Private networking with Railway generated ports

ciaranevansTRIAL

a year ago

Hey Folks,

Sorry if crossposting this is a big no-no, figured maybe Discord is easier for conversational things.

I raised https://community.railway.app/discuss/thread/how-do-i-use-private-networking-with-rai-65fa14c1 but TL;DR: How do I use private networking (internal hostnames) when I let Railway assign ports?

0 Replies

ciaranevansTRIAL

a year ago

cb5aa03d-c72c-426c-8dd7-f109b7f03b5d


a year ago

there's a wonderful guide here

but yes it's good your apps are listening on the automatically assigned PORT variable, so that means getting your apps to listen on a static port for use with the private network is as simple as setting a PORT service variable


ciaranevansTRIAL

a year ago

Yeah, found the guide, guessed it was the case that I would have to define a port instead 😄 No worries.


a year ago

what kind of frontend is this?


ciaranevansTRIAL

a year ago

Sveltekit


a year ago

server side rendered?


ciaranevansTRIAL

a year ago

🤷‍♂️ I'm a frontend noob, much more comfortable kneedeep in AWS infra and Python 😄


ciaranevansTRIAL

a year ago

I manage a bunch of Svelte devs so figured I should learn it a bit haha


a year ago

will the calls to the backend be made from the server side of your frontend app?


ciaranevansTRIAL

a year ago

Yes, it already is, you can't see the requests in devtools for example


a year ago

perfect then you will want a service variable on the frontend service like this

BACKEND_URL=http://${{.RAILWAY_PRIVATE_DOMAIN}}:${{.PORT}}

then use that variable in your frontend's code when you make the fetch call


ciaranevansTRIAL

a year ago

Ohlala.

Don't suppose there's a page with all these magic env vars?


a year ago

oh yes my bad


ciaranevansTRIAL

a year ago

Sweet. That snippet you sent would be super useful on the Private Networking guide, makes much more sense now 😄


ciaranevansTRIAL

a year ago

Annoyingly I don't seem to have the Solution App available


a year ago

I shall make that happen


ciaranevansTRIAL

a year ago

I have another question on the community page, feel bad duplicating it here also 🥲 Buuuuut if you're around 👀


a year ago

solution app?


ciaranevansTRIAL

a year ago

1193298341082189800


ciaranevansTRIAL

a year ago

1193298427317072000


a year ago

I turned that off because I had too many people marking the complete wrong message as the answer


ciaranevansTRIAL

a year ago

Ah 😛


a year ago

but I haven't turned off the message lol


ciaranevansTRIAL

a year ago

No worries haha


a year ago

I'll be honest I'm happy you posted here too, and I'd prefer you do, because as you said discord is easier for conversational things.

the forums is lacking a conversational aspect and that's why I don't like using them, but the cheerleader for the forums knows that too!


ciaranevansTRIAL

a year ago

Righto. I'll make a dupe here then 😅


a year ago

sounds good!


ciaranevansTRIAL

a year ago

Back on this one 😅 So I put:

BACKEND_URL=http://${{backend.RAILWAY_PRIVATE_DOMAIN}}:${{backend.PORT}}

This resolves but if I put Https or http, it fails to connect, the more concerning part is the PORT resolves to not what the backend service is actually listening on:

errno: -111,

code: 'ECONNREFUSED',

syscall: 'connect',

address: 'fd12:2030:e370::8f:bc37:5946',

Backend logs:

[INFO] Running on http://[::]:6642

Am I using the right variables?


ciaranevansTRIAL

a year ago

Hmmm okay, in the dashboard it resolves ${{backend.RAILWAY_PRIVATE_DOMAIN}} as backend.railway.internal however when that's injected into my service, it's actually the ipv6 address.


ciaranevansTRIAL

a year ago

If I then use [] for fetch like recommended for ipv6 addresses, it resolves to:

1193466052940673000


ciaranevansTRIAL

a year ago

Safe to say I'm scuppered 😛


ciaranevansTRIAL

a year ago

BACKEND_URL=http://[${{backend.RAILWAY_PRIVATE_DOMAIN}}]:${{backend.PORT}}

This is what I have right now, Railway setup the port for backend, so I assume I'll be able to access that value.

This resolves to 'http://[backend.railway.internal]:'

If I remove the [] from my ENV (Even though that's not what I should do), it resolves to the actual ipv6 address.

