Proxy error: Connection refused

[ledermann]

Since a few days all my applications that use puma-dev don't work any more because of this error:

http: proxy error: dial tcp 127.0.0.1:3035: connect: connection refused

I'm using Ruby on Rails and webpack-dev-server with the proxy support, so there is webpack.myapp.test. Accessing https://myapp.test works fine, but https://webpack.myapp.test fails.

From my ~/Library/Logs/puma-dev.log:

Booting app 'myapp-6046cd89' on socket /Users/ledermann/.puma-dev/myapp/tmp/puma-dev-8692.sock
myapp-6046cd89[9306]: Puma starting in single mode...
myapp-6046cd89[9306]: * Puma version: 5.5.2 (ruby 3.0.2-p107) ("Zawgyi")
myapp-6046cd89[9306]: *  Min threads: 0
myapp-6046cd89[9306]: *  Max threads: 5
myapp-6046cd89[9306]: *  Environment: development
myapp-6046cd89[9306]: *          PID: 9306
myapp-6046cd89[9306]: * Listening on unix:/Users/ledermann/.puma-dev/myapp/tmp/puma-dev-8692.sock
myapp-6046cd89[9306]: Use Ctrl-C to stop
! App 'myapp-6046cd89' booted
* Generated proxy connection for 'webpack.myapp' to http://127.0.0.1:3035
2021/10/26 07:42:26 http: proxy error: dial tcp 127.0.0.1:3035: connect: connection refused
2021/10/26 07:42:26 http: proxy error: dial tcp 127.0.0.1:3035: connect: connection refused
2021/10/26 07:42:26 http: proxy error: dial tcp 127.0.0.1:3035: connect: connection refused

It seems that 127.0.0.1:3035 does not work:

~  > curl -I http://127.0.0.1:3035/packs/runtime-656c7133b991c29ebdeb.js
curl: (7) Failed to connect to 127.0.0.1 port 3035: Connection refused

But when I change 127.0.0.1 to localhost, then the response is fine:

~  > curl -I http://localhost:3035/packs/runtime-656c7133b991c29ebdeb.js
HTTP/1.1 200 OK
X-Powered-By: Express
Access-Control-Allow-Origin: *
Content-Type: application/javascript; charset=utf-8
Accept-Ranges: bytes
Content-Length: 48565
ETag: W/"bdb5-hdxeShi+obi11mpsudBc4H7L02E"
Vary: Accept-Encoding
Date: Tue, 26 Oct 2021 05:44:18 GMT
Connection: keep-alive
Keep-Alive: timeout=5

It seems there is something broken with 127.0.0.1 on my machine. Are there any hints what I can do? I of course I have uninstalled and reinstalled puma-dev, rebooted the machine and disabled the firewall, but this didn't help.

More about my config:

~  > puma-dev -V
Version: 0.16.2 (go1.16.6)

~  > sw_vers
ProductName:	macOS
ProductVersion:	11.6
BuildVersion:	20G165

~  > nc -zv localhost 9253
nc: connectx to localhost port 9253 (tcp) failed: Connection refused
Connection to localhost port 9253 [tcp/*] succeeded!
~  > nc -zv 127.0.0.1 9253
Connection to 127.0.0.1 port 9253 [tcp/*] succeeded!

~  > ls -l /etc/resolver
total 8
-rw-r--r--  1 ledermann  staff  55 26 Okt 08:06 test

~  > cat /etc/resolver/test
# Generated by puma-dev
nameserver 127.0.0.1
port 9253

~  > ps ax|grep puma
12803   ??  S      0:00.05 /usr/local/bin/puma-dev -launchd -dir ~/.puma-dev -d test -timeout 15m0s -no-serve-public-paths
12839 s003  S+     0:00.01 puma-dev
13363 s004  R+     0:00.00 grep puma

~  > cat ~/.puma-dev/webpack.myapp
3035

[ledermann]

After upgrading my machine from macOS 11.6 to 11.6.1 (and the necessary reboot) the problem has gone. Strange.

~  > ps ax|grep puma
 1486   ??  S      0:00.83 /usr/local/bin/puma-dev -launchd -dir ~/.puma-dev -d test -timeout 15m0s -no-serve-public-paths
10638 s003  S+     0:00.00 grep puma

It seems there was an additional puma-dev process running, which is not there anymore. Don't know why this survived multiple reboots before. (wrong assumption)

Because it's all fine now, I close this issue.

[ledermann]

The problem is back :-( Rebooting helps, but after some time (minutes), accessing the proxy on port 3035 is not possible anymore. This means:

~/Projects/myapp > curl -I https://myapp.test
HTTP/1.1 200 OK
...
Date: Sun, 31 Oct 2021 10:04:06 GMT

~/Projects/myapp > curl -I https://webpack.myapp.test
HTTP/1.1 500 Internal Server Error
Date: Sun, 31 Oct 2021 10:04:11 GMT

The netcat output is:

~/Projects/myapp > nc -zv localhost 9253
nc: connectx to localhost port 9253 (tcp) failed: Connection refused
Connection to localhost port 9253 [tcp/*] succeeded!

