fix(snap): default seeded settings to sqlite, not dirty

settings.json.template's own comment says dirty is for testing only.
A Snap install is the "not testing" case — shipping it by default
means every `sudo snap install etherpad-lite` starts on a DB the
project explicitly recommends against.

Rewrite the postinstall sed to switch dbType: "dirty" → "sqlite" and
point filename at $SNAP_COMMON/var/etherpad.db. sqlite is already
shipped in-tree via ueberdb2 → rusty-store-kv (prebuilt napi-rs
binary, no build deps), so this works under strict confinement with
zero snap.yaml changes.

Only affects first-run seeding; existing $SNAP_COMMON/etc/settings.json
is never touched on refresh.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: JohnMcLear

snap/README.md

@@ -39,8 +39,12 @@ A few values are exposed as snap config for convenience:
 | `snap set etherpad-lite port=9001`  | `9001`    | Listen port     |
 | `snap set etherpad-lite ip=0.0.0.0` | `0.0.0.0` | Bind address    |
 
-Pad data (dirty DB, logs) lives in `/var/snap/etherpad-lite/common/` and
-survives `snap refresh`.
+Pad data (sqlite DB at `var/etherpad.db`, logs) lives in
+`/var/snap/etherpad-lite/common/` and survives `snap refresh`. The
+shipped `settings.json.template` defaults to `dbType: "dirty"`, which
+the template itself warns is dev-only; the launch wrapper rewrites the
+seeded copy to `sqlite` on first run so users get an ACID-safe DB out
+of the box.
 
 ## Publish to the Snap Store
 

snap/local/bin/etherpad-service

@@ -3,8 +3,8 @@
 #
 # 1. On first run, copy settings.json.template -> $SNAP_COMMON/etc/settings.json
 #    so the admin can edit it outside the read-only squashfs. Patch the
-#    seeded file so dirty-DB / ip / port point at writable paths and pick
-#    up env-var overrides.
+#    seeded file so the DB (switched from dev-only dirty to sqlite) / ip /
+#    port point at writable paths and pick up env-var overrides.
 # 2. Create writable data dirs under $SNAP_COMMON.
 # 3. Apply `snap set` overrides (port, ip) via env vars — Etherpad's
 #    settings.json supports ${PORT:9001}-style substitution natively.
@@ -27,9 +27,13 @@ SETTINGS="${ETC_DIR}/settings.json"
 if [ ! -f "${SETTINGS}" ]; then
   echo "[etherpad-snap] bootstrapping ${SETTINGS} from template"
   cp "${APP_DIR}/settings.json.template" "${SETTINGS}"
-  # Point the default dirty-DB at $SNAP_COMMON (absolute path, writable).
+  # Switch the template's dev-only dirty default to sqlite and point it
+  # at $SNAP_COMMON (absolute path, writable under strict confinement).
+  # sqlite is shipped by ueberdb2 via the prebuilt rusty-store-kv native
+  # module — no additional build deps required.
   sed -i \
-    -e 's|"filename": "var/dirty.db"|"filename": "'"${VAR_DIR}"'/dirty.db"|' \
+    -e 's|"dbType": "dirty"|"dbType": "sqlite"|' \
+    -e 's|"filename": "var/dirty.db"|"filename": "'"${VAR_DIR}"'/etherpad.db"|' \
     "${SETTINGS}"
   # Rewrite ip/port literals to Etherpad's env-substitution syntax so
   # `snap set etherpad-lite port=<n>` / `ip=<addr>` actually take effect.