Checking in cmd files | first attempt at linking up item service

.gitignore

@@ -12,7 +12,6 @@
 # Test binary, built with `go test -c`
 *.test
 bin
-**/cmd
 services/**/gen
 api-cli
 
@@ -24,3 +23,4 @@ api-cli
 
 # Go workspace file
 go.work
+.idea

clean

@@ -11,7 +11,7 @@ echo "Rebuilding services..."
 mkdir -p bin
 
 for svc in front character item inventory; do
-    rm -rf services/${svc}/gen services/${svc}/cmd services/${svc}/gen services/${svc}/*.go
+    rm -rf services/${svc}/gen
 done
 
 popd

services/character/cmd/character-cli/grpc.go

@@ -0,0 +1,27 @@
+package main
+
+import (
+	cli "crossnokaye-interview-assignment/services/character/gen/grpc/cli/character"
+	"fmt"
+	"os"
+
+	goa "goa.design/goa/v3/pkg"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/credentials/insecure"
+)
+
+func doGRPC(scheme, host string, timeout int, debug bool) (goa.Endpoint, any, error) {
+	conn, err := grpc.Dial(host, grpc.WithTransportCredentials(insecure.NewCredentials()))
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "could not connect to gRPC server at %s: %v\n", host, err)
+	}
+	return cli.ParseEndpoint(conn)
+}
+
+func grpcUsageCommands() string {
+	return cli.UsageCommands()
+}
+
+func grpcUsageExamples() string {
+	return cli.UsageExamples()
+}

services/character/cmd/character-cli/main.go

@@ -0,0 +1,120 @@
+package main
+
+import (
+	"context"
+	"encoding/json"
+	"flag"
+	"fmt"
+	"net/url"
+	"os"
+	"strings"
+
+	goa "goa.design/goa/v3/pkg"
+)
+
+func main() {
+	var (
+		hostF = flag.String("host", "localhost", "Server host (valid values: localhost)")
+		addrF = flag.String("url", "", "URL to service host")
+
+		verboseF = flag.Bool("verbose", false, "Print request and response details")
+		vF       = flag.Bool("v", false, "Print request and response details")
+		timeoutF = flag.Int("timeout", 30, "Maximum number of seconds to wait for response")
+	)
+	flag.Usage = usage
+	flag.Parse()
+	var (
+		addr    string
+		timeout int
+		debug   bool
+	)
+	{
+		addr = *addrF
+		if addr == "" {
+			switch *hostF {
+			case "localhost":
+				addr = "grpc://localhost:8083"
+			default:
+				fmt.Fprintf(os.Stderr, "invalid host argument: %q (valid hosts: localhost)\n", *hostF)
+				os.Exit(1)
+			}
+		}
+		timeout = *timeoutF
+		debug = *verboseF || *vF
+	}
+
+	var (
+		scheme string
+		host   string
+	)
+	{
+		u, err := url.Parse(addr)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "invalid URL %#v: %s\n", addr, err)
+			os.Exit(1)
+		}
+		scheme = u.Scheme
+		host = u.Host
+	}
+	var (
+		endpoint goa.Endpoint
+		payload  any
+		err      error
+	)
+	{
+		switch scheme {
+		case "grpc", "grpcs":
+			endpoint, payload, err = doGRPC(scheme, host, timeout, debug)
+		default:
+			fmt.Fprintf(os.Stderr, "invalid scheme: %q (valid schemes: grpc)\n", scheme)
+			os.Exit(1)
+		}
+	}
+	if err != nil {
+		if err == flag.ErrHelp {
+			os.Exit(0)
+		}
+		fmt.Fprintln(os.Stderr, err.Error())
+		fmt.Fprintln(os.Stderr, "run '"+os.Args[0]+" --help' for detailed usage.")
+		os.Exit(1)
+	}
+
+	data, err := endpoint(context.Background(), payload)
+	if err != nil {
+		fmt.Fprintln(os.Stderr, err.Error())
+		os.Exit(1)
+	}
+
+	if data != nil {
+		m, _ := json.MarshalIndent(data, "", "    ")
+		fmt.Println(string(m))
+	}
+}
+
+func usage() {
+	fmt.Fprintf(os.Stderr, `%s is a command line client for the character API.
+
+Usage:
+    %s [-host HOST][-url URL][-timeout SECONDS][-verbose|-v] SERVICE ENDPOINT [flags]
+
+    -host HOST:  server host (localhost). valid values: localhost
+    -url URL:    specify service URL overriding host URL (http://localhost:8080)
+    -timeout:    maximum number of seconds to wait for response (30)
+    -verbose|-v: print request and response details (false)
+
+Commands:
+%s
+Additional help:
+    %s SERVICE [ENDPOINT] --help
+
+Example:
+%s
+`, os.Args[0], os.Args[0], indent(grpcUsageCommands()), os.Args[0], indent(grpcUsageExamples()))
+}
+
+func indent(s string) string {
+	if s == "" {
+		return ""
+	}
+	return "    " + strings.Replace(s, "\n", "\n    ", -1)
+}

