share: dockerize the file-share pipeline and document it

The Python half of the short-lived share links lived in the repo; the Apache
config and the cron entries that make it work were hand-placed on the host, so
the feature could not be rebuilt from a checkout. This adds the missing half.

Scripts (defaults unchanged, so existing bare-metal cron keeps working):
* scan_shares.py / revoke_shares.py take their paths from CONJURER_SHARE_*
  instead of hardcoding the Pi layout, and create their parent dirs;
* the revoke TTL is now CONJURER_SHARE_TTL_SECONDS. Its --help claimed "2min"
  while the code used a hardcoded 3600 - the help text now reports the real,
  configured value.

New share service:
* docker/Dockerfile.share - Apache + the two jobs, reusing the same scripts
  rather than forking copies;
* docker/share-vhost.conf.tpl - the previously undocumented Apache half.
  Three settings are load-bearing and commented as such: +FollowSymLinks (the
  shares ARE symlinks), -Indexes (a listing would expose every live token), and
  a deny rule for dotfiles (revoke_shares.py keeps .downloads.json - a map of
  every live token - inside the served directory);
* docker/entrypoint.share.sh - renders the vhost, seeds the index on first run,
  then runs scanner/revoker in sleep loops beside Apache (no cron, so their
  output shows up in docker logs);
* compose + env example, incl. the two volumes that MUST be shared with the
  musician (it creates the links and reads the index).

docs/deployment/FILE_SHARING.md documents the mechanism, both deployment routes
(docker and existing host Apache), the Discord command, why each Apache setting
matters, verification commands, and the known limitations - notably that a link
nobody ever downloads is never revoked, since the TTL starts at first download.

Verified: scanner and revoker exercised end-to-end against temp dirs (index
built; token recorded from a combined-format log line and the symlink unlinked).
Compose file not validated - no docker on this machine.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

conjurer_musician/revoke_shares.py

@@ -7,9 +7,13 @@ import argparse
 import sys
 from pathlib import Path
 
-# — CONFIGURATION — adjust as needed —
+# — CONFIGURATION — env-overridable; defaults = original bare-metal Pi layout —
-APACHE_LOG     = '/var/log/apache2/share_access.log'  # <- point to your share-specific log!
+# APACHE_LOG must be the share-specific access log (see docker/share-vhost.conf);
-SHARE_DIR      = Path('/var/www/html/share')
+# pointing it at the site-wide log also works but wastes time scanning noise.
+APACHE_LOG     = os.getenv('CONJURER_APACHE_LOG', '/var/log/apache2/share_access.log')
+SHARE_DIR      = Path(os.getenv('CONJURER_SHARE_DIR', '/var/www/html/share'))
+# Seconds to keep a link alive after its FIRST download (not after creation).
+TTL_SECONDS    = int(os.getenv('CONJURER_SHARE_TTL_SECONDS', '3600'))
 METADATA_FILE  = SHARE_DIR / '.downloads.json'
 STATE_FILE     = SHARE_DIR / '.logpos'
 # Regex to match lines like: "GET /share/abcdef1234... HTTP/1.1"
@@ -66,7 +70,7 @@ def record_downloads(lines, metadata, args):
 
 def revoke_old(metadata, args):
     now = time.time()
-    to_remove = [tok for tok, ts in metadata.items() if now - ts >= 3600]
+    to_remove = [tok for tok, ts in metadata.items() if now - ts >= TTL_SECONDS]
     for tok in to_remove:
         link = SHARE_DIR / tok
         try:
@@ -78,7 +82,12 @@ def revoke_old(metadata, args):
     return bool(to_remove)
 
 def main():
-    p = argparse.ArgumentParser(description="Revoke share links 2min after download")
+    p = argparse.ArgumentParser(
+        description=(
+            "Revoke share links CONJURER_SHARE_TTL_SECONDS "
+            f"(currently {TTL_SECONDS}s) after their first download"
+        )
+    )
     p.add_argument('--debug', action='store_true', help='print debug info to stderr')
     args = p.parse_args()
 

conjurer_musician/scan_shares.py

@@ -1,12 +1,18 @@
 #!/usr/bin/env python3
+"""Build the share index that the musician's /get_share_list endpoint searches.
+
+Walks the media root and writes a JSON catalogue of every file/dir found.
+Meant to run periodically (cron on bare metal, the scheduler loop in the share
+container). Paths are environment-overridable; the defaults reproduce the
+original Raspberry Pi layout, so existing cron entries keep working unchanged.
+"""
 import os
 import json
 import time
-from pathlib import Path
 
