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/*
Copyright (c) 2013 Red Hat, Inc. <http://www.redhat.com>
This file is part of GlusterFS.
This file is licensed to you under your choice of the GNU Lesser
General Public License, version 3 or any later version (LGPLv3 or
later), or the GNU General Public License, version 2 (GPLv2), in all
cases as published by the Free Software Foundation.
*/
#include <regex.h>
//#include <stdlib.h>
#include <string.h>
#ifndef _CONFIG_H
#define _CONFIG_H
#include "config.h"
#endif
#include "call-stub.h"
#include "defaults.h"
#include "xlator.h"
#include "api/src/glfs.h"
#include "api/src/glfs-internal.h"
#ifndef NSR_SIM_ETCD
#include "etcd-api.h"
#endif
#include "nsr-internal.h"
#include "../../nsr-recon/src/recon_driver.h"
#include "../../nsr-recon/src/recon_xlator.h"
/* Vote format: UUID,vote_status,fitness,term_number */
#define VOTE_ELEMS 4 /* Whole match plus four actual pieces. */
#define DEFAULT_FITNESS 42
#define DEFAULT_KEY "nsr"
#define LEADER_TTL 5 /* TBD: make this tunable */
typedef enum { LS_SUCCESS, LS_FAILURE, LS_ERROR } leader_retval_t;
enum { NO_LEADER, TENTATIVE, CONFIRMED };
regex_t vote_re;
// Simulation of etcd routines
#ifndef NSR_SIM_ETCD
#endif
long
nsr_get_fitness (xlator_t *this)
{
/* TBD: calculate based on presence/absence from terms */
return 42;
}
static void
nsr_set_leader (xlator_t *this, etcd_session etcd)
{
long term = 0;
etcd_result res;
nsr_private_t *priv = this->private;
char *term_key = priv->term_uuid;
char n_t[sizeof(long)+1];
char *text = NULL;
gf_log (this->name, GF_LOG_INFO, "Just became leader");
text = etcd_get(etcd, priv->term_uuid);
if(text == NULL) {
term = 0;
} else {
term = strtol(text, NULL, 10);
}
sprintf(n_t,"%ld",term+1);
res = etcd_set(etcd, term_key,n_t,text,0);
if(res != ETCD_OK) {
gf_log (this->name, GF_LOG_ERROR, "failed to set term");
return;
}
priv->leader = _gf_true;
if (priv->nsr_recon_start == _gf_false) {
atomic_fetch_and(&(priv->fence_io), 0);
return;
}
priv->current_term = term + 1;
// Move this inside recon notify???
atomic_fetch_or(&(priv->fence_io), 1);
nsr_recon_notify_event_set_leader(priv);
return;
}
leader_retval_t
nsr_get_leader (xlator_t *this, etcd_session etcd, char *key)
{
char *text = NULL;
regmatch_t matches[VOTE_ELEMS];
char *nominee;
long state;
long fitness;
char *vote = NULL;
int retval = LS_ERROR;
nsr_private_t *priv = this->private;
for (;;sleep(1)) {
if (text) {
free(text);
}
text = etcd_get(etcd,key);
if (text) {
if (regexec(&vote_re,text,VOTE_ELEMS,matches,0) != 0) {
gf_log (this->name, GF_LOG_ERROR,
"got malformed vote %s\n", text);
continue;
}
/* We can be destructive here, so convert commas. */
text[matches[1].rm_eo] = '\0';
text[matches[2].rm_eo] = '\0';
nominee = text + matches[1].rm_so;
state = strtol(text+matches[2].rm_so,NULL,10);
fitness = strtol(text+matches[3].rm_so,NULL,10);
}
else {
nominee = NULL;
state = NO_LEADER;
fitness = 0;
}
if (state == CONFIRMED) {
gf_log (this->name, GF_LOG_TRACE,
"leader is %s\n",nominee);
if (strcmp(nominee,priv->brick_uuid) == 0) {
nsr_set_leader(this, etcd);
retval = LS_SUCCESS;
}
else {
priv->leader = _gf_false;
retval = LS_FAILURE;
}
break;
}
/* TBD: override based on fitness */
if ((state >= TENTATIVE) && (strcmp(nominee,
priv->brick_uuid) != 0)) {
continue;
}
if (vote) {
free(vote);
}
fitness = nsr_get_fitness(this);
if (asprintf(&vote,"%s,%ld,%ld",priv->brick_uuid,
state+1,fitness) < 0) {
gf_log (this->name, GF_LOG_ERROR,
"failed to construct vote\n");
break;
}
if (text) {
text[matches[1].rm_eo] = ',';
text[matches[2].rm_eo] = ',';
}
if (etcd_set(etcd,key,vote,text,LEADER_TTL) != ETCD_OK) {
gf_log (this->name, GF_LOG_ERROR,
"failed to cast vote\n");
continue;
}
}
if (text) {
free(text);
}
if (vote) {
free(vote);
}
return retval;
}
leader_retval_t
nsr_confirm (xlator_t *this, etcd_session etcd, char *key)
{
char *vote;
long fitness;
nsr_private_t *priv = this->private;
fitness = nsr_get_fitness(this);
if (asprintf(&vote,"%s,%ld,%ld",priv->brick_uuid,(long)CONFIRMED,
fitness) < 0) {
fprintf (stderr, "%s: failed to construct confirmation\n",
__func__);
return LS_ERROR;
}
if (etcd_set(etcd,key,vote,vote,LEADER_TTL) != ETCD_OK) {
fprintf (stderr, "%s: failed to confirm\n", __func__);
free(vote);
return LS_FAILURE;
}
free(vote);
return LS_SUCCESS;
}
gf_boolean_t
nsr_init_re (xlator_t *this)
{
static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
static int was_inited = 0;
static char *vote_re_str = "([^,]+),([^,]+),([^,]+)";
gf_boolean_t retval = _gf_false;
pthread_mutex_lock(&mutex);
if (!was_inited) {
if (regcomp(&vote_re,vote_re_str,REG_EXTENDED) == 0) {
retval = _gf_true;
}
else {
gf_log (this->name, GF_LOG_ERROR,
"failed to set up vote regex\n");
}
}
pthread_mutex_unlock(&mutex);
return retval;
}
void *
nsr_leader_thread (void *arg)
{
xlator_t *this = (xlator_t *) arg;
leader_retval_t retval;
nsr_private_t *priv = this->private;
if (!nsr_init_re(this)) {
gf_log (this->name, GF_LOG_ERROR, "could not init regex");
return NULL;
}
gf_log (this->name, GF_LOG_INFO,
"calling glfs_opens_str on servers %s", priv->etcd_servers);
priv->etcd = etcd_open_str(priv->etcd_servers);
if (!(priv->etcd)) {
gf_log (this->name, GF_LOG_ERROR,
"failed to open etcd session\n");
return NULL;
}
priv->leader_inited = 1;
for (;;) {
if (nsr_get_leader(this,priv->etcd,priv->vol_uuid) == LS_ERROR) {
break;
}
if (priv->leader) {
do {
sleep(1);
retval = nsr_confirm(this,priv->etcd,priv->vol_uuid);
} while (retval == LS_SUCCESS);
if (retval == LS_ERROR) {
break;
}
}
else {
sleep(1);
}
}
etcd_close_str(priv->etcd);
return NULL;
}
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