Redis-0x15-初始化server服务配置

预先填充redisServer实例中的一部分字段的值。

1 显式设值

/**
 * @brief 初始化server配置 即填充redisServer实例中的部分字段
 */
void initServerConfig(void) {
    int j;

    updateCachedTime(1);
    getRandomHexChars(server.runid,CONFIG_RUN_ID_SIZE);
    server.runid[CONFIG_RUN_ID_SIZE] = '\0';
    changeReplicationId();
    clearReplicationId2();
    server.hz = CONFIG_DEFAULT_HZ; /* Initialize it ASAP, even if it may get
                                      updated later after loading the config.
                                      This value may be used before the server
                                      is initialized. */
    server.timezone = getTimeZone(); /* Initialized by tzset(). */
    server.configfile = NULL;
    server.executable = NULL;
    server.arch_bits = (sizeof(long) == 8) ? 64 : 32;
    server.bindaddr_count = 0;
    server.unixsocketperm = CONFIG_DEFAULT_UNIX_SOCKET_PERM;
    server.ipfd.count = 0;
    server.tlsfd.count = 0;
    server.sofd = -1;
    server.active_expire_enabled = 1;
    server.skip_checksum_validation = 0;
    server.saveparams = NULL;
    server.loading = 0;
    server.loading_rdb_used_mem = 0;
    server.logfile = zstrdup(CONFIG_DEFAULT_LOGFILE);
    server.aof_state = AOF_OFF;
    server.aof_rewrite_base_size = 0;
    server.aof_rewrite_scheduled = 0;
    server.aof_flush_sleep = 0;
    server.aof_last_fsync = time(NULL);
    atomicSet(server.aof_bio_fsync_status,C_OK);
    server.aof_rewrite_time_last = -1;
    server.aof_rewrite_time_start = -1;
    server.aof_lastbgrewrite_status = C_OK;
    server.aof_delayed_fsync = 0;
    server.aof_fd = -1;
    server.aof_selected_db = -1; /* Make sure the first time will not match */
    server.aof_flush_postponed_start = 0;
    server.pidfile = NULL;
    server.active_defrag_running = 0;
    server.notify_keyspace_events = 0;
    server.blocked_clients = 0;
    memset(server.blocked_clients_by_type,0,
           sizeof(server.blocked_clients_by_type));
    server.shutdown_asap = 0;
    server.cluster_configfile = zstrdup(CONFIG_DEFAULT_CLUSTER_CONFIG_FILE);
    server.cluster_module_flags = CLUSTER_MODULE_FLAG_NONE;
    server.migrate_cached_sockets = dictCreate(&migrateCacheDictType,NULL);
    server.next_client_id = 1; /* Client IDs, start from 1 .*/
    server.loading_process_events_interval_bytes = (1024*1024*2);

    unsigned int lruclock = getLRUClock();
    atomicSet(server.lruclock,lruclock);
    resetServerSaveParams();

    appendServerSaveParams(60*60,1);  /* save after 1 hour and 1 change */
    appendServerSaveParams(300,100);  /* save after 5 minutes and 100 changes */
    appendServerSaveParams(60,10000); /* save after 1 minute and 10000 changes */

    /* Replication related */
    server.masterauth = NULL;
    server.masterhost = NULL;
    server.masterport = 6379;
    server.master = NULL;
    server.cached_master = NULL;
    server.master_initial_offset = -1;
    server.repl_state = REPL_STATE_NONE;
    server.repl_transfer_tmpfile = NULL;
    server.repl_transfer_fd = -1;
    server.repl_transfer_s = NULL;
    server.repl_syncio_timeout = CONFIG_REPL_SYNCIO_TIMEOUT;
    server.repl_down_since = 0; /* Never connected, repl is down since EVER. */
    server.master_repl_offset = 0;

    /* Replication partial resync backlog */
    server.repl_backlog = NULL;
    server.repl_backlog_histlen = 0;
    server.repl_backlog_idx = 0;
    server.repl_backlog_off = 0;
    server.repl_no_slaves_since = time(NULL);