-# Configuration
+# Configuration (env-overridable; defaults = original bare-metal Pi layout)
-SCAN_PATH = '/mnt/shares'
+SCAN_PATH = os.getenv('CONJURER_SHARE_SCAN_PATH', '/mnt/shares')
-OUTPUT_FILE = '/var/log/share_scan.json'
+OUTPUT_FILE = os.getenv('CONJURER_SHARE_DB', '/var/log/share_scan.json')
 
 def scan_directory(root):
     """Recursively walk `root` and collect metadata."""
@@ -34,7 +40,8 @@ def main():
         'root': SCAN_PATH,
         'entries': scan_directory(SCAN_PATH),
     }
-    # Write atomically
+    # Write atomically (create the target dir first so a fresh volume works)
+    os.makedirs(os.path.dirname(OUTPUT_FILE) or '.', exist_ok=True)
     temp = OUTPUT_FILE + '.tmp'
     with open(temp, 'w') as f:
         json.dump(data, f, indent=2)

docker/Dockerfile.share

@@ -0,0 +1,36 @@
+# Conjurer share service: Apache publishing short-lived symlink shares, plus
+# the two periodic jobs that build the search index and revoke expired links.
+#
+# This is the piece that used to live only as hand-placed scripts + hand-edited
+# Apache config on the host. Everything it needs is now in the image; the state
+# it shares with the musician (the link dir and the index) comes in as volumes.
+#
+# Build from the repository root:
+#   docker build -f docker/Dockerfile.share -t conjurer-share .
+FROM debian:bookworm-slim
+
+# apache2 serves the links; python3 runs the scanner/revoker (both stdlib-only,
+# so there is nothing to pip install).
+RUN apt-get update && apt-get install -y --no-install-recommends \
+        apache2 python3 \
+    && rm -rf /var/lib/apt/lists/*
+
+WORKDIR /app
+# Same scripts the bare-metal deployment uses - no forked copies.
+COPY conjurer_musician/scan_shares.py ./scan_shares.py
+COPY conjurer_musician/revoke_shares.py ./revoke_shares.py
+COPY docker/share-vhost.conf.tpl ./share-vhost.conf.tpl
+COPY docker/entrypoint.share.sh /usr/local/bin/entrypoint.sh
+RUN chmod +x /usr/local/bin/entrypoint.sh
+
+# /mnt/shares            - media library (mount read-only; symlink targets)
+# /var/www/html/share    - the symlinks themselves (SHARED with the musician,
+#                          which is what creates them)
+# /srv/share/db          - share_scan.json (SHARED with the musician, which
+#                          searches it)
+# /var/log/apache2       - access log the revoker tails
+VOLUME ["/mnt/shares", "/var/www/html/share", "/srv/share/db", "/var/log/apache2"]
+
+EXPOSE 80
+
+ENTRYPOINT ["/usr/local/bin/entrypoint.sh"]

docker/compose.share.yaml

@@ -0,0 +1,43 @@
+# Share VM/host: Apache publishing short-lived file links + the scan/revoke jobs.
+# Run from the repository root:
+#   cp docker/env/share.env.example docker/env/share.env   # then edit
+#   docker compose -f docker/compose.share.yaml up -d --build
+#
+# IMPORTANT - this service shares two paths with the musician, which is the
+# process that actually creates the links:
+#
+#   /srv/share/links  ->  the symlinks        (musician writes, Apache reads)
+#   /srv/share/db     ->  share_scan.json     (this service writes, musician reads)
+#
+# So the musician must mount the same two host paths (see the CONJURER_SHARE_*
+# block in docker/env/musician.env.example). If the musician runs on a different
+# machine, put both on shared storage - otherwise it will happily create links
+# that this container cannot see.
+#
+# The media library must be mounted here at the SAME absolute path that the
+# index recorded, because the symlink targets are absolute. Default: /mnt/shares.
+services:
+  conjurer-share:
+    build:
+      context: ..
+      dockerfile: docker/Dockerfile.share
+    image: conjurer-share:latest
+    container_name: conjurer-share
+    restart: unless-stopped
+    env_file:
+      - env/share.env
+    ports:
+      # Plain HTTP. Terminate TLS for czernobog.pl on your existing reverse
+      # proxy and forward /share here.
+      - "8081:80"
+    volumes:
+      # Media library the links point at. Read-only: this service only ever
+      # serves these files, it never writes them.
+      - /srv/share/media:/mnt/shares:ro
+      # The published symlinks - shared with the musician.
+      - /srv/share/links:/var/www/html/share
+      # The search index - shared with the musician.
+      - /srv/share/db:/srv/share/db
+      # Access log the revoker tails; kept on the host so link history survives
+      # a container rebuild.
+      - /srv/share/logs:/var/log/apache2

