it’s a new default in Cowboy 2 - can be changed using protocol_options - idle_timeout in the endpoint config

config :hello, HelloWeb.Endpoint,
  http: [ port: 4000, 
             protocol_options: [idle_timeout: 5_000_000] 
        ],...

https://github.com/phoenixframework/phoenix/issues/3190

This worked on my local clone of the linked repository:

$ time curl -v localhost:4001/api/test
*   Trying ::1...
* TCP_NODELAY set
* connect to ::1 port 4001 failed: Connection refused
*   Trying 127.0.0.1...
* TCP_NODELAY set
* Connected to localhost (127.0.0.1) port 4001 (#0)
> GET /api/test HTTP/1.1
> Host: localhost:4001
> User-Agent: curl/7.64.0
> Accept: */*
>
< HTTP/1.1 200 OK
< cache-control: max-age=0, private, must-revalidate
< content-length: 17
< content-type: application/json; charset=utf-8
< date: Wed, 13 Mar 2019 11:45:38 GMT
< server: Cowboy
< x-request-id: 2m5o42cfnvn7nmsujk0000e3
<
* Connection #0 to host localhost left intact
[{"test":"test"}]

The changes I did:

diff --git a/config/dev.exs b/config/dev.exs
index 6e25348..3e4b96d 100644
--- a/config/dev.exs
+++ b/config/dev.exs
@@ -7,7 +7,7 @@ use Mix.Config
 # watchers to your application. For example, we use it
 # with webpack to recompile .js and .css sources.
 config :demo, DemoWeb.Endpoint,
-  http: [port: 4001],
+  http: [port: 4001, protocol_options: [idle_timeout: 70_000]],
   debug_errors: true,
   code_reloader: true,
   check_origin: false,

yep, :infinity also works..

[idle_timeout: :infinity]

this issue also popped up here Video streaming connection closed automatically - one could argue for phoenix having :infinity as a default.. on the other hand 60 secs is a “sane” default..

would say there might be a need for an explicit config showing 60_000 as the configured.. the hidden default kinda falls into the implicit category - that I’m not a fan of..