ERROR: unsatisfiable constraints

[grichardomi]

docker build -t my_app . gives off this error. any idea?

• apk add --no-cache --virtual .app-builddeps nodejs=6.2.0-r0
  fetch http://dl-cdn.alpinelinux.org/alpine/v3.4/main/x86_64/APKINDEX.tar.gz
  fetch http://dl-cdn.alpinelinux.org/alpine/v3.4/community/x86_64/APKINDEX.tar.gz
  ERROR: unsatisfiable constraints:
  .app-builddeps-0:
  masked in: cache
  satisfies: world[.app-builddeps]
  The command '/bin/sh -c set -ex && apk add --no-cache --virtual .app-builddeps nodejs=6.2.0-r0 && mkdir -p /usr/src/app/tmp/cache && mkdir -p /usr/src/app/tmp/pids && mkdir -p /usr/src/app/tmp/sockets && DATABASE_URL=postgres://postgres@example.com:5432/fakedb AMQP_URL=amqp://guest:guest@amqp:5672 TWITTER_API_KEY=SOME_KEY TWITTER_API_SECRET=SOME_SECRET SECRET_KEY_BASE=10167c7f7654ed02b3557b05b88ece rails assets:precompile && echo "apk del .app-builddeps" && chown -R nobody /usr/src/app' returned a non-zero code: 2

[zealot128]

In my case, changing the nodejs version helped:

apk add --no-cache --virtual .app-builddeps nodejs=6.7.0-r1