Streamlit with Apache reverse proxy - "Please wait..."

Deployment
,
1

Hi all,

Setup:

Streamlit 1.4.0 deployed as a docker container, listening on port 8051, on an ec2 instance. Apache 2.4.18, on another node, is a reverse proxy to the streamlit app. Apache’s proxy, proxy_http and proxy_wstunnel modules are enabled.

Errors:

  1. “Please wait…” - message on the browser when the proxy URL is hit. The app loads fine when it’s accessed directly via http://<ec2_host_fqdn>:8051 though.

  2. Firing the proxy URL ‘https://streamlit-weekly.proxy.app.info’ (internal domain), on chrome’s debug console:

    WebSocket connection to 'wss://streamlit-weekly.proxy.app.info/stream' failed: WebSocket is closed before the connection is established.

    Uncaught Error: Unsupported state transition.
State: PINGING_SERVER
Event: CONNECTION_TIMED_OUT
 at Po.stepFsm (main.cb6e038a.chunk.js:2:491430)
 at main.cb6e038a.chunk.js:2:494477

Apache vhost:

<VirtualHost *:443>
    ServerName streamlit-weekly.proxy.app.info

  ## Vhost docroot
  DocumentRoot "/var/www/html"

  ## Directories, there should at least be a declaration for /var/www/html

  <Directory "/var/www/html">
    Options Indexes FollowSymLinks MultiViews
    AllowOverride None
    Require all granted
  </Directory>

  ## Logging
  ErrorLog "/var/log/apache2/streamlit-weekly.proxy.app.info_error_ssl.log"
  ServerSignature Off
  CustomLog "/var/log/apache2/streamlit-weekly.proxy.app.info_access_ssl.log" combined 

  ## Proxy rules
  ProxyRequests Off
  ProxyPass / http://streamlit01.app.us-west-2.private:8501/
  ProxyPassReverse / http://streamlit01.app.us-west-2.private:8501/

   <Location "/stream">
      ProxyPass wss://streamlit01.app.us-west-2.private:8501/stream
      ProxyPassReverse wss://streamlit01.app.us-west-2.private:8501/stream
   </Location>

  ## SSL directives
  SSLEngine on
  SSLCertificateFile      "/etc/ssl/certs/ssl-cert-snakeoil.pem"
  SSLCertificateKeyFile   "/etc/ssl/private/ssl-cert-snakeoil.key"
  SSLCACertificatePath    "/etc/ssl/certs"
  SSLProxyEngine On
</VirtualHost>

I referred quite a number of posts but I wasn’t able to find anything specific to Apache’s reverse proxy settings. Any help will be appreciated.

Thanks.

4 Likes
2

I am having a similar issue. I created a streamlit app and dockerized it. Now trying to reverse proxy my Apache server to connect to this docker container. But, the browser shows “Please Wait” and on inspecting the web page, the console shows the “Websocket connection failed”.
I am not well versed in how to upgrade the connection to websockets from my Apache SSL config.
Also, I am reverse proxying the docker IP to a subfolder rather than using the “/”. Like HTTP://my_server_name/my_awesome_app/

If you found a solution then please share.

3

Also looking for a solution to this. Running a streamlit app on Ubuntu behind Apache2 with LetsEncrypt, says “Please wait…” forever and giving the same messages everyone shows here.

This still happens when I start the app using streamlit run app.py with the flags

--server.enableCORS=false
-- server.enableWebsocketCompression=false
--server.headless=true
--server.port=8501

My apache vhost file(/etc/apache2/sites-available/dashboard.mysite.io.conf)

<VirtualHost *:80>
    RewriteEngine on
    RewriteCond %{SERVER_NAME} =dashboard.mysite.io
    RewriteRule ^ https://%{SERVER_NAME}%{REQUEST_URI}     [END,NE,R=permanent]
</VirtualHost>

<VirtualHost *:443>
   ServerName dashboard.mysite.io

   RewriteEngine On
   RewriteCond %{HTTP:Upgrade} =websocket
   RewriteRule /(.*) ws://localhost:8501/$1 [P]
   RewriteCond %{HTTP:Upgrade} !=websocket
   RewriteRule /(.*) http://localhost:8501/$1 [P]
   ProxyPassReverse / http://localhost:8501

    SSLCertificateFile /etc/letsencrypt/live/dashboard.mysite.io/fullchain.pem
    SSLCertificateKeyFile /etc/letsencrypt/live/dashboard.mysite.io/privkey.pem
Include /etc/letsencrypt/options-ssl-apache.conf
</VirtualHost>
4

Hi. Have you solved it?

5

I too face the same issue even without ssl and not dockerised. I get the same error as explained. How to resolve this? Stuck with “Please wait…”

1 Like
6

Hi. Have you solved it?

7

I am running into the same issue. So far i’ve tried everything that i came across

To the more savy, info from the logs might be useful. In there (/var/logs/apache2/error.log) I found repeated entries of

 [proxy_http:error] [pid 2901776:tid 140256410052160] [client XX.XX.XX.XX:XXXXX] AH01114: HTTP: failed to make connection to backend: 0.0.0.0, referer: https://my.domain.com/

Does that make sense to anyone?

Also just something I noticed: When i start the app from vscode on the remote, vscode can open the app with a forwarded port without a problem. At this point I am rather clueless but hope, that this can somehow help in finding the issue.

8

In my case the following lines in the apache configuration did the trick:

        SSLProxyEngine on
        RewriteEngine On
        RewriteCond %{HTTP:Connection} Upgrade [NC]
        RewriteCond %{HTTP:Upgrade} =websocket [NC]
        RewriteRule /(.*) ws://0.0.0.0:8501/$1 [P,L]
        ProxyPassReverse / http://0.0.0.0:8501/ 
        ProxyPass / http://0.0.0.0:8501/

When comparing that to the above i think that the main difference is the
RewriteCond %{HTTP:Connection} Upgrade [NC].

Hope that helps others, too!

9

This solution helped, but then it’s stripping logged-in user details from request headers. Could you please tell how to get them? I need to grant the access based on user roles.

10

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