services/character/cmd/character/grpc.go

@@ -0,0 +1,81 @@
+package main
+
+import (
+	"context"
+	character "crossnokaye-interview-assignment/services/character/gen/character"
+	characterpb "crossnokaye-interview-assignment/services/character/gen/grpc/character/pb"
+	charactersvr "crossnokaye-interview-assignment/services/character/gen/grpc/character/server"
+	"log"
+	"net"
+	"net/url"
+	"sync"
+
+	grpcmdlwr "goa.design/goa/v3/grpc/middleware"
+	"goa.design/goa/v3/middleware"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/reflection"
+)
+
+// handleGRPCServer starts configures and starts a gRPC server on the given
+// URL. It shuts down the server if any error is received in the error channel.
+func handleGRPCServer(ctx context.Context, u *url.URL, characterEndpoints *character.Endpoints, wg *sync.WaitGroup, errc chan error, logger *log.Logger, debug bool) {
+
+	// Setup goa log adapter.
+	var (
+		adapter middleware.Logger
+	)
+	{
+		adapter = middleware.NewLogger(logger)
+	}
+
+	// Wrap the endpoints with the transport specific layers. The generated
+	// server packages contains code generated from the design which maps
+	// the service input and output data structures to gRPC requests and
+	// responses.
+	var (
+		characterServer *charactersvr.Server
+	)
+	{
+		characterServer = charactersvr.New(characterEndpoints, nil)
+	}
+
+	// Initialize gRPC server with the middleware.
+	srv := grpc.NewServer(
+		grpc.ChainUnaryInterceptor(
+			grpcmdlwr.UnaryRequestID(),
+			grpcmdlwr.UnaryServerLog(adapter),
+		),
+	)
+
+	// Register the servers.
+	characterpb.RegisterCharacterServer(srv, characterServer)
+
+	for svc, info := range srv.GetServiceInfo() {
+		for _, m := range info.Methods {
+			logger.Printf("serving gRPC method %s", svc+"/"+m.Name)
+		}
+	}
+
+	// Register the server reflection service on the server.
+	// See https://grpc.github.io/grpc/core/md_doc_server-reflection.html.
+	reflection.Register(srv)
+
+	(*wg).Add(1)
+	go func() {
+		defer (*wg).Done()
+
+		// Start gRPC server in a separate goroutine.
+		go func() {
+			lis, err := net.Listen("tcp", u.Host)
+			if err != nil {
+				errc <- err
+			}
+			logger.Printf("gRPC server listening on %q", u.Host)
+			errc <- srv.Serve(lis)
+		}()
+
+		<-ctx.Done()
+		logger.Printf("shutting down gRPC server at %q", u.Host)
+		srv.Stop()
+	}()
+}

