For backend applications, startup and shutdown often involve routine processes. go-boot encapsulates these standardized workflows to streamline development and ensure consistency.
System Check: Ensure system resources, ports, file permissions, and other dependencies are available and ready.
Dependency Verification: Validate that required environment variables (e.g., JAVA_HOME, PYTHONPATH) and external dependencies are correctly configured.
Resource Initialization: Load SSL certificates, encryption keys, or other essential external files.
Configuration Loading: Support multiple sources such as configuration files, environment variables, and remote configuration centers.
Environment-Specific Parsing: Load configurations tailored to the running environment (e.g., development, testing, production).
Dynamic Updates: Enable hot-reload functionality by starting configuration watchers if needed.
Logger Setup: Configure log formats (e.g., JSON), log levels (DEBUG, INFO, ERROR), and log rotation rules (e.g., daily, file size-based).
Log Targets: Support multiple output destinations such as console, files, or remote log aggregation services.
Contextual Information: Set global context details like service name, version, and instance ID.
Database Connections: Initialize connection pools and perform health checks to ensure readiness.
Cache Clients: Set up and warm up caching systems like Redis or Memcached.
Message Queues: Start producers for Kafka, RabbitMQ, or other messaging systems.
External API Clients: Initialize clients for external services (e.g., HTTP, gRPC, GraphQL) and perform connectivity tests.
Task Scheduler: Start schedulers for periodic tasks using Quartz, cron expressions, or equivalent mechanisms.
Async Task Pools: Configure thread pools with optimal resource allocation (core threads, max threads, queue capacities).
Task Preloading: Load task states or prefetch dependencies to ensure readiness.
Server Configuration: Load server settings, such as IP addresses, ports, and protocol types.
Route Registration: Define API routes or service methods for REST, gRPC, WebSocket, etc.
Service Registration: Register with service discovery platforms like Eureka, Consul, or Nacos.
Dependency Health: Confirm all dependent services are functioning as expected.
Self-Health Checks: Trigger internal diagnostics to verify service readiness.
Logging: Record startup completion time and application version for auditing purposes.
Signal Handling: Support various termination signals (e.g., SIGTERM, SIGINT) and bind appropriate handlers.
Graceful Timeout: Define a timeout for graceful shutdown to prevent the system from being flagged as unresponsive.
Stop New Requests: Close listening ports to reject new connections.
Complete Ongoing Requests: Allow ongoing requests to complete, with a timeout to enforce closure.
Deregister Service: Remove the instance from service registries to avoid routing traffic to a stopped server.
Graceful Task Completion: Signal running tasks to finish their current cycles.
Forced Termination: Use interruption mechanisms for tasks exceeding the timeout.
State Persistence: Save task states and results to ensure proper recovery on restart.
Database Connections: Close connection pools, release resources, and disconnect from the database.
Cache Clients: Disconnect from caching services and finalize pending operations.
Message Queue Clients: Close producers and ensure no message loss during shutdown.
External API Clients: Terminate long-lived connections (e.g., WebSocket) to external services.
Flush Buffers: Ensure all log data in memory is written to the appropriate destination.
Resource Cleanup: Release file handles, network connections, and other resources.
Memory Cleanup: Free global or thread-local variables to prevent memory leaks.
File Cleanup: Remove temporary files or intermediate artifacts created during runtime.
Lock Cleanup: Clear distributed or local locks to avoid conflicts during the next startup.
Exit Logs: Record the exit time, runtime duration, and any error details.
Alerts: Notify on-call engineers or alerting systems if the shutdown is abnormal.
By standardizing these workflows, go-boot ensures robust startup and shutdown processes for backend applications.