[原]Redis源代码分析之六：Redis执行流程
现在我们分析Redis从启动开始的执行流程，从而顺藤摸瓜地理解其事件驱动模型。首先找到main入口：
int main(int argc, char **argv) {
time_t start;
initServerConfig();
if (argc == 2) {
if (strcmp(argv, "-v") == 0 ||
strcmp(argv, "--version") == 0) version();
if (strcmp(argv, "--help") == 0) usage();
resetServerSaveParams();
loadServerConfig(argv);
} else if ((argc > 2)) {
usage();
} else {
redisLog(REDIS_WARNING,"Warning: no config file specified, using the default config. In order to specify a config file use 'redis-server /path/to/redis.conf'");
}
if (server.daemonize) daemonize();
initServer();
if (server.daemonize) createPidFile();
redisLog(REDIS_NOTICE,"Server started, Redis version " REDIS_VERSION);
#ifdef __linux__
linuxOvercommitMemoryWarning();
#endif
start = time(NULL);
if (server.appendonly) {
if (loadAppendOnlyFile(server.appendfilename) == REDIS_OK)
redisLog(REDIS_NOTICE,"DB loaded from append only file: %ld seconds",time(NULL)-start);
} else {
if (rdbLoad(server.dbfilename) == REDIS_OK) {
redisLog(REDIS_NOTICE,"DB loaded from disk: %ld seconds",
time(NULL)-start);
} else if (errno != ENOENT) {
redisLog(REDIS_WARNING,"Fatal error loading the DB. Exiting.");
exit(1);
}
}
if (server.ipfd > 0)
redisLog(REDIS_NOTICE,"The server is now ready to accept connections on port %d", server.port);
if (server.sofd > 0)
redisLog(REDIS_NOTICE,"The server is now ready to accept connections at %s", server.unixsocket);
aeSetBeforeSleepProc(server.el,beforeSleep);
aeMain(server.el);
aeDeleteEventLoop(server.el);
return 0;
}
我们看到，在initServer()中完成了初始化工作：
void initServer() {
int j;
signal(SIGHUP, SIG_IGN);
signal(SIGPIPE, SIG_IGN);
setupSignalHandlers();
if (server.syslog_enabled) {
openlog(server.syslog_ident, LOG_PID | LOG_NDELAY | LOG_NOWAIT,
server.syslog_facility);
}
server.mainthread = pthread_self();
server.clients = listCreate();
server.slaves = listCreate();
server.monitors = listCreate();
server.unblocked_clients = listCreate();
createSharedObjects();
server.el = aeCreateEventLoop();
server.db = zmalloc(sizeof(redisDb)*server.dbnum);
if (server.port != 0) {
server.ipfd = anetTcpServer(server.neterr,server.port,server.bindaddr);
…… …… ……
aeCreateTimeEvent(server.el, 1, serverCron, NULL, NULL);
if (server.ipfd > 0 && aeCreateFileEvent(server.el,server.ipfd,AE_READABLE,
acceptTcpHandler,NULL) == AE_ERR) oom("creating file event");
if (server.sofd > 0 && aeCreateFileEvent(server.el,server.sofd,AE_READABLE,
acceptUnixHandler,NULL) == AE_ERR) oom("creating file event");
if (server.appendonly) {
server.appendfd = open(server.appendfilename,O_WRONLY|O_APPEND|O_CREAT,0644);
if (server.appendfd == -1) {
redisLog(REDIS_WARNING, "Can't open the append-only file: %s",
strerror(errno));
exit(1);
}
}
if (server.vm_enabled) vmInit();
slowlogInit();
bioInit();
srand(time(NULL)^getpid());
}
其中在redisServer结构体中定义了：
aeEventLoop *el;于是我们分析事件驱动模型，就可以从aeEventLoop入手，继续追随aeCreateTimeEvent函数和aeCreateFileEvent创建的事件是如何在事件驱动库下工作的。具体见下节。
作者：Aegeaner 发表于2012-2-27 14:09:40 原文链接
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