Running Nuxt.js in Docker Container build by Paketo.io / Cloud Native Buildpacks

Question

I want to Containerize my Nuxt.js application. I could write my own Dockerfile (as mentioned in the Nuxt.js Google Cloud Run docs for example), but as Cloud Native Buildpacks are here to free us from the need to write those over and over again I wanted to simply use Paketo.io to build a Container from my Nuxt.js app.

I ran

pack build microservice-ui-nuxt-js --path . --builder paketobuildpacks/builder:base

and a Container was created successfully. Here's the full log:

$ pack build microservice-ui-nuxt-js --path . --builder paketobuildpacks/builder:base
base: Pulling from paketobuildpacks/builder
Digest: sha256:3e2ee17348bd901e7e0748e0e1ddccdf8a602b624e418927145b5f84ca26f264
Status: Image is up to date for paketobuildpacks/builder:base
base-cnb: Pulling from paketobuildpacks/run
Digest: sha256:b6b1612ab2dfa294514fff2750e8d724287f81e89d5e91209dbdd562ed7f7daf
Status: Image is up to date for paketobuildpacks/run:base-cnb
===> DETECTING
4 of 7 buildpacks participating
paketo-buildpacks/ca-certificates 2.2.0
paketo-buildpacks/node-engine     0.4.0
paketo-buildpacks/npm-install     0.3.0
paketo-buildpacks/npm-start       0.2.0
===> ANALYZING
Previous image with name "microservice-ui-nuxt-js" not found
===> RESTORING
===> BUILDING

Paketo CA Certificates Buildpack 2.2.0
  https://github.com/paketo-buildpacks/ca-certificates
  Launch Helper: Contributing to layer
    Creating /layers/paketo-buildpacks_ca-certificates/helper/exec.d/ca-certificates-helper
Paketo Node Engine Buildpack 0.4.0
  Resolving Node Engine version
    Candidate version sources (in priority order):
                -> ""
      <unknown> -> ""

    Selected Node Engine version (using ): 14.17.0

  Executing build process
    Installing Node Engine 14.17.0
      Completed in 5.795s

  Configuring build environment
    NODE_ENV     -> "production"
    NODE_HOME    -> "/layers/paketo-buildpacks_node-engine/node"
    NODE_VERBOSE -> "false"

  Configuring launch environment
    NODE_ENV     -> "production"
    NODE_HOME    -> "/layers/paketo-buildpacks_node-engine/node"
    NODE_VERBOSE -> "false"

    Writing profile.d/0_memory_available.sh
      Calculates available memory based on container limits at launch time.
      Made available in the MEMORY_AVAILABLE environment variable.

Paketo NPM Install Buildpack 0.3.0
  Resolving installation process
    Process inputs:
      node_modules      -> "Not found"
      npm-cache         -> "Not found"
      package-lock.json -> "Found"

    Selected NPM build process: 'npm ci'

  Executing build process
    Running 'npm ci --unsafe-perm --cache /layers/paketo-buildpacks_npm-install/npm-cache'
      Completed in 14.988s

  Configuring launch environment
    NPM_CONFIG_LOGLEVEL -> "error"

  Configuring environment shared by build and launch
    PATH -> "$PATH:/layers/paketo-buildpacks_npm-install/modules/node_modules/.bin"


Paketo NPM Start Buildpack 0.2.0
  Assigning launch processes
    web: nuxt start

===> EXPORTING
Adding layer 'paketo-buildpacks/ca-certificates:helper'
Adding layer 'paketo-buildpacks/node-engine:node'
Adding layer 'paketo-buildpacks/npm-install:modules'
Adding layer 'paketo-buildpacks/npm-install:npm-cache'
Adding 1/1 app layer(s)
Adding layer 'launcher'
Adding layer 'config'
Adding layer 'process-types'
Adding label 'io.buildpacks.lifecycle.metadata'
Adding label 'io.buildpacks.build.metadata'
Adding label 'io.buildpacks.project.metadata'
Setting default process type 'web'
Saving microservice-ui-nuxt-js...
*** Images (5eb36ba20094):
      microservice-ui-nuxt-js
Adding cache layer 'paketo-buildpacks/node-engine:node'
Adding cache layer 'paketo-buildpacks/npm-install:modules'
Adding cache layer 'paketo-buildpacks/npm-install:npm-cache'
Successfully built image microservice-ui-nuxt-js

Now running

docker run --rm -i --tty -p 3000:3000 microservice-ui-nuxt-js

i hoped to see my app inside the Browser at http://localhost:3000. But no luck! My app doesn't seem to be fully running:

Although my console looks good:

What am I missing?

Answer 1

I read about the HOST variable in this post , which the whole problem is about! And then I also found this answer, since I now knew what to look for. The Nuxt.js configuration docs state it also:

By default, the Nuxt.js development server host is localhost which is only accessible from within the host machine. In order to view your app on another device you need to modify the host.

And the crucial config is mentioned also:

Host '0.0.0.0' is designated to tell Nuxt.js to resolve a host address, which is accessible to connections outside of the host machine (e.g. LAN)

So all we have to do is to define a Docker environment variable --env "HOST=0.0.0.0" and run the Paketo build Container like this:

docker run --rm -i --tty --env "HOST=0.0.0.0" -p 3000:3000 microservice-ui-nuxt-js

Now the Browser should also show our app at http://localhost:3000:

You can try it yourself using the GitHub Container Registry published image of the example project:

docker run --rm -i --tty --env "HOST=0.0.0.0" -p 3000:3000 ghcr.io/jonashackt/microservice-ui-nuxt-js:latest