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Sentinel: ability to execute notification scripts.

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1 parent 42c5718 commit baace5fc42dbe527a452d8864f37716d644f444a @antirez committed Jul 25, 2012
Showing with 95 additions and 11 deletions.
  1. +29 −5 sentinel.conf
  2. +66 −6 src/sentinel.c
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34 sentinel.conf
@@ -4,15 +4,17 @@
# The port that this sentinel instance will run on
port 26379
-# sentinel monitor <name> <ip> <redis-port> <quorum>
+# sentinel monitor <master-name> <ip> <redis-port> <quorum>
+#
# Tells Sentinel to monitor this slave, and to consider it in O_DOWN
# (Objectively Down) state only if at least <quorum> sentinels agree.
#
# Note: master name should not include special characters or spaces.
# The valid charset is A-z 0-9 and the three characters ".-_".
sentinel monitor mymaster 127.0.0.1 6379 2
-# sentinel down-after-milliseconds <mymaster> <milliseconds>
+# sentinel down-after-milliseconds <master-name> <milliseconds>
+#
# Number of milliseconds the master (or any attached slave or sentinel) should
# be unreachable (as in, not acceptable reply to PING, continuously, for the
# specified period) in order to consider it in S_DOWN state (Subjectively
@@ -21,18 +23,21 @@ sentinel monitor mymaster 127.0.0.1 6379 2
# Default is 30 seconds.
sentinel down-after-milliseconds mymaster 30000
-# sentinel can-failover <mymaster> <yes|no>
+# sentinel can-failover <master-name> <yes|no>
+#
# Specify if this Sentinel can start the failover for this master.
sentinel can-failover mymaster yes
-# sentinel parallel-syncs <mymaster> <numslaves>
+# sentinel parallel-syncs <master-name> <numslaves>
+#
# How many slaves we can reconfigure to point to the new slave simultaneously
# during the failover. Use a low number if you use the slaves to serve query
# to avoid that all the slaves will be unreachable at about the same
# time while performing the synchronization with the master.
sentinel parallel-syncs mymaster 1
-# sentinel failover-timeout <mymaster> <milliseconds>
+# sentinel failover-timeout <master-name> <milliseconds>
+#
# Specifies the failover timeout in milliseconds. When this time has elapsed
# without any progress in the failover process, it is considered concluded by
# the sentinel even if not all the attached slaves were correctly configured
@@ -47,3 +52,22 @@ sentinel parallel-syncs mymaster 1
# Default is 15 minutes.
sentinel failover-timeout mymaster 900000
+# sentinel notification-script <master-name> <script-path>
+#
+# Call the specified notification script for any sentienl event that is
+# generated in the WARNING level (for instance -sdown, -odown, and so forth).
+# This script should notify the system administrator via email, SMS, or any
+# other messaging system, that there is something wrong with the monitored
+# Redis systems.
+#
+# The script is called with just two arguments: the first is the event type
+# and the second the event description.
+#
+# The script must be exits and executable in order for sentinel to start if
+# this option is provided.
+#
+# Example:
+#
+# sentinel notification-script mymaster /var/redis/notify.sh
+
+
View
72 src/sentinel.c
@@ -37,6 +37,8 @@
#include <arpa/inet.h>
#include <sys/socket.h>
+extern char **environ;
+
#define REDIS_SENTINEL_PORT 26379
/* ======================== Sentinel global state =========================== */
@@ -169,7 +171,7 @@ typedef struct sentinelRedisInstance {
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 *notify_script;
+ char *notification_script;
char *client_reconfig_script;
} sentinelRedisInstance;
@@ -291,6 +293,7 @@ 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, ...);
/* ========================= Dictionary types =============================== */
@@ -403,7 +406,29 @@ void releaseSentinelAddr(sentinelAddr *sa) {
/* =========================== Events notification ========================== */
void sentinelCallNotificationScript(char *scriptpath, char *type, char *msg) {
- /* TODO: implement it. */
+ pid_t pid = fork();
+
+ if (pid == -1) {
+ /* Parent on error. */
+ sentinelEvent(REDIS_WARNING,"-notification-script-error",NULL,
+ "#can't fork: %s",strerror(errno));
+ return;
+ } else if (pid == 0) {
+ /* Child */
+ char *argv[4];
+
+ argv[0] = scriptpath;
+ argv[1] = type;
+ argv[2] = msg;
+ argv[3] = NULL;
+ execve(scriptpath,argv,environ);
+ /* If we are here an error occurred. */
+ sentinelEvent(REDIS_WARNING,"-notification-script-error",NULL,
+ "#execve(2): %s",strerror(errno));
+ _exit(1);
+ } else {
+ sentinelEvent(REDIS_DEBUG,"+child",NULL,"%ld",(long)pid);
+ }
}
/* Send an event to log, pub/sub, user notification script.
