thermograph/backend/Dockerfile

# Thermograph backend: FastAPI API + accounts/notifications + the SSR content
# JSON API frontend consumes. Split from the monorepo (repo-split Stage 7).

# thermograph-daemon (daemon/): the Go process that owns the Discord gateway
# websocket and the recurring-job timers, calling back into this app's
# /internal/* routes for anything that needs data. It is built INTO this image
# on purpose: daemon and backend share the internal API contract, so shipping
# one image (compose picks the process per-service) makes version skew between
# them impossible. CGO_ENABLED=0 gives a fully static binary that drops into
# the python:3.12-slim final stage with no runtime deps; go.mod/go.sum are
# copied and downloaded before the sources so the Go dep layer caches across
# daemon code-only changes, same reasoning as the pip layer below.
FROM golang:1.26 AS daemon-builder
WORKDIR /src
COPY daemon/go.mod daemon/go.sum ./
RUN go mod download
COPY daemon/ ./
# -trimpath keeps the build reproducible (identical sources -> identical
# binary), which is what lets the final stage's COPY layer cache-hit when only
# Python code changed.
RUN CGO_ENABLED=0 go build -trimpath -o /out/thermograph-daemon .

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

# The daemon binary lands before the app tree: it changes far less often than
# the Python code, so this layer usually cache-hits and only the COPY below
# rebuilds. NOT the entrypoint — deploy/entrypoint.sh stays that; compose
# selects this binary per-service for the daemon container.
COPY --from=daemon-builder /out/thermograph-daemon /usr/local/bin/thermograph-daemon

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"]