Proxy to serve external file

1. Caddy version (caddy version): 1.13.1

2. How I run Caddy:

a. System environment:


b. Command:

caddy.exe -conf ./caddy/Caddyfile.acceptance
caddy.exe -conf ./caddy/Caddyfile.production

c. Service/unit/compose file:

d. My complete Caddyfile or JSON config:

:2015 {
	# Add plugins/directives

	# Get Caddy to serve content from the dist folder as the root of the site
	# So https://<server>/index.html would serve out of /<path>/dist/index.html, if it exists
	root ./dist

	# Docker containers must log to stdout in order for logs to be pulled in to ELK
	log / stdout "{combined}"

  # these are required for the nosniff header below as they are not served by vue
  header /app.js {
    Content-Type text/javascript
  header /globals.js {
    Content-Type text/javascript
  header /analytics/digitalData.js {
    Content-Type text/javascript

  header / {
    # remove the default "Server: Caddy" header for all requests
    # enable HSTS
    Strict-Transport-Security "max-age=31536000; includeSubDomains; preload"
    # headers to get a better security rating
    Content-Security-Policy "form-action 'self'; frame-ancestors 'self'; manifest-src 'self'; media-src 'self'; base-uri 'self'; object-src 'none'; worker-src 'none'; upgrade-insecure-requests;"
    Cache-Control "no-cache"
    X-XSS-Protection "1; mode=block"
    X-Content-Type-Options "nosniff"
    X-Frame-Options "sameorigin"

  # Create proxy for adobe analytics - Aceptance
  proxy /adobeAssets {
    without /adobeAssets
    header_upstream Content-Type application/javascript
    header_downstream Content-Type application/javascript
  # Create proxy for adobe analytics - Production
  #proxy /adobeAssets {
  #  without /adobeAssets
  #  header_upstream Content-Type application/javascript
  #  header_downstream Content-Type application/javascript

	# Comment this in if you are using history mode for SPA routing
  rewrite {
    if {uri} not_has includes
    if {uri} not_has /login
    if {uri} not_has /logout
    if {uri} not_has /signin
    if {uri} not_has /adobeAssets
    to {path} {path}.html /


3. The problem I’m having:

This is the index.html

<!DOCTYPE html>
<html lang="en">
    <meta charset="utf-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <script type="application/javascript" src="<%= BASE_URL %>globals.js"></script>
    <!-- Begin Analytics-->
    <script type="application/javascript" src="<%= BASE_URL %>adobeAssets"></script>
	<script type="application/javascript" src="<%= BASE_URL %>analytics/digitalData.js"></script>
    <!-- End Analytics-->
    <!--Noto Font-->

    <link rel="icon" href="<%= BASE_URL %>MLI-favicon.ico" />
    <title>My website</title>
        >We're sorry, but this site doesn't work properly without JavaScript
        enabled. Please enable it to continue.
    <div id="app"></div>
    <!-- built files will be auto injected -->
    <script type="text/javascript">try{_satellite.pageBottom();}catch(e){}</script>

<%= BASE_URL %>adobeAssets tries to load Adobe Analytics .js file.

It uses the proxy from the caddy file to get to the actual file from

The file is different for Acceptance and Production. Using a proxy was a nice way to get to the correct file and it was working fine for months but not anymore. Now the request to returns “502 Bad Gateway”

The application is running in containers in Nomad and there is F5 load balancer in front of it. I suspect new iRule added to F5 is causing the problem but I am not sure.

4. Error messages and/or full log output:

“502 Bad Gateway”

5. What I already tried:

Running the application locally with the Acceptance caddy file does not have the problem. Only when it runs in Nomad it has the problem.

I have no control of F5 configuration. I would like to be able to load the correct .js file based on the environment. Is there a different way than using the proxy directive?

We’ve never released a v1.13.1, so I’m not sure where you got that from.

Caddy v1 is EOL and no longer supported. Please upgrade to Caddy v2.

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It looks like we use a proprietary version based on v1 to which we added some plugins. There is no corresponding version based on v2, so upgrading at this point is not possible.

Are there other ways similar to “proxy” that will result a specific file to be server when another specific url is requested?

Is there a way to troubleshoot the “502 bad gateway” error?

We no longer support Caddy v1, sorry.

You can port the plugins to Caddy v2:

If you need help with this, please consider sponsoring to get support:

1 Like

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