@@ -480,8 +505,9 @@ void sentinelEvent(int level, char *type, sentinelRedisInstance *ri,
if (level == REDIS_WARNING && ri != NULL) {
sentinelRedisInstance *master = (ri->flags & SRI_MASTER) ?
ri : ri->master;
- if (master->notify_script) {
- sentinelCallNotificationScript(master->notify_script,type,msg);
+ if (master->notification_script) {
+ sentinelCallNotificationScript(master->notification_script,
+ type,msg);
}
}
}
@@ -584,7 +610,7 @@ sentinelRedisInstance *createSentinelRedisInstance(char *name, int flags, char *
ri->failover_start_time = 0;
ri->failover_timeout = SENTINEL_DEFAULT_FAILOVER_TIMEOUT;
ri->promoted_slave = NULL;
- ri->notify_script = NULL;
+ ri->notification_script = NULL;
ri->client_reconfig_script = NULL;
/* Add into the right table. */
@@ -608,7 +634,7 @@ void releaseSentinelRedisInstance(sentinelRedisInstance *ri) {
/* Free other resources. */
sdsfree(ri->name);
sdsfree(ri->runid);
- sdsfree(ri->notify_script);
+ sdsfree(ri->notification_script);
sdsfree(ri->client_reconfig_script);
sdsfree(ri->slave_master_host);
sdsfree(ri->leader);
@@ -881,6 +907,21 @@ char *sentinelHandleConfiguration(char **argv, int argc) {
ri = sentinelGetMasterByName(argv[1]);
if (!ri) return "No such master with specified name.";
ri->parallel_syncs = atoi(argv[2]);
+ } else if (!strcasecmp(argv[0],"notification-script") && argc == 3) {
+ /* notification-script <name> <path> */
+ ri = sentinelGetMasterByName(argv[1]);
+ if (!ri) return "No such master with specified name.";
+ if (access(argv[2],X_OK) == -1)
+ return "Notification script seems non existing or non executable.";
+ ri->notification_script = sdsnew(argv[2]);
+ } else if (!strcasecmp(argv[0],"client-reconfig-script") && argc == 3) {
+ /* client-reconfig-script <name> <path> */
+ ri = sentinelGetMasterByName(argv[1]);
+ if (!ri) return "No such master with specified name.";
+ if (access(argv[2],X_OK) == -1)
+ return "Client reconfiguration script seems non existing or "
+ "non executable.";
+ ri->client_reconfig_script = sdsnew(argv[2]);
} else {
return "Unrecognized sentinel configuration statement.";
}
@@ -2511,8 +2552,27 @@ void sentinelCheckTiltCondition(void) {
sentinel.previous_time = mstime();
}
+/* Handle terminated childs resulting from calls to notifications and client
+ * reconfigurations scripts. */
+void sentinelHandleChildren(void) {
+ int statloc;
+ pid_t pid;
+
+ if ((pid = wait3(&statloc,WNOHANG,NULL)) != 0) {
+ int exitcode = WEXITSTATUS(statloc);
+ int bysignal = 0;
+
+ if (WIFSIGNALED(statloc)) bysignal = WTERMSIG(statloc);
+ sentinelEvent(REDIS_DEBUG,"-child",NULL,"%ld %d %d",
+ (long)pid, exitcode, bysignal);
+
+ /* TODO: remove client reconfiguration scripts from the queue. */
+ }
+}
+
void sentinelTimer(void) {
sentinelCheckTiltCondition();
sentinelHandleDictOfRedisInstances(sentinel.masters);
+ sentinelHandleChildren();
}

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