docker/entrypoint.share.sh

@@ -0,0 +1,67 @@
+#!/bin/sh
+# Entrypoint for the Conjurer share container: renders the vhost, seeds the
+# share index, then runs the two periodic jobs alongside Apache.
+#
+# Cron is deliberately not used. Both scripts are already written to be safe to
+# re-run (the scanner writes atomically, the revoker persists its log position),
+# so plain sleep loops give the same result with one less moving part and with
+# their output on the container's stdout where `docker logs` can see it.
+set -eu
+
+: "${CONJURER_SHARE_SERVER_NAME:=localhost}"
+: "${CONJURER_SHARE_SCAN_PATH:=/mnt/shares}"
+: "${CONJURER_SHARE_DB:=/srv/share/db/share_scan.json}"
+: "${CONJURER_SHARE_DIR:=/var/www/html/share}"
+: "${CONJURER_APACHE_LOG:=/var/log/apache2/share_access.log}"
+: "${CONJURER_SHARE_SCAN_INTERVAL:=3600}"
+: "${CONJURER_SHARE_REVOKE_INTERVAL:=60}"
+: "${CONJURER_SHARE_TTL_SECONDS:=3600}"
+export CONJURER_SHARE_SCAN_PATH CONJURER_SHARE_DB CONJURER_SHARE_DIR \
+       CONJURER_APACHE_LOG CONJURER_SHARE_TTL_SECONDS
+
+# Render the vhost (same placeholder pattern as icecast.xml.tpl).
+sed "s|__SERVER_NAME__|${CONJURER_SHARE_SERVER_NAME}|g" \
+    /app/share-vhost.conf.tpl > /etc/apache2/sites-available/000-default.conf
+
+mkdir -p "$CONJURER_SHARE_DIR" \
+         "$(dirname "$CONJURER_SHARE_DB")" \
+         "$(dirname "$CONJURER_APACHE_LOG")" \
+         /var/run/apache2
+chown -R www-data:www-data "$CONJURER_SHARE_DIR"
+
+# revoke_shares.py seeks to a stored byte offset, so the log must exist before
+# the first pass or it starts by reporting an error.
+touch "$CONJURER_APACHE_LOG"
+
+# Seed the index immediately when absent - otherwise /get_share_list returns
+# nothing until the first scheduled scan, which looks like a broken feature.
+if [ ! -f "$CONJURER_SHARE_DB" ]; then
+    echo "[share] no index at $CONJURER_SHARE_DB - running initial scan of $CONJURER_SHARE_SCAN_PATH"
+    python3 /app/scan_shares.py || echo "[share] initial scan failed, continuing"
+fi
+
+# Periodic index rebuild.
+(
+    while true; do
+        sleep "$CONJURER_SHARE_SCAN_INTERVAL"
+        echo "[share] rescanning $CONJURER_SHARE_SCAN_PATH"
+        python3 /app/scan_shares.py || echo "[share] scan failed"
+    done
+) &
+SCAN_PID=$!
+
+# Periodic revocation of links whose TTL expired after first download.
+(
+    while true; do
+        sleep "$CONJURER_SHARE_REVOKE_INTERVAL"
+        python3 /app/revoke_shares.py || echo "[share] revoke failed"
+    done
+) &
+REVOKE_PID=$!
+
+trap 'kill "$SCAN_PID" "$REVOKE_PID" 2>/dev/null || true' INT TERM
+
+echo "[share] serving $CONJURER_SHARE_DIR as ${CONJURER_SHARE_SERVER_NAME}/share"
+echo "[share] scan every ${CONJURER_SHARE_SCAN_INTERVAL}s, revoke sweep every ${CONJURER_SHARE_REVOKE_INTERVAL}s, TTL ${CONJURER_SHARE_TTL_SECONDS}s after first download"
+
+exec apache2ctl -D FOREGROUND

