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sentinel.c
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/* Redis Sentinel implementation
*
* Copyright (c) 2009-2012, Salvatore Sanfilippo <antirez at gmail dot com>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of Redis nor the names of its contributors may be used
* to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include "redis.h"
#include "hiredis.h"
#include "async.h"
#include <ctype.h>
#include <arpa/inet.h>
#include <sys/socket.h>
#include <sys/wait.h>
#include <fcntl.h>
extern char **environ;
#define REDIS_SENTINEL_PORT 26379
/* ======================== Sentinel global state =========================== */
/* Address object, used to describe an ip:port pair. */
typedef struct sentinelAddr {
char *ip;
int port;
} sentinelAddr;
/* A Sentinel Redis Instance object is monitoring. */
#define SRI_MASTER (1<<0)
#define SRI_SLAVE (1<<1)
#define SRI_SENTINEL (1<<2)
#define SRI_DISCONNECTED (1<<3)
#define SRI_S_DOWN (1<<4) /* Subjectively down (no quorum). */
#define SRI_O_DOWN (1<<5) /* Objectively down (confirmed by others). */
#define SRI_MASTER_DOWN (1<<6) /* A Sentinel with this flag set thinks that
its master is down. */
#define SRI_FAILOVER_IN_PROGRESS (1<<7) /* Failover is in progress for
this master. */
#define SRI_PROMOTED (1<<8) /* Slave selected for promotion. */
#define SRI_RECONF_SENT (1<<9) /* SLAVEOF <newmaster> sent. */
#define SRI_RECONF_INPROG (1<<10) /* Slave synchronization in progress. */
#define SRI_RECONF_DONE (1<<11) /* Slave synchronized with new master. */
#define SRI_FORCE_FAILOVER (1<<12) /* Force failover with master up. */
#define SRI_SCRIPT_KILL_SENT (1<<13) /* SCRIPT KILL already sent on -BUSY */
/* Note: times are in milliseconds. */
#define SENTINEL_INFO_PERIOD 10000
#define SENTINEL_PING_PERIOD 1000
#define SENTINEL_ASK_PERIOD 1000
#define SENTINEL_PUBLISH_PERIOD 2000
#define SENTINEL_DEFAULT_DOWN_AFTER 30000
#define SENTINEL_HELLO_CHANNEL "__sentinel__:hello"
#define SENTINEL_TILT_TRIGGER 2000
#define SENTINEL_TILT_PERIOD (SENTINEL_PING_PERIOD*30)
#define SENTINEL_DEFAULT_SLAVE_PRIORITY 100
#define SENTINEL_SLAVE_RECONF_TIMEOUT 10000
#define SENTINEL_DEFAULT_PARALLEL_SYNCS 1
#define SENTINEL_MIN_LINK_RECONNECT_PERIOD 15000
#define SENTINEL_DEFAULT_FAILOVER_TIMEOUT (60*3*1000)
#define SENTINEL_MAX_PENDING_COMMANDS 100
#define SENTINEL_ELECTION_TIMEOUT 10000
#define SENTINEL_MAX_DESYNC 1000
/* Failover machine different states. */
#define SENTINEL_FAILOVER_STATE_NONE 0 /* No failover in progress. */
#define SENTINEL_FAILOVER_STATE_WAIT_START 1 /* Wait for failover_start_time*/
#define SENTINEL_FAILOVER_STATE_SELECT_SLAVE 2 /* Select slave to promote */
#define SENTINEL_FAILOVER_STATE_SEND_SLAVEOF_NOONE 3 /* Slave -> Master */
#define SENTINEL_FAILOVER_STATE_WAIT_PROMOTION 4 /* Wait slave to change role */
#define SENTINEL_FAILOVER_STATE_RECONF_SLAVES 5 /* SLAVEOF newmaster */
#define SENTINEL_FAILOVER_STATE_UPDATE_CONFIG 6 /* Monitor promoted slave. */
#define SENTINEL_MASTER_LINK_STATUS_UP 0
#define SENTINEL_MASTER_LINK_STATUS_DOWN 1
/* Generic flags that can be used with different functions.
