gcloud App Engine Flexible Strangeness with Docker and Babel - node.js

Question

I've been deploying a server side node application to a custom app engine runtime for a few months without any problems. The only half interesting thing about it is that a run babel against the source when I build the container.
In this last few weeks this has been failing intermittently with an error to this effect in the remote build log.
import * as deps from './AppFactory';
SyntaxError: Unexpected token import
Leading me to believe that the babel transpilation wasn't happening; though the gcloud cli indicates it is:
> node_modules/babel-cli/bin/babel.js src/ -d dist/
src/AppFactory.js -> dist/AppFactory.js
src/Ddl.js -> dist/Ddl.js
src/Helpers.js -> dist/Helpers.js
src/MemoryResolver.js -> dist/MemoryResolver.js
src/Mysql.js -> dist/Mysql.js
src/Schema.js -> dist/Schema.js
src/index.js -> dist/index.js
---> 0282c805d5c9
In desperation I cat out the dist/index file in the Dockerfile. When I do, I see that indeed no transpilation occurs.
When I create a docker image locally, everything works perfectly.
My Dockerfile follows:
# Set the base image to Ubuntu
FROM gcr.io/google_appengine/nodejs:latest
ENV NODE_ENV production
# File Author / Maintainer
# Provides cached layer for node_modules
ADD package.json /tmp/package.json
RUN cd /tmp && npm install
RUN mkdir -p /src && cp -a /tmp/node_modules /src/
# Define working directory
WORKDIR /src
ADD . /src
RUN npm run deploy
RUN cat /src/dist/index.js
CMD ["npm", "start"]
Below is my .babelrc file:
{
"presets": [
"es2015",
]
}
And my vanilla yaml file:
service: metrics-api-test
runtime: custom
env: flex
env_variables:
NODE_ENV: 'production'
NODEPORT: '8080'
beta_settings:
cloud_sql_instances: pwc-sales-demos:us-east1:pawc-sales-demos-sql
I've been trying all sorts of variations with babel-register, babel-node. They all work perfectly when I build a local docker image. They all fail when I deploy to the app engine.
I posted this a few months ago and the issue is starting to plague me again. It started off as an intermittent problem and now it happens every time. It happens between services and even on different gcloud projects.
Any insight into this gets my appreciation and 150 points.

Answer 1

So finally getting back to this; it was completely my fault.
I had thought that I had moved all the babel dependencies into the runtime dependency strophe, like so:
"dependencies": {
"babel-cli": "^6.24.1",
"babel-preset-es2015": "^6.24.1"....
But I must have not. All works perfectly with the above and this Dockerfile:
FROM gcr.io/google_appengine/nodejs:latest
ENV NODE_ENV production
# File Author / Maintainer
# Provides cached layer for node_modules
ADD package.json /tmp/package.json
RUN cd /tmp && npm install
RUN mkdir -p /src && cp -a /tmp/node_modules /src/
# Define working directory
WORKDIR /src
ADD . /src
RUN node_modules/babel-cli/bin/babel.js src/ -d dist/
RUN cat dist/index.js
CMD ["npm", "start"]
No more manually building the file!