Docker build npm error logs

Question

If a npm install command fails while building a Dockerfile, how can I view the contents of npm-debug.log? My problems are exacerbating because they only take place on Elastic Beanstalk app uploads, but the question still applies for local docker builds.

Answer 1

The best way would be to run docker build --rm=false . in order to keep intermediary image and start bash from the last success build step then run the npm install from there.

Alternatively, you can also docker commit <id> with the id of the container which ran npm install. Example:

Step 9 : RUN  npm install
---> Running in 2955a741027a
blablabla
FAIL
$> docker commit 2955a741027a test && docker run -it test cat /path/to/npm-debug.log