Configuration

Settings come from environment variables. The catalog's address is not a setting: it is written in the source, as a placeholder, and you edit it there.

Environment variables

Variable	Script	Default	What it sets
LANG	both	S	The catalog language symbol, used in every request and in the catalog file name.
OUTPUT_PATH	both	/vtts/ (subtitles), /epubs/ (EPUBs)	The folder the files are saved to. Created if missing.
DB_PATH	both	/vtts/media.db, /epubs/pubs.db	The SQLite file that records what was fetched. Its folder is created if missing.
UNIT_DB_PATH	publications-epub.py	/app/db/unit.db	The catalog's unit.db, read to turn LANG into a numeric language id. The script only reads it; the compose file mounts it read-only.

LANG is also the variable your shell uses for its locale. Inside the containers the compose file sets it to S. Outside Docker, always set it on the command line, or the script asks the catalog for a language called en_US.UTF-8.

DB_PATH does not follow OUTPUT_PATH: if you change the output folder outside Docker, set DB_PATH too, or the state file still goes to /vtts/ or /epubs/.

The endpoints

Every catalog address in the source is https://place.holder. Replace it in each of these lines (grep -n place.holder src/*.py finds them):

File	What it fetches
src/media-vtt.py, catalog_url in __main__	The catalog index, <base>/<LANG>.json.gz: gzipped JSON, one object per line.
src/media-vtt.py, base_url in get_pub_media_links	The files of one media item, asked with langwritten, track, and pub or docid.
src/publications-epub.py, manifest_url in fetch_log_db	A JSON object whose current field names the latest catalog manifest.
src/publications-epub.py, log_url in fetch_log_db	The gzipped SQLite catalog for that manifest, with a Publication table.
src/publications-epub.py, the two url lines in download_epubs	The files of one publication, for a periodical issue (pub, issue) or a single publication (pub), with fileformat=epub.

How it works describes the answers each request must return.

The compose file

The shipped docker-compose.yml, word for word:

services:
  media-download-epubs:
    build:
      context: .
      dockerfile: Dockerfile-epubs
    volumes:
      - ./epubs:/epubs:rw
      - ./db:/app/db:ro   # the catalog's unit.db
    environment:
      - LANG=S
      - OUTPUT_PATH=/epubs

  media-download-media:
    build:
      context: .
      dockerfile: Dockerfile-media
    volumes:
      - ./vtts:/vtts:rw
    environment:
      - LANG=S
      - OUTPUT_PATH=/vtts

• ./vtts and ./epubs on the host receive the files and the state databases. Both are created by Docker if missing.
• ./db holds unit.db and is mounted read-only. The subtitles service does not need it.
• Both services build from the repository. There is no published image to pull.