`UPTIME_CHECKER_ALLOW_INTERNAL_IPS` can't be set in .env.custom

[keysmashes]

Self-Hosted Version

25.10.0

CPU Architecture

x86_64

Docker Version

28.5.1

Docker Compose Version

2.40.2

Machine Specification

• My system meets the minimum system requirements of Sentry

Steps to Reproduce

1. Set UPTIME_CHECKER_ALLOW_INTERNAL_IPS=true in .env.custom
2. docker compose --env-file .env --env-file .env.custom up --wait
3. Observe that uptime checks on private IP space don't work

Expected Result

It should be possible to enable uptime checks on private IPs without editing docker-compose.yml, because that dirties the git repo and makes updating annoying.

Actual Result

Putting this setting in a .env file apparently doesn't work:

$ docker compose exec uptime-checker env | grep UPTIME_CHECKER_ALLOW_INTERNAL_IPS
UPTIME_CHECKER_ALLOW_INTERNAL_IPS=false

(also, UPTIME_CHECKER_ALLOW_INTERNAL_IPS isn't documented anywhere except in the release notes for 25.7.0...)

Event ID

No response

[aldy505]

Actually, you can use docker-compose.override.yml and it won't mess with Git whatsoever since it's ignored:

self-hosted/.gitignore

Lines 75 to 76 in 6ae40d8

	# https://docs.docker.com/compose/extends/
	docker-compose.override.yml

Your docker-compose.override.yml should be:

services:
  uptime-checker:
    environment:
      UPTIME_CHECKER_ALLOW_INTERNAL_IPS: "true"

Then docker compose --env-file .env --env-file .env.custom up -d --wait uptime-checker. That's it!