Cloudrun omits content-encoding: zstd

Google Cloud Serverless Applications
1

Hello,

I wanted to bring to your attention that the latest version of Google Chrome has enabled zstd by default. However, we have noticed that the responses from our backend, which is hosted on Cloud Run, are not working as expected. Upon further investigation, we discovered that the content-encoding is being omitted from the response when zstd is set to accept-encoding in the request.

curl <url> -H 'accept-encoding: gzip,deflate,br,zstd' -i 

HTTP/2 200 
content-type: text/html; charset=utf-8
vary: Accept-Encoding, Accept-Language, Cookie, origin
content-language: th-th
x-frame-options: SAMEORIGIN
strict-transport-security: max-age=60; includeSubDomains
x-content-type-options: nosniff
referrer-policy: same-origin
cross-origin-opener-policy: same-origin
set-cookie: csrftoken=8Q2LzaIZQCil0OhbNd3ccBNfb4kNjrqT; expires=Thu, 20 Feb 2025 04:51:25 GMT; Max-Age=31449600; Path=/; SameSite=Lax
x-cloud-trace-context: 19caa61de33342e785793de2df1aab56
date: Thu, 22 Feb 2024 04:51:25 GMT
server: Google Frontend
content-length: 4106
expires: Thu, 22 Feb 2024 04:51:25 GMT
cache-control: private
alt-svc: h3=":443"; ma=2592000,h3-29=":443"; ma=2592000

However, it works normally if we remove zstd from the accept-encoding header.

curl <url> -H 'accept-encoding: gzip,deflate,br' -i

HTTP/2 200 
content-type: text/html; charset=utf-8
vary: Accept-Encoding, Accept-Language, Cookie, origin
content-language: th-th
x-frame-options: SAMEORIGIN
strict-transport-security: max-age=60; includeSubDomains
x-content-type-options: nosniff
referrer-policy: same-origin
cross-origin-opener-policy: same-origin
set-cookie: csrftoken=URmkfnDknLkmI0Q4hrNUTwTMTuIQyOXI; expires=Thu, 20 Feb 2025 04:53:35 GMT; Max-Age=31449600; Path=/; SameSite=Lax
content-encoding: br
x-cloud-trace-context: c2778673e2254dd8e5d56bbb097d7385
date: Thu, 22 Feb 2024 04:53:35 GMT
server: Google Frontend
content-length: 4008
expires: Thu, 22 Feb 2024 04:53:35 GMT
cache-control: private
alt-svc: h3=":443"; ma=2592000,h3-29=":443"; ma=2592000

We found that the zstd encoded content was returned from our backend and can be decoded, but the content-encoding is missing.

curl <url> -H 'accept-encoding: zstd' --output - | unzstd

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="utf-8">
    <meta http-equiv="x-ua-compatible" content="ie=edge">
...

We would like to know how we can fix this issue.

Please help.

2 Likes
2

Hi @napat ,

Welcome to Google Cloud Community!

Cloud Run isn’t setting the content-encoding: zstd header when Chrome requests it.

These might help you:

  • Update your backend application: Check if your framework handles content encoding automatically.
    If not, manually set the content-encoding header based on the request.
  • Use Cloud Functions: They automatically handle content encoding, including zstd.
  • Explore Cloud Run settings (experimental): Look for “Content Encoding” in the service’s “Settings” tab.