Redis源码分析（三十三）--- redis-cli.c客户端命令行接口的实现(2)

今天学习完了命令行客户端的后续内容，整体感觉就是围绕着2个东西转，config和mode。为什么我会这么说呢，请继续往下看，客户端中的配置结构体和之前我们所学习的配置结构体，不是指的同一个概念，cli中的结构体除了基本的ip，Port端口号，还有就是各种mode的配置了。

/* Redis配置结构体 */
static struct config {
    char *hostip;
    int hostport;
    char *hostsocket;
    long repeat;
    long interval;
    int dbnum;
    int interactive;
    int shutdown;
    int monitor_mode;
    int pubsub_mode;
    int latency_mode;
    int latency_history;
    int cluster_mode;
    int cluster_reissue_command;
    int slave_mode;
    int pipe_mode;
    int pipe_timeout;
    int getrdb_mode;
    int stat_mode;
    int scan_mode;
    int intrinsic_latency_mode;
    int intrinsic_latency_duration;
    char *pattern;
    char *rdb_filename;
    int bigkeys;
    int stdinarg; /* get last arg from stdin. (-x option) */
    char *auth;
    int output; /* output mode, see OUTPUT_* defines */
    sds mb_delim;
    char prompt[128];
    char *eval;
    int last_cmd_type;
} config;

里面少说也有10个mode模式了吧。我们先倒过来，看看cli的主程序运行的流程，也就是main函数的执行步骤：

/*main函数主程序操作*/
int main(int argc, char **argv) {
    int firstarg;

	//首先初始化客户端配置操作
    config.hostip = sdsnew("127.0.0.1");
    config.hostport = 6379;
    config.hostsocket = NULL;
    config.repeat = 1;
    config.interval = 0;
    config.dbnum = 0;
    config.interactive = 0;
    config.shutdown = 0;
    config.monitor_mode = 0;
    config.pubsub_mode = 0;
    config.latency_mode = 0;
    config.latency_history = 0;
    config.cluster_mode = 0;
    config.slave_mode = 0;
    config.getrdb_mode = 0;
    config.stat_mode = 0;
    config.scan_mode = 0;
    config.intrinsic_latency_mode = 0;
    config.pattern = NULL;
    config.rdb_filename = NULL;
    config.pipe_mode = 0;
    config.pipe_timeout = REDIS_CLI_DEFAULT_PIPE_TIMEOUT;
    config.bigkeys = 0;
    config.stdinarg = 0;
    config.auth = NULL;
    config.eval = NULL;
    config.last_cmd_type = -1;

    if (!isatty(fileno(stdout)) && (getenv("FAKETTY") == NULL))
        config.output = OUTPUT_RAW;
    else
        config.output = OUTPUT_STANDARD;
    config.mb_delim = sdsnew("\n");
    cliInitHelp();

	//根据用户输入的参数，配置config
    firstarg = parseOptions(argc,argv);
    argc -= firstarg;
    argv += firstarg;

	//配置设置完毕，根据配置中的模式设置，调用相应的mode方法
    /* Latency mode */
    if (config.latency_mode) {
        if (cliConnect(0) == REDIS_ERR) exit(1);
        latencyMode();
    }

    /* Slave mode */
    if (config.slave_mode) {
        if (cliConnect(0) == REDIS_ERR) exit(1);
        slaveMode();
    }
	....

后面的代码与此相同，所以就省略了，步骤简单来说，就是设置配置，根据配置启动相应的模式，下面说说，里面的主要几种模式

1.statMode:

/* statMode主要输出一些读取数据统计的一些信息 */
static void statMode(void) {
    redisReply *reply;
    long aux, requests = 0;
    int i = 0;

    while(1) {
        char buf[64];
        int j;

        reply = reconnectingInfo();
        if (reply->type == REDIS_REPLY_ERROR) {
            printf("ERROR: %s\n", reply->str);
            exit(1);
        }

        if ((i++ % 20) == 0) {
            printf(
"------- data ------ --------------------- load -------------------- - child -\n"
"keys       mem      clients blocked requests            connections          \n");
        }

        /* Keys */
        aux = 0;
        for (j = 0; j < 20; j++) {
            long k;

            sprintf(buf,"db%d:keys",j);
            k = getLongInfoField(reply->str,buf);
            if (k == LONG_MIN) continue;
            aux += k;
        }
        sprintf(buf,"%ld",aux);
        printf("%-11s",buf);

        /* Used memory */
        aux = getLongInfoField(reply->str,"used_memory");
        bytesToHuman(buf,aux);
        printf("%-8s",buf);

        /* Clients */
        aux = getLongInfoField(reply->str,"connected_clients");
        sprintf(buf,"%ld",aux);
        printf(" %-8s",buf);

        /* Blocked (BLPOPPING) Clients */
        aux = getLongInfoField(reply->str,"blocked_clients");
        sprintf(buf,"%ld",aux);
        printf("%-8s",buf);
		....

