From 73427462ed8fc089a0fd6cecf0ae73f1339f68f6 Mon Sep 17 00:00:00 2001
From: antirez <antirez@gmail.com>
Date: Tue, 13 Oct 2015 10:58:08 +0200
Subject: [PATCH] Server: restartServer() API.
This new function is able to restart the server "in place". The current
Redis process executes the same executable it was executed with, using
the same arguments and configuration file.
---
src/server.c | 70 +++++++++++++++++++++++++++++++++++++++++++++++++---
src/server.h | 7 ++++++
2 files changed, 73 insertions(+), 4 deletions(-)
diff --git a/src/server.c b/src/server.c
index 267e585e..96cd28d4 100644
--- a/src/server.c
+++ b/src/server.c
@@ -1436,6 +1436,7 @@ void initServerConfig(void) {
getRandomHexChars(server.runid,CONFIG_RUN_ID_SIZE);
server.configfile = NULL;
+ server.executable = NULL;
server.hz = CONFIG_DEFAULT_HZ;
server.runid[CONFIG_RUN_ID_SIZE] = '\0';
server.arch_bits = (sizeof(long) == 8) ? 64 : 32;
@@ -1595,6 +1596,50 @@ void initServerConfig(void) {
server.watchdog_period = 0;
}
+extern char **environ;
+
+/* Restart the server, executing the same executable that started this
+ * instance, with the same arguments and configuration file.
+ *
+ * The list of flags, that may be bitwise ORed together, alter the
+ * behavior of this function:
+ *
+ * RESTART_SERVER_NONE No flags.
+ * RESTART_SERVER_GRACEFULLY Do a proper shutdown before restarting.
+ * RESTART_SERVER_CONFIG_REWRITE Rewrite the config file before restarting.
+ *
+ * On success the function does not return, because the process turns into
+ * a different process. On error C_ERR is returned. */
+int restartServer(int flags, mstime_t delay) {
+ int j;
+
+ /* Check if we still have accesses to the executable that started this
+ * server instance. */
+ if (access(server.executable,X_OK) == -1) return C_ERR;
+
+ /* Config rewriting. */
+ if (flags & RESTART_SERVER_CONFIG_REWRITE &&
+ server.configfile &&
+ rewriteConfig(server.configfile) == -1) return C_ERR;
+
+ /* Perform a proper shutdown. */
+ if (flags & RESTART_SERVER_GRACEFULLY &&
+ prepareForShutdown(SHUTDOWN_NOFLAGS) != C_OK) return C_ERR;
+
+ /* Close all file descriptors, with the exception of stdin, stdout, strerr
+ * which are useful if we restart a Redis server which is not daemonized. */
+ for (j = 3; j < (int)server.maxclients + 1024; j++) close(j);
+
+ /* Execute the server with the original command line. */
+ if (delay) usleep(delay*1000);
+ execve(server.executable,server.exec_argv,environ);
+
+ /* If an error occurred here, there is nothing we can do, but exit. */
+ _exit(1);
+
+ return C_ERR; /* Never reached. */
+}
+
/* This function will try to raise the max number of open files accordingly to
* the configured max number of clients. It also reserves a number of file
* descriptors (CONFIG_MIN_RESERVED_FDS) for extra operations of
@@ -2730,6 +2775,7 @@ sds genRedisInfoString(char *section) {
"uptime_in_days:%jd\r\n"
"hz:%d\r\n"
"lru_clock:%ld\r\n"
+ "executable:%s\r\n"
"config_file:%s\r\n",
REDIS_VERSION,
redisGitSHA1(),
@@ -2751,6 +2797,7 @@ sds genRedisInfoString(char *section) {
(intmax_t)(uptime/(3600*24)),
server.hz,
(unsigned long) server.lruclock,
+ server.executable ? server.executable : "",
server.configfile ? server.configfile : "");
}
@@ -3793,6 +3840,7 @@ int redisIsSupervised(int mode) {
int main(int argc, char **argv) {
struct timeval tv;
+ int j;
#ifdef REDIS_TEST
if (argc == 3 && !strcasecmp(argv[1], "test")) {
@@ -3833,6 +3881,13 @@ int main(int argc, char **argv) {
server.sentinel_mode = checkForSentinelMode(argc,argv);
initServerConfig();
+ /* Store the executable path and arguments in a safe place in order
+ * to be able to restart the server later. */
+ server.executable = getAbsolutePath(argv[0]);
+ server.exec_argv = zmalloc(sizeof(char*)*(argc+1));
+ server.exec_argv[argc] = NULL;
+ for (j = 0; j < argc; j++) server.exec_argv[j] = zstrdup(argv[j]);
+
/* We need to init sentinel right now as parsing the configuration file
* in sentinel mode will have the effect of populating the sentinel
* data structures with master nodes to monitor. */
@@ -3848,7 +3903,7 @@ int main(int argc, char **argv) {
exit(redis_check_rdb_main(argv,argc));
if (argc >= 2) {
- int j = 1; /* First option to parse in argv[] */
+ j = 1; /* First option to parse in argv[] */
sds options = sdsempty();
char *configfile = NULL;
@@ -3869,8 +3924,16 @@ int main(int argc, char **argv) {
}
/* First argument is the config file name? */
- if (argv[j][0] != '-' || argv[j][1] != '-')
- configfile = argv[j++];
+ if (argv[j][0] != '-' || argv[j][1] != '-') {
+ configfile = argv[j];
+ server.configfile = getAbsolutePath(configfile);
+ /* Replace the config file in server.exec_argv with
+ * its absoulte path. */
+ zfree(server.exec_argv[j]);
+ server.exec_argv[j] = zstrdup(server.configfile);
+ j++;
+ }
+
/* All the other options are parsed and conceptually appended to the
* configuration file. For instance --port 6380 will generate the
* string "port 6380\n" to be parsed after the actual file name
@@ -3900,7 +3963,6 @@ int main(int argc, char **argv) {
"Sentinel needs config file on disk to save state. Exiting...");
exit(1);
}
- if (configfile) server.configfile = getAbsolutePath(configfile);
resetServerSaveParams();
loadServerConfig(configfile,options);
sdsfree(options);
diff --git a/src/server.h b/src/server.h
index 9f3e9b0d..6d9e7002 100644
--- a/src/server.h
+++ b/src/server.h
@@ -694,6 +694,8 @@ struct redisServer {
/* General */
pid_t pid; /* Main process pid. */
char *configfile; /* Absolute config file path, or NULL */
+ char *executable; /* Absolute executable file path. */
+ char **exec_argv; /* Executable argv vector (copy). */
int hz; /* serverCron() calls frequency in hertz */
redisDb *db;
dict *commands; /* Command table */
@@ -1321,6 +1323,11 @@ void resetServerStats(void);
unsigned int getLRUClock(void);
const char *maxmemoryToString(void);
+#define RESTART_SERVER_NONE 0
+#define RESTART_SERVER_GRACEFULLY (1<<0) /* Do proper shutdown. */
+#define RESTART_SERVER_CONFIG_REWRITE (1<<1) /* CONFIG REWRITE before restart.*/
+int restartServer(int flags, mstime_t delay);
+
/* Set data type */
robj *setTypeCreate(sds value);
int setTypeAdd(robj *subject, sds value);