XQA - XML Quality Assurance

1. Introduction

• XQA is a suite of Docker based microservices that improves the scalability of BaseX - an XML database engine.
• Instead of loading each XML file into a single BaseX engine, XQA distributes them - via an AMQP message broker - across multiple BaseX engines.
• XQA ships with a basic web frontend - as well as a REST API - which lets you run XQuery, and analytics, against the distributed data.

2. High Level Design

3. Key Features

• Easy to deploy / extend:
  • each microservice runs in its own container.
  • add extra BaseX engines easily - they self register against the AMQP message broker.
  • can run in either a docker-compose or k8s environment.
• Proven scalability & performance improvements - graphs in xqa-perf show:
  • ingest timing statistics.
  • XML file distribution.
• Quality Radiatior for CI; static analysis and coverage metrics.
• Transparency:
  • container console logging.
  • JSON instrumentation sent to a central PstgreSQL instance.

4. Open Source Technologies

• ActiveMQ
• Angular
• Docker - containers can be built from GitHub or pull'd from hub.docker.com.
• Java 10/11.
• PostgreSQL 11
• Python 3.6
• Ubuntu 18.04

5. Microservices

CI	GitHub
	xqa-commons-qpid-jms	a Maven Central shared library.
	xqa-db	PostgreSQL.
	xqa-db-amqp	AMQP interface to PostgresSQL.
	xqa-ingest	XML file loader.
	xqa-ingest-balancer	distributes XML across XQA BaseX engine(s).
	xqa-message-broker	ActiveMQ.
	xqa-perf	end to end integration tests, with Matplotlib graphs.
	xqa-query-balancer	XQA REST API.
	xqa-query-ui	UI for querying XQA.
	xqa-shard	BaseX engine with AMQP interface.
	xqa-test-data	a collection of XML files used by XQA.

6. Limitatons

XQA is a proof of concept project. It scratched an itch and achieved what it set out to prove. Refer to the GitHub issue board for outstanding issues.