linux系统信息和容器信息获取和上报

一. 命令行获取

通过调用shell命令获取系统信息，如cpu个数，cpu/内存磁盘使用情况，网络信息等。

获取IP地址：ifconfig ens33 | awk '/inet addr/{ print $2; }' | cut -d : -f 2
CPU一分钟平均使用率： cat /proc/loadavg | cut -d ' ' -f 1
CPU当前使用率：IDLE=$(top -b -n 1|grep Cpu|awk '{print $8; }' )     (100-IDLE)%
CPU当前用户使用率：top -b -n 1|grep Cpu|awk '{print $2; }'
总内存：cat /proc/meminfo | awk '/MemTotal/{print $2}'
空闲内存：cat /proc/meminfo | awk '/MemFree/{print $2}'
磁盘占用率：df -h | grep '/dev/root' | awk '{print $5}'

当前时间：date +%Y%m%d-%H:%M:%S 
系统运行时间：uptime | awk '{ print $3; }' | cut -d ',' -f1

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>

#define CMD_BUF_SIZE    256 

typedef float (*func_trans)(char *buf, int buf_size);
static float trans_cpu_avg_rate(char *buf, int buf_size);
static float trans_cpu_now_rate(char *buf, int buf_size);
static float trans_mem_rate(char *buf, int buf_size);

static int exec_cmd(char *buf, int buf_size, char *cmd)
{
    if(NULL == cmd || NULL == buf || buf_size <= 0){
        return -1;
    }

    FILE *f = NULL;
    int len = 0;

    f= popen(cmd, "r");
    if(NULL == f){
        return -1;
    }

//    memset(buf, '', buf_size);
    if(NULL == fgets(buf, buf_size, f)){
        pclose(f);
        return -1;
    }

    pclose(f);

    len = strlen(buf);
    if(len > 0 && (buf[len-1] == '
')){
        buf[len-1] = '';
        len --;
    }

    return len;
}

struct st_cmd_gw{
    char *item;
    char format;
    char *cmd;
    func_trans trans;
    char *factor;
} cmd_gw[] = {
    {"ip1", 's', "ifconfig eth0 | awk '/inet /{ print $2; }' | cut -d : -f 2", NULL, NULL},
    {"wlp1s0", 's', "ifconfig wlp1s0 | awk '/inet /{ print $2; }' | cut -d : -f 2", NULL, NULL},
    {"pppoe", 's', "ifconfig ppp0 | awk '/inet /{ print $2; }' | cut -d : -f 2", NULL, NULL},    
    {"time_now", 's', "date '+%Y-%m-\%d %H:%M:\%S'", NULL, NULL},
    {"time_up", 's', "uptime | awk '{ print $3; }' | cut -d ',' -f1", NULL, NULL},
    {"cpu_avg_rate", 'f', "cat /proc/loadavg | cut -d ' ' -f 1", trans_cpu_avg_rate, "100*\%f/4"},
    {"cpu_now_rate", 'f', "top -b -n 1|grep Cpu|awk '{print $8; }' ", trans_cpu_now_rate, "100.00-\%f"},
    {"cpu_usr_now_rate", 'f', "top -b -n 1|grep Cpu|awk '{print $2; }'", NULL, NULL},
    {"disk_rate", 'f', "df -h | grep '/dev/root' | awk '{print $5}'", NULL, NULL},
    {"disk_use_f", 'f', "df -h | grep '/dev/root' | awk '{print $3}'", NULL, NULL},
    {"disk_avail_f", 'f', "df -h | grep '/dev/root' | awk '{print $4}'", NULL, NULL},
    {"disk_use_s", 's', "df -h | grep '/dev/root' | awk '{print $3}'", NULL, NULL},
    {"disk_avail_s", 's', "df -h | grep '/dev/root' | awk '{print $4}'", NULL, NULL},
    {"ram_rate", 'f', "cat /proc/meminfo | awk '/MemTotal/{print $2}'", trans_mem_rate, NULL},
    {"ram_all", 'f', "cat /proc/meminfo | awk '/MemTotal/{print $2}'", NULL, NULL},
    {"ram_free", 'f', "cat /proc/meminfo | awk '/MemFree/{print $2}'", NULL, NULL},
    {"cpu_num", 's', "cat /proc/cpuinfo | grep "processor" | wc -l | awk '{print $1}'", NULL, NULL}
};

