Redis server启动源码

入口main函数

src/redis.c文件main函数

int main(int argc, char **argv) {struct timeval tv;/* We need to initialize our libraries, and the server configuration. */// 初始化库
#ifdef INIT_SETPROCTITLE_REPLACEMENTspt_init(argc, argv);
#endif//设置本地时间setlocale(LC_COLLATE,"");zmalloc_enable_thread_safeness();zmalloc_set_oom_handler(redisOutOfMemoryHandler);srand(time(NULL)^getpid());gettimeofday(&tv,NULL);//设置随机数种子dictSetHashFunctionSeed(tv.tv_sec^tv.tv_usec^getpid());// 检查服务器是否以 Sentinel 模式启动server.sentinel_mode = checkForSentinelMode(argc,argv);// 初始化服务器initServerConfig();/* 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. */// 如果服务器以 Sentinel 模式启动，那么进行 Sentinel 功能相关的初始化// 并为要监视的主服务器创建一些相应的数据结构if (server.sentinel_mode) {initSentinelConfig();initSentinel();}// 检查用户是否指定了配置文件，或者配置选项if (argc >= 2) {int j = 1; /* First option to parse in argv[] */sds options = sdsempty();char *configfile = NULL;/* Handle special options --help and --version */// 处理特殊选项 -h 、-v 和 --test-memoryif (strcmp(argv[1], "-v") == 0 ||strcmp(argv[1], "--version") == 0) version();if (strcmp(argv[1], "--help") == 0 ||strcmp(argv[1], "-h") == 0) usage();if (strcmp(argv[1], "--test-memory") == 0) {if (argc == 3) {memtest(atoi(argv[2]),50);exit(0);} else {fprintf(stderr,"Please specify the amount of memory to test in megabytes.\n");fprintf(stderr,"Example: ./redis-server --test-memory 4096\n\n");exit(1);}}/* First argument is the config file name? */// 如果第一个参数（argv[1]）不是以 "--" 开头// 那么它应该是一个配置文件if (argv[j][0] != '-' || argv[j][1] != '-')configfile = argv[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* is parsed, if any. */// 对用户给定的其余选项进行分析，并将分析所得的字符串追加稍后载入的配置文件的内容之后// 比如 --port 6380 会被分析为 "port 6380\n"while(j != argc) {if (argv[j][0] == '-' && argv[j][1] == '-') {/* Option name */if (sdslen(options)) options = sdscat(options,"\n");options = sdscat(options,argv[j]+2);options = sdscat(options," ");} else {/* Option argument */options = sdscatrepr(options,argv[j],strlen(argv[j]));options = sdscat(options," ");}j++;}if (configfile) server.configfile = getAbsolutePath(configfile);// 重置保存条件resetServerSaveParams();// 载入配置文件， options 是前面分析出的给定选项loadServerConfig(configfile,options);sdsfree(options);// 获取配置文件的绝对路径if (configfile) server.configfile = getAbsolutePath(configfile);} else {redisLog(REDIS_WARNING, "Warning: no config file specified, using the default config. In order to specify a config file use %s /path/to/%s.conf", argv[0], server.sentinel_mode ? "sentinel" : "redis");}// 将服务器设置为守护进程if (server.daemonize) daemonize();// 创建并初始化服务器数据结构initServer();// 如果服务器是守护进程，那么创建 PID 文件if (server.daemonize) createPidFile();// 为服务器进程设置名字redisSetProcTitle(argv[0]);// 打印 ASCII LOGOredisAsciiArt();// 如果服务器不是运行在 SENTINEL 模式，那么执行以下代码if (!server.sentinel_mode) {/* Things not needed when running in Sentinel mode. */// 打印问候语redisLog(REDIS_WARNING,"Server started, Redis version " REDIS_VERSION);#ifdef __linux__// 打印内存警告linuxOvercommitMemoryWarning();#endif// 从 AOF 文件或者 RDB 文件中载入数据loadDataFromDisk();// 启动集群？if (server.cluster_enabled) {if (verifyClusterConfigWithData() == REDIS_ERR) {redisLog(REDIS_WARNING,"You can't have keys in a DB different than DB 0 when in ""Cluster mode. Exiting.");exit(1);}}// 打印 TCP 端口if (server.ipfd_count > 0)redisLog(REDIS_NOTICE,"The server is now ready to accept connections on port %d", server.port);// 打印本地套接字端口if (server.sofd > 0)redisLog(REDIS_NOTICE,"The server is now ready to accept connections at %s", server.unixsocket);} else {sentinelIsRunning();}/* Warning the user about suspicious maxmemory setting. */// 检查不正常的 maxmemory 配置if (server.maxmemory > 0 && server.maxmemory < 1024*1024) {redisLog(REDIS_WARNING,"WARNING: You specified a maxmemory value that is less than 1MB (current value is %llu bytes). Are you sure this is what you really want?", server.maxmemory);}// 运行事件处理器，一直到服务器关闭为止aeSetBeforeSleepProc(server.el,beforeSleep);aeMain(server.el);// 服务器关闭，停止事件循环aeDeleteEventLoop(server.el);return 0;
}

