Docker Support, Meow Expiry and Time-Zone-Aware Clock

Date: 2026-08-23 Project: ScratchingPost Status: resolved Tags: docker, expiry, scheduling, timezone, clock, sqlite, v1.1.0, v1.1.1

Context

Jess wanted Scratching Post deployable in Docker as an alternative to IIS, and wanted slides (Meows) to be able to expire automatically after an end date. Running in a container exposed a time-zone problem: containers default to UTC, so expiry checks against DateTime.Now fired at the wrong local time. Released as v1.1.0 (Docker + expiry, 2026-08-22) and v1.1.1 (timezone, 2026-08-23).

Key Decisions

ExpiresAt on the Slide (Meow) model, nullable — no expiry by default.
Expired Meows are filtered server-side from both the live display and the playlist API, not hidden client-side.
Auto-add the ExpiresAt column for existing databases at startup — because the app uses EnsureCreated() (no migrations), existing IIS databases wouldn't otherwise get the new column.
Central Clock helper instead of raw DateTime.Now — one place that knows the configured time zone; used for expiry checks, the Expired badge, and form text.
TimeZone setting: blank = host local time — so existing IIS installs behave exactly as before; Docker image defaults to UTC with tzdata installed so a named zone can be set.
Configurable data directory so the SQLite DB and uploads live on persistent Docker volumes.

Technical Details

Infrastructure/Clock.cs — Clock.Now returns time in the configured zone; configured from the TimeZone setting at startup. Imported into Razor views.
appsettings.json → TimeZone (e.g. an IANA zone name; blank = host local).
Docker: multi-stage Dockerfile, .dockerignore, docker-compose.yml with persistent volumes for DB and uploads; tzdata installed in the runtime image.
Create/Edit Meow forms have a Scheduling card with an expiry date field and text clarifying which time zone it uses.
Meows list shows an Expires column and an Expired badge (computed with Clock.Now).

Code Changes

Models/ — ExpiresAt on Slide.
Data/ — configurable data directory; startup check adds ExpiresAt column if missing.
Display/playlist controllers — skip expired Meows.
Views/ — Scheduling card on Create/Edit; Expires column + Expired badge on list; Clock import.
Infrastructure/Clock.cs — new.
Program.cs — configure Clock from TimeZone.
Dockerfile, .dockerignore, docker-compose.yml — new.
README.md — Docker deployment, Meow expiration, TimeZone setting; version bumps to v1.1.0 / v1.1.1.

Open Questions / Next Steps

Add a start date ("publish from") to pair with expiry, if needed.
ASK priority-slide feature still planned.
If more schema changes accumulate, consider moving from EnsureCreated() + ad-hoc column checks to real EF migrations.

Artifacts

Release v1.1.1 — 6a6d524 Document TimeZone setting; bump to v1.1.1
baac95d — Use Clock.Now for expiry checks
v1.1.0 — Docker deployment and Meow expiration
Repo: https://gitea.hideawaygaming.com.au/jessikitty/ScratchingPost

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