* They use higher bits to avoid colliding with the function specific
* flags. */
#define SENTINEL_NO_FLAGS 0
#define SENTINEL_GENERATE_EVENT (1<<16)
#define SENTINEL_LEADER (1<<17)
#define SENTINEL_OBSERVER (1<<18)
/* Script execution flags and limits. */
#define SENTINEL_SCRIPT_NONE 0
#define SENTINEL_SCRIPT_RUNNING 1
#define SENTINEL_SCRIPT_MAX_QUEUE 256
#define SENTINEL_SCRIPT_MAX_RUNNING 16
#define SENTINEL_SCRIPT_MAX_RUNTIME 60000 /* 60 seconds max exec time. */
#define SENTINEL_SCRIPT_MAX_RETRY 10
#define SENTINEL_SCRIPT_RETRY_DELAY 30000 /* 30 seconds between retries. */
typedef struct sentinelRedisInstance {
int flags; /* See SRI_... defines */
char *name; /* Master name from the point of view of this sentinel. */
char *runid; /* run ID of this instance. */
uint64_t config_epoch; /* Configuration epoch. */
sentinelAddr *addr; /* Master host. */
redisAsyncContext *cc; /* Hiredis context for commands. */
redisAsyncContext *pc; /* Hiredis context for Pub / Sub. */
int pending_commands; /* Number of commands sent waiting for a reply. */
mstime_t cc_conn_time; /* cc connection time. */
mstime_t pc_conn_time; /* pc connection time. */
mstime_t pc_last_activity; /* Last time we received any message. */
mstime_t last_avail_time; /* Last time the instance replied to ping with
a reply we consider valid. */
mstime_t last_ping_time; /* Last time a pending ping was sent in the
context of the current command connection
with the instance. 0 if still not sent or
if pong already received. */
mstime_t last_pong_time; /* Last time the instance replied to ping,
whatever the reply was. That's used to check
if the link is idle and must be reconnected. */
mstime_t last_pub_time; /* Last time we sent hello via Pub/Sub. */
mstime_t last_hello_time; /* Only used if SRI_SENTINEL is set. Last time
we received a hello from this Sentinel
via Pub/Sub. */
mstime_t last_master_down_reply_time; /* Time of last reply to
SENTINEL is-master-down command. */
mstime_t s_down_since_time; /* Subjectively down since time. */
mstime_t o_down_since_time; /* Objectively down since time. */
mstime_t down_after_period; /* Consider it down after that period. */
mstime_t info_refresh; /* Time at which we received INFO output from it. */
/* Role and the first time we observed it.
* This is useful in order to delay replacing what the instance reports
* with our own configuration. We need to always wait some time in order
* to give a chance to the leader to report the new configuration before
* we do silly things. */
int role_reported;
mstime_t role_reported_time;
mstime_t slave_conf_change_time; /* Last time slave master addr changed. */
/* Master specific. */
dict *sentinels; /* Other sentinels monitoring the same master. */
dict *slaves; /* Slaves for this master instance. */
unsigned int quorum;/* Number of sentinels that need to agree on failure. */
int parallel_syncs; /* How many slaves to reconfigure at same time. */
char *auth_pass; /* Password to use for AUTH against master & slaves. */
/* Slave specific. */
mstime_t master_link_down_time; /* Slave replication link down time. */
int slave_priority; /* Slave priority according to its INFO output. */
mstime_t slave_reconf_sent_time; /* Time at which we sent SLAVE OF <new> */
struct sentinelRedisInstance *master; /* Master instance if it's slave. */
char *slave_master_host; /* Master host as reported by INFO */
int slave_master_port; /* Master port as reported by INFO */
int slave_master_link_status; /* Master link status as reported by INFO */
unsigned long long slave_repl_offset; /* Slave replication offset. */
/* Failover */
char *leader; /* If this is a master instance, this is the runid of
the Sentinel that should perform the failover. If
this is a Sentinel, this is the runid of the Sentinel
that this Sentinel voted as leader. */
uint64_t leader_epoch; /* Epoch of the 'leader' field. */
uint64_t failover_epoch; /* Epoch of the currently started failover. */
int failover_state; /* See SENTINEL_FAILOVER_STATE_* defines. */
mstime_t failover_state_change_time;
mstime_t failover_start_time; /* Last failover attempt start time. */
mstime_t failover_timeout; /* Max time to refresh failover state. */
mstime_t failover_delay_logged; /* For what failover_start_time value we
logged the failover delay. */
struct sentinelRedisInstance *promoted_slave; /* Promoted slave instance. */
/* Scripts executed to notify admin or reconfigure clients: when they
* are set to NULL no script is executed. */
char *notification_script;
char *client_reconfig_script;
sds info; /* cached INFO output */
} sentinelRedisInstance;
/* Main state. */
struct sentinelState {
uint64_t current_epoch; /* Current epoch. */
dict *masters; /* Dictionary of master sentinelRedisInstances.