1、本地配置基本初始化

包括设置 server 运行的时区、设置哈希函数的随机种子。

    //设置本地时间setlocale(LC_COLLATE,"");zmalloc_enable_thread_safeness();zmalloc_set_oom_handler(redisOutOfMemoryHandler);srand(time(NULL)^getpid());gettimeofday(&tv,NULL);//设置随机数种子dictSetHashFunctionSeed(tv.tv_sec^tv.tv_usec^getpid());

2、检查哨兵模式

检查是不是以哨兵模式启动
/* Returns 1 if there is --sentinel among the arguments or if* argv[0] is exactly "redis-sentinel". */
int checkForSentinelMode(int argc, char **argv) {int j;if (strstr(argv[0],"redis-sentinel") != NULL) return 1;for (j = 1; j < argc; j++)if (!strcmp(argv[j],"--sentinel")) return 1;return 0;
}/* 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. */// 如果服务器以 Sentinel 模式启动，那么进行 Sentinel 功能相关的初始化// 并为要监视的主服务器创建一些相应的数据结构if (server.sentinel_mode) {initSentinelConfig();initSentinel();}

3、运行参数解析

解析options，加载配置文件

    // 检查用户是否指定了配置文件，或者配置选项if (argc >= 2) {int j = 1; /* First option to parse in argv[] */sds options = sdsempty();char *configfile = NULL;/* Handle special options --help and --version */// 处理特殊选项 -h 、-v 和 --test-memoryif (strcmp(argv[1], "-v") == 0 ||strcmp(argv[1], "--version") == 0) version();if (strcmp(argv[1], "--help") == 0 ||strcmp(argv[1], "-h") == 0) usage();if (strcmp(argv[1], "--test-memory") == 0) {if (argc == 3) {memtest(atoi(argv[2]),50);exit(0);} else {fprintf(stderr,"Please specify the amount of memory to test in megabytes.\n");fprintf(stderr,"Example: ./redis-server --test-memory 4096\n\n");exit(1);}}/* First argument is the config file name? */// 如果第一个参数（argv[1]）不是以 "--" 开头// 那么它应该是一个配置文件if (argv[j][0] != '-' || argv[j][1] != '-')configfile = argv[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* is parsed, if any. */// 对用户给定的其余选项进行分析，并将分析所得的字符串追加稍后载入的配置文件的内容之后// 比如 --port 6380 会被分析为 "port 6380\n"while(j != argc) {if (argv[j][0] == '-' && argv[j][1] == '-') {/* Option name */if (sdslen(options)) options = sdscat(options,"\n");options = sdscat(options,argv[j]+2);options = sdscat(options," ");} else {/* Option argument */options = sdscatrepr(options,argv[j],strlen(argv[j]));options = sdscat(options," ");}j++;} 
loadServerConfig(configfile,options);

