python模块之psutil源码解析

做监控的时候，可能会用到psutil这个python包来获取机器的cpu、memory、disk、net、os和一些其他的信息，今天对psutil这个包做了进一步的分析。各项参数的获取大同小异，此处以memory为例。

获取psutil python包,github

https://github.com/giampaolo/psutil

此处指定获取相关信息的主目录，如：linux环境下，

psutil/init.py

if LINUX:
    ...
    PROCFS_PATH = "/proc"
    ...

获取内存的信息，从如下代码可以看到内存信息的获取“/proc/meminfo”。

/psutil/_pslinux.py

def virtual_memory():

    ...

    missing_fields = []
    mems = {}
    with open_binary('%s/meminfo' % get_procfs_path()) as f:
        for line in f:
            fields = line.split()
            mems[fields[0]] = int(fields[1]) * 1024
    total = mems[b'MemTotal:']
    free = mems[b'MemFree:']
    
    ...



def swap_memory():
    
    ...

    mems = {}
    with open_binary('%s/meminfo' % get_procfs_path()) as f:
        for line in f:
            fields = line.split()
            mems[fields[0]] = int(fields[1]) * 1024
    try:
        total = mems[b'SwapTotal:']
        free = mems[b'SwapFree:']
    ...
    used = total - free
    percent = usage_percent(used, total, round_=1)

    ...

函数“open_binary”：

def open_binary(fname, **kwargs):
    return open(fname, "rb", **kwargs)

官方文档：

https://psutil.readthedocs.io/en/latest/#