Move cover bytes to content-addressed filesystem storage (#65)

Refs #56

## Summary

Moves Kagane cover bytes out of Postgres bytea storage into an immutable, content-addressed filesystem store. Reader-visible behavior remains unchanged: the existing session-gated route serves stored bytes, missing bytes use the existing browser fetch path, and no browser still returns a missing cover.

## Changes

- Added migration 0008, which drops the legacy `covers` table and recreates it with only `address`, `path`, and `content_type`. Existing byte rows are intentionally dropped.
- Added SHA-256 source-URL addressing with two-level sharding (`ab/cd/<sha256>`). Writes use a temp file plus atomic link; reads validate the stored relative path before opening it.
- Made `COVER_DIR` required in runtime config and Compose. Compose passes it as a Docker build argument and volume target, so custom durable paths keep image ownership, runtime config, and the named `cover-data` volume aligned.
- Updated every `store.Open` caller and documented configuration, deployment, backup, and troubleshooting behavior.
- Added filesystem, restart, migration-drop, no-browser, and content-addressing coverage.

## Verification

- `go test ./...`
- `CGO_ENABLED=0 go build ./...`
- `docker build --build-arg COVER_DIR=/data/covers -t manga-bookmark-cover-check-custom ./backend`
- `docker compose config --format json` confirms custom `COVER_DIR` is the volume target
- `git diff --check origin/main`
- LSP diagnostics clean for touched Go files

Parents #47 and #55 remain open as required by #56.

Reviewed-on: #65
Co-authored-by: Sulthan Zaki <sultankiki05@gmail.com>
Co-committed-by: Sulthan Zaki <sultankiki05@gmail.com>

This commit was merged in pull request #65.

This commit is contained in:

Sulthan Zaki

2026-08-10 00:11:20 +07:00

committed by

sulthan

parent 30c57bd39c

commit e8d1cba6c5

15 changed files with 264 additions and 42 deletions

									
										backend/AGENTS.md
									
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				@@ -114,6 +114,7 @@ Guidance for OpenCode (and Claude Code) working under `backend/`. See root `AGEN

				  the owner of every pre-registration bookmark; required),

				  `ALLOWED_ORIGINS` (comma list),

				  `DATABASE_URL` (Postgres connection URL, required — no default),

				  `COVER_DIR` (required filesystem volume for content-addressed Cover bytes),

				  `PORT` (default `8080`), `DISCORD_CLIENT_ID`/`_CLIENT_SECRET`/`_GUILD_ID`/

				  `_REDIRECT_URI` (required; Discord OAuth for the browser UI),

				  `DISCORD_REQUIRED_ROLE` (optional role gate, empty by default),