docker/env/musician.env.example

@@ -15,3 +15,17 @@ CONJURER_MUSIC_FOLDER=/music
 # Runtime paths (mounted volume) — playlists/logs the service writes.
 CONJURER_MUSICIAN_BASE=/data
 CONJURER_LOGSTORE=/data/logs
+
+# --- File sharing (optional; see docs/deployment/FILE_SHARING.md) --------
+# The musician SEARCHES the index and CREATES the symlinks; the share container
+# builds the index, serves the links and revokes them. Both must therefore point
+# at the same two host paths — mount them into this container as well:
+#   - /srv/share/db:/srv/share/db
+#   - /srv/share/links:/var/www/html/share
+# Leave these unset to keep the feature off (the endpoints then just find
+# nothing).
+# CONJURER_SHARE_DB=/srv/share/db/share_scan.json
+# CONJURER_SHARE_DIR=/var/www/html/share
+# Public URL prefix handed back to Discord; host half must match the share
+# container's CONJURER_SHARE_SERVER_NAME.
+# CONJURER_SHARE_BASE_URL=https://czernobog.pl/share

docker/share-vhost.conf.tpl

@@ -0,0 +1,49 @@
+# Apache vhost for the Conjurer file-share links.
+#
+# The entrypoint substitutes __SERVER_NAME__ from CONJURER_SHARE_SERVER_NAME and
+# writes the result to /etc/apache2/sites-available/000-default.conf (same
+# pattern as docker/icecast.xml.tpl).
+#
+# What this serves: media_search_functions.publish() creates a symlink named
+# after a random 32-hex token inside the share dir, pointing at a file in the
+# media library. Apache hands that file out at /share/<token>; revoke_shares.py
+# later unlinks it. Nothing is ever copied.
+
+<VirtualHost *:80>
+    ServerName __SERVER_NAME__
+    DocumentRoot /var/www/html
+
+    # The share links ARE symlinks into the media library, so FollowSymLinks is
+    # mandatory. SymLinksIfOwnerMatch is deliberately NOT used: the targets are
+    # owned by whoever owns the media, not by www-data, so it would break every
+    # link. -Indexes is equally mandatory - a directory listing here would hand
+    # out every currently live token at once.
+    <Directory /var/www/html/share>
+        Options +FollowSymLinks -Indexes
+        AllowOverride None
+        Require all granted
+
+        # revoke_shares.py keeps its state (.downloads.json, .logpos) in this
+        # very directory. .downloads.json maps every live token to its download
+        # time, so serving it would leak the entire active link set.
+        <FilesMatch "^\.">
+            Require all denied
+        </FilesMatch>
+    </Directory>
+
+    # Nothing outside /share is published. The more specific block above wins
+    # for the share dir itself.
+    <Directory /var/www/html>
+        Options -Indexes -FollowSymLinks
+        AllowOverride None
+        Require all denied
+    </Directory>
+
+    # Dedicated access log. revoke_shares.py tails exactly this file and matches
+    # the standard "%r" request line against:
+    #     "\s*GET\s+/share/([0-9a-f]{32})\s+HTTP/
+    # so the format must stay `combined` (or any format containing %r).
+    SetEnvIf Request_URI "^/share/" conjurer_share
+    CustomLog ${APACHE_LOG_DIR}/share_access.log combined env=conjurer_share
+    ErrorLog ${APACHE_LOG_DIR}/share_error.log
+</VirtualHost>

docs/deployment/DOCKER_PROXMOX.md

@@ -7,6 +7,11 @@ Runbook for running Conjurer as Docker containers across Proxmox VMs:
 | **Main bot** | VM-bot | `conjurer-bot` | 5000 (Flask comm) | `docker/Dockerfile.bot` |
 | **Librarian** | VM-librarian | `conjurer-librarian` | 5001 | `docker/Dockerfile.librarian` |
 | **Musician** | VM-musician | `conjurer-musician` | 5000 (+ radio) | `docker/Dockerfile.musician` |
+| **Share** (optional) | VM-musician or its own | `conjurer-share` | 8081 → 80 | `docker/Dockerfile.share` |
+
+The share service publishes short-lived file links over Apache and is documented
+separately in [FILE_SHARING.md](FILE_SHARING.md) — it shares two volumes with the
+musician, so set it up after the musician is running.
 
