How to create simple proxy image

create_proxy_image.txt

$ TMP_DIR=$(mktemp -d) && cd $TMP_DIR

$ cat << EOF > Dockerfile
FROM nginx:alpine

ENV NGINX_PORT=8080

ENV PROXY_PROTOCOL=https
ENV PROXY_HOST=localhost
ENV PROXY_PATH=

COPY ./templates /etc/nginx/templates

EXPOSE 8080
EOF

$ mkdir templates

$ cat << EOF > templates/default.conf.template
server {
    listen ${NGINX_PORT};

    location / {
        proxy_pass ${PROXY_PROTOCOL}://${PROXY_HOST}${PROXY_PATH};
    }
}
EOF

$ tree
.
├── Dockerfile
└── templates
    └── default.conf.template

$ docker build -t gcr.io/your-project/pubsub-proxy:blog .