Exit when lightningd fails before RPC startup

.github/workflows/docker.yml

@@ -31,6 +31,9 @@ jobs:
       - name: Check out repository
         uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
 
+      - name: Test entrypoint lifecycle
+        run: bash tests/docker-entrypoint-test.sh
+
       - name: Validate versions
         shell: bash
         run: |

docker-entrypoint.sh

@@ -13,8 +13,20 @@ LIGHTNINGD_PID=$!
 trap 'kill -TERM "$LIGHTNINGD_PID" 2>/dev/null' TERM INT
 
 echo "Core-Lightning starting"
-while read -r i; do if [ "$i" = "lightning-rpc" ]; then break; fi; done \
-    < <(inotifywait -e create,open --format '%f' --quiet "${networkdatadir}" --monitor)
+while [[ ! -e "${networkdatadir}/lightning-rpc" ]]; do
+    if ! kill -0 "$LIGHTNINGD_PID" 2>/dev/null; then
+        wait "$LIGHTNINGD_PID"
+        status=$?
+        trap - TERM INT
+        exit "$status"
+    fi
+
+    if [[ -d "${networkdatadir}" ]]; then
+        inotifywait -e create,open --quiet --timeout 1 "${networkdatadir}" >/dev/null 2>&1 || true
+    else
+        sleep 1
+    fi
+done
 
 if [ "$EXPOSE_TCP" == "true" ]; then
     echo "Core-Lightning started, RPC available on port $LIGHTNINGD_RPC_PORT"

tests/docker-entrypoint-test.sh

@@ -0,0 +1,71 @@
+#!/usr/bin/env bash
+
+set -euo pipefail
+
+repo_dir="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+test_dir="$(mktemp -d)"
+trap 'rm -rf "$test_dir"' EXIT
+
+mkdir -p "$test_dir/bin"
+
+cat >"$test_dir/bin/lightningd" <<'EOF'
+#!/usr/bin/env bash
+
+case "$TEST_LIGHTNINGD_MODE" in
+    fail)
+        sleep 0.1
+        exit 42
+        ;;
+    ready)
+        sleep 0.1
+        touch "$LIGHTNINGD_DATA/$LIGHTNINGD_NETWORK/lightning-rpc"
+        sleep 0.1
+        ;;
+esac
+EOF
+
+cat >"$test_dir/bin/inotifywait" <<'EOF'
+#!/usr/bin/env bash
+sleep 0.05
+exit 2
+EOF
+
+chmod +x "$test_dir/bin/lightningd" "$test_dir/bin/inotifywait"
+
+failure_data="$test_dir/failure"
+mkdir -p "$failure_data/bitcoin"
+
+set +e
+PATH="$test_dir/bin:$PATH" \
+    LIGHTNINGD_DATA="$failure_data" \
+    LIGHTNINGD_NETWORK="bitcoin" \
+    TEST_LIGHTNINGD_MODE="fail" \
+    timeout 3 bash "$repo_dir/docker-entrypoint.sh" >/dev/null 2>&1
+failure_status=$?
+set -e
+
+if [[ "$failure_status" -ne 42 ]]; then
+    echo "expected early lightningd failure status 42, got $failure_status" >&2
+    exit 1
+fi
+
+ready_data="$test_dir/ready"
+mkdir -p "$ready_data/bitcoin" "$ready_data/lightning-poststart.d"
+cat >"$ready_data/lightning-poststart.d/verify" <<EOF
+#!/usr/bin/env bash
+touch "$test_dir/poststart-ran"
+EOF
+chmod +x "$ready_data/lightning-poststart.d/verify"
+
+PATH="$test_dir/bin:$PATH" \
+    LIGHTNINGD_DATA="$ready_data" \
+    LIGHTNINGD_NETWORK="bitcoin" \
+    TEST_LIGHTNINGD_MODE="ready" \
+    timeout 3 bash "$repo_dir/docker-entrypoint.sh" >/dev/null 2>&1
+
+if [[ ! -f "$test_dir/poststart-ran" ]]; then
+    echo "expected post-start hook to run after RPC became available" >&2
+    exit 1
+fi
+
+echo "docker-entrypoint tests passed"