Key is the instance name, value is the
sentinelRedisInstance structure pointer. */
int tilt; /* Are we in TILT mode? */
int running_scripts; /* Number of scripts in execution right now. */
mstime_t tilt_start_time; /* When TITL started. */
mstime_t previous_time; /* Last time we ran the time handler. */
list *scripts_queue; /* Queue of user scripts to execute. */
char *announce_ip; /* IP addr that is gossiped to other sentinels if
not NULL. */
int announce_port; /* Port that is gossiped to other sentinels if
non zero. */
} sentinel;
/* A script execution job. */
typedef struct sentinelScriptJob {
int flags; /* Script job flags: SENTINEL_SCRIPT_* */
int retry_num; /* Number of times we tried to execute it. */
char **argv; /* Arguments to call the script. */
mstime_t start_time; /* Script execution time if the script is running,
otherwise 0 if we are allowed to retry the
execution at any time. If the script is not
running and it's not 0, it means: do not run
before the specified time. */
pid_t pid; /* Script execution pid. */
} sentinelScriptJob;
/* ======================= hiredis ae.c adapters =============================
* Note: this implementation is taken from hiredis/adapters/ae.h, however
* we have our modified copy for Sentinel in order to use our allocator
* and to have full control over how the adapter works. */
typedef struct redisAeEvents {
redisAsyncContext *context;
aeEventLoop *loop;
int fd;
int reading, writing;
} redisAeEvents;
static void redisAeReadEvent(aeEventLoop *el, int fd, void *privdata, int mask) {
((void)el); ((void)fd); ((void)mask);
redisAeEvents *e = (redisAeEvents*)privdata;
redisAsyncHandleRead(e->context);
}
static void redisAeWriteEvent(aeEventLoop *el, int fd, void *privdata, int mask) {
((void)el); ((void)fd); ((void)mask);
redisAeEvents *e = (redisAeEvents*)privdata;
redisAsyncHandleWrite(e->context);
}
static void redisAeAddRead(void *privdata) {
redisAeEvents *e = (redisAeEvents*)privdata;
aeEventLoop *loop = e->loop;
if (!e->reading) {
e->reading = 1;
aeCreateFileEvent(loop,e->fd,AE_READABLE,redisAeReadEvent,e);
}
}
static void redisAeDelRead(void *privdata) {
redisAeEvents *e = (redisAeEvents*)privdata;
aeEventLoop *loop = e->loop;
if (e->reading) {
e->reading = 0;
aeDeleteFileEvent(loop,e->fd,AE_READABLE);
}
}
static void redisAeAddWrite(void *privdata) {
redisAeEvents *e = (redisAeEvents*)privdata;
aeEventLoop *loop = e->loop;
if (!e->writing) {
e->writing = 1;
aeCreateFileEvent(loop,e->fd,AE_WRITABLE,redisAeWriteEvent,e);
}
}
static void redisAeDelWrite(void *privdata) {
redisAeEvents *e = (redisAeEvents*)privdata;
aeEventLoop *loop = e->loop;
if (e->writing) {
e->writing = 0;
aeDeleteFileEvent(loop,e->fd,AE_WRITABLE);
}
}
static void redisAeCleanup(void *privdata) {
redisAeEvents *e = (redisAeEvents*)privdata;
redisAeDelRead(privdata);
redisAeDelWrite(privdata);
zfree(e);
}
static int redisAeAttach(aeEventLoop *loop, redisAsyncContext *ac) {
redisContext *c = &(ac->c);
redisAeEvents *e;
/* Nothing should be attached when something is already attached */
if (ac->ev.data != NULL)
return REDIS_ERR;
/* Create container for context and r/w events */
e = (redisAeEvents*)zmalloc(sizeof(*e));
e->context = ac;
e->loop = loop;
e->fd = c->fd;
e->reading = e->writing = 0;
/* Register functions to start/stop listening for events */
ac->ev.addRead = redisAeAddRead;
ac->ev.delRead = redisAeDelRead;
ac->ev.addWrite = redisAeAddWrite;
ac->ev.delWrite = redisAeDelWrite;
ac->ev.cleanup = redisAeCleanup;
ac->ev.data = e;
return REDIS_OK;
}
/* ============================= Prototypes ================================= */
void sentinelLinkEstablishedCallback(const redisAsyncContext *c, int status);
void sentinelDisconnectCallback(const redisAsyncContext *c, int status);
void sentinelReceiveHelloMessages(redisAsyncContext *c, void *reply, void *privdata);
sentinelRedisInstance *sentinelGetMasterByName(char *name);
char *sentinelGetSubjectiveLeader(sentinelRedisInstance *master);
char *sentinelGetObjectiveLeader(sentinelRedisInstance *master);
int yesnotoi(char *s);
void sentinelDisconnectInstanceFromContext(const redisAsyncContext *c);
void sentinelKillLink(sentinelRedisInstance *ri, redisAsyncContext *c);
const char *sentinelRedisInstanceTypeStr(sentinelRedisInstance *ri);
void sentinelAbortFailover(sentinelRedisInstance *ri);
void sentinelEvent(int level, char *type, sentinelRedisInstance *ri, const char *fmt, ...);
sentinelRedisInstance *sentinelSelectSlave(sentinelRedisInstance *master);
