File monitoring gRPC service

This gRPC service is used and called by the RESTful Gateway project.

A gRPC microservice that monitors a given folder with files (e.g. json files), uses in memory cache to update any file changed. It has one method ParseJsonFiles which when called will return all files in the cache.

Design pattern

The decorator design pattern is used for the file service, to extend the package without changing existing code. This pattern was used achieve the second principle of SOLID: open/close principle. Other principles were also used from SOLID overall: single responsibility and interfaces.

In memory cache

Thread safe with auto changes detection mechanism. Incoming requests will be served the cache, which is faster and more efficient than reading files on every request.

Unit tests

The are some unit test examples for the cache and file services.

Docker

This service is created as docker image and pushed to docker hub in order to use it later in the gateway network and container.

How to test?

The default config has a port of 8081. If you want to change simply create a .env file and then run make dockerBuildRun. Note that in either way, the .env file is required for docker to run.

Test using grpcurl

To test the service after running you can call make grpcurl or:

$ grpcurl -plaintext -d '{}' localhost:8080 JsonParsingService.ParseJsonFiles

Have a look on Makefile for more examples.

Test using the client

Alternatively, you can run the client in cmd/client:

$ go run .

Tools and frameworks used

• Zerlog for logging