 The three talk to each other over HTTP on the Proxmox LAN. Direction of calls:
 

docs/deployment/FILE_SHARING.md

@@ -0,0 +1,197 @@
+# File sharing (short-lived share links)
+
+Publishes a file from the media library behind a random, unguessable URL that
+stops working shortly after someone downloads it. Driven from Discord.
+
+Historically only the Python half of this lived in the repo; the Apache config
+and the cron entries were placed on the host by hand. This document plus
+`docker/Dockerfile.share` close that gap.
+
+## What it actually does
+
+1. A **scanner** walks the media library and writes a JSON index of every path.
+2. From Discord you search that index and pick files.
+3. **Publishing** creates a `symlink` named after a random token
+   (`uuid.uuid4().hex`, 32 hex chars) inside the share directory, pointing at the
+   real file. Nothing is copied.
+4. **Apache** serves that symlink at `https://<host>/share/<token>`.
+5. A **revoker** tails Apache's access log, records when each token was *first*
+   downloaded, and unlinks it once the TTL expires.
+
+Two things worth being precise about, because the names suggest otherwise:
+
+- The token is **random, not a hash** of the file. Nothing about the content is
+  recoverable from the URL, and the same file shared twice gets two URLs.
+- The "database" is a **JSON file**, not a SQL database.
+  (`utils/import_to_mysql.py` is an unrelated, unfinished scratch script.)
+
+## The pieces
+
+| Path | Role | Runs in |
+|---|---|---|
+| `conjurer_musician/scan_shares.py` | Builds the JSON index from the media root | share container (or cron) |
+| `conjurer_musician/revoke_shares.py` | Tails the access log, unlinks expired tokens | share container (or cron) |
+| `conjurer_musician/media_search_functions.py` | Search + publish helpers used by the service | musician |
+| `conjurer_musician.py` → `/get_share_list`, `/get_share_links` | HTTP API, both behind `X-Conjurer-Api-Key` | musician |
+| `file_search_functions.py` | Bot-side HTTP client | bot |
+| `file_search_commands.py` | Discord cog: search UI + Accept/Cancel | bot |
+| `docker/share-vhost.conf.tpl` | Apache vhost (symlinks, no indexes, dedicated log) | share container |
+| `conjurer_musician/search_and_share.py` | Standalone CLI doing steps 1–3 by hand | anywhere (optional) |
+
+Flow:
+
+```
+   media library ──► scan_shares.py ──► share_scan.json ──┐
+                                                          │ (reads)
+Discord ──► bot cog ──► musician /get_share_list ─────────┘
+                    └─► musician /get_share_links ──► symlink in share dir
+                                                          │ (serves)
+                        Apache vhost ─────────────────────┘
+                             │ (logs)
+                             └──► share_access.log ──► revoke_shares.py ──► unlink
+```
+
+The share directory and the index are **shared state between the musician and
+the share service**: the musician creates links and reads the index, the share
+service serves links and writes the index. Both must see the same two paths.
+
+## Enabling it — Docker (recommended)
+
+```bash
+cp docker/env/share.env.example docker/env/share.env
+# edit: CONJURER_SHARE_SERVER_NAME, and the TTL/intervals if you want
+docker compose -f docker/compose.share.yaml up -d --build
+```
+
+Host layout the compose file expects:
+
+| Host path | Contents |
+|---|---|
+| `/srv/share/media` | the media library (mounted read-only) |
+| `/srv/share/links` | the published symlinks — **also mount into the musician** |
+| `/srv/share/db` | `share_scan.json` — **also mount into the musician** |
+| `/srv/share/logs` | Apache logs, incl. `share_access.log` |
+
+Then point the musician at the same two paths. In `docker/env/musician.env`:
+
+```ini
+CONJURER_SHARE_DB=/srv/share/db/share_scan.json
+CONJURER_SHARE_DIR=/var/www/html/share
+CONJURER_SHARE_BASE_URL=https://czernobog.pl/share
+```
+
+and add the matching mounts to `docker/compose.musician.yaml`:
+
+```yaml
+      - /srv/share/db:/srv/share/db
+      - /srv/share/links:/var/www/html/share
+```
+
+Finally forward `/share` from your public TLS endpoint to the container's port
+(`8081` by default). The container speaks plain HTTP on purpose — TLS for
+`czernobog.pl` stays on the reverse proxy you already run.
+
+> **The media library must be mounted at the same absolute path the index
+> recorded** (`/mnt/shares` by default). The symlinks are absolute, so if the