services/character/cmd/character/main.go

@@ -0,0 +1,109 @@
+package main
+
+import (
+	"context"
+	characterapi "crossnokaye-interview-assignment/services/character"
+	character "crossnokaye-interview-assignment/services/character/gen/character"
+	"flag"
+	"fmt"
+	"log"
+	"net"
+	"net/url"
+	"os"
+	"os/signal"
+	"sync"
+	"syscall"
+)
+
+func main() {
+	// Define command line flags, add any other flag required to configure the
+	// service.
+	var (
+		hostF     = flag.String("host", "localhost", "Server host (valid values: localhost)")
+		domainF   = flag.String("domain", "", "Host domain name (overrides host domain specified in service design)")
+		grpcPortF = flag.String("grpc-port", "", "gRPC port (overrides host gRPC port specified in service design)")
+		secureF   = flag.Bool("secure", false, "Use secure scheme (https or grpcs)")
+		dbgF      = flag.Bool("debug", false, "Log request and response bodies")
+	)
+	flag.Parse()
+
+	// Setup logger. Replace logger with your own log package of choice.
+	var (
+		logger *log.Logger
+	)
+	{
+		logger = log.New(os.Stderr, "[characterapi] ", log.Ltime)
+	}
+
+	// Initialize the services.
+	var (
+		characterSvc character.Service
+	)
+	{
+		characterSvc = characterapi.NewCharacter(logger)
+	}
+
+	// Wrap the services in endpoints that can be invoked from other services
+	// potentially running in different processes.
+	var (
+		characterEndpoints *character.Endpoints
+	)
+	{
+		characterEndpoints = character.NewEndpoints(characterSvc)
+	}
+
+	// Create channel used by both the signal handler and server goroutines
+	// to notify the main goroutine when to stop the server.
+	errc := make(chan error)
+
+	// Setup interrupt handler. This optional step configures the process so
+	// that SIGINT and SIGTERM signals cause the services to stop gracefully.
+	go func() {
+		c := make(chan os.Signal, 1)
+		signal.Notify(c, syscall.SIGINT, syscall.SIGTERM)
+		errc <- fmt.Errorf("%s", <-c)
+	}()
+
+	var wg sync.WaitGroup
+	ctx, cancel := context.WithCancel(context.Background())
+
+	// Start the servers and send errors (if any) to the error channel.
+	switch *hostF {
+	case "localhost":
+		{
+			addr := "grpc://localhost:8083"
+			u, err := url.Parse(addr)
+			if err != nil {
+				logger.Fatalf("invalid URL %#v: %s\n", addr, err)
+			}
+			if *secureF {
+				u.Scheme = "grpcs"
+			}
+			if *domainF != "" {
+				u.Host = *domainF
+			}
+			if *grpcPortF != "" {
+				h, _, err := net.SplitHostPort(u.Host)
+				if err != nil {
+					logger.Fatalf("invalid URL %#v: %s\n", u.Host, err)
+				}
+				u.Host = net.JoinHostPort(h, *grpcPortF)
+			} else if u.Port() == "" {
+				u.Host = net.JoinHostPort(u.Host, "8080")
+			}
+			handleGRPCServer(ctx, u, characterEndpoints, &wg, errc, logger, *dbgF)
+		}
+
+	default:
+		logger.Fatalf("invalid host argument: %q (valid hosts: localhost)\n", *hostF)
+	}
+
+	// Wait for signal.
+	logger.Printf("exiting (%v)", <-errc)
+
+	// Send cancellation signal to the goroutines.
+	cancel()
+
+	wg.Wait()
+	logger.Println("exited")
+}

services/front/client/item/itemClient.go

@@ -1,4 +1,4 @@
-package itemClient
+package item
 
 import (
 	"context"
@@ -38,7 +38,7 @@ func New(clientConnection *grpc.ClientConn) ItemClient {
 
 // createItemRequest implements ItemClient.
 func (itemClient *itemClient) CreateItemRequest(ctx context.Context, item genItem.Item) (*genItem.Item, error) {
-	res, err := itemClient.createItem(ctx, item);
+	res, err := itemClient.createItem(ctx, item)
 	if err != nil {
 		return nil, err
 	}

services/front/cmd/front-cli/grpc.go

@@ -0,0 +1,19 @@
+package main
+
+import (
+	cli "crossnokaye-interview-assignment/services/front/gen/grpc/cli/front"
+	"fmt"
+	"os"
+
+	goa "goa.design/goa/v3/pkg"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/credentials/insecure"
+)
+
+func doGRPC(scheme, host string, timeout int, debug bool) (goa.Endpoint, any, error) {
+	conn, err := grpc.Dial(host, grpc.WithTransportCredentials(insecure.NewCredentials()))
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "could not connect to gRPC server at %s: %v\n", host, err)
+	}
+	return cli.ParseEndpoint(conn)
+}

services/front/cmd/front-cli/http.go

@@ -0,0 +1,39 @@
+package main
+
+import (
+	cli "crossnokaye-interview-assignment/services/front/gen/http/cli/front"
+	"net/http"
+	"time"
+
+	goahttp "goa.design/goa/v3/http"
+	goa "goa.design/goa/v3/pkg"
+)
+
+func doHTTP(scheme, host string, timeout int, debug bool) (goa.Endpoint, any, error) {
+	var (
+		doer goahttp.Doer
+	)
+	{
+		doer = &http.Client{Timeout: time.Duration(timeout) * time.Second}
+		if debug {
+			doer = goahttp.NewDebugDoer(doer)
+		}
+	}
+
+	return cli.ParseEndpoint(
+		scheme,
+		host,
+		doer,
+		goahttp.RequestEncoder,
+		goahttp.ResponseDecoder,
+		debug,
+	)
+}
+
+func httpUsageCommands() string {
+	return cli.UsageCommands()
+}
+
+func httpUsageExamples() string {
+	return cli.UsageExamples()
+}