// out: output the result of the string type
// f: output the result of the float type
int out_gw(char *out, int out_len, const char *in, float *f)
{
    if(NULL == in || NULL == out || out_len <= 0){
        return -1;
    }

    int i = 0;
    int len = strlen(in);
    int count = sizeof(cmd_gw)/sizeof(cmd_gw[0]);

    for(; i < count; i++){
        if(!strncasecmp(in, cmd_gw[i].item, len)){
            break;            
        }    
    }

    if(i >count){
        return -1;
    }

    int ret = exec_cmd(out, out_len, cmd_gw[i].cmd);
    if(ret <= 0){
        return -1;
    }
    
    *f = 0.0;
    if('f' == cmd_gw[i].format){
        if(cmd_gw[i].trans){
            *f = (cmd_gw[i].trans)(out, out_len);    
        } else {
            *f = atof(out);
        }
    }
    
    return cmd_gw[i].format;
}

static float trans_cpu_avg_rate(char *buf, int buf_size)
{
    return 100 * atof(buf) / 4;
}

static float trans_cpu_now_rate(char *buf, int buf_size)
{
    return 100.00 - atof(buf);
}

static float trans_mem_rate(char *buf, int buf_size)
{
    float f = 0.0;
    char out_free[CMD_BUF_SIZE] = {''};
    int ret_free = out_gw(out_free, sizeof(out_free), "mem_free", &f);

    if('f' != (char)ret_free){
        return -1;
    }

    return 100.00 - 100.00 * atof(out_free) / atof(buf);
}

容器信息也可通过docker stats获取到：

docker stats --no-stream --format "{"container":"{{ .Name }}","memory":{"raw":"{{ .MemUsage }}","percent":"{{ .MemPerc }}"},"cpu":"{{ .CPUPerc }}","networkIO":"{{.NetIO}},"BlockIO":"{{.BlockIO}}"}"
{"container":"cadvisor","memory":{"raw":"40.45MiB / 3.701GiB","percent":"1.07%"},"cpu":"2.40%","networkIO":"11.9MB / 1.27GB,"BlockIO":"0B / 0B"}
{"container":"orderer.example.com","memory":{"raw":"21.18MiB / 3.701GiB","percent":"0.56%"},"cpu":"0.29%","networkIO":"57.7MB / 57.9MB,"BlockIO":"0B / 0B"}
{"container":"orderer4.example.com","memory":{"raw":"18.62MiB / 3.701GiB","percent":"0.49%"},"cpu":"0.28%","networkIO":"57.5MB / 57.4MB,"BlockIO":"0B / 0B"}
{"container":"orderer2.example.com","memory":{"raw":"18.6MiB / 3.701GiB","percent":"0.49%"},"cpu":"0.32%","networkIO":"57.5MB / 57.4MB,"BlockIO":"0B / 0B"}
{"container":"orderer5.example.com","memory":{"raw":"18.2MiB / 3.701GiB","percent":"0.48%"},"cpu":"0.35%","networkIO":"57.4MB / 57.3MB,"BlockIO":"0B / 0B"}
{"container":"orderer3.example.com","memory":{"raw":"25.19MiB / 3.701GiB","percent":"0.66%"},"cpu":"0.63%","networkIO":"228MB / 229MB,"BlockIO":"0B / 0B"}

参考：docker查询容器转态，并转成json数据

当然docker信息可通过dockerAPI或SDK获取，参考：Develop with Docker Engine SDKs and API    https://docs.docker.com/engine/api/v1.39/# 

二. cadvisor

参考：

1. linux内存查看及释放

2. /proc/meminfo分析

3. prometheus 容器监控：cAdvisor