Standalone backend: no-walk paths.py, own Dockerfile, own CI

paths.py drops the sibling-directory walk (backend is now the repo
root, no more frontend/ sibling to walk toward). requirements.txt
drops jinja2/PyYAML (only needed for frontend_ssr's sake in the old
shared monorepo Dockerfile) and fixes stale backend/push.py-style
path comments. New Dockerfile (COPY . /app/, no THERMOGRAPH_SERVICE_ROLE
branch -- this image only ever runs backend) and entrypoint.sh (cd
/app instead of /app/backend). Minimal build.yml: docker build + boot
+ /healthz check.

Verified: image builds and boots standalone (real alembic migration
against SQLite, /healthz and /api/v2/place both 200), full pytest
suite green (301 passed, 4 skipped) against the rewritten paths.py.

.forgejo/workflows/build.yml

@@ -0,0 +1,43 @@
+name: Build + boot check
+
+# Proves the split Dockerfile actually builds and boots standalone (repo-split
+# Stage 7b) -- not yet a full pytest-suite migration (that's separate, real
+# follow-up work, same category as thermograph-copy's deferred vendoring).
+# THERMOGRAPH_FRONTEND_BASE_INTERNAL is required (fails loud if unset) but
+# never actually exercised here -- /healthz doesn't go through the
+# catch-all proxy, so an unreachable placeholder is fine for this check.
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  build:
+    runs-on: docker
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install Docker CLI
+        run: |
+          apt-get update -qq
+          apt-get install -y -qq docker.io
+
+      - name: Build
+        run: docker build -t thermograph-backend:ci .
+
+      - name: Boot + health check
+        run: |
+          docker run -d --name backend-ci \
+            -e THERMOGRAPH_FRONTEND_BASE_INTERNAL=http://127.0.0.1:1 \
+            -p 8137:8137 thermograph-backend:ci
+          ok=0
+          for i in $(seq 1 30); do
+            if curl -fsS -o /dev/null http://127.0.0.1:8137/healthz; then ok=1; break; fi
+            sleep 1
+          done
+          docker logs backend-ci
+          docker rm -f backend-ci >/dev/null 2>&1 || true
+          if [ "$ok" != 1 ]; then echo "backend never became healthy"; exit 1; fi
+          echo "OK: backend booted standalone"

.gitignore

@@ -0,0 +1,14 @@
+.venv/
+__pycache__/
+*.pyc
+data/cache/*.parquet
+data/geonames/
+data/thermograph.sqlite*
+data/accounts.sqlite*
+data/vapid.json
+data/indexnow_key.txt
+data/indexnow_state.txt
+data/homepage.json
+logs/
+.DS_Store
+.env

Dockerfile

@@ -0,0 +1,42 @@
+# Thermograph backend: FastAPI API + accounts/notifications + the SSR content
+# JSON API frontend consumes. Split from the monorepo (repo-split Stage 7).
+FROM python:3.12-slim
+
+# curl is only for the container HEALTHCHECK below. Everything Python needs
+# ships as manylinux wheels (asyncpg, psycopg[binary], polars, numpy,
+# cryptography via pywebpush, PyNaCl), so no compiler/build toolchain is
+# required.
+RUN apt-get update \
+    && apt-get install -y --no-install-recommends curl \
+    && rm -rf /var/lib/apt/lists/*
+
+# Install deps first so this layer caches across code-only changes.
+COPY requirements.txt /tmp/requirements.txt
+RUN pip install --no-cache-dir -r /tmp/requirements.txt
+
+COPY . /app/
+RUN chmod +x /app/deploy/entrypoint.sh
+
+# Non-root runtime user. Create the writable state dirs and own the whole tree
+# so the parquet cache, logs, notifier.lock, homepage.json, vapid.json can be
+# written. When the named volumes first mount over /app/data and /app/logs,
+# Docker seeds them from this image content -- including this ownership --
+# so they stay writable.
+RUN useradd --system --create-home --uid 10001 thermograph \
+    && mkdir -p /app/data /app/logs \
+    && chown -R thermograph:thermograph /app
+
+USER thermograph
+WORKDIR /app
+
+ENV PORT=8137 \
+    WORKERS=4 \
+    THERMOGRAPH_BASE=/ \
+    PYTHONUNBUFFERED=1
+
+EXPOSE 8137
+
+HEALTHCHECK --interval=30s --timeout=5s --start-period=40s --retries=3 \
+    CMD curl -fsS http://127.0.0.1:${PORT}/healthz || exit 1
+
+ENTRYPOINT ["/app/deploy/entrypoint.sh"]

deploy/entrypoint.sh

@@ -7,18 +7,7 @@
 # ready to accept the migration.
 set -euo pipefail
 
-# THERMOGRAPH_SERVICE_ROLE (repo-split Stage 4): which app this container
-# actually runs -- backend (default, today's exact behavior: migrations, then
-# backend/app.py) or frontend (frontend_ssr/app.py -- stateless, no DB, no
-# migrations at all). Not to be confused with THERMOGRAPH_ROLE (web|worker),
-# which only applies within the backend role.
-if [ "${THERMOGRAPH_SERVICE_ROLE:-backend}" = "frontend" ]; then
-  cd /app/frontend_ssr
-  echo "==> Starting uvicorn (frontend) on 0.0.0.0:${PORT:-8137} with ${WORKERS:-4} worker(s)"
-  exec uvicorn app:app --host 0.0.0.0 --port "${PORT:-8137}" --workers "${WORKERS:-4}"
-fi
-
-cd /app/backend
+cd /app
 
