no live upstreams while connecting to upstream, client: ip_address , server: example.com, request: "GET / HTTP/1.1", upstream: "http://example.com", host: "example.com", referrer: "http://example.com/mypages/"

upstream prematurely closed connection while reading response header from upstream, client: ip_address , server: example.com, request: "GET / HTTP/1.1", upstream: "http://example.com", host: "example.com", referrer: "http://example.com/mypages/"

    if (rc == NGX_BUSY) {

        ngx_log_error(NGX_LOG_ERR, c->log, 0, "no live upstreams");

        ngx_stream_proxy_finalize(s, NGX_STREAM_BAD_GATEWAY);

        return;

    }

                if (upstream->read->eof) {

                    ngx_log_error(NGX_LOG_ERR, upstream->log, 0,

                                  "upstream prematurely closed connection");

                    ngx_http_upstream_finalize_request(r, u,

                                                       NGX_HTTP_BAD_GATEWAY);

                    return;

                }

        location ^~ /plus-image {

            proxy_set_header X-Real-IP $remote_addr;

            proxy_set_header Host plus.image.google.co.kr;

            proxy_pass http://plus.image.google.co.kr/meta/;

}

14.23 Host

The Host request-header field specifies the Internet host and port number of the resource being requested, as obtained from the original URI given by the user or referring resource (generally an HTTP URL,

as described in section 3.2.2). The Host field value MUST represent the naming authority of the origin server or gateway given by the original URL. This allows the origin server or gateway to differentiate between internally-ambiguous URLs, such as the root "/" URL of a server for multiple host names on a single IP address.

       Host = "Host" ":" host [ ":" port ] ; Section 3.2.2

A "host" without any trailing port information implies the default port for the service requested (e.g., "80" for an HTTP URL). For example, a request on the origin server for <http://www.w3.org/pub/WWW/> would properly include:

       GET /pub/WWW/ HTTP/1.1
       Host: www.w3.org

A client MUST include a Host header field in all HTTP/1.1 request messages . If the requested URI does not include an Internet host name for the service being requested, then the Host header field MUST be given with an empty value. An HTTP/1.1 proxy MUST ensure that any request message it forwards does contain an appropriate Host header field that identifies the service being requested by the proxy. All Internet-based HTTP/1.1 servers MUST respond with a 400 (Bad Request) status code to any HTTP/1.1 request message which lacks a Host header field.

// $ curl -v -I -o /dev/null  http://.....jpg  아래 커맨드와 동일하다. 알아서 host 헤더를 채운다.

$ curl -v -I -o /dev/null -H "host:plus.google.com" http://.....jpg

  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current

                                 Dload  Upload   Total   Spent    Left  Speed

  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0*   Trying 1.1.1.1

* Connected to ...

> HEAD ....jpg HTTP/1.1

> host:plus.google.com

> User-Agent: curl/7.43.0

> Accept: */*

>

< HTTP/1.1 200 OK

< Server: openresty

< Date: Wed, 01 Feb 2017 08:41:06 GMT

< Content-Type: image/jpg

< Content-Length: 23357

< Connection: keep-alive

< X-Kakao-crc32: 75299291

< Expires: Thu, 31 Dec 2037 23:55:55 GMT

< Cache-Control: max-age=315360000

< Age: 601526

<

  0 23357    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0

* Connection #0 to host plus.google.com left intact

$ curl -v -I -o /dev/null -H "host:" http://.....jpg

* Connected to ...

> HEAD ....jpg HTTP/1.1

> host:

> User-Agent: curl/7.43.0

> Accept: */*

>

< HTTP/1.1 400 Bad Request

proxy_set_header Host $host;

2017/02/01 20:00:21 [error] 61700#0: *103 no resolver defined to resolve dn.google.com,

http {

    lua_shared_dict dicts    16k;

    ....

     server {

        server_name _;

        listen 80;

        root /...

        location / {

            return 404;

        }

        location ~* \.(?:ico|css|js|gif|jpe?g|png|gif|eot|ttf|ott|woff2?|swf|svg|zip)$ {

            expires 1y;

        }

        location /health_off {

            default_type text/html;

            content_by_lua_block {

                local d = ngx.shared.dicts

                d:set("health", 400)

                ngx.say("health-off")

             }

             allow       192.168.0.0/16;

             allow       172.16.0.0/12;

             allow       127.0.0.1;

             deny        all;

         }

        location /health_on {

            default_type text/html;

            content_by_lua_block {

                local d = ngx.shared.dicts

                d:set("health", 200)

                ngx.say("health-on")

            }

            allow       192.168.0.0/16;

            allow       172.16.0.0/12;

            allow       127.0.0.1;

            deny        all;

        }

        location /health_check.html {

            access_log  off;

            allow       all;

            default_type text/html;

            access_by_lua_block {

                local dogs = ngx.shared.dicts

                local status = tonumber(dogs:get("health")) or 200

                if status == 400 then

                        return ngx.exit(400)

                end

                return ngx.exit(200)

            }

        }

...

