Duplicated log on single request with a minus sign at the end - nginx

Question

I have a setup where one nginx does reverse proxy to a second one.
I observed in my logs, that one nginx sees two request but the second one sees just one of them. I also observed that the browser is just sending one request, so the duplication if exists, does not come from the client.
Here is a sample of the logs:
nginx_1 | 192.168.64.8 - - [15/Jul/2016:11:43:32 +0000] "GET /images/mypic1.jpg HTTP/1.0" 200 9402 "http://localhost/es" "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/50.0.2661.94 Safari/537.36"
proxy_1 | 192.168.64.1 - - [15/Jul/2016:11:43:32 +0000] "GET /images/mypic1.jpg HTTP/1.1" 200 111773 "http://localhost/es" "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/50.0.2661.94 Safari/537.36" "-"
proxy_1 | 192.168.64.1 - - [15/Jul/2016:11:43:32 +0000] "GET /images/mypic1.jpg HTTP/1.1" 200 111773 "http://localhost/es" "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/50.0.2661.94 Safari/537.36"
proxy_1 | 192.168.64.1 - - [15/Jul/2016:11:43:32 +0000] "GET /images/mypic2.jpg HTTP/1.1" 200 25619 "http://localhost/es" "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/50.0.2661.94 Safari/537.36" "-"
proxy_1 | 192.168.64.1 - - [15/Jul/2016:11:43:32 +0000] "GET /images/mypic2.jpg HTTP/1.1" 200 25619 "http://localhost/es" "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/50.0.2661.94 Safari/537.36"
nginx_1 | 192.168.64.8 - - [15/Jul/2016:11:43:32 +0000] "GET /images/mypic2.jpg HTTP/1.0" 200 25619 "http://localhost/es" "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/50.0.2661.94 Safari/537.36"
As you can see, proxy_1 is the nginx working as reverse proxy, and nginx_1 is the one receiving and processing the requests.
In the end of every duplicated line you can see a "-" that I don't know what it means. I suspect is doing some sort of rewriting I'm not aware of but don't understand how it happens.
Could you give me some clue about what is going on here?
Here I also provide the server config:
access_log /dev/stdout;
error_log /dev/stdout;
server {
listen 7000;
listen 80;
client_max_body_size 24M;
server_name *.rareconnect.org;
include /etc/nginx/params/gzip_on;
location / {
include /etc/nginx/params/proxy_pass_local_rareconnect_org_8000;
}
}
This is on top of the standard configuration of nginx:1.9.5 as appears in the official docker registry.
user nginx;
worker_processes 1;
error_log /var/log/nginx/error.log warn;
pid /var/run/nginx.pid;
events {
worker_connections 1024;
}
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"';
access_log /var/log/nginx/access.log main;
sendfile on;
#tcp_nopush on;
keepalive_timeout 65;
#gzip on;
include /etc/nginx/conf.d/*.conf;
}
Thanks in advance.

Answer 1

Looks like there are few records access_log. Can you check nginx.conf as well?