void sentinelScheduleScriptExecution(char *path, ...);
void sentinelStartFailover(sentinelRedisInstance *master);
void sentinelDiscardReplyCallback(redisAsyncContext *c, void *reply, void *privdata);
int sentinelSendSlaveOf(sentinelRedisInstance *ri, char *host, int port);
char *sentinelVoteLeader(sentinelRedisInstance *master, uint64_t req_epoch, char *req_runid, uint64_t *leader_epoch);
void sentinelFlushConfig(void);
void sentinelGenerateInitialMonitorEvents(void);
int sentinelSendPing(sentinelRedisInstance *ri);
int sentinelForceHelloUpdateForMaster(sentinelRedisInstance *master);
/* ========================= Dictionary types =============================== */
unsigned int dictSdsHash(const void *key);
int dictSdsKeyCompare(void *privdata, const void *key1, const void *key2);
void releaseSentinelRedisInstance(sentinelRedisInstance *ri);
void dictInstancesValDestructor (void *privdata, void *obj) {
REDIS_NOTUSED(privdata);
releaseSentinelRedisInstance(obj);
}
/* Instance name (sds) -> instance (sentinelRedisInstance pointer)
*
* also used for: sentinelRedisInstance->sentinels dictionary that maps
* sentinels ip:port to last seen time in Pub/Sub hello message. */
dictType instancesDictType = {
dictSdsHash, /* hash function */
NULL, /* key dup */
NULL, /* val dup */
dictSdsKeyCompare, /* key compare */
NULL, /* key destructor */
dictInstancesValDestructor /* val destructor */
};
/* Instance runid (sds) -> votes (long casted to void*)
*
* This is useful into sentinelGetObjectiveLeader() function in order to
* count the votes and understand who is the leader. */
dictType leaderVotesDictType = {
dictSdsHash, /* hash function */
NULL, /* key dup */
NULL, /* val dup */
dictSdsKeyCompare, /* key compare */
NULL, /* key destructor */
NULL /* val destructor */
};
/* =========================== Initialization =============================== */
void sentinelCommand(redisClient *c);
void sentinelInfoCommand(redisClient *c);
void sentinelSetCommand(redisClient *c);
void sentinelPublishCommand(redisClient *c);
void sentinelRoleCommand(redisClient *c);
struct redisCommand sentinelcmds[] = {
{"ping",pingCommand,1,"",0,NULL,0,0,0,0,0},
{"sentinel",sentinelCommand,-2,"",0,NULL,0,0,0,0,0},
{"subscribe",subscribeCommand,-2,"",0,NULL,0,0,0,0,0},
{"unsubscribe",unsubscribeCommand,-1,"",0,NULL,0,0,0,0,0},
{"psubscribe",psubscribeCommand,-2,"",0,NULL,0,0,0,0,0},
{"punsubscribe",punsubscribeCommand,-1,"",0,NULL,0,0,0,0,0},
{"publish",sentinelPublishCommand,3,"",0,NULL,0,0,0,0,0},
{"info",sentinelInfoCommand,-1,"",0,NULL,0,0,0,0,0},
{"role",sentinelRoleCommand,1,"l",0,NULL,0,0,0,0,0},
{"client",clientCommand,-2,"rs",0,NULL,0,0,0,0,0},
{"shutdown",shutdownCommand,-1,"",0,NULL,0,0,0,0,0}
};
/* This function overwrites a few normal Redis config default with Sentinel
* specific defaults. */
void initSentinelConfig(void) {
server.port = REDIS_SENTINEL_PORT;
}
/* Perform the Sentinel mode initialization. */
void initSentinel(void) {
unsigned int j;
/* Remove usual Redis commands from the command table, then just add
* the SENTINEL command. */
dictEmpty(server.commands,NULL);
for (j = 0; j < sizeof(sentinelcmds)/sizeof(sentinelcmds[0]); j++) {
int retval;
struct redisCommand *cmd = sentinelcmds+j;
retval = dictAdd(server.commands, sdsnew(cmd->name), cmd);
redisAssert(retval == DICT_OK);
}
/* Initialize various data structures. */
sentinel.current_epoch = 0;
sentinel.masters = dictCreate(&instancesDictType,NULL);
sentinel.tilt = 0;
sentinel.tilt_start_time = 0;
sentinel.previous_time = mstime();
sentinel.running_scripts = 0;
sentinel.scripts_queue = listCreate();
sentinel.announce_ip = NULL;
sentinel.announce_port = 0;
}
/* This function gets called when the server is in Sentinel mode, started,
* loaded the configuration, and is ready for normal operations. */
void sentinelIsRunning(void) {
redisLog(REDIS_WARNING,"Sentinel runid is %s", server.runid);
if (server.configfile == NULL) {
redisLog(REDIS_WARNING,
"Sentinel started without a config file. Exiting...");
exit(1);
} else if (access(server.configfile,W_OK) == -1) {
redisLog(REDIS_WARNING,
"Sentinel config file %s is not writable: %s. Exiting...",
server.configfile,strerror(errno));
exit(1);
}
/* We want to generate a +monitor event for every configured master
* at startup. */
sentinelGenerateInitialMonitorEvents();
}
/* ============================== sentinelAddr ============================== */
/* Create a sentinelAddr object and return it on success.
