I've got a particular scenario where I'm needing to route to a different backend based on query parameter:
https://edge1.cdn.com/file.zip?{secure_link}&{tokens}&route=aws1
Where aws1 would be say http://edge1.amazonwebservices.com
and if its aws2 then proxy backend would be http://edge2.amazonwebservices.com
and so on... but I still have not figured out how to do this.
You can use map directive to get a proxy hostname from the $arg_route variable (which contains a value of the route query argument):
map $arg_route $aws {
aws1 edge1.amazonwebservices.com;
aws2 edge2.amazonwebservices.com;
...
default <default_hostname>;
}
server {
...
# if you want to proxy the request, you'd need a 'resolver' directive
resolver <some_working_DNS_server_address>;
location / {
# if you want to proxy the request
proxy_pass http://$aws;
# or if you want to redirect the request
rewrite ^ http://$aws$uri permanent;
}
}
If you don't want to serve the request without route query argument, you can omit the last default line at the map block and add the following if block to your server configuration:
if ($aws = '') {
return 403; # HTTP 403 denied
}
If you need to proxy the request you'd additionally need a resolver directive (you can read some technical details about it in this article).
Related
I have a usecase where node exporter is running under reverse proxy. Here is the snippet of my current configuration:
location /node_exporter {
proxy_pass http://127.0.0.1:9100/metrics;
}
This is running fine, but I want to implement it without metrics subpath, for which I did this change:
location /node_exporter {
proxy_pass http://127.0.0.1:9100/;
}
It is opening the initial page of node exporter with metrics button, but when clicked on it, redirects to /metrics instead of /node_exporter/metrics which inturn gives 404.
Please suggest on how to use the rewrite rule for this usecase.
The following site configuration should be enough
location /node_exporter {
proxy_pass http://127.0.0.1:9100/;
}
as long the telemetry path is changed when starting the node_exporter
./node_exporter/node_exporter --web.telemetry-path="/node_exporter/metrics"
I have a lua script that uses lua-resty to call another service via co-sockets.
Now I would like to use the information from this call to route the request in nginx.
nginx includes the lua script in access_by_lua*
which sets the var like this:
ngx.var.blocked = '1'
and routes in the location like this:
if ( $blocked ) {
proxy_pass http://haproxy-9001;
break;
}
the problem is now that nginx does not pick up the variable change (in this phase).
if I include the lua script in set_by_lua* phase then the variable passing works but I dont have access to the co-sockets in this phase.
Any idea how to get the variable out of lua land into the nginx variable in the access_by_lua, rewrite_by_lua or content_by_lua phase so that I can use the co-socket api to make a http call?
if nginx directive is implemented by https://nginx.ru/en/docs/http/ngx_http_rewrite_module.html.
Obviously it works on rewrite phase, so your changes at access phase doesn't work.
Just don't use if. Below is snippet from one of my nginx config:
proxy_pass $scheme://$upstream$uri$is_args$args;
Just set $upstream variable at access phase and it will work at content phase (proxy_pass).
Maybe you could capture location with that proxy instead of variable, it works in access_by_lua scope
https://github.com/openresty/lua-nginx-module#ngxlocationcapture
I want to change an existing nginx configuration in a way where I can completely "mask" the configuration and proxy everything to the upstream when a certain cookie is available (to hide a certain server).
This includes not just some location directives but basically every location directive (as opposed to set or map a variable and update n-location's try_files and more).
My basic idea was to use lua and jump into the Rewrite/Access phase like this:
access_by_lua_block {
# proceed as usual if our cookie is not detected
if ngx.var.cookie_demo ~= nil and string.len(ngx.var.cookie_demo) ~= 32 then
return
end
# proxy and return w/out further processing
ngx.exec("#ngxbackend")
return ngx.exit(ngx.HTTP_OK)
}
# proxy upstream
location #ngxbackend {
include /etc/nginx/proxy_params_demo;
proxy_pass https://demo-upstreams;
}
But this leads to an ERR with rewrite or internal redirection cycle while redirect to named location "#ngxbackend" as the named location is probably never reached because of the access_by_lua_block after it's internal redirect.
Can I solve this by use of variables and further condition checking?
We know that HAProxy and Nginx can do the URL hash based upstream but how can we hash the part of the URL.
We have 4 back-end original image servers, each will store all the original large size image files. The image server will resize the file based on user request on the fly. (Tomcat Java load the file into memory and resize then response)
The original file is:
http://imageserver.company.com/path/to/imageA.jpg
The end-user will request:
httpurl://imageserver.company.com/path/to/imageA.jpg/crop/400x300.jpg
httpurl://imageserver.company.com/path/to/imageA.jpg/400x224.jpg
httpurl://imageserver.company.com/path/to/imageA.jpg/1280x720.jpg
I would like HAProxy and Nginx will do the hash on "/path/to/imageA.jpg";
Hash (substring (url, 0, find (url, ".jpg/")
Any idea of how to config?
In nginx you can use the map and upstream::hash directives:
map $uri $image_hash {
default $uri;
"~(?<image_path>.+(?:jpg|png))/" $image_path;
}
upstream image_backends {
hash $image_hash;
server server1;
server server2;
server server3;
server server4;
}
server {
...
location / {
# add debug header to view the hash
add_header ImageHash $image_hash;
proxy_pass http://image_backends;
}
}
I'm not sure what the exact syntax would be for HAProxy, but it's uri hash supports specifying the "depth" of the URI hash. So if the original path to the URL has a fixed depth then you can use that (though I'm guessing that's not the case)?
The "depth" parameter indicates the maximum directory depth
to be used to compute the hash. One level is counted for each
slash in the request. If both parameters are specified, the
evaluation stops when either is reached.
I am looking for a way to do the following using Nginx:
Intercept a request
Read URL, parse it and read a value from it.
Add that value as a new request header
Update the URL (remove a particular value)
Forward the request to another server
e.g
Request URL - http://<<nginx>>/test/001.xml/25
Final URL - http://<<server>>/test/001.xml with header (x-replica: 25)
I have a nginx server setup with a upstream for the actual server. I was wondering how do I setup Nginx to achieve this ?
Since the data exists within the request URI itself (available by the $uri variable in nginx), you can parse that using the nginx lua module. nginx will need to be compiled with lua for this to work, see: openresty's nginx lua module.
From there you can use the set_by_lua_block or set_by_lua_file directive given $uri as a parameter.
In configuration this would look something like:
location / {
...
set_by_lua_file $var_to_set /path/to/script.lua $uri;
# $var_to_set would contain the result of the script from this point
proxy_set_header X-Replica $var_to_set;
...
}
In script.lua we can access the $uri variable from in the ngx.arg list (see these docs):
function parse_uri( uri )
parsed_uri = uri
-- Parse logic here
return parsed_uri
end
return parse_uri( ngx.arg[1] )
Similarly, you can modify this function or create another to make a variable with the updated $uri.