How to use psutil to obtain system information in Python

3. psutil

Using Python to write scripts to simplify daily operation and maintenance work is an important use of Python. Under Linux, there are many system commands that allow us to monitor the running status of the system at all times, such as ps, top, free, etc. To obtain these system information, Python can call and obtain the results through the subprocess module. But it seems very troublesome to do so, especially if you have to write a lot of parsing code.

Another good way to get system information in Python is to use the psutil third-party module. As the name suggests, psutil = process and system utilities. It can not only realize system monitoring through one or two lines of code, but also can be used across platforms. It supports Linux/UNIX/OSX/Windows, etc., and is indispensable for system administrators and operation and maintenance partners. Required module.

1. Install psutil

If Anaconda is installed, psutil is already available. Otherwise, you need to install it through pip on the command line:

$ pip install psutil

If you encounter a Permission denied installation failure, please add sudo and try again.

2. Obtain CPU information

Let’s first obtain CPU information:

>>> import psutil
>>> psutil.cpu_count() # CPU逻辑数量
4
>>> psutil.cpu_count(logical=False) # CPU物理核心
2
# 2说明是双核超线程, 4则是4核非超线程

Statistics on CPU user/system/idle time :

>>> psutil.cpu_times()
scputimes(user=10963.31, nice=0.0, system=5138.67, idle=356102.45)

Then implement the CPU usage similar to the top command, refresh once per second, 10 times in total:

>>> for x in range(10):
...     print(psutil.cpu_percent(interval=1, percpu=True))
... 
[14.0, 4.0, 4.0, 4.0]
[12.0, 3.0, 4.0, 3.0]
[8.0, 4.0, 3.0, 4.0]
[12.0, 3.0, 3.0, 3.0]
[18.8, 5.1, 5.9, 5.0]
[10.9, 5.0, 4.0, 3.0]
[12.0, 5.0, 4.0, 5.0]
[15.0, 5.0, 4.0, 4.0]
[19.0, 5.0, 5.0, 4.0]
[9.0, 3.0, 2.0, 3.0]

3. Obtain memory information

Use psutil to obtain physical memory and swap memory information, respectively:

>>> psutil.virtual_memory()
svmem(total=8589934592, available=2866520064, percent=66.6, used=7201386496, free=216178688, active=3342192640, inactive=2650341376, wired=1208852480)
>>> psutil.swap_memory()
sswap(total=1073741824, used=150732800, free=923009024, percent=14.0, sin=10705981440, sout=40353792)

returns an integer in bytes. You can see that the total memory size is 8589934592 = 8 GB, and 7201386496 = 6.7 GB has been used. , 66.6% is used.

The swap area size is 1073741824 = 1 GB.

Get disk information

You can get disk partition, disk usage and disk IO information through psutil:

>>> psutil.disk_partitions() # 磁盘分区信息
[sdiskpart(device='/dev/disk1', mountpoint='/', fstype='hfs', opts='rw,local,rootfs,dovolfs,journaled,multilabel')]
>>> psutil.disk_usage('/') # 磁盘使用情况
sdiskusage(total=998982549504, used=390880133120, free=607840272384, percent=39.1)
>>> psutil.disk_io_counters() # 磁盘IO
sdiskio(read_count=988513, write_count=274457, read_bytes=14856830464, write_bytes=17509420032, read_time=2228966, write_time=1618405)

You can see that the disk '/'## The total capacity of # is 998982549504 = 930 GB, 39.1% used. The file format is HFS, opts contains rw to indicate readability and writability, and journaled indicates support for journaling.

4. Obtain network information

psutil can obtain the network interface and network connection information:

>>> psutil.net_io_counters() # 获取网络读写字节／包的个数
snetio(bytes_sent=3885744870, bytes_recv=10357676702, packets_sent=10613069, packets_recv=10423357, errin=0, errout=0, dropin=0, dropout=0)
>>> psutil.net_if_addrs() # 获取网络接口信息
{
  'lo0': [snic(family=, address='127.0.0.1', netmask='255.0.0.0'), ...],
  'en1': [snic(family=, address='10.0.1.80', netmask='255.255.255.0'), ...],
  'en0': [...],
  'en2': [...],
  'bridge0': [...]
}
>>> psutil.net_if_stats() # 获取网络接口状态
{
  'lo0': snicstats(isup=True, duplex=, speed=0, mtu=16384),
  'en0': snicstats(isup=True, duplex=, speed=0, mtu=1500),
  'en1': snicstats(...),
  'en2': snicstats(...),
  'bridge0': snicstats(...)
}

To obtain the current network connection information, use

net_connections():