~/Projects/myapp > nc -zv 127.0.0.1 9253
Connection to 127.0.0.1 port 9253 [tcp/*] succeeded!

From the puma-dev logs:

~/Projects/myapp > tail -f ~/Library/Logs/puma-dev.log
myapp-50b9e92c[22599]: *  Environment: development
myapp-50b9e92c[22599]: *          PID: 22599
myapp-50b9e92c[22599]: * Listening on unix:/Users/ledermann/.puma-dev/myapp/tmp/puma-dev-1102.sock
myapp-50b9e92c[22599]: Use Ctrl-C to stop
! App 'myapp-50b9e92c' booted
* Generated proxy connection for 'webpack.myapp' to http://127.0.0.1:3035
2021/10/31 11:03:22 http: proxy error: dial tcp 127.0.0.1:3035: connect: connection refused

Any tips on how I can fix the problem?

[nonrational]

This is a stab in the dark, but have you tried binding your webpack dev server to 0.0.0.0 ?

[ledermann]

@nonrational Yes, that works - as does 127.0.0.1, which I tried in the meantime.

I wonder why localhost fails, but 127.0.0.1 works. In the webpacker gem the default is localhost, so I prefer to use this instead of a workaround.

BTW: I tried the issue on a second Mac, which behaves the same: Since a few days, localhost fails (which has been worked for years), but 127.0.0.1 works.

[nonrational]

Can you post the output of dscacheutil -q host -a name localhost, scutil --dns, and confirm that 127.0.0.1 has an entry in /etc/hosts?

[ledermann]

Ok, here we go:

~  > dscacheutil -q host -a name localhost
name: localhost
ipv6_address: ::1

name: localhost
ip_address: 127.0.0.1

~  > scutil --dns
DNS configuration

resolver #1
  nameserver[0] : 10.0.1.1
  if_index : 5 (en1)
  flags    : Request A records
  reach    : 0x00020002 (Reachable,Directly Reachable Address)

resolver #2
  domain   : local
  options  : mdns
  timeout  : 5
  flags    : Request A records
  reach    : 0x00000000 (Not Reachable)
  order    : 300000

resolver #3
  domain   : 254.169.in-addr.arpa
  options  : mdns
  timeout  : 5
  flags    : Request A records
  reach    : 0x00000000 (Not Reachable)
  order    : 300200

resolver #4
  domain   : 8.e.f.ip6.arpa
  options  : mdns
  timeout  : 5
  flags    : Request A records
  reach    : 0x00000000 (Not Reachable)
  order    : 300400

resolver #5
  domain   : 9.e.f.ip6.arpa
  options  : mdns
  timeout  : 5
  flags    : Request A records
  reach    : 0x00000000 (Not Reachable)
  order    : 300600

resolver #6
  domain   : a.e.f.ip6.arpa
  options  : mdns
  timeout  : 5
  flags    : Request A records
  reach    : 0x00000000 (Not Reachable)
  order    : 300800

resolver #7
  domain   : b.e.f.ip6.arpa
  options  : mdns
  timeout  : 5
  flags    : Request A records
  reach    : 0x00000000 (Not Reachable)
  order    : 301000

resolver #8
  domain   : test
  nameserver[0] : 127.0.0.1
  port     : 9253
  flags    : Request A records, Request AAAA records
  reach    : 0x00030002 (Reachable,Local Address,Directly Reachable Address)

DNS configuration (for scoped queries)

resolver #1
  nameserver[0] : 10.0.1.1
  if_index : 5 (en1)
  flags    : Scoped, Request A records
  reach    : 0x00020002 (Reachable,Directly Reachable Address)

~  > cat /etc/hosts
##
# Host Database
#
# localhost is used to configure the loopback interface
# when the system is booting.  Do not change this entry.
##
127.0.0.1	localhost minio.test
255.255.255.255	broadcasthost
::1             localhost

# Added by Docker Desktop
# To allow the same kube context to work on the host and the container:
127.0.0.1 kubernetes.docker.internal
# End of section

[mrhead]

I'm experiencing the same issue. I solved it by writing http://localhost:3035 to ~/.puma/webpack-dev-server.memberful AND rebooting the computer. Changing the file content (and restarting puma-dev) without rebooting did not help. Also, rebooting without updating the file did not help either.

I used just the port in ~/.puma/webpack-dev-server.memberful for a long time, but it suddenly stopped working. I'm not sure when. Probably after puma-dev update.