request: support use of docker secret for pihole password

[jeremyhayes]

Feature request to support reading pihole password and/or api key from docker secrets.

• https://docs.docker.com/engine/swarm/secrets/#build-support-for-docker-secrets-into-your-images

The "standard" way would be to support a PIHOLE_PASSWORD_FILE env var, and read the file contents into the configuration, falling back to the existing variable.

For reference, here is the PR which added this support to pihole itself:

• https://github.com/pi-hole/docker-pi-hole/pull/584

Steps for Reproduction

1. Setup the following docker-compose

   
   version: '3.8'

services:

pihole: image: pihole/pihole:v5.8.1 environment:

pihole supports reading password from a mounted secret

  - WEBPASSWORD_FILE=/run/secrets/pihole-password
secrets:
  - pihole-password
# other pihole configuration, ports etc

pihole-exporter: image: ekofr/pihole-exporter:v0.0.11 environment:

• PIHOLE_HOSTNAME=pihole
• PIHOLE_PASSWORD_FILE=/run/secrets/pihole-password secrets:
• pihole-password

secrets: pihole-password: external: true

2. Create the docker secret
```sh
$ echo "hunter2" | docker secret create pihole-password

3. Deploy the stack

   $ docker stack deploy -c docker-compose.yml test

Expected behavior: pihole-exporter would read the contents of /run/secrets/pihole-password as the password

Actual behavior: PIHOLE_PASSWORD_FILE is ignored; exporter returns only the "unauthenticated" metrics.

Platforms: Docker swarm cluster.

Versions: ekofr/pihole-exporter:v0.0.11

[moritzj29]

would love to see this implemented!

[lebenitza]

Thanks to you @jeremyhayes and to https://github.com/pi-hole/docker-pi-hole/pull/584 it was easy to find a quick workaround to this:

FROM ekofr/pihole-exporter:v0.4.0 as source

FROM alpine:3.17

RUN apk update --no-cache && apk add bash

COPY --from=source /root/pihole-exporter /root/pihole-exporter
COPY start.sh /root/start.sh

CMD /root/start.sh

#!/bin/bash

# See: https://github.com/pi-hole/docker-pi-hole/pull/584
load_password_secret() {
   # If PIHOLE_PASSWORD is not set at all, attempt to read password from PIHOLE_PASSWORD_FILE,
   # allowing secrets to be passed via docker secrets
   if [ -z "${PIHOLE_PASSWORD+x}" ] && [ -n "${PIHOLE_PASSWORD_FILE}" ] && [ -r "${PIHOLE_PASSWORD_FILE}" ]; then
     export PIHOLE_PASSWORD=$(<"${PIHOLE_PASSWORD_FILE}")
   fi;
}

load_password_secret

exec /root/pihole-exporter