Saga Product

Transaction services of my saga pattern implementation, including product, order, payment and orchestrator.

Features:

• Entirely event-driven
• Idempotency for all transactions
• Stateless saga orchestrator making transactions scalable
• Sonyflake distributed unique ID generator
• Redis cache for fast data retrieval
• Bloom/Cuckoo filters for preventing cache penatration
• Prometheus metrics
• Distributed tracing with OpenTelemetry
  • HTTP server
  • gRPC server
  • gPRC client
  • Event handlers
• Four microservices in a monorepo and compiled to a single binary, minimizing deployment efforts
• Comprehensive application struture with domain-driven design (DDD), decoupling service implementations from configurations and transports
• Compile-time dependecy injection using wire
• Graceful shutdown
• Unit testing and continuous integration using Drone CI

Usage

See docker-compose example for details on how to start each service.

Exported Metrics

• APP could be product, order, payment, or orchestrator.
• HTTPAPP could be product, order, or payment.

Metric	Description	Labels
APP_pubsub_subscriber_messages_received_total	A Prometheus Counter. Counts the number of messages obtained by the subscriber.	acked ("acked" or "nacked"), handler_name, subscriber_name
APP_pubsub_handler_execution_time_seconds (APP_pubsub_handler_execution_time_seconds_count, APP_pubsub_handler_execution_time_bucket, APP_pubsub_handler_execution_time_seconds_sum)	A Prometheus Histogram. Records the execution time of the handler function wrapped by the middleware.	handler_name, success ("true" or "false")
APP_pubsub_publish_time_seconds (APP_pubsub_publish_time_seconds_count, APP_pubsub_publish_time_seconds_bucket, APP_pubsub_publish_time_seconds_sum)	A Prometheus Histogram. Registers the time of execution of the Publish function of the decorated publisher.	handler_name, success ("true" or "false"), publisher_name
HTTPAPP_http_request_duration_seconds (HTTPAPP_http_request_duration_seconds_count, HTTPAPP_http_request_duration_seconds_bucket, HTTPAPP_http_request_duration_sum)	A Prometheus histogram. Records the latency of the HTTP requests.	code, handler, method
HTTPAPP_http_requests_inflight	A Prometheus gauge. Records the number of inflight requests being handled at the same time.	code, handler, method
HTTPAPP_http_response_size_bytes (HTTPAPP_http_response_size_bytes_count, HTTPAPP_http_response_size_bytes_bucket, HTTPAPP_http_response_size_bytes_sum)	A Prometheus histogram. Records the size of the HTTP responses.	handler