Authenticating HTTP request with Nginx
How to authenticate HTTP request with Nginx
Authgear has an internal endpoint that can authenticate HTTP request.
Below is a very simple application server written in Python that echoes most of the request headers.
from wsgiref.simple_server import make_server
def header_name(key):
parts = key.split("_")[1:]
parts = [part.lower() for part in parts]
return "-".join(parts)
def app(environ, start_response):
status = '200 OK'
headers = [('Content-type', 'text/plain; charset=utf-8')]
start_response(status, headers)
for key, value in environ.items():
if key.startswith("HTTP_"):
name = header_name(key)
yield ("%s: %s\n" % (name, value)).encode()
with make_server('', 8000, app) as httpd:
print("listening on port 8000...")
httpd.serve_forever()
Run it with:
python3 app.py
We have to write a Dockerfile for our application server.
FROM python:3.7-slim
COPY app.py .
EXPOSE 8000
CMD ["python3", "app.py"]
We then declare it as a new service in docker-compose.yaml:
services:
# Other services are omitted for brevity
app:
build:
context: .
ports:
- "8000:8000"
Finally, run it!
docker-compose up
Copy the following nginx.conf and save it as nginx.conf.
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;
server {
server_name _;
listen 80;
location / {
# See Note
proxy_pass http://authgear:3000;
proxy_set_header Host $host;
}
location /app {
# See Note
proxy_pass http://app:8000;
proxy_set_header Host $host;
auth_request /_auth;
auth_request_set $x_authgear_session_valid $upstream_http_x_authgear_session_valid;
auth_request_set $x_authgear_user_id $upstream_http_x_authgear_user_id;
auth_request_set $x_authgear_user_anonymous $upstream_http_x_authgear_user_anonymous;
auth_request_set $x_authgear_user_verified $upstream_http_x_authgear_user_verified;
auth_request_set $x_authgear_session_acr $upstream_http_x_authgear_session_acr;
auth_request_set $x_authgear_session_amr $upstream_http_x_authgear_session_amr;
proxy_set_header x-authgear-session-valid $x_authgear_session_valid;
proxy_set_header x-authgear-user-id $x_authgear_user_id;
proxy_set_header x-authgear-user-anonymous $x_authgear_user_anonymous;
proxy_set_header x-authgear-user-verified $x_authgear_user_verified;
proxy_set_header x-authgear-session-acr $x_authgear_session_acr;
proxy_set_header x-authgear-session-amr $x_authgear_session_amr;
}
location = /_auth {
internal;
# See Note
proxy_pass http://authgear:3001/_resolver/resolve;
proxy_pass_request_body off;
proxy_set_header Content-Length "";
}
}
}
Note: When plain domain is used in proxy_pass directive, the domain is resolved once and then cached indefinite. If the domain is public, then you use use variable in proxy_pass with resolver directive to respect DNS TTL. See https://www.nginx.com/blog/dns-service-discovery-nginx-plus/ For instructions on how to setup Nginx for production deployment, see Using Nginx as the reverse proxy.
Add Nginx in docker-compose.yaml:
services:
# Other services are omitted for brevity
nginx:
image: nginx:1.18
volumes:
- ./nginx.conf:/etc/nginx/nginx.conf
ports:
- "8080:80"
You should see the following:
x-authgear-session-valid: true
x-authgear-user-id: acdc0d99-f784-43d5-b53d-70f3506dfbf7
x-authgear-user-anonymous: false
Sometimes you may want to cache resolver response in nginx, for example, when the reverse proxy and Authgear is in different regions.
You may modify the nginx configuration as following to enable caching:
http {
# ...
proxy_cache_path /tmp/cache keys_zone=auth_cache:10m;
server {
# ...
location = /_auth {
# ...
proxy_cache auth_cache;
proxy_cache_key "$cookie_session|$http_authorization";
proxy_cache_valid 200 10m; # Adjust cache duration as desired.
}
}
}