十五天Python系统学习教程第七天

// Java执行命令  
Process proc = Runtime.getRuntime().exec("ls -l");  
BufferedReader reader = new BufferedReader(  
    new InputStreamReader(proc.getInputStream()));  
String line;  
while ((line = reader.readLine()) != null) {  
    System.out.println(line);  
}  

# Python执行命令  
import subprocess  

# 同步执行（推荐）  
result = subprocess.run(["ls", "-l"], capture_output=True, text=True)  
print(result.stdout)  

# 异步执行  
proc = subprocess.Popen(["ping", "google.com"], stdout=subprocess.PIPE)  
while proc.poll() is None:  
    print(proc.stdout.readline())  

# 父进程发送数据到子进程  
from multiprocessing import Pipe  

parent_conn, child_conn = Pipe()  
child_conn.send("Hello from child")  
print(parent_conn.recv())  # 输出接收的数据  

from multiprocessing import Value, Array  

# 共享整型值  
counter = Value('i', 0)  
counter.value += 1  

# 共享数组  
arr = Array('d', [1.0, 2.0])  
arr[0] = 3.14  

import daemon  

def run_as_service():  
    while True:  
        do_work()  

# 转换为守护进程  
with daemon.DaemonContext():  
    run_as_service()  

import logging  
from logging.handlers import RotatingFileHandler  

# 配置日志（类似Log4j）  
logging.basicConfig(  
    handlers=[RotatingFileHandler("app.log", maxBytes=1e6, backupCount=3)],  
    level=logging.INFO,  
    format="%(asctime)s [%(levelname)s] %(message)s"  
)  

logging.info("Service started")  

import psutil  # 第三方库，需安装  

def get_process_info(name):  
    for proc in psutil.process_iter(['pid', 'name', 'cpu_percent', 'memory_info']):  
        if proc.info['name'] == name:  
            return {  
                'pid': proc.info['pid'],  
                'cpu': proc.info['cpu_percent'],  
                'memory': proc.info['memory_info'].rss / 1024 / 1024  # MB  
            }  
    return None  

def restart_process(cmd):  
    subprocess.run(["pkill", "-f", cmd[0]])  
    return subprocess.Popen(cmd)  

def monitor(process_name, cmd, max_cpu=90, max_mem=1024):  
    while True:  
        info = get_process_info(process_name)  
        if not info or info['cpu'] > max_cpu or info['memory'] > max_mem:  
            restart_process(cmd)  
        time.sleep(5)  

monitor("nginx", ["nginx", "-g", "daemon off;"])  

proc = subprocess.Popen(...)  
try:  
    proc.wait(timeout=10)  
except subprocess.TimeoutExpired:  
    proc.terminate()  

import signal  
signal.signal(signal.SIGTERM, handler)  # Unix only  

from flask import Flask  
app = Flask(__name__)  

@app.route('/health')  
def health():  
    return {"status": "OK", "pid": os.getpid()}  

# 支持命令：python manager.py start|stop|status  
import argparse  
parser = argparse.ArgumentParser()  
parser.add_argument("action", choices=["start", "stop", "status"])  
args = parser.parse_args()  

# Dockerfile示例  
FROM python:3.10  
COPY monitor.py .  
RUN pip install psutil  
CMD ["python", "monitor.py"]