Docker Swarm and Postgraphile: How to add DATABASE_URL_FILE environment variable? - docker

Question

I am actually new to programming and Docker. I tried to rebuild the graphile/postgraphile:4.7.0 image to add DATABASE_URL_FILE environment variable support. This is what I do and the output.
Dockerfile
FROM node:alpine
LABEL description="Instant high-performance GraphQL API for your PostgreSQL database https://github.com/graphile/postgraphile"
# Install PostGraphile and PostGraphile connection filter plugin
RUN npm install -g postgraphile
RUN npm install -g postgraphile-plugin-connection-filter
EXPOSE 5000
# patch postgraphile:4.7.1; DATABASE_URL_FILE environment variable implementation.
RUN apk add bash
COPY docker-entrypoint.sh /usr/local/bin/
RUN ln -s /usr/local/bin/docker-entrypoint.sh / # backwards compat
ENTRYPOINT ["docker-entrypoint.sh"]
CMD ["postgraphile", "-n", "0.0.0.0"]
docker-entrypoint.sh copied from postgres docker-entrypoint.sh
#!/usr/bin/env bash
# usage: file_env VAR [DEFAULT]
# ie: file_env 'XYZ_DB_PASSWORD' 'example'
# (will allow for "$XYZ_DB_PASSWORD_FILE" to fill in the value of
# "$XYZ_DB_PASSWORD" from a file, especially for Docker's secrets feature)
file_env() {
local var="$1"
local fileVar="${var}_FILE"
local def="${2:-}"
if [ "${!var:-}" ] && [ "${!fileVar:-}" ]; then
echo >&2 "error: both $var and $fileVar are set (but are exclusive)"
exit 1
fi
local val="$def"
if [ "${!var:-}" ]; then
val="${!var}"
elif [ "${!fileVar:-}" ]; then
val="$(< "${!fileVar}")"
fi
export "$var"="$val"
unset "$fileVar"
}
# Loads various settings that are used elsewhere in the script
# This should be called before any other functions
docker_setup_env() {
file_env 'DATABASE_URL'
}
output
$ docker-compose up postgraphile
Attaching to test_postgraphile_1
test_postgraphile_1 | exited with code 0
Sincerely,
kidfrom

Answer 1

Edit: Benjie (Postgraphile maintainer) helped me alot on this one. This should work as is.
Dockerfile
FROM node:alpine
LABEL description="Instant high-performance GraphQL API for your PostgreSQL database https://github.com/graphile/postgraphile"
# Install PostGraphile and PostGraphile connection filter plugin
RUN npm install -g postgraphile
RUN npm install -g postgraphile-plugin-connection-filter
EXPOSE 5000
# patch postgraphile:4.7.1; DATABASE_URL_FILE environment variable implementation.
RUN apk add bash
COPY docker-entrypoint.sh /usr/local/bin/
RUN ln -s /usr/local/bin/docker-entrypoint.sh / # backwards compat
ENTRYPOINT ["docker-entrypoint.sh"]
CMD ["postgraphile", "-n", "0.0.0.0"]
docker-entrypoint.sh copied from postgres docker-entrypoint.sh
#!/usr/bin/env bash
# usage: file_env VAR [DEFAULT]
# ie: file_env 'XYZ_DB_PASSWORD' 'example'
# (will allow for "$XYZ_DB_PASSWORD_FILE" to fill in the value of
# "$XYZ_DB_PASSWORD" from a file, especially for Docker's secrets feature)
file_env() {
local var="$1"
local fileVar="${var}_FILE"
local def="${2:-}"
if [ "${!var:-}" ] && [ "${!fileVar:-}" ]; then
echo >&2 "error: both $var and $fileVar are set (but are exclusive)"
exit 1
fi
local val="$def"
if [ "${!var:-}" ]; then
val="${!var}"
elif [ "${!fileVar:-}" ]; then
val="$(< "${!fileVar}")"
fi
export "$var"="$val"
unset "$fileVar"
}
# Loads various settings that are used elsewhere in the script
# This should be called before any other functions
docker_setup_env() {
file_env 'DATABASE_URL'
}
# call the function
docker_setup_env
# call postgraphile
exec "$#"
Sincerely,
kidfrom