Dockerfile build multistage

Dockerfile

### STAGE 1: clone ###
FROM node:12.16.3-alpine3.9 AS clone

LABEL mantainer="Facu de la Cruz <fmdlc.unix@gmail.com>"
LABEL type="builder"

WORKDIR /usr/src/frontend

# We need to install those packages to use npm
# A few repositories are cloned by using Git over SSH
RUN apk add --update --no-cache \
		build-base=0.5-r1 \
		git=2.20.4-r0 \
		openssh-client=7.9_p1-r6

# configure git credentials
RUN mkdir /root/.ssh/
COPY ./config/id_rsa_overwatch /root/.ssh/id_rsa
RUN	chmod 400 /root/.ssh/id_rsa && \
	touch /root/.ssh/known_hosts && \
	ssh-keyscan bitbucket.org >> /root/.ssh/known_hosts && \
	git config --global user.email "fmdlc.unix@gmail.com" && \
	git clone --branch walmart git@bitbucket.org:repository/repo.git

## STAGE 2: build
FROM node:12.16.3-alpine3.9 AS build

LABEL mantainer="Facu de la Cruz <fmdlc.unix@gmail.com>"
LABEL type="builder"
LABEL app="frontend-node8"

RUN apk add --update --no-cache \
        build-base=0.5-r1 \
        git=2.20.4-r0 \
        openssh-client=7.9_p1-r6

WORKDIR /usr/src/frontend
COPY --from=clone /usr/src/frontend/ /usr/src/frontend

# Hide warning coming from NPM
ENV npm_config_loglevel=error

# Increase memory space size for ng
ENV NODE_OPTIONS="--max_old_space_size=4096"

RUN awk -v COMMIT=$(git log --format="%h" -n 1) \
		-v BRANCH=$(git rev-parse --abbrev-ref HEAD) \
		-v DATE=$(date +%s) \
		-F'=' '/currentVersion/ { gsub("(\;| )",""); \
		print "{\n\t\"version\": \""$2"-"COMMIT"\",\n\t\"built-branch\": \""BRANCH"\",\n\t\"built-date\": \""DATE"\"\n}"}' \
		src/app/shared/footer/footer.component.ts | tr -d \' > \
		/usr/src/frontend/version.json

RUN npm install --loglevel verbose && \
	npm install -g  @angular/cli@9.1.6  && \
	ng build --prod

### STAGE 3: Run ###
FROM nginx:1.17.9-alpine

LABEL mantainer="Facu  de la Cruz <fmdlc.unix@gmail.com>"
LABEL type="app"
LABEL app="frontend-node8"

ENV NGINX_PORT=80

# copy nginx configuration
COPY ./config/nginx.conf /etc/nginx/nginx.conf
COPY ./config/default.conf /etc/nginx/conf.d/default.conf

# copy frontend and landing page
COPY --from=build /usr/src/frontend/dist/ /usr/share/nginx/html
COPY --from=build /usr/src/frontend/version.json /usr/share/nginx/html/version.json

STOPSIGNAL SIGINT
EXPOSE 80