+> scanner saw `/mnt/shares/x.mkv` and Apache has the library somewhere else, every
+> link 404s.
+
+The container does not use cron: the entrypoint runs the scanner and the revoker
+in sleep loops next to Apache, so their output lands in `docker logs`.
+
+## Enabling it — existing Apache on the host
+
+If you keep serving from the host's Apache instead:
+
+1. Install the vhost. Take `docker/share-vhost.conf.tpl`, replace
+   `__SERVER_NAME__`, and drop it into `/etc/apache2/sites-available/`, then
+   `a2ensite` + `systemctl reload apache2`. The three settings that matter are
+   explained in the Security section below — do not simplify them away.
+
+2. Schedule both jobs. The scripts default to the original bare-metal paths, so
+   plain cron entries work with no environment at all:
+
+   ```cron
+   */5 *  * * *  /usr/bin/python3 /opt/conjurer/conjurer_musician/revoke_shares.py
+   17  *  * * *  /usr/bin/python3 /opt/conjurer/conjurer_musician/scan_shares.py
+   ```
+
+   Defaults: media root `/mnt/shares`, index `/var/log/share_scan.json`, links
+   `/var/www/html/share`, log `/var/log/apache2/share_access.log`, TTL 3600s.
+   Override any of them with the `CONJURER_SHARE_*` variables from
+   `docker/env/share.env.example`.
+
+3. Point the musician at the same paths via `CONJURER_SHARE_DB`,
+   `CONJURER_SHARE_DIR` and `CONJURER_SHARE_BASE_URL`.
+
+## Using it
+
+```
+$tajna_biblioteka_inkwizycji <1-10> <keywords>
+```
+
+Restricted to the **Jarl** and **Thane** roles. It replies with the matches, you
+select from the dropdown and press Accept; the bot answers with one URL per file.
+(The docstring in the cog still says `!findfiles` — that name is stale.)
+
+## Security
+
+The vhost is not boilerplate; three of its settings are load-bearing:
+
+- **`Options +FollowSymLinks`** — the shares *are* symlinks, so without it every
+  link 403s. `SymLinksIfOwnerMatch` cannot be substituted: the targets are owned
+  by whoever owns the media, not by `www-data`.
+- **`Options -Indexes`** — a directory listing of the share dir would hand out
+  every currently live token in one request.
+- **Deny dotfiles** — `revoke_shares.py` keeps `.downloads.json` (a map of every
+  live token to its download time) and `.logpos` *inside the served directory*.
+  Serving `.downloads.json` would leak the entire active link set.
+
+Also worth knowing:
+
+- Both HTTP endpoints call `_authorize_request()`, so they require
+  `X-Conjurer-Api-Key` whenever `CONJURER_API_KEY` is set. The bot sends it via
+  `service_headers()`.
+- Anyone with the URL can download the file until it expires — the token is the
+  only credential.
+- Mount the media read-only, as the compose file does. This service never needs
+  to write to the library.
+
+## Verifying
+
+```bash
+# index built?
+docker compose -f docker/compose.share.yaml exec conjurer-share \
+    python3 -c "import json;d=json.load(open('/srv/share/db/share_scan.json'));print(len(d['entries']),'entries')"
+
+# a link resolves? (create one from Discord first)
+curl -sI https://czernobog.pl/share/<token> | head -1
+
+# the listing must NOT work, and neither must the state file
+curl -sI https://czernobog.pl/share/            | head -1   # expect 403
+curl -sI https://czernobog.pl/share/.downloads.json | head -1   # expect 403
+
+# revoker seeing downloads?
+docker compose -f docker/compose.share.yaml logs --tail=20 conjurer-share
+```
+
+Common failures:
+
+| Symptom | Cause |
+|---|---|
+| Search finds nothing | index missing/empty — check the scanner ran and `CONJURER_SHARE_SCAN_PATH` is right |
+| Every link 404s | media not mounted at the path the index recorded |
+| Every link 403s | `FollowSymLinks` missing on the share directory |
+| Links never expire | revoker not running, or reading a log the vhost isn't writing |
+| Bot gets 401 | `CONJURER_API_KEY` set on the musician but not on the bot |
+
+## Known limitations
+
+- **A link nobody downloads is never revoked.** The TTL starts at the first
+  download, so unused symlinks accumulate in the share directory forever. Prune
+  it periodically if that matters.
+- **Log rotation confuses the revoker.** It stores a byte offset into the access
+  log; when the file is rotated the offset points into the new, shorter file and
+  entries can be skipped. Prefer a long rotation interval, or clear
+  `.logpos` after rotating.
+- **The index is a full rescan**, not incremental — cost grows with library size.