040-Dockerfile.label.sample

FROM alpine:3.9

ARG AUTHOR="Raju Gandhi"
ARG BUILD_DATE
ARG VCS_REF

# Don't
# LABEL org.label-schema.author=$AUTHOR
# LABEL org.label-schema.build-date=$BUILD_DATE
# LABEL org.label-schema.vcs-ref=$VCS_REF

# Do
LABEL org.label-schema.author=$AUTHOR \
  org.label-schema.build-date=$BUILD_DATE \
  org.label-schema.vcs-ref=$VCS_REF

# USAGE
# docker build -f 040-Dockerfile.label.sample -t test .
# docker inspect test | grep -A 5 Labels
# set at build time
# docker build --build-arg AUTHOR="Solomon Hykes" -f 040-Dockerfile.label.sample -t test .
# docker inspect test | grep -A 5 Labels