add multihop example script

scripts/run_multihop_example.sh

@@ -0,0 +1,74 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+# Navigate to repository root
+cd "$(dirname "$0")/.."
+
+# Configuration
+PORT=3050
+DB_PATH="/tmp/databuild_multihop.db"
+FLAG_FILE="/tmp/databuild_multihop_alpha_complete"
+PID_FILE="/tmp/databuild_multihop.pid"
+
+echo "=== DataBuild Multi-Hop Example ==="
+echo
+
+# Clean up previous state
+echo "Cleaning up previous state..."
+rm -f "$DB_PATH" "$FLAG_FILE" "$PID_FILE"
+pkill -f "databuild.*serve.*port $PORT" || true
+sleep 1
+
+# Build the binary
+echo "Building databuild CLI..."
+bazel build //databuild:databuild
+
+# Start the server in background
+echo "Starting databuild server on port $PORT..."
+./bazel-bin/databuild/databuild serve \
+  --port $PORT \
+  --database "$DB_PATH" \
+  --config examples/multihop/config.json &
+
+SERVER_PID=$!
+echo $SERVER_PID > "$PID_FILE"
+echo "Server started with PID $SERVER_PID"
+
+# Wait for server to be ready
+echo "Waiting for server to start..."
+sleep 2
+
+# Test server health
+if curl -s http://localhost:$PORT/health > /dev/null 2>&1; then
+    echo "Server is ready!"
+else
+    echo "WARNING: Server health check failed, but continuing..."
+fi
+
+echo
+echo "=== Server is running ==="
+echo
+echo "You can now interact with the server:"
+echo
+echo "  # Create a want for data/beta (triggers dependency chain)"
+echo "  ./bazel-bin/databuild/databuild --server http://localhost:$PORT want data/beta"
+echo
+echo "  # Monitor wants"
+echo "  ./bazel-bin/databuild/databuild --server http://localhost:$PORT wants list"
+echo
+echo "  # Monitor job runs"
+echo "  ./bazel-bin/databuild/databuild --server http://localhost:$PORT job-runs list"
+echo
+echo "  # Monitor partitions"
+echo "  ./bazel-bin/databuild/databuild --server http://localhost:$PORT partitions list"
+echo
+echo "To stop the server:"
+echo "  kill $SERVER_PID"
+echo "  # or: pkill -f 'databuild.*serve.*port $PORT'"
+echo
+echo "Server logs will appear below. Press Ctrl+C to stop."
+echo "=========================================="
+echo
+
+# Wait for the server process
+wait $SERVER_PID