anchor.diff:  # https://www.google.com/linuxrepositories/
   	gpg --batch --keyserver ha.pool.sks-keyservers.net --recv-keys 'EB4C 1BFD 4F04 2F6D DDCC EC91 7721 F63B D38B 4796'; \
   	gpg --batch --verify go.tgz.asc go.tgz; \
  +	gpgconf --kill all; \
   	rm -rf "$GNUPGHOME" go.tgz.asc; \
   	\
   	tar -C /usr/local -xzf go.tgz; \
  
positive.code: 	esac; \
  	\
  # https://github.com/golang/go/issues/38536#issuecomment-616897960
  	url='https://storage.googleapis.com/golang/go1.15.1.src.tar.gz'; \
  	sha256='d3743752a421881b5cc007c76b4b68becc3ad053e61275567edab1c99e154d30'; \
  	\
  	wget -O go.tgz.asc "$url.asc"; \
  	wget -O go.tgz "$url"; \
  
negative.code: 
  ENV PATH /usr/local/go/bin:$PATH
  
  ENV GOLANG_VERSION 1.15.8
  
  RUN set -eux; \
  	apk add --no-cache --virtual .build-deps \
  