    /* Failover related */
    server.failover_end_time = 0;
    server.force_failover = 0;
    server.target_replica_host = NULL;
    server.target_replica_port = 0;
    server.failover_state = NO_FAILOVER;

    /* Client output buffer limits */
    for (j = 0; j < CLIENT_TYPE_OBUF_COUNT; j++)
        server.client_obuf_limits[j] = clientBufferLimitsDefaults[j];

    /* Linux OOM Score config */
    for (j = 0; j < CONFIG_OOM_COUNT; j++)
        server.oom_score_adj_values[j] = configOOMScoreAdjValuesDefaults[j];

    /* Double constants initialization */
    R_Zero = 0.0;
    R_PosInf = 1.0/R_Zero;
    R_NegInf = -1.0/R_Zero;
    R_Nan = R_Zero/R_Zero;

    /* Command table -- we initialize it here as it is part of the
     * initial configuration, since command names may be changed via
     * redis.conf using the rename-command directive. */
    // 预定义的命令缓存到字典
    server.commands = dictCreate(&commandTableDictType,NULL);
    server.orig_commands = dictCreate(&commandTableDictType,NULL);
    populateCommandTable();
    server.delCommand = lookupCommandByCString("del");
    server.multiCommand = lookupCommandByCString("multi");
    server.lpushCommand = lookupCommandByCString("lpush");
    server.lpopCommand = lookupCommandByCString("lpop");
    server.rpopCommand = lookupCommandByCString("rpop");
    server.zpopminCommand = lookupCommandByCString("zpopmin");
    server.zpopmaxCommand = lookupCommandByCString("zpopmax");
    server.sremCommand = lookupCommandByCString("srem");
    server.execCommand = lookupCommandByCString("exec");
    server.expireCommand = lookupCommandByCString("expire");
    server.pexpireCommand = lookupCommandByCString("pexpire");
    server.xclaimCommand = lookupCommandByCString("xclaim");
    server.xgroupCommand = lookupCommandByCString("xgroup");
    server.rpoplpushCommand = lookupCommandByCString("rpoplpush");
    server.lmoveCommand = lookupCommandByCString("lmove");

    /* Debugging */
    server.watchdog_period = 0;

    /* By default we want scripts to be always replicated by effects
     * (single commands executed by the script), and not by sending the
     * script to the slave / AOF. This is the new way starting from
     * Redis 5. However it is possible to revert it via redis.conf. */
    server.lua_always_replicate_commands = 1;

    /* Client Pause related */
    server.client_pause_type = CLIENT_PAUSE_OFF;
    server.client_pause_end_time = 0;   

    initConfigValues();
}

2 通过宏函数设值

/**
 * @brief 通过宏函数设置默认值
 */
void initConfigValues() {
    for (standardConfig *config = configs; config->name != NULL; config++) {
        config->interface.init(config->data);
    }
}

2.1 以内存淘汰策略为例

createEnumConfig("maxmemory-policy", NULL, MODIFIABLE_CONFIG, maxmemory_policy_enum, server.maxmemory_policy, MAXMEMORY_NO_EVICTION, NULL, NULL), // 内存淘汰策略

createEnumConfig(name, alias, flags, enum, config_addr, default, is_valid, update){ \
    .name = (name), \
    .alias = (alias), \
    .flags = (flags),
    
    .interface = { \
        .init = (enumConfigInit), \
        .set = (enumConfigSet), \
        .get = (enumConfigGet), \
        .rewrite = (enumConfigRewrite) \
	},
    .data.enumd = { \
        .config = &(config_addr), \
        .default_value = (default), \
        .is_valid_fn = (is_valid), \
        .update_fn = (update), \
        .enum_value = (enum), \
    } \
}

static void enumConfigInit(typeData data) {
    *data.enumd.config = data.enumd.default_value;
}

将宏展开代入enumConfigInit，就是向enum实例赋值一个默认值，即server.maxmemory_policy=MAXMEMORY_NO_EVICTION。

即默认的内存淘汰策略是不进行淘汰，内存OOM了就回调处理器。