nuttawut503 / grpc-gateway-otel-example

building gRPC Gateway and tracing requests to gRPC with Otelgrpc's OpenTelemetry-contrib

gRPC Gateway with Otelgrpc

Modules

• gRPC | Go
• gRPC Gateway
• OpenTelemetry-go
• otelgrpc from OpenTelemetry-contrib

This application has two services - Customer and Order

• Customer, I added two default customers and their IDs are "A310" and "K423" each customer has credit_limit (will explain about why it exists)
• Order, when making an order, we need a customer_id and the order_price if the order_price is more than the customer's credit_limit then the order service won't allow the order to be created. But if the order_price is less than or equal to the customer's credit_limit then the order service will create the order and return transaction_id back to the customer

For my gRPC, it has three functions

• CustomerService; GetCustomers() get all customers' info
• CustomerService; GetCustomerCreditLimit(), get credit_limit of a customer (customer_id is required)
• OrderService; CreateCustomerOrder() to make an order (customer_id and the price is required) when a customer request for an order, the service will talk to the customer service to get the customer's credit_limit then check if it is ok to continue the order. If the order service allows, the customer will get a transaction_id in response else the customer will get an error and can't make the order

How to run

• Docker or Jaeger required

# if docker
chmod +x jaeger-docker.sh
./jaeger-docker.sh
# open two terminals and run these two services individually
go run grpc-tracing/customer
go run grpc-tracing/order

Available URLs to test

• GET localhost:8081/customers
• POST localhost:8082/order

Example

curl localhost:8081/customers
curl localhost:8082/order \
-H 'Content-Type: application/json' \
-d '{"customerId": "A310", "price": 22}'

Visit the Jaeger UI http://localhost:16686/