Error "PC01 instance refused connection" on port 3000 when using port 8080

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1

Hi,

I’m using LiteFS proxy, and I see a lot of error [PC01] instance refused connection. is your app listening on 0.0.0.0:3000? make sure it is not only listening on 127.0.0.1 (hint: look at your startup logs, servers often print the address they are listening on) on my app.

When launching my app, I can see that it’s starting on the right port ([remix-serve] http://localhost:8081)

In my litefs.yml file, I have the following values:

proxy:
  # matches the internal_port in fly.toml
  addr: ':8080'
  target: 'localhost:8081'
  db: '${DATABASE_FILENAME}'

What is this error and where does the 3000 come from?

2

Hi… This would be the internal_port, in fly.toml.

You can get a little more context in the following two recent forum threads:

(Note that the second is not precisely your own situation, but the overall debugging steps, etc., are related.)

LiteFS is a niche database with still a few rough edges, particularly with regard to fly launch auto-configuration.

Basically, you have to roll up your sleeves a fair amount initially…

3

Thank you for your answer! I had a look at those posts before posting, unfortunately, it didn’t help.

In my fly.toml file, I have those for service:

[[services]]
  internal_port = 8080
  processes = [ "app" ]
  protocol = "tcp"
  script_checks = [ ]

which match why I have in litefs.yml:

proxy:
  # matches the internal_port in fly.toml
  addr: ':8080'
  target: 'localhost:8081'
  db: '${DATABASE_FILENAME}'

I’m not sure what’s happening, because I can still access my app, but maybe it’s bypassing the proxy?

By running the command on the second post on the machine, I have the following:

Screenshot-202408-24 at 21.39.20
Screenshot-202408-24 at 21.39.201826×102 11.5 KB

4

Odd… It shouldn’t be possible to bypass the Fly edge proxy, since that’s how requests to app-name.fly.dev reach your Machine in the first place.

The ss output looks correct, as well.

Do the machine IDs in the log match the ones shown in fly m list?

Also, the Fly.io platform as a whole sometimes gets confused by redundant [[services]]/[http_service] blocks. Perhaps you could post your full fly.toml file?

(Feel free to * out any sensitive names.)

5

I changed my app port to 3000 (while keeping 8080 for internal_process) and the error PC01 is no longer present in my logs

here my full fly.toml file

app = '*'
primary_region = 'cdg'
kill_signal = 'SIGINT'
kill_timeout = 5
swap_size_mb = 512

[experimental]
auto_rollback = true

[mounts]
source = 'data'
destination = '/data'

[[services]]
  internal_port = 8080
  processes = [ "app" ]
  protocol = "tcp"
  script_checks = [ ]

  [services.concurrency]
  hard_limit = 100
  soft_limit = 80
  type = "requests"

  [[services.ports]]
  handlers = [ "http" ]
  port = 80
  force_https = true

  [[services.ports]]
  handlers = [ "tls", "http" ]
  port = 443

  [[services.tcp_checks]]
  grace_period = "1s"
  interval = "15s"
  restart_limit = 0
  timeout = "2s"

  [[services.http_checks]]
  interval = "10s"
  grace_period = "5s"
  method = "get"
  path = "/healthcheck"
  protocol = "http"
  timeout = "2s"
  tls_skip_verify = false
  headers = { }
  [[services.http_checks]]
  grace_period = "10s"
  interval = "30s"
  method = "GET"
  timeout = "5s"
  path = "/litefs/health"

[[vm]]
  memory = '512mb'
  cpu_kind = 'shared'
  cpus = 1