; i < g_num_daemons; ++i) {
+		cconn_close(io_array + i);
+	}
+	if (some_unreachable) {
+		DEBUG("cconn_main_loop: some Ceph daemons were unreachable.");
+	}
+	else {
+		DEBUG("cconn_main_loop: reached all Ceph daemons :)");
+	}
+	return ret;
+}
+
+static int ceph_read(void)
+{
+	return cconn_main_loop(ASOK_REQ_DATA);
+}
+
+/******* lifecycle *******/
+static int ceph_init(void)
+{
+	DEBUG("ceph_init");
+	ceph_daemons_print();
+
+	return cconn_main_loop(ASOK_REQ_VERSION);
+}
+
+static int ceph_shutdown(void)
+{
+	int i;
+	for (i = 0; i < g_num_daemons; ++i) {
+		ceph_daemon_free(g_daemons[i]);
+	}
+	sfree(g_daemons);
+	g_daemons = NULL;
+	g_num_daemons = 0;
+	DEBUG("finished ceph_shutdown");
+	return 0;
+}
+
+void module_register(void)
+{
+	plugin_register_complex_config("ceph", ceph_config);
+	plugin_register_init("ceph", ceph_init);
+	plugin_register_read("ceph", ceph_read);
+	plugin_register_shutdown("ceph", ceph_shutdown);
+}
diff --git a/src/collectd.conf.in b/src/collectd.conf.in
index 81d7055..88281c7 100644
--- a/src/collectd.conf.in
+++ b/src/collectd.conf.in
@@ -69,6 +69,7 @@
 #@BUILD_PLUGIN_ASCENT_TRUE at LoadPlugin ascent
 #@BUILD_PLUGIN_BATTERY_TRUE at LoadPlugin battery
 #@BUILD_PLUGIN_BIND_TRUE at LoadPlugin bind
+#@BUILD_PLUGIN_CEPH_TRUE at LoadPlugin ceph
 #@BUILD_PLUGIN_CONNTRACK_TRUE at LoadPlugin conntrack
 #@BUILD_PLUGIN_CONTEXTSWITCH_TRUE at LoadPlugin contextswitch
 @BUILD_PLUGIN_CPU_TRUE@@BUILD_PLUGIN_CPU_TRUE at LoadPlugin cpu
-- 
1.7.9




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