timetracker/docs/configuration.md

Configuration

All configurable Django settings are read through a single helper, config() in timetracker/config.py. It resolves each value from a fixed chain of sources so the same setting can come from an environment variable, a .env file, an .ini file, or a built-in default — without any per-setting special-casing in settings.py.

Resolution priority

For a setting named NAME, the first source that provides a value wins:

Priority	Source	Notes
1	NAME__FILE env var	Path to a file; its stripped contents are the value. Opt-in per setting (allow_file=True). For Docker/Kubernetes secrets.
2	NAME env var	A real process environment variable.
3	.env file	KEY=value lines (see .env syntax).
4	settings.ini file	The [timetracker] section, parsed with configparser.
5	default	The in-code fallback in settings.py.

If no source supplies a value and no default is defined, startup fails with ImproperlyConfigured rather than silently using an empty value.

Worked example. With VALUE set in the environment and in .env and in settings.ini, the environment variable wins. Remove it and .env wins; remove that and settings.ini wins; remove that and the code default applies.

Settings reference

Setting	Cast	Default	__FILE?	Description
SECRET_KEY	str	insecure dev key	yes	Django secret key. Required in production (DEBUG off) — a missing value is a hard error, not a silent insecure fallback.
DEBUG	bool	true (dev)	no	Debug mode. Turn off in production. Defaults on for local development.
APP_URL	str (or comma-separated URLs)	http://localhost:8000	no	Public URL(s) of the site. One full URL or a comma-separated list. Derives ALLOWED_HOSTS and CSRF_TRUSTED_ORIGINS from all listed URLs.
ALLOWED_HOSTS	list	derived from APP_URL	no	Comma-separated hostnames. Overrides the APP_URL derivation (useful for ALLOWED_HOSTS=* behind a reverse proxy).
TZ	str	Europe/Prague (dev) / UTC (prod)	no	Time zone.
DATA_DIR	path	project root	no	Directory holding the SQLite database. Also read by entrypoint.sh.

cast understands bool (true/1/yes/on → True), list (comma-separated, whitespace-trimmed, empty items dropped), int, Path, or any callable.

APP_URL, ALLOWED_HOSTS and CSRF

APP_URL accepts one full URL or a comma-separated list of full URLs. Both ALLOWED_HOSTS and CSRF_TRUSTED_ORIGINS are derived from all listed URLs — no need to repeat the same information in separate variables.

Single domain (common case):

APP_URL=https://tracker.example.com
# -> ALLOWED_HOSTS     = ["tracker.example.com"]
# -> CSRF_TRUSTED_ORIGINS = ["https://tracker.example.com"]

Multiple domains:

APP_URL=https://tracker.example.com,https://www.tracker.example.com
# -> ALLOWED_HOSTS     = ["tracker.example.com", "www.tracker.example.com"]
# -> CSRF_TRUSTED_ORIGINS = ["https://tracker.example.com", "https://www.tracker.example.com"]

ALLOWED_HOSTS can still be overridden directly for edge cases. A typical reverse-proxy setup where the proxy validates the host:

ALLOWED_HOSTS=*

Secrets and __FILE

Secret managers (Docker secrets, Kubernetes) mount secrets as files. For any setting that opts in (currently SECRET_KEY), point a *__FILE variable at the mounted path:

SECRET_KEY__FILE=/run/secrets/timetracker_secret_key

The file contents are read and .strip()-ed. The strip matters: editors and echo often append a trailing newline, and a stray \n inside SECRET_KEY would silently invalidate every signed cookie/token when the file is recreated without it.

.env syntax

# full-line comment
KEY=value
export KEY=value            # optional leading "export"
QUOTED="value with spaces"  # surrounding quotes are stripped
SINGLE='also fine'
WITH_HASH="a # b"           # '#' inside quotes is literal
INLINE=value  # trailing comment after an unquoted value is dropped

Deliberately not supported (documented limits, not bugs):

• variable interpolation (${OTHER})
• multiline values

File locations default to .env and settings.ini at the project root and can be moved with the ENV_FILE / INI_FILE environment variables. Missing files are ignored, so env-only deployments need neither. A .env file used by docker-compose for ${VAR} substitution is the same file Django reads in local development; inside the container, real environment variables apply.

See .env.example and settings.ini.example for starting points.

Container / entrypoint-only variables

These are consumed by entrypoint.sh during container bootstrap, not by Django. They are intentionally not part of the Python config — moving them there would buy nothing and force a bash↔Python bridge.

Variable	Default	Purpose
PUID / PGID	1000 / 100	uid/gid the container process runs as.
DATA_DIR	/home/timetracker/app/data	Database directory. Shared with Django via the same env var + matching default.
CREATE_DEFAULT_SUPERUSER	false	Create an admin/admin superuser on first start.
STAGING	false	Scrub copied sessions / django-q schedule on staging.
LOAD_SAMPLE_DATA	false	Seed sample fixtures when the database is empty.

Migrating from the old config

• PROD=1 → DEBUG=false. PROD still works as a deprecated alias for one release and emits a DeprecationWarning.
• ALLOWED_HOSTS is now configurable (it was previously hard-coded to *). After upgrading, set APP_URL (or ALLOWED_HOSTS explicitly) or the host will be rejected. Reverse-proxy deployments that relied on * should set ALLOWED_HOSTS=*.