>>> psutil.net_connections()
Traceback (most recent call last):
  ...
PermissionError: [Errno 1] Operation not permitted

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  ...
psutil.AccessDenied: psutil.AccessDenied (pid=3847)

You may get an

AccessDenied error. The reason is that psutil also needs to use the system interface to obtain information, and obtaining network connection information requires root privileges. In this case, you can exit Python interactive environment, use sudo to restart:

$ sudo python3
Password: ******
Python 3.8 ... on darwin
Type "help", ... for more information.
>>> import psutil
>>> psutil.net_connections()
[
    sconn(fd=83, family=, type=1, laddr=addr(ip='::127.0.0.1', port=62911), raddr=addr(ip='::127.0.0.1', port=3306), status='ESTABLISHED', pid=3725),
    sconn(fd=84, family=, type=1, laddr=addr(ip='::127.0.0.1', port=62905), raddr=addr(ip='::127.0.0.1', port=3306), status='ESTABLISHED', pid=3725),
    sconn(fd=93, family=, type=1, laddr=addr(ip='::', port=8080), raddr=(), status='LISTEN', pid=3725),
    sconn(fd=103, family=, type=1, laddr=addr(ip='::127.0.0.1', port=62918), raddr=addr(ip='::127.0.0.1', port=3306), status='ESTABLISHED', pid=3725),
    sconn(fd=105, family=, type=1, ..., pid=3725),
    sconn(fd=106, family=, type=1, ..., pid=3725),
    sconn(fd=107, family=, type=1, ..., pid=3725),
    ...
    sconn(fd=27, family=, type=2, ..., pid=1)
]

5. Obtain process information

You can obtain detailed information of all processes through psutil:

>>> psutil.pids() # 所有进程ID
[3865, 3864, 3863, 3856, 3855, 3853, 3776, ..., 45, 44, 1, 0]
>>> p = psutil.Process(3776) # 获取指定进程ID=3776，其实就是当前Python交互环境
>>> p.name() # 进程名称
'python3.6'
>>> p.exe() # 进程exe路径
'/Users/michael/anaconda3/bin/python3.6'
>>> p.cwd() # 进程工作目录
'/Users/michael'
>>> p.cmdline() # 进程启动的命令行
['python3']
>>> p.ppid() # 父进程ID
3765
>>> p.parent() # 父进程

>>> p.children() # 子进程列表
[]
>>> p.status() # 进程状态
'running'
>>> p.username() # 进程用户名
'michael'
>>> p.create_time() # 进程创建时间
1511052731.120333
>>> p.terminal() # 进程终端
'/dev/ttys002'
>>> p.cpu_times() # 进程使用的CPU时间
pcputimes(user=0.081150144, system=0.053269812, children_user=0.0, children_system=0.0)
>>> p.memory_info() # 进程使用的内存
pmem(rss=8310784, vms=2481725440, pfaults=3207, pageins=18)
>>> p.open_files() # 进程打开的文件
[]
>>> p.connections() # 进程相关网络连接
[]
>>> p.num_threads() # 进程的线程数量
1
>>> p.threads() # 所有线程信息
[pthread(id=1, user_time=0.090318, system_time=0.062736)]
>>> p.environ() # 进程环境变量
{'SHELL': '/bin/bash', 'PATH': '/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:...', 'PWD': '/Users/michael', 'LANG': 'zh_CN.UTF-8', ...}
>>> p.terminate() # 结束进程
Terminated: 15 <-- 自己把自己结束了

Similar to obtaining a network connection, obtaining a root user's process requires root permissions. When starting the Python interactive environment or the

.py file, sudo permissions are required.

psutil also provides a

test() function, which can simulate the effect of the ps command:

$ sudo python3
Password: ******
Python 3.6.3 ... on darwin
Type "help", ... for more information.
>>> import psutil
>>> psutil.test()
USER         PID %MEM     VSZ     RSS TTY           START    TIME  COMMAND
root           0 24.0 74270628 2016380 ?             Nov18   40:51  kernel_task
root           1  0.1 2494140    9484 ?             Nov18   01:39  launchd
root          44  0.4 2519872   36404 ?             Nov18   02:02  UserEventAgent
root          45    ? 2474032    1516 ?             Nov18   00:14  syslogd
root          47  0.1 2504768    8912 ?             Nov18   00:03  kextd
root          48  0.1 2505544    4720 ?             Nov18   00:19  fseventsd
_appleeven    52  0.1 2499748    5024 ?             Nov18   00:00  appleeventsd
root          53  0.1 2500592    6132 ?             Nov18   00:02  configd
...

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