我在Elixir中有一个伞式应用程序，它有两个应用程序端点，一个用于API，另一个用于IoT。我使用反向代理来服务应用程序，因为有两个端点在不同的端口上运行。
用于反向代理的生成包为：https://github.com/heroku/heroku-buildpack-nginx
这是我的Nginx配置文件。

daemon off;
worker_processes <%= ENV['NGINX_WORKERS'] || 4 %>;

events {
 use epoll;
 accept_mutex on;
 worker_connections <%= ENV['NGINX_WORKER_CONNECTIONS'] || 1024 %>;
}

http {
    gzip on;
    gzip_comp_level 2;
    gzip_min_length 512;

server_tokens off;

log_format l2met 'measure#nginx.service=$request_time request_id=$http_x_request_id';
access_log <%= ENV['NGINX_ACCESS_LOG_PATH'] || 'logs/nginx/access.log' %> l2met;
error_log <%= ENV['NGINX_ERROR_LOG_PATH'] || 'logs/nginx/error.log' %>;

include mime.types;
default_type application/octet-stream;
sendfile on;

#Must read the body in 5 seconds.
client_body_timeout 5;

upstream api {
    server 127.0.0.1:4000 max_fails=5 fail_timeout=60s;
}

upstream iot {
    server 127.0.0.1:4001 max_fails=5 fail_timeout=60s;
}

server {
    listen <%= ENV["PORT"] %>;
    server_name 0.0.0.0;
    keepalive_timeout 5;

    location /api {
        allow all;

        # Proxy Headers
        proxy_http_version 1.1;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header Host $http_host;
        proxy_set_header X-Cluster-Client-Ip $remote_addr;

        # The Important Websocket Bits!
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection "upgrade";

        proxy_pass http://api;

    }

    location /iot {
        allow all;

        # Proxy Headers
        proxy_http_version 1.1;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header Host $http_host;
        proxy_set_header X-Cluster-Client-Ip $remote_addr;

        # The Important Websocket Bits!
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection "upgrade";

        proxy_pass http://iot;

    }
}

}
显然，一旦应用程序初始化，buildpack期望写入一个文件/tmp/app-initialized。
我使用的命令是mix phx.server来启动保护伞。在Phoenix保护伞中的应用程序初始化后，写这个文件（/tmp/app-initialized）的正确方法是什么？