Dockerfile.backend

# ── ChainForge Express Backend ─────────────────────────────────────────────────
#
# Directory layout inside the container:
#   /app/backend/      ← backend code (server.js, node_modules, etc.) — __dirname
#   /go-root/          ← GO_ROOT env var — where the Go binary reads/writes
#                         blockchain_<NODE_ID>.db / wallet_<NODE_ID>.dat.
#                         chain-data volume is mounted here in docker-compose.
#   /go-bin/           ← shared volume from go-builder
#     chainforge        ← Linux binary copied here by go-builder
#
# IMPORTANT: backend code must NOT live inside /go-root (or any path under the
# chain-data mount point). Mounting a named volume REPLACES everything the
# image had at that path — it does not merge with it. Once the volume has data
# in it (after its first use), any code baked into a later image build at that
# same path is silently hidden behind the volume's older snapshot. That's why
# GO_ROOT is resolved from an explicit env var (see goRunner.js) instead of
# being derived from __dirname like it used to be.
#
# At startup the CMD copies /go-bin/chainforge → /usr/local/bin/chainforge.exe
# so server.js can call `chainforge.exe` from any cwd and it resolves on PATH.
# ──────────────────────────────────────────────────────────────────────────────

FROM node:20-alpine

WORKDIR /app/backend

# Install dependencies
COPY backend/package.json backend/package-lock.json* ./
RUN npm install --omit=dev

# Copy backend source (server.js, db.js, goRunner.js, models/, routes/, etc.)
COPY backend/ ./

ENV GO_ROOT=/go-root

EXPOSE 5000

# At startup:
#  1. Copy the Go binary from the shared go-bin volume to /usr/local/bin
#     named chainforge.exe so server.js execSync(`chainforge.exe ...`) works.
#  2. Start the Node server.
CMD ["sh", "-c", "cp /go-bin/chainforge /usr/local/bin/chainforge.exe && chmod +x /usr/local/bin/chainforge.exe && node server.js"]