CODEWITHSUNDEEP
shellnginx
Saswat Padhi
Saswat Padhi

Reputation: 6542

How to run a shell script on every request?

I want to run a shell script every time my nginx server receives any HTTP request. Any simple ways to do this?

Upvotes: 96

Views: 133801

Answers (7)

George Y.
George Y.

Reputation: 11789

Here is a hackish way to do it without any additional modules and without FastCGI:

  1. Create a systemd nginxfeeder.socket service, which will listen on a specified port, i.e. 8765, and invoke nginxfeeder.service:
[Unit]
Description=Nginx callback status

[Socket]
ListenStream=127.0.0.1:8765
Accept=yes
    
[Install]
WantedBy=sockets.target
  1. Create a corresponding [email protected] file invoked by this:
[Service]
ExecStart=/opt/scripts/nginxhandler.sh
StandardError=journal
StandardInput=socket
StandardOutput=socket
User=wwwrun
Group=wwwrun
  1. Register this with systemd (you don't need to copy scripts to /etc) and start:
systemctl enable `pwd`/nginxfeeder.socket
systemctl enable `pwd`/[email protected]
systemctl start nginxfeeder.socket

  1. Test it with telnet 127.0.0.1 8765 and you should see the output of your script.

  2. Now your script is available at 127.0.0.1:8765 and you can use nginx proxy_pass directive to have it invoked for a specific URL.

Upvotes: 4

kierzo
kierzo

Reputation: 123

You can also use the nginx mirror module and proxy_pass it to a web script that runs whatever. In my case I just added this to my main site location, {...

mirror /mirror;
mirror_request_body off;

and then made a new location called mirror that I had run a php script that executed whatever...

location = /mirror {
    internal;
    proxy_pass http://localhost/run_script.php;
    proxy_pass_request_body off;
    proxy_set_header Content-Length "";
    proxy_set_header X-Original-URI $request_uri;
}

https://nginx.org/en/docs/http/ngx_http_mirror_module.html

Upvotes: 0

Denis Ryzhkov
Denis Ryzhkov

Reputation: 2619

If you prefer full control in Python:

  • Create /opt/httpbot.py:
#!/usr/bin/env python3
from http.server import HTTPServer, BaseHTTPRequestHandler
import subprocess

class Handler(BaseHTTPRequestHandler):
    def do_GET(self):
        self._handle()

    def do_POST(self):
        self._handle()

    def _handle(self):
        try:
            self.log_message("command: %s", self.path)
            if self.path == '/foo':
                subprocess.run(
                    "cd /opt/bar && GIT_SSH_COMMAND='ssh -i .ssh/id_rsa' git pull",
                    shell=True,
                )
        finally:
            self.send_response(200)
            self.send_header("content-type", "application/json")
            self.end_headers()
            self.wfile.write('{"ok": true}\r\n'.encode())

if __name__ == "__main__":
    HTTPServer(("127.0.0.1", 4242), Handler).serve_forever()
  • No concurrency/parallelism here, so httpbot runs one command at a time, no conflicts.
  • Run apt install supervisor
  • Create /etc/supervisor/conf.d/httpbot.conf:
[program:httpbot]
environment=PYTHONUNBUFFERED="TRUE"
directory=/opt
command=/opt/httpbot.py
autorestart=true
redirect_stderr=true
stdout_logfile=/var/log/httpbot.log
stdout_logfile_maxbytes=1MB
stdout_logfile_backups=10
  • Add to your nginx server:
    location /foo {
        proxy_pass http://127.0.0.1:4242/foo;
    }
  • Run:
chmod u+x /opt/httpbot.py

service supervisor status
# If stopped:
service supervisor start

supervisorctl status
# If httpbot is not running:
supervisorctl update

curl https://example.com/foo
# Should return {"ok": true}

tail /var/log/httpbot.log
# Should show `command: /foo` and the output of shell script

Upvotes: 3

Andrei .F
Andrei .F

Reputation: 31

You can use nginx's perl module which is usually part of a repo and can be easily installed. Sample to call system curl command:

   location /mint {
       perl '
            sub {
               my $r = shift;
               $r->send_http_header("text/html");
               $r->print(`curl -X POST --data \'{"method":"evm_mine"}\' localhost:7545`);
               return OK;
            }
       '; 
}

Upvotes: 1

Durgesh Pandey
Durgesh Pandey

Reputation: 33

  1. Install OpenResty (OpenResty is just an enhanced version of Nginx by means of addon modules ) Refer https://openresty.org/en/getting-started.html for this
  2. Configure aws cli on the instance
  3. Write a shell script which download a file from specified S3 bucket
  4. Do the required changes in nginx.conf file
  5. Restart the nginx server

I have tested the http request using curl and file gets download in /tmp directory of respective instance:

curl -I http://localhost:8080/

OutPut: 

curl -I http://localhost:8080/
HTTP/1.1 200 OK
Server: openresty/1.13.6.2
Date: Tue, 14 Aug 2018 07:34:49 GMT
Content-Type: text/plain
Connection: keep-alive

Content of nginx.conf file:

worker_processes  1;
error_log logs/error.log;
events {
    worker_connections 1024;
}
http {
    server {
        listen 8080;
        location / {
           default_type text/html;
           content_by_lua '
                ngx.say("<p>hello, world</p>")
           ';
        }

        location / {
            content_by_lua_block{
            os.execute("sh /tmp/s3.sh")
            }
        }

    }
}

Upvotes: 2

Chirag Bhatia - chirag64
Chirag Bhatia - chirag64

Reputation: 4526

You can execute a shell script via Lua code from the nginx.conf file to achieve this. You need to have the HttpLuaModule to be able to do this.

Here's an example to do this.

location /my-website {
  content_by_lua_block {
    os.execute("/bin/myShellScript.sh")
  } 
}

Upvotes: 85

Don Duvall
Don Duvall

Reputation: 889

I found the following information online at this address: https://www.ruby-forum.com/topic/2960191

This does expect that you have fcgiwrap installed on the machine. It is really as simple as:

sudo apt-get install fcgiwrap

Example script (Must be executable)

#!/bin/sh
# -*- coding: utf-8 -*-
NAME=`"cpuinfo"`
echo "Content-type:text/html\r\n"
echo "<html><head>"
echo "<title>$NAME</title>"
echo '<meta name="description" content="'$NAME'">'
echo '<meta name="keywords" content="'$NAME'">'
echo '<meta http-equiv="Content-type"
content="text/html;charset=UTF-8">'
echo '<meta name="ROBOTS" content="noindex">'
echo "</head><body><pre>"
date
echo "\nuname -a"
uname -a
echo "\ncpuinfo"
cat /proc/cpuinfo
echo "</pre></body></html>"

Also using this as an include file, not restricted to only shell scripts.

location ~ (\.cgi|\.py|\.sh|\.pl|\.lua)$ {
    gzip off;
    root /var/www/$server_name;
    autoindex on;
    fastcgi_pass unix:/var/run/fcgiwrap.socket;
    include /etc/nginx/fastcgi_params;
    fastcgi_param DOCUMENT_ROOT /var/www/$server_name;
    fastcgi_param SCRIPT_FILENAME /var/www/$server_name$fastcgi_script_name;
}

I found it extremely helpful for what I am working on, I hope it help you out with your RaspberryPI project.

Upvotes: 62

Related Questions