Load balancing & proxies

Lenses can be placed behind a proxy, but you must allow websocket connections.

These are the paths used for WebSocket connections:

/api/ws
/api/kafka/ws
/api/v1/ws

TLS termination

Lenses supports TLS termination out of the box, see Enabling TLS

Sample Apache configuration

# Add these settings to your httpd.conf or under the VirtualHost section
# for Lenses.
# The rewrite directives need the rewrite module:
#   LoadModule rewrite_module modules/mod_rewrite.so
# The proxy directives need the proxy, proxy_http and proxy_wstunnel modules:
#   LoadModule proxy_module modules/mod_proxy.so
#   LoadModule proxy_http_module modules/mod_proxy_http.so
#   LoadModule proxy_wstunnel_module modules/mod_proxy_wstunnel.so

RewriteEngine On
RewriteCond %{HTTP:Upgrade} =websocket [NC]
RewriteRule ^/(.*)$           ws://lenses.url:9991/$1 [P,L]
RewriteCond %{HTTP:Upgrade} !=websocket [NC]
RewriteRule ^/(.*)$           http://lenses.url:9991/$1 [P,L]

ProxyRequests On
ProxyPreserveHost On
ProxyPass / http://lenses.url:9991/
ProxyPassReverse / http://lenses.url:9991/

Sample Caddy configuration

proxy /api/kafka/ws http://lenses.url:9991 {
    websocket
}
proxy /api/ws http://lenses.url:9991 {
    websocket
}
proxy / http://lenses.url:9991

Sample NGINX configuration

map $http_upgrade $connection_upgrade {
    default upgrade;
    '' close;
}

server {
    listen 80;
    server_name example.lenses.url;

    # websocket paths
    location /api/ws {
        proxy_pass http://lenses.url:9991;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection $connection_upgrade;

        proxy_redirect off;
        proxy_set_header  X-Real-IP  $remote_addr;
        proxy_set_header  X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header  Host $http_host;
    }
    location /api/kafka/ws {
        proxy_pass http://lenses.url:9991;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection $connection_upgrade;

        proxy_redirect off;
        proxy_set_header  X-Real-IP  $remote_addr;
        proxy_set_header  X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header  Host $http_host;
    }

    # SSE paths
    location /api/sse {
        proxy_pass http://lenses.url:9991;
        proxy_http_version 1.1;

        proxy_buffering off;
        proxy_redirect off;
        proxy_set_header  X-Real-IP  $remote_addr;
        proxy_set_header  X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header  Host $http_host;
    }

    # all other paths
    location / {
        proxy_pass http://lenses.url:9991;
        proxy_http_version 1.1;

        proxy_redirect off;
        proxy_set_header  X-Real-IP  $remote_addr;
        proxy_set_header  X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header  Host $http_host;
    }
}