* On error NULL is returned and errno is set to:
* ENOENT: Can't resolve the hostname.
* EINVAL: Invalid port number.
*/
sentinelAddr *createSentinelAddr(char *hostname, int port) {
char ip[REDIS_IP_STR_LEN];
sentinelAddr *sa;
if (port <= 0 || port > 65535) {
errno = EINVAL;
return NULL;
}
if (anetResolve(NULL,hostname,ip,sizeof(ip)) == ANET_ERR) {
errno = ENOENT;
return NULL;
}
sa = zmalloc(sizeof(*sa));
sa->ip = sdsnew(ip);
sa->port = port;
return sa;
}
/* Return a duplicate of the source address. */
sentinelAddr *dupSentinelAddr(sentinelAddr *src) {
sentinelAddr *sa;
sa = zmalloc(sizeof(*sa));
sa->ip = sdsnew(src->ip);
sa->port = src->port;
return sa;
}
/* Free a Sentinel address. Can't fail. */
void releaseSentinelAddr(sentinelAddr *sa) {
sdsfree(sa->ip);
zfree(sa);
}
/* Return non-zero if two addresses are equal. */
int sentinelAddrIsEqual(sentinelAddr *a, sentinelAddr *b) {
return a->port == b->port && !strcasecmp(a->ip,b->ip);
}
/* =========================== Events notification ========================== */
/* Send an event to log, pub/sub, user notification script.
*
* 'level' is the log level for logging. Only REDIS_WARNING events will trigger
* the execution of the user notification script.
*
* 'type' is the message type, also used as a pub/sub channel name.
*
* 'ri', is the redis instance target of this event if applicable, and is
* used to obtain the path of the notification script to execute.
*
* The remaining arguments are printf-alike.
* If the format specifier starts with the two characters "%@" then ri is
* not NULL, and the message is prefixed with an instance identifier in the
* following format:
*
* <instance type> <instance name> <ip> <port>
*
* If the instance type is not master, than the additional string is
* added to specify the originating master:
*
* @ <master name> <master ip> <master port>
*
* Any other specifier after "%@" is processed by printf itself.
*/
void sentinelEvent(int level, char *type, sentinelRedisInstance *ri,
const char *fmt, ...) {
va_list ap;
char msg[REDIS_MAX_LOGMSG_LEN];
robj *channel, *payload;
/* Handle %@ */
if (fmt[0] == '%' && fmt[1] == '@') {
sentinelRedisInstance *master = (ri->flags & SRI_MASTER) ?
NULL : ri->master;
if (master) {
snprintf(msg, sizeof(msg), "%s %s %s %d @ %s %s %d",
sentinelRedisInstanceTypeStr(ri),
ri->name, ri->addr->ip, ri->addr->port,
master->name, master->addr->ip, master->addr->port);
} else {
snprintf(msg, sizeof(msg), "%s %s %s %d",
sentinelRedisInstanceTypeStr(ri),
ri->name, ri->addr->ip, ri->addr->port);
}
fmt += 2;
} else {
msg[0] = '\0';
}
/* Use vsprintf for the rest of the formatting if any. */
if (fmt[0] != '\0') {
va_start(ap, fmt);
vsnprintf(msg+strlen(msg), sizeof(msg)-strlen(msg), fmt, ap);
va_end(ap);
}
/* Log the message if the log level allows it to be logged. */
if (level >= server.verbosity)
redisLog(level,"%s %s",type,msg);
/* Publish the message via Pub/Sub if it's not a debugging one. */
if (level != REDIS_DEBUG) {
channel = createStringObject(type,strlen(type));
payload = createStringObject(msg,strlen(msg));
pubsubPublishMessage(channel,payload);
decrRefCount(channel);
decrRefCount(payload);
}
/* Call the notification script if applicable. */
if (level == REDIS_WARNING && ri != NULL) {
sentinelRedisInstance *master = (ri->flags & SRI_MASTER) ?