4、初始化 server

初始化数据库数据结构和pool，网络交互初始化（线程初始化、工作队列初始化）

void initServer() {int j;// 设置信号处理函数signal(SIGHUP, SIG_IGN);signal(SIGPIPE, SIG_IGN);setupSignalHandlers();// 设置 syslogif (server.syslog_enabled) {openlog(server.syslog_ident, LOG_PID | LOG_NDELAY | LOG_NOWAIT,server.syslog_facility);}// 初始化并创建数据结构server.current_client = NULL;server.clients = listCreate();server.clients_to_close = listCreate();server.slaves = listCreate();server.monitors = listCreate();server.slaveseldb = -1; /* Force to emit the first SELECT command. */server.unblocked_clients = listCreate();server.ready_keys = listCreate();server.clients_waiting_acks = listCreate();server.get_ack_from_slaves = 0;server.clients_paused = 0;// 创建共享对象createSharedObjects();adjustOpenFilesLimit();server.el = aeCreateEventLoop(server.maxclients+REDIS_EVENTLOOP_FDSET_INCR);server.db = zmalloc(sizeof(redisDb)*server.dbnum);/* Open the TCP listening socket for the user commands. */// 打开 TCP 监听端口，用于等待客户端的命令请求if (server.port != 0 &&listenToPort(server.port,server.ipfd,&server.ipfd_count) == REDIS_ERR)exit(1);/* Open the listening Unix domain socket. */// 打开 UNIX 本地端口if (server.unixsocket != NULL) {unlink(server.unixsocket); /* don't care if this fails */server.sofd = anetUnixServer(server.neterr,server.unixsocket,server.unixsocketperm, server.tcp_backlog);if (server.sofd == ANET_ERR) {redisLog(REDIS_WARNING, "Opening socket: %s", server.neterr);exit(1);}anetNonBlock(NULL,server.sofd);}/* Abort if there are no listening sockets at all. */if (server.ipfd_count == 0 && server.sofd < 0) {redisLog(REDIS_WARNING, "Configured to not listen anywhere, exiting.");exit(1);}/* Create the Redis databases, and initialize other internal state. */// 创建并初始化数据库结构for (j = 0; j < server.dbnum; j++) {server.db[j].dict = dictCreate(&dbDictType,NULL);server.db[j].expires = dictCreate(&keyptrDictType,NULL);server.db[j].blocking_keys = dictCreate(&keylistDictType,NULL);server.db[j].ready_keys = dictCreate(&setDictType,NULL);server.db[j].watched_keys = dictCreate(&keylistDictType,NULL);server.db[j].eviction_pool = evictionPoolAlloc();server.db[j].id = j;server.db[j].avg_ttl = 0;}// 创建 PUBSUB 相关结构server.pubsub_channels = dictCreate(&keylistDictType,NULL);server.pubsub_patterns = listCreate();listSetFreeMethod(server.pubsub_patterns,freePubsubPattern);listSetMatchMethod(server.pubsub_patterns,listMatchPubsubPattern);server.cronloops = 0;server.rdb_child_pid = -1;server.aof_child_pid = -1;aofRewriteBufferReset();server.aof_buf = sdsempty();server.lastsave = time(NULL); /* At startup we consider the DB saved. */server.lastbgsave_try = 0;    /* At startup we never tried to BGSAVE. */server.rdb_save_time_last = -1;server.rdb_save_time_start = -1;server.dirty = 0;resetServerStats();/* A few stats we don't want to reset: server startup time, and peak mem. */server.stat_starttime = time(NULL);server.stat_peak_memory = 0;server.resident_set_size = 0;server.lastbgsave_status = REDIS_OK;server.aof_last_write_status = REDIS_OK;server.aof_last_write_errno = 0;server.repl_good_slaves_count = 0;updateCachedTime();/* Create the serverCron() time event, that's our main way to process* background operations. */// 为 serverCron() 创建时间事件if(aeCreateTimeEvent(server.el, 1, serverCron, NULL, NULL) == AE_ERR) {redisPanic("Can't create the serverCron time event.");exit(1);}/* Create an event handler for accepting new connections in TCP and Unix* domain sockets. */// 为 TCP 连接关联连接应答（accept）处理器// 用于接受并应答客户端的 connect() 调用for (j = 0; j < server.ipfd_count; j++) {if (aeCreateFileEvent(server.el, server.ipfd[j], AE_READABLE,acceptTcpHandler,NULL) == AE_ERR){redisPanic("Unrecoverable error creating server.ipfd file event.");}}// 为本地套接字关联应答处理器if (server.sofd > 0 && aeCreateFileEvent(server.el,server.sofd,AE_READABLE,acceptUnixHandler,NULL) == AE_ERR) redisPanic("Unrecoverable error creating server.sofd file event.");/* Open the AOF file if needed. */// 如果 AOF 持久化功能已经打开，那么打开或创建一个 AOF 文件if (server.aof_state == REDIS_AOF_ON) {server.aof_fd = open(server.aof_filename,O_WRONLY|O_APPEND|O_CREAT,0644);if (server.aof_fd == -1) {redisLog(REDIS_WARNING, "Can't open the append-only file: %s",strerror(errno));exit(1);}}/* 32 bit instances are limited to 4GB of address space, so if there is* no explicit limit in the user provided configuration we set a limit* at 3 GB using maxmemory with 'noeviction' policy'. This avoids* useless crashes of the Redis instance for out of memory. */// 对于 32 位实例来说，默认将最大可用内存限制在 3 GBif (server.arch_bits == 32 && server.maxmemory == 0) {redisLog(REDIS_WARNING,"Warning: 32 bit instance detected but no memory limit set. Setting 3 GB maxmemory limit with 'noeviction' policy now.");server.maxmemory = 3072LL*(1024*1024); /* 3 GB */server.maxmemory_policy = REDIS_MAXMEMORY_NO_EVICTION;}// 如果服务器以 cluster 模式打开，那么初始化 clusterif (server.cluster_enabled) clusterInit();// 初始化复制功能有关的脚本缓存replicationScriptCacheInit();// 初始化脚本系统scriptingInit();// 初始化慢查询功能slowlogInit();// 初始化 BIO 系统bioInit();
}

5、执行事件驱动框架（Reactor模型）

   // 运行事件处理器，一直到服务器关闭为止aeSetBeforeSleepProc(server.el,beforeSleep);//事件处理的入口函数aeMain(server.el);// 服务器关闭，停止事件循环aeDeleteEventLoop(server.el);