I'm setting up a continuous deployment process with CircleCI, targeting Google Container Engine. I'm following this documentation, alongside this example.

I'm stucked at this stage:

test:
  post:
    - docker run -d -p 3000:3000 -e "SECRET_KEY_BASE=${SECRET_KEY}" eu.gcr.io/${PROJECT_NAME}/${MAIN_CONTAINER_NAME}:latest; sleep 10
    - curl --retry 10 --retry-delay 5 -v http://localhost:3000

This is a simple test, verifying that my docker image is able to answer to an http request. I get this result after the curl:

* Rebuilt URL to: http://localhost:3000/
* Hostname was NOT found in DNS cache
*   Trying 127.0.0.1...
* connect to 127.0.0.1 port 3000 failed: Connection refused
* Failed to connect to localhost port 3000: Connection refused
* Closing connection 0
curl: (7) Failed to connect to localhost port 3000: Connection refused

curl --retry 10 --retry-delay 5 -v http://localhost:3000 returned exit code 7

The same command works if i'm trying it in my local shell. I get this result locally:

* Rebuilt URL to: http://localhost:3000/
*   Trying ::1...
* TCP_NODELAY set
* Connected to localhost (::1) port 3000 (#0)
> GET / HTTP/1.1
> Host: localhost:3000
> User-Agent: curl/7.51.0
> Accept: */*
>
* Curl_http_done: called premature == 0
* Empty reply from server
* Connection #0 to host localhost left intact
curl: (52) Empty reply from server

I don't get the reason of this difference.