Protocol-Independent Context Propagation for Sharing Microservices in Multiple Environments

In systems designed based on microservice architecture, many production-like environments should be deployed for testing, staging, debugging, and previewing. One way to reduce resource consumption while deploying many environments is to allow sharing of common microservices in multiple environments, and current mechanisms extend application layer protocols like HTTP and gRPC to propagate contexts including environment identifiers and to route requests. However, microservices also use other protocols such as MySQL, Redis, Memcached, and AMQP, and extending each protocol requires lots of effort to implement the extensions. This paper proposes PiCoP, a framework to propagate contexts and route requests independently of application layer protocols. PiCoP consists of a protocol that propagates contexts without interpreting application layer protocols by adding contexts to the front of each TCP byte stream and a proxy that uses the protocol to route requests. We design the protocol to make instrumentation into a system as easy as possible. We showed that PiCoP could reduce resource usage, that the proxy's communication delay is within a practical range, and that it makes sharing microservices in multiple environments with any application layer protocols possible.