Dokku: Rails 5.1 and yarn - how to add support ? (Yarn executable was not detected in the system)

[kjakub]

-----> Preparing app for Rails asset pipeline
Running: rake assets:precompile
Yarn executable was not detected in the system.
Download Yarn at https://yarnpkg.com/en/docs/install

-----> uname: Linux ubuntu-512mb-sgp1-01 4.4.0-78-generic #99-Ubuntu SMP Thu Apr 27 15:29:09 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux
-----> memory:
total used free shared buff/cache available
Mem: 992 105 87 16 799 688
Swap: 0 0 0
-----> docker version:
Client:
Version: 17.05.0-ce
API version: 1.29
Go version: go1.7.5
Git commit: 89658be
Built: Thu May 4 22:10:54 2017
OS/Arch: linux/amd64

Server:
Version: 17.05.0-ce
API version: 1.29 (minimum version 1.12)
Go version: go1.7.5
Git commit: 89658be
Built: Thu May 4 22:10:54 2017
OS/Arch: linux/amd64
Experimental: false
-----> docker daemon info:
Containers: 8
Running: 1
Paused: 0
Stopped: 7
Images: 22
Server Version: 17.05.0-ce
Storage Driver: aufs
Root Dir: /var/lib/docker/aufs
Backing Filesystem: extfs
Dirs: 60
Dirperm1 Supported: true
Logging Driver: json-file
Cgroup Driver: cgroupfs
Plugins:
Volume: local
Network: bridge host macvlan null overlay
Swarm: inactive
Runtimes: runc
Default Runtime: runc
Init Binary: docker-init
containerd version: 9048e5e50717ea4497b757314bad98ea3763c145
runc version: 9c2d8d184e5da67c95d601382adf14862e4f2228
init version: 949e6fa
Security Options:
apparmor
seccomp
Profile: default
Kernel Version: 4.4.0-78-generic
Operating System: Ubuntu 16.04.2 LTS
OSType: linux
Architecture: x86_64
CPUs: 1
Total Memory: 992.3MiB
Name: ubuntu-512mb-sgp1-01
ID: DQQN:NBAN:XH3S:IQUI:K3NM:OKBQ:Y6X7:I3JN:WQWV:NYB2:NB7E:VSMP
Docker Root Dir: /var/lib/docker
Debug Mode (client): true
Debug Mode (server): false
Registry: https://index.docker.io/v1/
Experimental: false
Insecure Registries:
127.0.0.0/8
Live Restore Enabled: false

WARNING: No swap limit support
-----> sigil version: 0.4.0
-----> herokuish version:
herokuish: 0.3.29
buildpacks:
heroku-buildpack-multi v1.0.0
heroku-buildpack-ruby v159
heroku-buildpack-nodejs v99
heroku-buildpack-clojure v76
heroku-buildpack-python v99
heroku-buildpack-java v51
heroku-buildpack-gradle v21
heroku-buildpack-grails v21
heroku-buildpack-scala v76
heroku-buildpack-play v26
heroku-buildpack-php v121
heroku-buildpack-go v64
heroku-buildpack-erlang fa17af9
buildpack-nginx v8
-----> dokku version: 0.9.4
-----> dokku plugins:
! Deprecated: Please use plugin:list
plugn: 0.3.0
00_dokku-standard 0.9.4 enabled dokku core standard plugin
20_events 0.9.4 enabled dokku core events logging plugin
apps 0.9.4 enabled dokku core apps plugin
build-env 0.9.4 enabled dokku core build-env plugin
certs 0.9.4 enabled dokku core certificate management plugin
checks 0.9.4 enabled dokku core checks plugin
common 0.9.4 enabled dokku core common plugin
config 0.9.4 enabled dokku core config plugin
docker-options 0.9.4 enabled dokku core docker-options plugin
domains 0.9.4 enabled dokku core domains plugin
enter 0.9.4 enabled dokku core enter plugin
git 0.9.4 enabled dokku core git plugin
logs 0.9.4 enabled dokku core logs plugin
named-containers 0.9.4 enabled dokku core named containers plugin
nginx-vhosts 0.9.4 enabled dokku core nginx-vhosts plugin
plugin 0.9.4 enabled dokku core plugin plugin
postgres 1.0.0 enabled dokku postgres service plugin
proxy 0.9.4 enabled dokku core proxy plugin
ps 0.9.4 enabled dokku core ps plugin
repo 0.9.4 enabled dokku core repo plugin
shell 0.9.4 enabled dokku core shell plugin
ssh-keys 0.9.4 enabled dokku core ssh-keys plugin
storage 0.9.4 enabled dokku core storage plugin
tags 0.9.4 enabled dokku core tags plugin
tar 0.9.4 enabled dokku core tar plugin

[joshmanders]

You need to use multipack's with Ruby/Rails and NodeJS buildpacks.

http://dokku.viewdocs.io/dokku/deployment/methods/buildpacks/#using-multiple-buildpacks

[kjakub]

@joshmanders thanks! also i needed webpacker gem

[andyklimczak]

also needed to add:

  "engines": {
    "yarn": "1.7.0"
  },

to my rail's package.json file for the buildpack to prefer yarn over npm. change the yarn version to whatever you're using locally (yarn -v)