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#!/usr/bin/env python3
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print("Hello Python!")

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name = "运维工程师"
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job = 'DevOps'
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# 字符串拼接，对应Shell的 ${a}${b}
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msg = "你好，" + name
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# Python推荐用f-string（格式化字符串），比+拼接更灵活
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server = "web01"
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ip = "192.168.1.10"
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info = f"服务器{server}的IP是{ip}"
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print(info)  # 输出：服务器web01的IP是192.168.1.10

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age = 25
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cpu_threshold = 80
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disk_free = 100_000  # Python 3.6+支持下划线增加可读性
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# 直接算术运算，对应Shell的 $(( ))
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sum_val = 10 + 20
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quotient = 100 // 10  # 整除
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remainder = 100 % 3   # 取余

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# 定义列表，对应Shell的 services=("nginx" "mysql" "redis")
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services = ["nginx", "mysql", "redis"]
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# 访问元素，下标从0开始，对应Shell的 ${services[0]}
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print(services[0])  # 输出 nginx
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# 获取长度，对应Shell的 ${#services[@]}
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print(len(services))  # 输出 3
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# 追加元素，对应Shell的 services+=("tomcat")
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services.append("tomcat")
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# 遍历列表
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for svc in services:
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    print(svc)
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# 列表切片（强大功能，Shell没有直接对应）
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print(services[1:3])  # 输出 ['mysql', 'redis']

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# 定义字典，对应Shell的 declare -A server_info
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server_info = {
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    "ip": "192.168.1.100",
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    "hostname": "web01",
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    "role": "nginx"
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}
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# 按键取值，对应Shell的 ${server_info["ip"]}
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print(server_info["ip"])  # 输出 192.168.1.100
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# 新增/修改键值
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server_info["status"] = "running"
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# 遍历字典
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for key, value in server_info.items():
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    print(f"{key}: {value}")
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# 判断键是否存在
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if "port" in server_info:
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    print(server_info["port"])
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else:
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    print("键不存在")

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score = 85
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if score >= 90:
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    print("优秀")
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elif score >= 80:
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    print("良好")
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elif score >= 60:
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    print("及格")
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else:
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    print("不及格")
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# 运维常见的服务状态检查
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status = "running"
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if status == "running":
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    print("服务正常")
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elif status == "stopped":
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    print("服务已停止")
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else:
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    print("服务异常")

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services = ["nginx", "mysql", "redis"]
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for svc in services:
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    print("正在检查服务：", svc)
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# 运维场景：批量检查多个服务
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for svc in services:
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    if svc == "nginx":
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        print(f"重启 {svc}...")
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        # 这里调用重启命令
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        continue
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    print(f"检查 {svc} 状态")

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# 遍历1到10（range左闭右开，10不包含）
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for i in range(1, 11):
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    print(i)
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# 从0开始，步长为2
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for i in range(0, 20, 2):
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    print(i)  # 输出 0, 2, 4, 6, ... 18
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# 运维场景：重试机制
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for attempt in range(1, 4):
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    print(f"第 {attempt} 次尝试连接...")
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    # 连接逻辑
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    if attempt == 3:
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        print("连接失败，最后一次尝试")

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i = 1
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while i <= 5:
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    print("第", i, "次检测")
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    i = i + 1
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# 运维场景：监控告警循环
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retry_count = 0
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while retry_count < 3:
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    try:
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        # 执行风险操作
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        result = connect_to_server()
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        break  # 成功则退出循环
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    except Exception as e:
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        retry_count += 1
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        print(f"连接失败，准备第 {retry_count} 次重试")

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# 定义加法函数
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def add(a, b):
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    result = a + b
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    return result
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# 调用并接收返回值
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sum_result = add(10, 20)
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print(sum_result)  # 输出 30
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# 运维场景：检查端口是否开放
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def check_port(host, port):
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    """检查服务器指定端口是否可达"""
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    try:
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        import socket
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        sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
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        result = sock.connect_ex((host, port))
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        sock.close()
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        return result == 0  # 返回True/False
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    except Exception as e:
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        print(f"检查端口异常: {e}")
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        return False
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# 调用
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if check_port("192.168.1.10", 22):
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    print("SSH服务可达")
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else:
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    print("SSH服务不可达")

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# 列出当前目录下所有文件和目录
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for item in os.listdir("."):
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    full_path = os.path.join(".", item)
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    if os.path.isdir(full_path):
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        print(f"[目录] {item}")
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    else:
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        print(f"[文件] {item}")

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# 递归查找/var/log下所有.log文件，等价于 find /var/log -type f -name "*.log"
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for root, dirs, files in os.walk("/var/log"):
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    # root: 当前遍历到的目录路径
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    # dirs: 当前目录下的子目录列表
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    # files: 当前目录下的文件列表
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    for file in files:
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        if file.endswith(".log"):
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            full_path = os.path.join(root, file)
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            # 获取文件大小
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            size = os.path.getsize(full_path)
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            print(f"{full_path} ({size} bytes)")
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# 运维场景：查找所有超过1GB的日志文件并清理
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import os
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for root, dirs, files in os.walk("/var/log"):
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    for file in files:
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        if file.endswith(".log"):
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            full_path = os.path.join(root, file)
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            size = os.path.getsize(full_path)
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            # 1GB = 1073741824 bytes
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            if size > 1073741824:
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                print(f"清理大日志：{full_path} ({size/1024/1024:.2f}MB)")
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                os.remove(full_path)