Make the container deployable on Dokploy

domains.json was written next to server.js, i.e. into the image filesystem,
so every redeploy discarded the domain -> glossary_id mappings. Its path is
now overridable via DOMAINS_FILE and the image defaults it to /app/data,
a subdirectory so that mounting a volume there does not shadow server.js
and index.html in /app.

Also adds a GET /health endpoint plus a Docker HEALTHCHECK that uses it. The
probe deliberately does not call DeepL, so an upstream DeepL outage does not
get the container restarted.

.gitignore is new; .env holds a real API key and was previously untracked
only by convention.

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

.dockerignore

@@ -1,6 +1,8 @@
 .env
 .env.example
+.env.testcopy
 domains.json
+data
 node_modules
 .git
 *.md

.gitignore

@@ -0,0 +1,4 @@
+.env
+.env.testcopy
+node_modules
+data/

DEPLOY.md

@@ -0,0 +1,94 @@
+# Deploying to Dokploy
+
+The app is a single Node process with no dependencies. Dokploy builds it from
+the `Dockerfile` in this repo and puts Traefik in front of it.
+
+## 1. Push the repo to a Git host
+
+Dokploy pulls from GitHub/GitLab/Gitea (or a raw Git URL over SSH).
+
+**Before the first push:** `.env` and `.env.testcopy` contain a real DeepL API
+key. They are untracked from now on via `.gitignore`, but if they were already
+committed they still exist in history — remove them from tracking and rotate
+the key rather than relying on the file being gone from the working tree.
+
+## 2. Create the application in Dokploy
+
+Project → **Create Service** → **Application**.
+
+| Field         | Value                          |
+| ------------- | ------------------------------ |
+| Source        | Git provider + this repo/branch |
+| Build Type    | **Dockerfile**                 |
+| Dockerfile    | `Dockerfile`                   |
+
+## 3. Environment variables
+
+**Environment** tab:
+
+```
+DEEPL_API_KEY=<your DeepL Growth API key>
+```
+
+`PORT` and `DOMAINS_FILE` are already set in the Dockerfile — do not override
+them unless you also change the volume mount path to match.
+
+The key is server-side only; it is never sent to the browser.
+
+## 4. Volume (required)
+
+Without this, every redeploy resets all glossary mappings.
+
+**Advanced → Volumes → Add** :
+
+| Field       | Value          |
+| ----------- | -------------- |
+| Type        | Volume Mount   |
+| Volume Name | `deepl-data`   |
+| Mount Path  | `/app/data`    |
+
+`DOMAINS_FILE=/app/data/domains.json` writes into that volume. The path is a
+subdirectory of `/app` on purpose — mounting `/app` itself would hide
+`server.js` and `index.html`.
+
+## 5. Domain
+
+**Domains** tab → Add:
+
+| Field         | Value                    |
+| ------------- | ------------------------ |
+| Host          | your hostname            |
+| Container Port| `3000`                   |
+| HTTPS         | on, Let's Encrypt        |
+
+## 6. Deploy
+
+Hit **Deploy**. Verify with:
+
+```
+curl https://<your-host>/health
+# {"status":"ok","apiKeyConfigured":true}
+```
+
+`apiKeyConfigured: false` means `DEEPL_API_KEY` did not reach the container.
+
+## Seeding existing glossary mappings
+
+A fresh volume starts empty and the app writes a default `domains.json` with
+all four domains and no glossaries. The `domains.json` in this repo is **not**
+copied into the image (it is in `.dockerignore`), so any glossary IDs recorded
+there are not carried over. Either re-save the glossaries through the UI after
+the first deploy, or copy the file in once:
+
+```
+docker cp domains.json <container>:/app/data/domains.json
+docker restart <container>
+```
+
+## Notes
+
+- The app has **no authentication**. Anything on the public domain can use your
+  DeepL quota and edit the shared glossaries. Put Traefik basic auth or an
+  IP allowlist in front of it if it is internet-facing.
+- Docker `HEALTHCHECK` hits `/health` every 30s. It does not call DeepL, so a
+  DeepL outage will not restart the container.

Dockerfile

@@ -7,10 +7,21 @@ FROM node:18-alpine
 WORKDIR /app
 COPY server.js index.html package.json ./
 
-# DEEPL_API_KEY is passed at "docker run" time (via -e or --env-file), not
-# baked into the image. domains.json should be bind-mounted so glossary
-# data survives container restarts/recreation (see README).
+# DEEPL_API_KEY is passed at runtime (docker run -e / --env-file, or the
+# Dokploy "Environment" tab), never baked into the image.
+#
+# domains.json holds which DeepL glossary_id belongs to which domain and
+# direction. It must live on a mounted volume, otherwise every redeploy
+# builds a fresh filesystem and the mappings are lost. /app/data is a
+# subdirectory so mounting it does not shadow the app files in /app.
 ENV PORT=3000
+ENV DOMAINS_FILE=/app/data/domains.json
+RUN mkdir -p /app/data
+VOLUME ["/app/data"]
+
 EXPOSE 3000
 
+HEALTHCHECK --interval=30s --timeout=5s --start-period=5s --retries=3 \
+  CMD wget -qO- http://127.0.0.1:3000/health || exit 1
+
 CMD ["node", "server.js"]

server.js

@@ -66,7 +66,10 @@ function baseUrlFor(apiKey) {
 // the server disk, not in any user's browser, so every visitor to the site
 // sees and edits the same shared glossaries.
 
-const DOMAINS_FILE = path.join(__dirname, 'domains.json');
+// The path is overridable via DOMAINS_FILE so a container deployment can point
+// it at a mounted volume (e.g. /app/data/domains.json) instead of the image's
+// own filesystem, which is recreated on every redeploy.
+const DOMAINS_FILE = process.env.DOMAINS_FILE || path.join(__dirname, 'domains.json');
 const VALID_DOMAINS = ['scheer-group', 'scheer-ids', 'scheer-pas', 'scheer-imc'];
 const DOMAIN_LABELS = {
   'scheer-group': 'Scheer Group',
@@ -137,6 +140,7 @@ function loadDomains() {
 }
 
 function saveDomains(data) {
+  fs.mkdirSync(path.dirname(DOMAINS_FILE), { recursive: true });
   fs.writeFileSync(DOMAINS_FILE, JSON.stringify(data, null, 2));
 }
 
@@ -448,7 +452,15 @@ function serveStatic(req, res) {
   });
 }
 
+// Liveness probe for container platforms (Docker HEALTHCHECK, Dokploy).
+// Deliberately does not call DeepL: it answers "is this process serving?",
+// not "is the upstream API up", so a DeepL outage doesn't restart the app.
+function handleHealth(req, res) {
+  sendJson(res, 200, { status: 'ok', apiKeyConfigured: Boolean(DEEPL_API_KEY) });
+}
+
 const routes = {
+  'GET /health': handleHealth,
   'POST /api/translate': handleTranslate,
   'POST /api/usage': handleUsage,
   'POST /api/document/upload': handleDocumentUpload,