feat(integration): add logging to improve observability

Add logging statements to the codebase to improve observability. In `grpc.go`, add a log statement to the `GetBalance` function to log when the function is called. In `utils.go`, add a log statement to the `setHeaderFromContext` function to log the key and value of the trace context.

services/integration/grpc.go

@@ -3,6 +3,7 @@ package main
 import (
 	"context"
 	"fmt"
+	"log"
 	"net/http"
 
 	"github.com/bufbuild/connect-go"
@@ -54,6 +55,7 @@ func (s *GRPCServer) GetBalance(
 	ctx context.Context,
 	req *connect.Request[integration.GetBalanceRequest],
 ) (*connect.Response[integration.GetBalanceResponse], error) {
+	log.Println("get balance")
 	reqBalance := connect.NewRequest(&integration.GetBalanceRequest{})
 
 	resBalance, err := s.integrationService.GetBalance(ctx, reqBalance)

services/integration/helpers/utils.go

@@ -8,6 +8,7 @@ import (
 
 func setHeaderFromContext(key traceContextKey, header http.Header, ctx context.Context) {
 	value := ExtractTrace(ctx, key)
+	log.Println("set header from context", key, value)
 	if value != "" {
 		header.Set(string(key), value)
 	}