ri : ri->master;
if (master && master->notification_script) {
sentinelScheduleScriptExecution(master->notification_script,
type,msg,NULL);
}
}
}
/* This function is called only at startup and is used to generate a
* +monitor event for every configured master. The same events are also
* generated when a master to monitor is added at runtime via the
* SENTINEL MONITOR command. */
void sentinelGenerateInitialMonitorEvents(void) {
dictIterator *di;
dictEntry *de;
di = dictGetIterator(sentinel.masters);
while((de = dictNext(di)) != NULL) {
sentinelRedisInstance *ri = dictGetVal(de);
sentinelEvent(REDIS_WARNING,"+monitor",ri,"%@ quorum %d",ri->quorum);
}
dictReleaseIterator(di);
}
/* ============================ script execution ============================ */
/* Release a script job structure and all the associated data. */
void sentinelReleaseScriptJob(sentinelScriptJob *sj) {
int j = 0;
while(sj->argv[j]) sdsfree(sj->argv[j++]);
zfree(sj->argv);
zfree(sj);
}
#define SENTINEL_SCRIPT_MAX_ARGS 16
void sentinelScheduleScriptExecution(char *path, ...) {
va_list ap;
char *argv[SENTINEL_SCRIPT_MAX_ARGS+1];
int argc = 1;
sentinelScriptJob *sj;
va_start(ap, path);
while(argc < SENTINEL_SCRIPT_MAX_ARGS) {
argv[argc] = va_arg(ap,char*);
if (!argv[argc]) break;
argv[argc] = sdsnew(argv[argc]); /* Copy the string. */
argc++;
}
va_end(ap);
argv[0] = sdsnew(path);
sj = zmalloc(sizeof(*sj));
sj->flags = SENTINEL_SCRIPT_NONE;
sj->retry_num = 0;
sj->argv = zmalloc(sizeof(char*)*(argc+1));
sj->start_time = 0;
sj->pid = 0;
memcpy(sj->argv,argv,sizeof(char*)*(argc+1));
listAddNodeTail(sentinel.scripts_queue,sj);
/* Remove the oldest non running script if we already hit the limit. */
if (listLength(sentinel.scripts_queue) > SENTINEL_SCRIPT_MAX_QUEUE) {
listNode *ln;
listIter li;
listRewind(sentinel.scripts_queue,&li);
while ((ln = listNext(&li)) != NULL) {
sj = ln->value;
if (sj->flags & SENTINEL_SCRIPT_RUNNING) continue;
/* The first node is the oldest as we add on tail. */
listDelNode(sentinel.scripts_queue,ln);
sentinelReleaseScriptJob(sj);
break;
}
redisAssert(listLength(sentinel.scripts_queue) <=
SENTINEL_SCRIPT_MAX_QUEUE);
}
}
/* Lookup a script in the scripts queue via pid, and returns the list node
* (so that we can easily remove it from the queue if needed). */
listNode *sentinelGetScriptListNodeByPid(pid_t pid) {
listNode *ln;
listIter li;
listRewind(sentinel.scripts_queue,&li);
while ((ln = listNext(&li)) != NULL) {
sentinelScriptJob *sj = ln->value;
if ((sj->flags & SENTINEL_SCRIPT_RUNNING) && sj->pid == pid)
return ln;
}
return NULL;
}
/* Run pending scripts if we are not already at max number of running
* scripts. */
void sentinelRunPendingScripts(void) {
listNode *ln;
listIter li;
mstime_t now = mstime();
/* Find jobs that are not running and run them, from the top to the
* tail of the queue, so we run older jobs first. */
listRewind(sentinel.scripts_queue,&li);
while (sentinel.running_scripts < SENTINEL_SCRIPT_MAX_RUNNING &&
(ln = listNext(&li)) != NULL)
{
sentinelScriptJob *sj = ln->value;
pid_t pid;
/* Skip if already running. */
if (sj->flags & SENTINEL_SCRIPT_RUNNING) continue;
/* Skip if it's a retry, but not enough time has elapsed. */
if (sj->start_time && sj->start_time > now) continue;
sj->flags |= SENTINEL_SCRIPT_RUNNING;
sj->start_time = mstime();
sj->retry_num++;
pid = fork();
if (pid == -1) {
/* Parent (fork error).
* We report fork errors as signal 99, in order to unify the
* reporting with other kind of errors. */
sentinelEvent(REDIS_WARNING,"-script-error",NULL,
"%s %d %d", sj->argv[0], 99, 0);
sj->flags &= ~SENTINEL_SCRIPT_RUNNING;
sj->pid = 0;
} else if (pid == 0) {
/* Child */
execve(sj->argv[0],sj->argv,environ);
/* If we are here an error occurred. */
_exit(2); /* Don't retry execution. */
} else {
sentinel.running_scripts++;
sj->pid = pid;
sentinelEvent(REDIS_DEBUG,"+script-child",NULL,"%ld",(long)pid);
}
}
}
/* How much to delay the execution of a script that we need to retry after
* an error?
