Nginx服务器配置详解

/etc/nginx/
├── nginx.conf                 # 主配置：main + events + http
├── mime.types                 # 文件扩展名与 Content-Type 映射
├── fastcgi_params             # FastCGI 默认参数（PHP 用）
├── proxy_params               # 反向代理默认参数
├── sites-available/           # 可用站点配置（Debian 系约定）
│   ├── default
│   └── example.com.conf
├── sites-enabled/             # 已启用站点（通常是指向 available 的软链接）
│   └── default -> ../sites-available/default
└── conf.d/                    # 额外配置片段，nginx.conf 中 include 进来
    └── gzip.conf

# ===== main 块（全局）=====
user  www-data;
worker_processes  auto;
error_log  /var/log/nginx/error.log warn;
pid        /run/nginx.pid;

# ===== events 块：连接处理模型 =====
events {
    worker_connections  10240;
    use                 epoll;
    multi_accept        on;
}

# ===== http 块：所有 HTTP 相关配置 =====
http {
    include       /etc/nginx/mime.types;
    default_type  application/octet-stream;

    log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
                      '$status $body_bytes_sent "$http_referer" '
                      '"$http_user_agent" "$http_x_forwarded_for" '
                      'rt=$request_time urt=$upstream_response_time';
    access_log  /var/log/nginx/access.log  main;

    sendfile        on;
    tcp_nopush      on;
    tcp_nodelay     on;
    keepalive_timeout  65;
    server_tokens   off;

    gzip  on;
    gzip_types  text/plain text/css application/json application/javascript;

    # ===== upstream 块：定义后端服务器组 =====
    upstream backend {
        server 127.0.0.1:8080 weight=3 max_fails=3 fail_timeout=30s;
        server 127.0.0.1:8081 weight=1 backup;
        keepalive 32;
    }

    # ===== server 块：一个虚拟主机 =====
    server {
        listen       80;
        server_name  example.com www.example.com;
        root         /var/www/example;
        index        index.html index.htm;

        # ===== location 块：按 URI 匹配 =====
        location / {
            try_files $uri $uri/ =404;
        }

        location /api/ {
            proxy_pass http://backend;
            proxy_set_header Host $host;
            proxy_set_header X-Real-IP $remote_addr;
            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
            proxy_connect_timeout 5s;
            proxy_read_timeout    60s;
        }

        location ~* \.(jpg|jpeg|png|gif|ico|css|js)$ {
            expires 30d;
            access_log off;
        }
    }

    include /etc/nginx/conf.d/*.conf;
    include /etc/nginx/sites-enabled/*;
}

http {
    add_header X-Frame-Options SAMEORIGIN;      # http 级别
    server {
        # 未声明 add_header → 继承 http 的 X-Frame-Options
        location /a/ {
            add_header X-Custom "1";            # 声明了 → X-Frame-Options 不再生效！
        }
    }
}

# 全站 HTTP 跳 HTTPS（推荐用 return，性能更好、语义清晰）
server {
    listen 80;
    server_name example.com www.example.com;
    return 301 https://$host$request_uri;
}

# rewrite 三要素：regex  replacement  flag
# flag: last(重新走 location 匹配) / break(停止 rewrite) / redirect(302) / permanent(301)
location /old/ {
    rewrite ^/old/(.*)$ /new/$1 permanent;
}

# 前端路由 SPA 的 history 模式兜底
location / {
    try_files $uri $uri/ /index.html;
}

# 只能写在 http 块中
log_format  detailed  escape=json  '{'
    '"time":"$time_iso8601",'
    '"remote_addr":"$remote_addr",'
    '"request":"$request",'
    '"status":$status,'
    '"bytes":$body_bytes_sent,'
    '"referer":"$http_referer",'
    '"ua":"$http_user_agent",'
    '"request_time":$request_time,'
    '"upstream_time":"$upstream_response_time",'
    '"upstream_addr":"$upstream_addr"'
'}';

access_log  /var/log/nginx/access.log  detailed  buffer=64k flush=5s;

# 按状态码过滤：只记录 5xx 到单独文件（map 需在 http 块）
map $status $loggable {
    ~^5  1;
    default 0;
}
access_log /var/log/nginx/error-only.log detailed if=$loggable;

# 1. 语法校验，-t 会输出配置文件路径与是否 OK
sudo nginx -t
# nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
# nginx: configuration file /etc/nginx/nginx.conf test is successful

# 2. 校验指定的非默认配置文件（-c 指定主配置）
sudo nginx -t -c /etc/nginx/nginx.conf

# 3. 热加载：master 进程重新读配置，平滑替换 worker，不断连接
sudo nginx -s reload
# 等价：sudo systemctl reload nginx

# 4. 其他信号
sudo nginx -s reopen    # 重新打开日志文件（日志切割后）
sudo nginx -s quit      # 优雅停止（处理完当前请求）
sudo nginx -s stop      # 立即停止

# 5. 修改配置后忘记 reload 是最常见的"改了没生效"原因