gRPC practice

Done while following this guide Udemy course: https://www.udemy.com/grpc-golang/

What's in this project

Three different go packages. All have to do with learning gRPC and are independent from each other

greet

Demoes types of gRPC communication (check it's proto file)
Uses SSL unlike the other two services
Proper gRPC error handling examples
Proper deadline examples

calculator

Lessons learned from greet. Where greet was instructor lead, calculator was meant for students to figure out their own solution
Not sure if it has proper eror/deadline examples. I might have implemented some.

blog

CRUD demonstration with a "blog" app.
Instructor lead, but I deviated and used DynamoDB.
If you are using my docker-compose.yml, there will be no need to worry about AWS credentials and region setup as I'm using a "dynamodb-local" image to provide the DynamoDB functionality.
Only of the three that uses DynamoDB
Not sure if it has proper eror/deadline examples. I might have implemented some.

Setup:

Requires:

docker
docker-compose
Optional (if you want to mess around with files directly without docker-compose)
- GoLang 1.12+
- Properly set-up GoLang environment (GOROOT/GOHOME)
- make

Usage

Spin up the servers

docker-compose up

In a separate tab, run clients

Skip this if you just want to explore with Evans

## GREET

# Grabbing the SSL cert. Needed for greet_client because that has an SSL example
docker cp grpc_greet_1:/code/ssl/server.crt ssl/server.crt
go run github.com/Kaurin/gRPC/greet/greet_client

## CALCULATOR
go run github.com/Kaurin/gRPC/calculator/calculator_client

### BLOG
go run github.com/Kaurin/gRPC/blog/blog_client

Exploring the gRPC API manually with Evans

Unfortunately, Evans doesn't support a simple "go get -u" :(

# Install the "evans" utility. Check the Makefile for details
make evans

## GREET
# Grabbing the SSL cert. Needed for greet_client because that has an SSL example
docker cp grpc_greet_1:/code/ssl/server.crt ssl/server.crt
evans -p 50052 --tls --host localhost --cacert ssl/server.crt --reflection

## CALCULATOR
evans -p 50053 -r

## BLOG
evans -p 50051 -r

What you want in all three is to use call <functionName>.

Evans has tab-compoletion, but if you want to see all functions in a given run, then use show rpc.

Also, you can use ctrl+d to end sending messages in examples that require it, or to just bail on input.

Cleanup

Don't forget to run:

docker-compose down

Manual cleanup of remaining files

WARNING Please make sure to read the makefile before running the command

make cleanimages