*
* We double the retry delay for every further retry we do. So for instance
* if RETRY_DELAY is set to 30 seconds and the max number of retries is 10
* starting from the second attempt to execute the script the delays are:
* 30 sec, 60 sec, 2 min, 4 min, 8 min, 16 min, 32 min, 64 min, 128 min. */
mstime_t sentinelScriptRetryDelay(int retry_num) {
mstime_t delay = SENTINEL_SCRIPT_RETRY_DELAY;
while (retry_num-- > 1) delay *= 2;
return delay;
}
/* Check for scripts that terminated, and remove them from the queue if the
* script terminated successfully. If instead the script was terminated by
* a signal, or returned exit code "1", it is scheduled to run again if
* the max number of retries did not already elapsed. */
void sentinelCollectTerminatedScripts(void) {
int statloc;
pid_t pid;
while ((pid = wait3(&statloc,WNOHANG,NULL)) > 0) {
int exitcode = WEXITSTATUS(statloc);
int bysignal = 0;
listNode *ln;
sentinelScriptJob *sj;
if (WIFSIGNALED(statloc)) bysignal = WTERMSIG(statloc);
sentinelEvent(REDIS_DEBUG,"-script-child",NULL,"%ld %d %d",
(long)pid, exitcode, bysignal);
ln = sentinelGetScriptListNodeByPid(pid);
if (ln == NULL) {
redisLog(REDIS_WARNING,"wait3() returned a pid (%ld) we can't find in our scripts execution queue!", (long)pid);
continue;
}
sj = ln->value;
/* If the script was terminated by a signal or returns an
* exit code of "1" (that means: please retry), we reschedule it
* if the max number of retries is not already reached. */
if ((bysignal || exitcode == 1) &&
sj->retry_num != SENTINEL_SCRIPT_MAX_RETRY)
{
sj->flags &= ~SENTINEL_SCRIPT_RUNNING;
sj->pid = 0;
sj->start_time = mstime() +
sentinelScriptRetryDelay(sj->retry_num);
} else {
/* Otherwise let's remove the script, but log the event if the
* execution did not terminated in the best of the ways. */
if (bysignal || exitcode != 0) {
sentinelEvent(REDIS_WARNING,"-script-error",NULL,
"%s %d %d", sj->argv[0], bysignal, exitcode);
}
listDelNode(sentinel.scripts_queue,ln);
sentinelReleaseScriptJob(sj);
sentinel.running_scripts--;
}
}
}
/* Kill scripts in timeout, they'll be collected by the
* sentinelCollectTerminatedScripts() function. */
void sentinelKillTimedoutScripts(void) {
listNode *ln;
listIter li;
mstime_t now = mstime();
listRewind(sentinel.scripts_queue,&li);
while ((ln = listNext(&li)) != NULL) {
sentinelScriptJob *sj = ln->value;
if (sj->flags & SENTINEL_SCRIPT_RUNNING &&
(now - sj->start_time) > SENTINEL_SCRIPT_MAX_RUNTIME)
{
sentinelEvent(REDIS_WARNING,"-script-timeout",NULL,"%s %ld",
sj->argv[0], (long)sj->pid);
kill(sj->pid,SIGKILL);
}
}
}
/* Implements SENTINEL PENDING-SCRIPTS command. */
void sentinelPendingScriptsCommand(redisClient *c) {
listNode *ln;
listIter li;
addReplyMultiBulkLen(c,listLength(sentinel.scripts_queue));
listRewind(sentinel.scripts_queue,&li);
while ((ln = listNext(&li)) != NULL) {
sentinelScriptJob *sj = ln->value;
int j = 0;
addReplyMultiBulkLen(c,10);
addReplyBulkCString(c,"argv");
while (sj->argv[j]) j++;
addReplyMultiBulkLen(c,j);
j = 0;
while (sj->argv[j]) addReplyBulkCString(c,sj->argv[j++]);
addReplyBulkCString(c,"flags");
addReplyBulkCString(c,
(sj->flags & SENTINEL_SCRIPT_RUNNING) ? "running" : "scheduled");
addReplyBulkCString(c,"pid");
addReplyBulkLongLong(c,sj->pid);
if (sj->flags & SENTINEL_SCRIPT_RUNNING) {
addReplyBulkCString(c,"run-time");
addReplyBulkLongLong(c,mstime() - sj->start_time);
} else {
mstime_t delay = sj->start_time ? (sj->start_time-mstime()) : 0;
if (delay < 0) delay = 0;
addReplyBulkCString(c,"run-delay");
addReplyBulkLongLong(c,delay);
}
addReplyBulkCString(c,"retry-num");
addReplyBulkLongLong(c,sj->retry_num);
}
}
/* This function calls, if any, the client reconfiguration script with the
* following parameters:
*
* <master-name> <role> <state> <from-ip> <from-port> <to-ip> <to-port>
*
* It is called every time a failover is performed.
*
* <state> is currently always "failover".
* <role> is either "leader" or "observer".
*
* from/to fields are respectively master -> promoted slave addresses for
* "start" and "end". */
void sentinelCallClientReconfScript(sentinelRedisInstance *master, int role, char *state, sentinelAddr *from, sentinelAddr *to) {
char fromport[32], toport[32];
if (master->client_reconfig_script == NULL) return;
ll2string(fromport,sizeof(fromport),from->port);
ll2string(toport,sizeof(toport),to->port);
sentinelScheduleScriptExecution(master->client_reconfig_script,
master->name,
(role == SENTINEL_LEADER) ? "leader" : "observer",
state, from->ip, fromport, to->ip, toport, NULL);
}
/* ========================== sentinelRedisInstance ========================= */
/* Create a redis instance, the following fields must be populated by the
* caller if needed:
* runid: set to NULL but will be populated once INFO output is received.
