Nginx upstream retry based on response - nginx

Not all API operations are retriable, so backend send a header retriable = true if the operations can be retried.
How can I say Nginx: retry if the upstream response contains the retriable header?
upstream mash {
ip_hash;
server 127.0.0.1:8081;
server 192.168.0.11:8081;
}
server {
location / {
if ($request_method = POST ) {
proxy_next_upstream error;
}
if ($request_method = PUT ) {
proxy_next_upstream error;
}
proxy_pass http://mash/;
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
}
}
The logic I want to implement is the following:
if(response.hasHeader('Retriable') {
do_retry
} else{
return_backend_response;
}

The Retrier Service
Create a second upstream retrier with a very simple web server running that forwards all requests back to nginx on a special port. Then nginx will forward the requests to the mash upstream. When the response comes back to nginx, the response will get sent to retrier and the logic for retrying can be executed there.

Related

Let Nginx pass current location

I have nginx reverse-proxy to my site on IIS and here is my nginx config:
UPDATE
upstream backend {
server 43.128.77.101;
}
server {
server_name domain.subdomain.com;
location /products {
if ($query_string ~ Jeans){
return 301 /get-all-products/?filter=jeans;
}
if ($query_string ~ Shirts){
return 301 /get-all-products/?filter=shirts;
}
if ($query_string ~ Hats){
return 301 /get-all-products/?filter=hats;
}
}
location / {
proxy_pass http://backend;
proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection 'upgrade';
proxy_set_header Host $host;
proxy_cache_bypass $http_upgrade;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
}
}
It redirects from /products page to certain URLs by query string. But for page /products-available it fails with error 404. Nginx error log contains error:
"/usr/share/nginx/html/products-available" failed (2: No such file or directory)
The page /products-available doesn't need any redirections. I want it to pass on backend IIS server as it is. How can I tell nginx to pass it through? What am I doing wrong?
Thank you.
This would be because you are only defining the behavior of Nginx for a given path (/products).
If you want to define a default behavior for Nginx requests that don't match the /products path (like /products-available) you can add the following after your current location section to proxy any other path request to a different application/port.
location / {
proxy_pass http://127.0.0.1:3000;
}
You can see more information on sending a request to a different application in https://docs.nginx.com/nginx/admin-guide/web-server/reverse-proxy/#passing-a-request-to-a-proxied-server

After Nginx and the backend server establish a connection timeout, I want Nginx to return json data to the client. How to configure it?

Suppose the requirements are like this:
The port that Nginx listens on is 80, and the backend server domain name is assumed to be: http://hello.com,
Nginx accepts the request from the client as a proxy, and Nginx forwards the request to http://hello.com. If Nginx and the backend server establish a connection timeout, the data in json format must be returned to the client. The data is assumed to be like this:
{
"code": -1
"message":"failed to connect remote error"
}
And I want the client to receive a status code of 500.
I would like to ask the seniors to achieve this function, how to configure Nginx?
Try the following:
server {
listen 80;
server_name auth.example.com;
set $upstream 111.222.333.444:8080;
location / {
proxy_pass_header Authorization;
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_http_version 1.1;
proxy_set_header Connection "";
proxy_intercept_errors on;
proxy_buffering off;
client_max_body_size 10M;
proxy_read_timeout 36000s;
proxy_redirect off;
proxy_pass http://$upstream;
error_page 500 502 503 504 = #outage;
}
location #outage {
return 500 '{ "code": -1 "message":"failed to connect remote error" }';
}
}
Basically we give it a proxy to the upstream server, then if the upstream server responds with the server-related errors, we'll return our JSON content and a 500 status.

nginx ignores one of every two request

I'm using nginx 1.12.2 (downloaded from official site) on windows 8.1 as a reverse proxy server. I got a problem that one of every two request is ignored.
nginx config:
server {
listen 80;
server_name my_fake_domain.com;
access_log C:/nginxlogs/access.txt;
location / {
proxy_pass http://localhost:8080;
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_read_timeout 1800;
proxy_connect_timeout 1800;
}
}
my nodejs server:
'use strict';
const http = require('http');
const httpServer = http.createServer((req, res) => {
res.writeHead(200, { 'Content-Type': 'text/plain' });
res.end('okay');
});
httpServer.listen(8080, '0.0.0.0');
I'm using postman to send test requests. A request to http://my_fake_domain.com after a succeeded request will always loading. This always loading request does not actually ignored. If I cancel it, it will show up in the access log.
Note that a request to http://localhost:8080 always succeed.
Where might I get wrong?

Nginx keep-alive w/o upstream

I'm using a variable to define my proxy_pass target, similar to this answer except in my case the value is extracted from a query param on the incoming request, so e.g. /?url=http://example.com will be proxied to example.com. Since the proxy_pass argument is a variable, I have no upstream directive in my config. The proxying works fine. However, the connection is closed after each request and I want to them alive to amortize the TCP handshake. According to these directions, that requires a keepalive directive in the upstream directive. How can I do this without an upstream directive?
Here's my full config:
server {
if ($arg_url ~ \/\/([^\/]*)) {
set $proxy_host $1;
}
if ($proxy_host = "") {
return 404;
}
resolver 8.8.8.8;
location / {
proxy_http_version 1.1;
proxy_set_header Connection "";
proxy_set_header Host $proxy_host;
proxy_pass $arg_url;
}
}

Nginx proxy_pass returns [No Host] while reverse proxying

I'm trying to reverse proxy an api with Nginx. I have the following configuration:
worker_processes 4;
events { worker_connections 1024; }
http {
upstream some_upstream {
server 1.something.com;
server 2.something.com;
}
server {
listen 80;
location ~/proxyNow/(?<zvar>(\w+))/(?<xvar>(\w+))/(?<yvar>(\w+))/ {
proxy_pass http://some_upstream/hello/something/$zvar/$xvar/$yvar/somethingelese;
proxy_set_header Host $http_host;
proxy_set_header Host $host;
proxy_set_header X-Forwarded-For $remote_addr;
proxy_cache maps_cache;
proxy_cache_valid 200 302 365d;
proxy_cache_valid 404 1m;
proxy_redirect off;
}
}
}
When I try to call the following url http://localhost:82/proxyNow/1/2/3/?app_id=someAppId&app_code=someCode
I get the following error message:
Invalid URL
The requested URL
"http://%5bNo%20Host%5d/hello/something/1/2/3/somethingelese", is
invalid. Reference #9.be35dd58.1489086561.5c9bd3c
It seems that the host cannot be retrieved by nginx. But if I execute the call directly:
http://1.something.com/hello/something/$zvar/$xvar/$yvar/somethingelese?app_id=someAppId&app_code=someCode
http://2.something.com/hello/something/$zvar/$xvar/$yvar/somethingelese?app_id=someAppId&app_code=someCode
It seems that Nginx for some reason is not able to resolve the host
You should take a look into the doc.
http://nginx.org/en/docs/http/ngx_http_proxy_module.html#proxy_pass
When location is specified using a regular expression.
In this case, the directive should be specified without a URI.
I suggest the following solution without expensive regex location.
http://nginx.org/en/docs/http/ngx_http_core_module.html#location
location /proxyNow/ {
rewrite /proxyNow/(?<zvar>(\w+))/(?<xvar>(\w+))/(?<yvar>(\w+))/.* /hello/something/$zvar/$xvar/$yvar/somethingelese$is_args?$args break;
proxy_pass http://some_upstream;
... other nginx diretives;
}

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