Environment variable NODE_ENV being ignored?

Questions / Help
1

So I am trying to deploy an Node.js + express web app to Fly.io. The website works correctly, but I just realized it never detects the NODE_ENV variable, even if I added it to the fly.toml file:

This is the output after running $ flyctl deploy

[Installing Node.js distribution]
Reusing Node.js 18.9.1
[INFO] Installing toolbox
[INFO] Using npm v8.19.1 from Node
[INFO] Reusing node modules

[Warning: Skip pruning because NODE_ENV is not 'production'.]

And you can see how in the file it is set:

$ cat fly.toml 
# fly.toml file generated for myaccount on 2022-09-25T18:29:52+02:00

app = "myaccount-app"
kill_signal = "SIGINT"
kill_timeout = 5
processes = []

[build]
  builder = "heroku/buildpacks:20"

[env]
  NODE_ENV = "production"
  PORT = "8080"

# Some other stuff here

Could anyone tell me what am I doing wrong?
Thanks!

2

Try checking what flyctl logs is responding back with and also check Fly.io Docs: env you might need to place some sensitive information with Fly.io Docs: secrets which should allow your app to detect what’s missing.

3

There’s nothing in the logs, and I have some other env variables set in fly.toml that are correctly set within my app.

4

Secrets and env vars aren’t automatically injected into the Docker builder during deployment (I know, that’s a “fun” fact), so you need to use some combination of the following to get those into the Docker builder.

fly deploy \
    --build-args="foo=bar" \
    --build-secrets="bar=baz" \
    -e "foo=bar"

Secrets in particular require a bit of extra work to use in your Dockerfile : Build Secrets · Fly Docs

1 Like
5

Fly’s more strict with secrets (a good thing!), but if folks could set secrets for remote builders, then that should work-out nicely afa devex is concerned?

That is, imagine if fly secrets set k1=v1 k2=v2 -a <free-builder-name> set approp env vars for remote deploys?

fly env set k1=v1 k2=v2 -a <free-builder-name> would also be neat.

6

Thanks for the info! I am not an expert with deploying websites and DevOps in general. In this case then, the problem is that the docker builder is not detecting this variable, so I should inject it in the deployment with the call:
flyctl deploy --build-args="NODE_ENV=production"
Is this correct?
Thanks

7

Yes, mostly!

I’m not exactly sure how the buildpack operates (vs using a Dockerfile), I would experiment with:

fly deploy -e "NODE_ENV=production"

The --build-args flag likely requires a Dockerfile with an ARG defined in it.

8

I see… I have tried with:

flyctl deploy -e "NODE_ENV=production"
flyctl deploy -e NODE_ENV="production"
flyctl deploy -e NODE_ENV=production

So finally I tried with:

flyctl deploy --build-arg NODE_ENV=production

And it did work (I think), I see some other warnings now, like:

[INFO] Installing node modules from ./package-lock.json
npm WARN config production Use `--omit=dev` instead.

But it looks like now it is pruning the dev dependencies, so I expect NODE_ENV to be production.

[INFO] Successfully pruned devdependencies!

Thank you.

EDIT: Also, a [build.args] section can be added to the fly.toml file to not have to add the variable every time manually.

1 Like
9

Another way is, to set it with the ENV directive of the Dockerfile.