* info_refresh: is set to 0 to mean that we never received INFO so far.
*
* If SRI_MASTER is set into initial flags the instance is added to
* sentinel.masters table.
*
* if SRI_SLAVE or SRI_SENTINEL is set then 'master' must be not NULL and the
* instance is added into master->slaves or master->sentinels table.
*
* If the instance is a slave or sentinel, the name parameter is ignored and
* is created automatically as hostname:port.
*
* The function fails if hostname can't be resolved or port is out of range.
* When this happens NULL is returned and errno is set accordingly to the
* createSentinelAddr() function.
*
* The function may also fail and return NULL with errno set to EBUSY if
* a master or slave with the same name already exists. */
sentinelRedisInstance *createSentinelRedisInstance(char *name, int flags, char *hostname, int port, int quorum, sentinelRedisInstance *master) {
sentinelRedisInstance *ri;
sentinelAddr *addr;
dict *table = NULL;
char slavename[REDIS_PEER_ID_LEN], *sdsname;
redisAssert(flags & (SRI_MASTER|SRI_SLAVE|SRI_SENTINEL));
redisAssert((flags & SRI_MASTER) || master != NULL);
/* Check address validity. */
addr = createSentinelAddr(hostname,port);
if (addr == NULL) return NULL;
/* For slaves and sentinel we use ip:port as name. */
if (flags & (SRI_SLAVE|SRI_SENTINEL)) {
anetFormatAddr(slavename, sizeof(slavename), hostname, port);
name = slavename;
}
/* Make sure the entry is not duplicated. This may happen when the same
* name for a master is used multiple times inside the configuration or
* if we try to add multiple times a slave or sentinel with same ip/port
* to a master. */
if (flags & SRI_MASTER) table = sentinel.masters;
else if (flags & SRI_SLAVE) table = master->slaves;
else if (flags & SRI_SENTINEL) table = master->sentinels;
sdsname = sdsnew(name);
if (dictFind(table,sdsname)) {
releaseSentinelAddr(addr);
sdsfree(sdsname);
errno = EBUSY;
return NULL;
}
/* Create the instance object. */
ri = zmalloc(sizeof(*ri));
/* Note that all the instances are started in the disconnected state,
* the event loop will take care of connecting them. */
ri->flags = flags | SRI_DISCONNECTED;
ri->name = sdsname;
ri->runid = NULL;
ri->config_epoch = 0;
ri->addr = addr;
ri->cc = NULL;
ri->pc = NULL;
ri->pending_commands = 0;
ri->cc_conn_time = 0;
ri->pc_conn_time = 0;
ri->pc_last_activity = 0;
/* We set the last_ping_time to "now" even if we actually don't have yet
* a connection with the node, nor we sent a ping.
* This is useful to detect a timeout in case we'll not be able to connect
* with the node at all. */
ri->last_ping_time = mstime();
ri->last_avail_time = mstime();
ri->last_pong_time = mstime();
ri->last_pub_time = mstime();
ri->last_hello_time = mstime();
ri->last_master_down_reply_time = mstime();
ri->s_down_since_time = 0;
ri->o_down_since_time = 0;
ri->down_after_period = master ? master->down_after_period :
SENTINEL_DEFAULT_DOWN_AFTER;
ri->master_link_down_time = 0;
ri->auth_pass = NULL;
ri->slave_priority = SENTINEL_DEFAULT_SLAVE_PRIORITY;
ri->slave_reconf_sent_time = 0;
ri->slave_master_host = NULL;
ri->slave_master_port = 0;
ri->slave_master_link_status = SENTINEL_MASTER_LINK_STATUS_DOWN;
ri->slave_repl_offset = 0;
ri->sentinels = dictCreate(&instancesDictType,NULL);
ri->quorum = quorum;
ri->parallel_syncs = SENTINEL_DEFAULT_PARALLEL_SYNCS;
ri->master = master;
ri->slaves = dictCreate(&instancesDictType,NULL);
ri->info_refresh = 0;
/* Failover state. */
ri->leader = NULL;
ri->leader_epoch = 0;
ri->failover_epoch = 0;
ri->failover_state = SENTINEL_FAILOVER_STATE_NONE;
ri->failover_state_change_time = 0;
ri->failover_start_time = 0;
ri->failover_timeout = SENTINEL_DEFAULT_FAILOVER_TIMEOUT;
ri->failover_delay_logged = 0;
ri->promoted_slave = NULL;
ri->notification_script = NULL;
ri->client_reconfig_script = NULL;
ri->info = NULL;
/* Role */
ri->role_reported = ri->flags & (SRI_MASTER|SRI_SLAVE);
ri->role_reported_time = mstime();
ri->slave_conf_change_time = mstime();
/* Add into the right table. */
dictAdd(table, ri->name, ri);
return ri;
}
/* Release this instance and all its slaves, sentinels, hiredis connections.
* This function does not take care of unlinking the instance from the main