How to solve problem: customized projection is not running in Event Store

The defualt setting is  --run-projections=SYSTEM
Need to change
--run-projections=ALL

Reference:
https://github.com/EventStore/EventStore/wiki/Command-Line-Arguments

Refactoring code that accesses external services by Martin Fowler

http://martinfowler.com/articles/refactoring-external-service.html