客户端当前的数据统计信息。

2.latencyMode中会用到的测试硬件计算性能的方法:

/* This is just some computation the compiler can't optimize out.
 * Should run in less than 100-200 microseconds even using very
 * slow hardware. Runs in less than 10 microseconds in modern HW. */
/* 普通的计算操作，测试硬件计算的速度快慢 */
unsigned long compute_something_fast(void) {
    unsigned char s[256], i, j, t;
    int count = 1000, k;
    unsigned long output = 0;

    for (k = 0; k < 256; k++) s[k] = k;

    i = 0;
    j = 0;
    while(count--) {
        i++;
        j = j + s[i];
        t = s[i];
        s[i] = s[j];
        s[j] = t;
        output += s[(s[i]+s[j])&255];
    }
    return output;
}

帮助命令的输出文档是由下面的函数输出的:

/* 帮助命令的输出文档 */
static void usage(void) {
    sds version = cliVersion();
    fprintf(stderr,
"redis-cli %s\n"
"\n"
"Usage: redis-cli [OPTIONS] [cmd [arg [arg ...]]]\n"
"  -h <hostname>      Server hostname (default: 127.0.0.1).\n"
"  -p <port>          Server port (default: 6379).\n"
"  -s <socket>        Server socket (overrides hostname and port).\n"
"  -a <password>      Password to use when connecting to the server.\n"
"  -r <repeat>        Execute specified command N times.\n"
"  -i <interval>      When -r is used, waits <interval> seconds per command.\n"
"                     It is possible to specify sub-second times like -i 0.1.\n"
"  -n <db>            Database number.\n"
"  -x                 Read last argument from STDIN.\n"
"  -d <delimiter>     Multi-bulk delimiter in for raw formatting (default: \\n).\n"
"  -c                 Enable cluster mode (follow -ASK and -MOVED redirections).\n"
"  --raw              Use raw formatting for replies (default when STDOUT is\n"
"                     not a tty).\n"
"  --no-raw           Force formatted output even when STDOUT is not a tty.\n"
"  --csv              Output in CSV format.\n"
"  --latency          Enter a special mode continuously sampling latency.\n"
"  --latency-history  Like --latency but tracking latency changes over time.\n"
"                     Default time interval is 15 sec. Change it using -i.\n"
"  --slave            Simulate a slave showing commands received from the master.\n"
"  --rdb <filename>   Transfer an RDB dump from remote server to local file.\n"
"  --pipe             Transfer raw Redis protocol from stdin to server.\n"
"  --pipe-timeout <n> In --pipe mode, abort with error if after sending all data.\n"
"                     no reply is received within <n> seconds.\n"
"                     Default timeout: %d. Use 0 to wait forever.\n"
"  --bigkeys          Sample Redis keys looking for big keys.\n"
"  --scan             List all keys using the SCAN command.\n"
"  --pattern <pat>    Useful with --scan to specify a SCAN pattern.\n"
"  --intrinsic-latency <sec> Run a test to measure intrinsic system latency.\n"
"                     The test will run for the specified amount of seconds.\n"
"  --eval <file>      Send an EVAL command using the Lua script at <file>.\n"
"  --help             Output this help and exit.\n"
"  --version          Output version and exit.\n"
"\n"
"Examples:\n"
"  cat /etc/passwd | redis-cli -x set mypasswd\n"
"  redis-cli get mypasswd\n"
"  redis-cli -r 100 lpush mylist x\n"
"  redis-cli -r 100 -i 1 info | grep used_memory_human:\n"
"  redis-cli --eval myscript.lua key1 key2 , arg1 arg2 arg3\n"
"  redis-cli --scan --pattern '*:12345*'\n"
"\n"
"  (Note: when using --eval the comma separates KEYS[] from ARGV[] items)\n"
"\n"
"When no command is given, redis-cli starts in interactive mode.\n"
"Type \"help\" in interactive mode for information on available commands.\n"
"\n",
        version, REDIS_CLI_DEFAULT_PIPE_TIMEOUT);
    sdsfree(version);
    exit(1);
}

在命令里面，会由于2个概念，1个叫一般性的Command命令还有一个是CommandGroup命令组的概念，举个例子，比如list，set等经常会用到的一些命令，后面可以接好多种参数的命令，属性命令组命令，一般CONFIG GET，这种功能非常单一的命令我们就叫他为普通的命令，Dump,Exist啊等等这些命令都是普通的命令，CommandGroup的命令不是很多就下面这么几个:

/* 所有的命令组 */
static char *commandGroups[] = {
    "generic",
    "string",
    "list",
    "set",
    "sorted_set",
    "hash",
    "pubsub",
    "transactions",
    "connection",
    "server",
    "scripting",
    "hyperloglog"
};

也是最最常用的命令，在redis的系统中。