Enhance run.sh with improved error handling (#87)

Updated error handling and logging for gunicorn process.

run.sh

@@ -1,5 +1,5 @@
 #!/usr/bin/env bash
-set -e
+set -euo pipefail
 
 # Default to 1 worker to prevent OOM on low-memory hosts
 WORKERS_VALUE="${WORKERS:-1}"
@@ -17,16 +17,16 @@ until python scripts/init_pgvector.py; do
     echo "Database initialization failed after $i attempts; exiting."
     exit 1
   fi
-  echo "init_pgvector.py failed (attempt $i/$MAX_RETRIES). Sleeping $((SLEEP_BASE ** i))s before retry..."
-  sleep $((SLEEP_BASE ** i))
+  echo "init_pgvector.py failed (attempt $i/$MAX_RETRIES). Sleeping $((SLEEP_BASE * i))s before retry..."
+  sleep $((SLEEP_BASE * i))
   i=$((i + 1))
 done
 
 echo "Starting gunicorn on port ${PORT_VALUE} with ${WORKERS_VALUE} workers and timeout ${TIMEOUT_VALUE}s"
 export PYTHONPATH="/app${PYTHONPATH:+:$PYTHONPATH}"
 
-# Use explicit logging options so any worker crash or import error is visible
-exec gunicorn \
+# Start gunicorn in background so we can trap signals and collect diagnostics
+gunicorn \
   --bind 0.0.0.0:${PORT_VALUE} \
   --workers "${WORKERS_VALUE}" \
   --timeout "${TIMEOUT_VALUE}" \
@@ -34,4 +34,28 @@ exec gunicorn \
   --access-logfile - \
   --error-logfile - \
   --capture-output \
-  app:app
+  app:app &
+
+GUNICORN_PID=$!
+
+# Trap TERM and INT, log diagnostics, forward the signal to gunicorn, and wait
+handle_term() {
+  echo "===== SIGTERM received at $(date -u +'%Y-%m-%dT%H:%M:%SZ') ====="
+  echo "--- Top processes by RSS ---"
+  ps aux --sort=-rss | head -n 20 || true
+  echo "--- /proc/meminfo ---"
+  cat /proc/meminfo || true
+  echo "Forwarding SIGTERM to gunicorn (pid ${GUNICORN_PID})"
+  kill -TERM "${GUNICORN_PID}" 2>/dev/null || true
+  # Wait for gunicorn to exit
+  wait "${GUNICORN_PID}" || true
+  echo "Gunicorn exited; wrapper exiting"
+  exit 0
+}
+trap 'handle_term' SIGTERM SIGINT
+
+# Wait for gunicorn to exit normally
+wait "${GUNICORN_PID}"
+EXIT_CODE=$?
+echo "Gunicorn stopped with exit code ${EXIT_CODE}"
+exit "${EXIT_CODE}"