NGINX Reverse Proxy Configuration Structure - docker

Question

Is there a "proper" structure for the directives of an NGINX Reverse Proxy? I have seen 2 main differences when looking for examples of an NGINX reverse proxy.
http directive is used to house all server directives. Servers with data are listed in a pool within the upstream directive.
server directives are listed directly within the main directive.
Is there any reason for this or is this just a syntactical sugar difference?
Example of #1 within ./nginx.conf file:
upstream docker-registry {
server registry:5000;
}
http {
server {
listen 80;
listen [::]:80;
return 301 https://$host#request_uri;
}
server {
listen 443 default_server;
ssl on;
ssl_certificate external/cert.pem;
ssl_certificate_key external/key.pem;
# set HSTS-Header because we only allow https traffic
add_header Strict-Transport-Security "max-age=31536000;";
proxy_set_header Host $http_host; # required for Docker client sake
proxy_set_header X-Real-IP $remote_addr; # pass on real client IP
location / {
auth_basic "Restricted"
auth_basic_user_file external/docker-registry.htpasswd;
proxy_pass http://docker-registry; # the docker container is the domain name
}
location /v1/_ping {
auth_basic off;
proxy_pass http://docker-registry;
}
}
}
Example of #2 within ./nginx.conf file:
server {
listen 80;
listen [::]:80;
return 301 https://$host#request_uri;
}
server {
listen 443 ssl;
listen [::]:443 ssl;
error_log /var/log/nginx/error.log info;
access_log /var/log/nginx/access.log main;
ssl_certificate /etc/ssl/private/{SSL_CERT_FILENAME};
ssl_certificate_key /etc/ssl/private/{SSL_CERT_KEY_FILENAME};
location / {
proxy_pass http://app1
proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection "upgrade";
proxy_set_header Host $host;
proxy_set_header X-Forwarded-Proto $scheme;
proxy_set_header X-Forwarded-For $remote_addr; # could also be `$proxy_add_x_forwarded_for`
proxy_set_header X-Forwarded-Port $server_port;
proxy_set_header X-Request-Start $msec;
}
}

Answer 1

I dont quite understand your question, but it seems to me that the second example is missing the http {}, I dont think that nginx will start without it.
unless your example2 file is included somehow in the nginx.conf that has the http{}