 # --- Swarm secrets shim ------------------------------------------------------
 # The app reads config from os.environ everywhere (users.py falls back to a random
@@ -74,8 +63,8 @@ run_migrations() {
 }
 
 # One-shot migrate mode (`entrypoint.sh migrate`, or THERMOGRAPH_MIGRATE_ONLY=1): run
-# the migration and exit — the Swarm one-shot task from the hop-1 cutover runbook, so
-# it runs once against the DB rather than racing per web replica.
+# the migration and exit — a one-shot task, so it runs once against the DB rather
+# than racing per web replica.
 if [ "${1:-}" = "migrate" ] || [ "${THERMOGRAPH_MIGRATE_ONLY:-0}" = "1" ]; then
   run_migrations
   exit 0
@@ -88,5 +77,5 @@ if [ "${RUN_MIGRATIONS:-1}" != "0" ]; then
   run_migrations
 fi
 
-echo "==> Starting uvicorn (backend) on 0.0.0.0:${PORT:-8137} with ${WORKERS:-4} worker(s)"
+echo "==> Starting uvicorn on 0.0.0.0:${PORT:-8137} with ${WORKERS:-4} worker(s)"
 exec uvicorn app:app --host 0.0.0.0 --port "${PORT:-8137}" --workers "${WORKERS:-4}"

paths.py

@@ -11,30 +11,11 @@ keep doing so; these are only the defaults.
 """
 import os
 
-_HERE = os.path.dirname(os.path.abspath(__file__))
-
-
-def _repo_root() -> str:
-    """Walk up from this file until a directory holds both ``backend/`` and
-    ``frontend/`` — the repository root, in every checkout (dev, prod, worktree)."""
-    d = _HERE
-    while True:
-        if os.path.isdir(os.path.join(d, "backend")) and os.path.isdir(os.path.join(d, "frontend")):
-            return d
-        parent = os.path.dirname(d)
-        if parent == d:
-            raise RuntimeError(
-                "cannot locate the repo root (no ancestor has sibling backend/ and frontend/)"
-            )
-        d = parent
-
-
-REPO_DIR = _repo_root()
-BACKEND_DIR = os.path.join(REPO_DIR, "backend")
+REPO_DIR = os.path.dirname(os.path.abspath(__file__))
 DATA_DIR = os.path.join(REPO_DIR, "data")
 LOGS_DIR = os.path.join(REPO_DIR, "logs")
 
 # Bundled reference data shipped alongside the code (generated by gen_cities /
-# gen_flavor), not runtime state — hence under backend/, not data/.
-CITIES_JSON = os.path.join(BACKEND_DIR, "cities.json")
-CITIES_FLAVOR_JSON = os.path.join(BACKEND_DIR, "cities_flavor.json")
+# gen_flavor), not runtime state — hence at the repo root, not data/.
+CITIES_JSON = os.path.join(REPO_DIR, "cities.json")
+CITIES_FLAVOR_JSON = os.path.join(REPO_DIR, "cities_flavor.json")

requirements.txt

@@ -12,19 +12,11 @@ aiosqlite==0.22.1
 asyncpg==0.30.0
 psycopg[binary]==3.2.3
 alembic==1.14.0
-# Web Push (VAPID) delivery of notifications (see backend/push.py). Pulls in
+# Web Push (VAPID) delivery of notifications (see notifications/push.py). Pulls in
 # py-vapid, cryptography, and http-ece.
 pywebpush==2.0.0
-# Ed25519 verification of Discord interaction webhooks (see backend/discord_interactions.py).
+# Ed25519 verification of Discord interaction webhooks (see notifications/discord_interactions.py).
 PyNaCl==1.5.0
-# Not used by backend itself (its own content.py/content_loader.py were
-# deleted in repo-split Stage 4) -- installed here because frontend_ssr/
-# shares this requirements.txt in the current shared Dockerfile. See
-# frontend_ssr/content.py (server-rendered SEO content pages).
-jinja2==3.1.6
-# Structured SSR copy (glossary, static-page SEO meta) — see
-# frontend_ssr/content_loader.py and content/.
-PyYAML==6.0.3
 # Recurring worker-tier jobs — city warming, IndexNow pings (see
 # notifications/scheduler.py). In-process; no broker/queue needed at this scale.
 apscheduler==3.11.3