}

$ curl -i http://localhost/health_check.html

200

$ curl -i http://localhost/health_off

$ curl -i http://localhost/health_check.html

400

$ curl -i http://localhost/health_on

$ curl -i http://localhost/health_check.html

200

$ ./configure -j2 --with-pcre=/home/www/pcre-8.39

platform: linux (linux)

you need to have ldconfig in your PATH env when enabling luajit.

https://openresty.org/en/installation.html

You should have perl 5.6.1+, libreadline, libpcre, libssl installed into your system. For Linux, you should also ensure that ldconfig is in your PATH environment.

$ ls  /sbin/ldconfig

/sbin/ldconfig

$ vi ~/.bashrc

export PATH=$PATH:/sbin

$ source ~/.bashrc

$ sudo yum clean all

$ sudo yum -q -y install pcre-devel.x86_64 curl-devel boost-devel readline-devel pcre-devel openssl-devel gcc

$ cd /home/www

$ wget http://story-ftp.daumkakao.io/ftp/archives/install/binaries/pcre-8.39.tar.gz

$ tar -xvf pcre-8.39.tar.gz

$ wget http://story-ftp.daumkakao.io/ftp/archives/install/binaries/openresty-1.11.2.1.tar.gz

$ tar -xvf openresty-1.11.2.1.tar.gz

$ cd /home/www/openresty-1.11.2.1 

$ ./configure -j2 --with-pcre=/home/www/pcre-8.39  --prefix=/usr/local/nginx --with-http_v2_module --with-http_stub_status_module

$ make -j2

$ sudo make install

$ mkdir -p /usr/local/nginx/conf

$ sudo ln -sf /usr/local/nginx/nginx/logs /usr/local/nginx/logs

/usr/local/nginx/bin/openresty -c /usr/local/nginx/conf/nginx.conf

/usr/local/nginx/bin/openresty -s reload -c /usr/local/nginx/conf/nginx.conf

#!/usr/bin/env python

"""

Very simple HTTP server in python.

Usage::

    ./dummy-web-server.py [<port>]

Send a GET request::

    curl http://localhost

Send a HEAD request::

    curl -I http://localhost

Send a POST request::

    curl -d "foo=bar&bin=baz" http://localhost

"""

from BaseHTTPServer import BaseHTTPRequestHandler, HTTPServer

import SocketServer

class S(BaseHTTPRequestHandler):

    def _set_headers(self):

        self.send_response(200)

        self.send_header('Content-type', 'text/html')

        self.end_headers()

    def do_GET(self):

        self._set_headers()

        self.wfile.write("<html><body><h1>hi!</h1></body></html>")

    def do_HEAD(self):

        self._set_headers()

    def do_POST(self):

        # Doesn't do anything with posted data

        self._set_headers()

        self.wfile.write("<html><body><h1>POST!</h1></body></html>")

def run(server_class=HTTPServer, handler_class=S, port=80):

    server_address = ('', port)

    httpd = server_class(server_address, handler_class)

    print 'Starting httpd...'

    httpd.serve_forever()

if __name__ == "__main__":

    from sys import argv

    if len(argv) == 2:

        run(port=int(argv[1]))

    else:

        run()

    server {

        listen       8888;

        server_name  localhost;

        #charset koi8-r;

        #access_log  logs/host.access.log  main;

        location / {

            proxy_pass http://backends;

            proxy_next_upstream error timeout invalid_header http_502 http_503 http_504;

            proxy_http_version 1.1;

            proxy_set_header Host $host;

           proxy_set_header X-Real-IP  $remote_addr;

           proxy_set_header X-Forwarded-For $remote_addr;

        }

$ python server.py

$ curl http://localhost:8888

<html><body><h1>hi!</h1></body></html>

$ curl -X POST http://localhost:8888

<html><body><h1>POST!</h1></body></html>[/usr/local/nginx/conf] curl -X POST http://localhost:8888

<!DOCTYPE html>

<html>

<head>

<title>Error</title>

<style>

    body {

        width: 35em;

        margin: 0 auto;

        font-family: Tahoma, Verdana, Arial, sans-serif;

    }

</style>

</head>

<body>

<h1>An error occurred.</h1>

<p>Sorry, the page you are looking for is currently unavailable.<br/>

Please try again later.</p>

<p>If you are the system administrator of this resource then you should check

the <a href="http://nginx.org/r/error_log">error log</a> for details.</p>

<p><em>Faithfully yours, nginx.</em></p>

</body>

</html>

--prefix=/usr/local/nginx --with-http_stub_status_module --with-http_ssl_module --with-http_v2_module --with-http_secure_link_module --with-openssl=/usr/local/src/openssl-1.0.2h 

    listen               443 http2 default_server;

$ ./nginx/sbin/nginx -V

nginx version: nginx/1.10.1

built by gcc 4.4.7 20120313 (Red Hat 4.4.7-17) (GCC)

built with OpenSSL 1.0.2h  3 May 2016

TLS SNI support enabled