Append sh -c "$HANDLER" to handle failures
FROM alpine:latest
ENV HANDLER 'echo build failed. You can debug this container by running \`docker exec -it THIS_CONTAINER_ID sh\`. \(available for 1 hour\); sleep 3600'
RUN echo "something good 1 happened" || sh -c "$HANDLER"
RUN echo "something good 2 happened" || sh -c "$HANDLER"
RUN echo "something good 3 happened" || sh -c "$HANDLER"
RUN echo "something bad happend"; false || sh -c "$HANDLER"$ docker build -t tmp1 .
Sending build context to Docker daemon 2.048 kB
Step 1 : FROM alpine:latest
---> 13e1761bf172
Step 2 : ENV HANDLER 'echo build failed. You can debug this container by running \`docker exec -it THIS_CONTAINER_ID sh\`. \(available for 1 hour\); sleep 3600'
---> Using cache
---> 4f0f82d8901f
Step 3 : RUN echo "something good 1 happened" || sh -c "$HANDLER"
---> Using cache
---> ef3f4c00de1a
Step 4 : RUN echo "something good 2 happened" || sh -c "$HANDLER"
---> Using cache
---> d699259b0fb3
Step 5 : RUN echo "something good 3 happened" || sh -c "$HANDLER"
---> Using cache
---> ed6478617762
Step 6 : RUN echo "something bad happend"; false || sh -c "$HANDLER"
---> Running in 834cc509987e
something bad happend
build failed. You can debug this container by running `docker exec -it THIS_CONTAINER_ID sh`. (available for 1 hour)