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node/Dockerfile
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beardthelion 803d83efdb fix(node): reap leaked git child processes (#53) (#61)
* fix(docker): reap orphan processes via tini + init, cap pids

The node runs as PID 1 in the container and never reaps reparented
orphans, so git grandchildren (e.g. pack-objects left behind when a
served clone disconnects) accumulate as zombies until fork() fails with
EAGAIN. Run under tini and set compose init: true so reparented orphans
are reaped, and add pids_limit as a blast-radius cap.

Refs #53

* fix(node): reap leaked git child processes (#53)

Serving git over smart-HTTP could leak zombie processes that, over weeks,
exhaust the PID table until fork() fails with EAGAIN and all git
operations break until restart.

The serve path (run_git_service) now runs git in its own process group and
SIGKILLs that group when the request future is dropped (client disconnect)
or returns early, so git and its pack-objects child are torn down together
instead of orphaning the grandchild to PID 1 as a zombie. A drop guard,
disarmed once the request completes cleanly, owns this teardown.

create_issue and build_filtered_pack spawned a std Child and dropped it
unwaited if the stdin write failed (and build_filtered_pack could panic on
a missing stdin handle). Both now always wait the child before surfacing
any error, so the failure path cannot leak.

Adds libc for the group-kill syscall and three regression tests covering
direct-child kill, grandchild reaping via the group, and the disarmed
no-kill path.

Refs #53

* fix(review): reap-then-disarm on serve-path errors; tini/comment nits

Address code-review findings on the #53 fix:

- run_git_service no longer early-returns on a stdin-write error. It captures
  the write result, always reaps the child, then disarms the group guard
  before surfacing the error. Previously a write/wait error path could drop
  the still-armed guard after the child was already reaped, so the group
  SIGKILL could in theory land on a reused pgid. (correctness, reliability,
  adversarial all flagged this region.)
- Drop tini's -g flag: the node manages its own children and graceful
  shutdown, so group-wide signalling would only disturb in-flight git helpers
  on shutdown.
- Correct the SAFETY comment (kill(2) is not relevant to async-signal-safety
  here) and the alive() test-helper comment (EPERM does not read as alive).

* fix(node): SIGTERM (not SIGKILL) the served-git group on disconnect

SIGKILL gave git no chance to run its signal cleanup, so an aborted
receive-pack could leave a stale .git/*.lock that blocks the next push.
SIGTERM lets git remove its lock files before exiting. Signalling the
whole process group still reaches pack-objects directly, so the grandchild
is terminated rather than orphaned, and a single immediate signal avoids
any delayed-kill pid-reuse window.

Refs #53

* docs(node): correct stale SIGKILL comments to SIGTERM in served-git teardown
2026-06-23 10:10:17 +08:00

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3.7 KiB
Docker

# syntax=docker/dockerfile:1.6
#
# gitlawb-node — production image for operators.
# Multi-arch (linux/amd64, linux/arm64), non-root runtime, HEALTHCHECK.
# ── Build stage ─────────────────────────────────────────────────────────────
FROM rust:1.91-bookworm AS builder
WORKDIR /build
# Cache dependencies first for faster rebuilds
COPY Cargo.toml Cargo.lock ./
COPY crates/gitlawb-core/Cargo.toml crates/gitlawb-core/
COPY crates/gitlawb-node/Cargo.toml crates/gitlawb-node/
COPY crates/gl/Cargo.toml crates/gl/
COPY crates/git-remote-gitlawb/Cargo.toml crates/git-remote-gitlawb/
# Fetch deps (this layer caches until Cargo.{toml,lock} change)
RUN mkdir -p crates/gitlawb-core/src crates/gitlawb-node/src crates/gl/src crates/git-remote-gitlawb/src && \
echo 'fn main() {}' > crates/gitlawb-node/src/main.rs && \
echo 'fn main() {}' > crates/gl/src/main.rs && \
echo 'fn main() {}' > crates/git-remote-gitlawb/src/main.rs && \
echo '' > crates/gitlawb-core/src/lib.rs && \
cargo build --release -p gitlawb-node -p gl -p git-remote-gitlawb || true
# Now copy real sources and build for real.
# Force-bump mtimes so cargo's fingerprint check rebuilds — without this,
# cargo can keep the dummy `fn main() {}` binaries from the cache layer above
# and the runtime container exits immediately with code 0.
COPY crates/ crates/
COPY bootstrap-peers.json ./
RUN find crates -name "*.rs" -exec touch {} + && \
rm -f target/release/gitlawb-node target/release/gl target/release/git-remote-gitlawb && \
rm -rf target/release/.fingerprint/gitlawb-node-* \
target/release/.fingerprint/gl-* \
target/release/.fingerprint/git-remote-gitlawb-* && \
cargo build --release -p gitlawb-node -p gl -p git-remote-gitlawb && \
strip target/release/gitlawb-node target/release/gl target/release/git-remote-gitlawb
# ── Runtime stage ───────────────────────────────────────────────────────────
FROM debian:bookworm-slim
RUN apt-get update && apt-get install -y --no-install-recommends \
git \
ca-certificates \
curl \
tini \
&& rm -rf /var/lib/apt/lists/*
# Non-root user for runtime
RUN groupadd -r gitlawb --gid=1000 \
&& useradd -r -g gitlawb --uid=1000 --home-dir=/data --shell=/sbin/nologin gitlawb \
&& mkdir -p /data/repos /data/keys \
&& chown -R gitlawb:gitlawb /data
COPY --from=builder /build/target/release/gitlawb-node /usr/local/bin/
COPY --from=builder /build/target/release/gl /usr/local/bin/
COPY --from=builder /build/target/release/git-remote-gitlawb /usr/local/bin/
USER gitlawb
WORKDIR /data
ENV GITLAWB_REPOS_DIR=/data/repos \
GITLAWB_KEY=/data/keys/identity.pem \
GITLAWB_HOST=0.0.0.0 \
GITLAWB_PORT=7545 \
GITLAWB_P2P_PORT=7546
EXPOSE 7545 7546/udp
VOLUME ["/data"]
HEALTHCHECK --interval=30s --timeout=5s --start-period=15s --retries=3 \
CMD curl -fsS http://127.0.0.1:${GITLAWB_PORT}/health || exit 1
# Run under tini so the node is never PID 1. As PID 1 a process must reap
# reparented orphans itself; the node does not, so git's reparented grandchildren
# (e.g. pack-objects orphaned when a served upload-pack dies on a client
# disconnect) would accumulate as zombies until fork() fails with EAGAIN (#53).
# tini reaps them and forwards SIGTERM/SIGINT to the node, which runs its own
# graceful shutdown. (No `-g`: the node manages its own children, so group-wide
# signalling would only disturb in-flight git helpers during shutdown.)
ENTRYPOINT ["tini", "--", "gitlawb-node"]