Either way I do it, PORT Is empty anyway 🥲


ciaranevansTRIAL

a year ago

Okay, so a little progress:

BACKEND_URL=http://${{backend.RAILWAY_PRIVATE_DOMAIN}}:6642

If I hardcode the port to what I see in my backends logs (from the port Railway generated), I get a connection

So I guess the real question is - How the heck do I get that port without log diving 😄


ciaranevansTRIAL

a year ago

(I'd rather not pin it as it just another bit of config to remember)


a year ago

pinning the port by setting a PORT service variable is perfectly fine as long as your app is still listening on the PORT environment variable, and that's exactly what you need to do to get that reference variable to render correctly.

it's also absolutely necessary because without pinning the port, railway will assign a random port (via the PORT environment variable) on every deployment that it expects your app to listen on, you can't reference this magic variable and even of you could it would just makes things worse because its random

also I have never seen the square brackets be necessary, so try not using the brackets


ciaranevansTRIAL

a year ago

Yeah, it's just strange that if I set the value, I can refer to it, but if Railway does, I can't 😂

Alright, I shall just pin it!


ciaranevansTRIAL

a year ago

Is that something I can define in railway.json? Or dashboard only?


a year ago

yeah I get ya, but it's a good thing you can't reference the automatically generated PORT, as the value would become stale very quickly anyway, it's random and only available to the deployment at runtime.

has to be defined as a service variable in the dashboard


ciaranevansTRIAL

a year ago

Yeah that's fair enough, just somewhat invalidates the 'magic' 😂


ciaranevansTRIAL

a year ago

Anyway, I'll switch to that, thanks once again Brody! You the MVP


a year ago

its now in the docs!


fcms14PRO

a year ago

Hi folks,

I'm having trouble using private networks
I read all the content above, including the links, followed the tutorial in the last link sent above, but I was unsuccessful.

I have two backend services running on railway, where currently one communicates with the other via the public network.

I would like to leave this second service with the public route disabled, and use the private network to communicate with it.

The two services have the same project name and environment, as I understood from the document above.
The service that will receive requests via the private route is configured to listen on IPv6.

I tested calling the url numerous times using ###.railway.internal and port, but it always returns "getaddrinfo ENOTFOUND"

I don't know what else I can try, does anyone suggest anything?

Both projects are in nestJs with typescript.


a year ago

nixpacks or dockerfile based deployments?


fcms14PRO

a year ago

Nixpacks


a year ago

at what point in your apps lifecycle are you trying to call the other service?


fcms14PRO

a year ago

The first service, with public routes, is an API gateway that, depending on the requested route, makes a call to this second service.
This call I would like to make via private route internally.


a year ago

does your service make a call to the other service within the first 3 seconds of itself starting?


fcms14PRO

a year ago

no, never


a year ago

screenshot of your project please


fcms14PRO

a year ago

what do you want i screen shot exactly?


a year ago

of your railway project


fcms14PRO

a year ago

the second service

1227330303299944400


a year ago

where is the other service


fcms14PRO

a year ago

the first, that uses the second

1227330479322038300


a year ago

these are separate projects


fcms14PRO

a year ago

they are different reppositories


fcms14PRO

a year ago

is there any how deploy toggether?


fcms14PRO

a year ago

ok, i got it


fcms14PRO

a year ago

i just saw the "new" button


a year ago

you can't communicate to services in different projects


fcms14PRO

a year ago

1227331037856796700


a year ago

wouldn't be very private if you could


fcms14PRO

a year ago

yeah, i undertand it
i thought as i set the project name as the same, it would work as one


a year ago

gotcha


fcms14PRO

a year ago

i use railway for almost 2 years the wrong way 🥲
I'd never seen that "new" button


fcms14PRO

a year ago

i have a lot to do now.. re-managing the services of my projects


a year ago

yeah you aren't the first


a year ago

and until railway stops allowing users to deploy services from the dashboard, you will not be the last


fcms14PRO

a year ago

now it makes more sense why it has to be in the same project AND enviroment


a year ago

indeed


fcms14PRO

a year ago

thank you
its already working


a year ago

awesome


espectrosoftHOBBY

8 months ago

Hello @Brody , I have a question

I want my front to connect to my backend using Private Network, but I haven't been able to do it… I checked this post but nothing helps… any ideas?

I have this as follows:

1289309371792101600


espectrosoftHOBBY

8 months ago

And my code is this:

export const getStrapiURL = () => {

    if (process.env.NODE_ENV === 'production') {
        return 'https://espectrosoft-backend.railway.internal'
    }

    if (process.env.NODE_ENV === 'development') {
        return 'http://localhost:1337';
    }
}

8 months ago

a client side rendered frontend app can not use the internal domain of the backend, you need to use the public domain.

it wouldnt be a very private network if anyone's browser could make requests to it.


espectrosoftHOBBY

8 months ago

I'm not exactly using client side, I'm doing it with Nextjs and I make these requests using server side


8 months ago

please read this then -


espectrosoftHOBBY

8 months ago

I tried to do that but in my variables I can't find the port


8 months ago

you need to set it then


espectrosoftHOBBY

8 months ago

1289311163829719000


espectrosoftHOBBY

8 months ago

And it can be any port or is there any guide regarding that?


8 months ago

8080 is a good port


8 months ago

make sure your app is listening on the $PORT environment variable too


espectrosoftHOBBY

8 months ago

Got it, I'll try it