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_REPLACEMENT
spt_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-memory
if (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 LOGO
redisAsciiArt();
// 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-memory
if (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 syslog
if (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 GB
if (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 cluster
if (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);