Firebase serve fails to rewrite URL to containerized app after 8.18.0

[REQUIRED] Environment info

firebase-tools:

$ npx firebase --version 9.1.2

Platform:

macOS

[REQUIRED] Test case

I’ve create a repo to demonstrate the bug: https://github.com/clarmso/firebase-serve-bug. The repo contains some modified code from examples to demonstrate the bug.

[REQUIRED] Steps to reproduce

1. Create a firebase project (“firebase-serve-bug”) for hosting.
2. Create new project on Google Cloud Platform (“firebase-serve-bug”).
3. Clone the repo.
4. cd to rest-api/. Enable Cloud Run API, install gcloud beta, containerize the app and deploy the container (See steps 2-3 from https://firebase.google.com/docs/hosting/cloud-run).
5. cd to ui/. Run npm i.
6. Run firebase init. Make sure to select the newly created firebase project in the setup. .firebaserc should have the correct project name.
7. Open .firebase.json. Ensure the routes to /api are rewritten to the Cloud Run service(https://github.com/clarmso/firebase-serve-bug/blob/main/ui/firebase.json#L15). (See step 4 from https://firebase.google.com/docs/hosting/cloud-run)
8. On one terminal, run npx firebase serve --debug.
9. On another terminal, run curl http://localhost:5000/api/v1/hello.

[REQUIRED] Expected behavior

v8.18.0 or prior:

curl command is successful:

$ curl http://localhost:5000/api/v1/hello
Hello World!

Here’s the relevant snippet of debug log from firebase:

[hosting] Cloud Run rewrite {"source":"/api/**","run":{"serviceId":"firebase-serve-bug","region":"us-central1"}} triggered
[hosting] Looking up Cloud Run service "/v1/projects/firebase-serve-bug-301205/locations/us-central1/services/firebase-serve-bug" for its URL
[2021-01-09T07:22:29.608Z] >>> HTTP REQUEST GET https://run.googleapis.com/v1/projects/firebase-serve-bug-301205/locations/us-central1/services/firebase-serve-bug  
 
[2021-01-09T07:22:29.913Z] <<< HTTP RESPONSE 200 {"content-type":"application/json; charset=UTF-8","vary":"X-Origin, Referer, Origin,Accept-Encoding","date":"Sat, 09 Jan 2021 07:22:29 GMT","server":"ESF","cache-control":"private","x-xss-protection":"0","x-frame-options":"SAMEORIGIN","x-content-type-options":"nosniff","alt-svc":"h3-29=\":443\"; ma=2592000,h3-T051=\":443\"; ma=2592000,h3-Q050=\":443\"; ma=2592000,h3-Q046=\":443\"; ma=2592000,h3-Q043=\":443\"; ma=2592000,quic=\":443\"; ma=2592000; v=\"46,43\"","accept-ranges":"none","transfer-encoding":"chunked"}
[hosting] Rewriting /api/v1/hello to https://firebase-serve-bug-jg4ma3c3za-uc.a.run.app for Cloud Run service "firebase-serve-bug" for region "us-central1"
[2021-01-09T07:22:29.916Z] >>> [apiv2][query] GET https://firebase-serve-bug-jg4ma3c3za-uc.a.run.app/api/v1/hello 
[2021-01-09T07:22:31.150Z] <<< [apiv2][status] GET https://firebase-serve-bug-jg4ma3c3za-uc.a.run.app/api/v1/hello 200
[2021-01-09T07:22:31.150Z] <<< [apiv2][body] GET https://firebase-serve-bug-jg4ma3c3za-uc.a.run.app/api/v1/hello [stream]
i  hosting: 127.0.0.1 - - [09/Jan/2021:07:22:31 +0000] "GET /api/v1/hello HTTP/1.1" 200 13 "-" "curl/7.64.1" {"metadata":{"emulator":{"name":"hosting"},"message":"127.0.0.1 - - [09/Jan/2021:07:22:31 +0000] \"GET /api/v1/hello HTTP/1.1\" 200 13 \"-\" \"curl/7.64.1\""}}

[REQUIRED] Actual behavior

curl command failed:

$ curl http://localhost:5000/api/v1/hello
An internal error occurred while proxying for Cloud Run service "firebase-serve-bug" for region "us-central1"

Here’s the relevant snippet of debug log from firebase serve. Note the HTTP 500:

[hosting] Cloud Run rewrite {"source":"/api/**","run":{"serviceId":"firebase-serve-bug","region":"us-central1"}} triggered
[hosting] Looking up Cloud Run service "/v1/projects/firebase-serve-bug-301205/locations/us-central1/services/firebase-serve-bug" for its URL
[2021-01-09T07:20:48.695Z] >>> HTTP REQUEST GET https://run.googleapis.com/v1/projects/firebase-serve-bug-301205/locations/us-central1/services/firebase-serve-bug  
 
[2021-01-09T07:20:49.121Z] <<< HTTP RESPONSE 200 {"content-type":"application/json; charset=UTF-8","vary":"X-Origin, Referer, Origin,Accept-Encoding","date":"Sat, 09 Jan 2021 07:20:49 GMT","server":"ESF","cache-control":"private","x-xss-protection":"0","x-frame-options":"SAMEORIGIN","x-content-type-options":"nosniff","alt-svc":"h3-29=\":443\"; ma=2592000,h3-T051=\":443\"; ma=2592000,h3-Q050=\":443\"; ma=2592000,h3-Q046=\":443\"; ma=2592000,h3-Q043=\":443\"; ma=2592000,quic=\":443\"; ma=2592000; v=\"46,43\"","accept-ranges":"none","transfer-encoding":"chunked"}
[hosting] Rewriting /api/v1/hello to https://firebase-serve-bug-jg4ma3c3za-uc.a.run.app for Cloud Run service "firebase-serve-bug" for region "us-central1"
[2021-01-09T07:20:49.125Z] >>> [apiv2][query] GET https://firebase-serve-bug-jg4ma3c3za-uc.a.run.app/api/v1/hello 
i  hosting: 127.0.0.1 - - [09/Jan/2021:07:20:49 +0000] "GET /api/v1/hello HTTP/1.1" 500 - "-" "curl/7.64.1" {"metadata":{"emulator":{"name":"hosting"},"message":"127.0.0.1 - - [09/Jan/2021:07:20:49 +0000] \"GET /api/v1/hello HTTP/1.1\" 500 - \"-\" \"curl/7.64.1\""}}

[bkendall]

Ahh! I think I figured it out. The proxy is bringing along the host header when making the proxy request (along with x-forwarded-host) which causes an issue when it hits Cloud Run. The fix is trivial, but I’ll see if it breaks anything else in my basic testing first.

[samtstern]

@clarmso thank you for the clear reproduction steps! @bkendall can you take a look?