services/front/cmd/front-cli/main.go

@@ -0,0 +1,122 @@
+package main
+
+import (
+	"context"
+	"encoding/json"
+	"flag"
+	"fmt"
+	"net/url"
+	"os"
+	"strings"
+
+	goa "goa.design/goa/v3/pkg"
+)
+
+func main() {
+	var (
+		hostF = flag.String("host", "localhost", "Server host (valid values: localhost)")
+		addrF = flag.String("url", "", "URL to service host")
+
+		verboseF = flag.Bool("verbose", false, "Print request and response details")
+		vF       = flag.Bool("v", false, "Print request and response details")
+		timeoutF = flag.Int("timeout", 30, "Maximum number of seconds to wait for response")
+	)
+	flag.Usage = usage
+	flag.Parse()
+	var (
+		addr    string
+		timeout int
+		debug   bool
+	)
+	{
+		addr = *addrF
+		if addr == "" {
+			switch *hostF {
+			case "localhost":
+				addr = "http://localhost:8000"
+			default:
+				fmt.Fprintf(os.Stderr, "invalid host argument: %q (valid hosts: localhost)\n", *hostF)
+				os.Exit(1)
+			}
+		}
+		timeout = *timeoutF
+		debug = *verboseF || *vF
+	}
+
+	var (
+		scheme string
+		host   string
+	)
+	{
+		u, err := url.Parse(addr)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "invalid URL %#v: %s\n", addr, err)
+			os.Exit(1)
+		}
+		scheme = u.Scheme
+		host = u.Host
+	}
+	var (
+		endpoint goa.Endpoint
+		payload  any
+		err      error
+	)
+	{
+		switch scheme {
+		case "http", "https":
+			endpoint, payload, err = doHTTP(scheme, host, timeout, debug)
+		case "grpc", "grpcs":
+			endpoint, payload, err = doGRPC(scheme, host, timeout, debug)
+		default:
+			fmt.Fprintf(os.Stderr, "invalid scheme: %q (valid schemes: grpc|http)\n", scheme)
+			os.Exit(1)
+		}
+	}
+	if err != nil {
+		if err == flag.ErrHelp {
+			os.Exit(0)
+		}
+		fmt.Fprintln(os.Stderr, err.Error())
+		fmt.Fprintln(os.Stderr, "run '"+os.Args[0]+" --help' for detailed usage.")
+		os.Exit(1)
+	}
+
+	data, err := endpoint(context.Background(), payload)
+	if err != nil {
+		fmt.Fprintln(os.Stderr, err.Error())
+		os.Exit(1)
+	}
+
+	if data != nil {
+		m, _ := json.MarshalIndent(data, "", "    ")
+		fmt.Println(string(m))
+	}
+}
+
+func usage() {
+	fmt.Fprintf(os.Stderr, `%s is a command line client for the front API.
+
+Usage:
+    %s [-host HOST][-url URL][-timeout SECONDS][-verbose|-v] SERVICE ENDPOINT [flags]
+
+    -host HOST:  server host (localhost). valid values: localhost
+    -url URL:    specify service URL overriding host URL (http://localhost:8080)
+    -timeout:    maximum number of seconds to wait for response (30)
+    -verbose|-v: print request and response details (false)
+
+Commands:
+%s
+Additional help:
+    %s SERVICE [ENDPOINT] --help
+
+Example:
+%s
+`, os.Args[0], os.Args[0], indent(httpUsageCommands()), os.Args[0], indent(httpUsageExamples()))
+}
+
+func indent(s string) string {
+	if s == "" {
+		return ""
+	}
+	return "    " + strings.Replace(s, "\n", "\n    ", -1)
+}

services/front/cmd/front/http.go

@@ -0,0 +1,115 @@
+package main
+
+import (
+	"context"
+	front "crossnokaye-interview-assignment/services/front/gen/front"
+	frontsvr "crossnokaye-interview-assignment/services/front/gen/http/front/server"
+	"log"
+	"net/http"
+	"net/url"
+	"os"
+	"sync"
+	"time"
+
+	goahttp "goa.design/goa/v3/http"
+	httpmdlwr "goa.design/goa/v3/http/middleware"
+	"goa.design/goa/v3/middleware"
+)
+
+// handleHTTPServer starts configures and starts a HTTP server on the given
+// URL. It shuts down the server if any error is received in the error channel.
+func handleHTTPServer(ctx context.Context, u *url.URL, frontEndpoints *front.Endpoints, wg *sync.WaitGroup, errc chan error, logger *log.Logger, debug bool) {
+
+	// Setup goa log adapter.
+	var (
+		adapter middleware.Logger
+	)
+	{
+		adapter = middleware.NewLogger(logger)
+	}
+
+	// Provide the transport specific request decoder and response encoder.
+	// The goa http package has built-in support for JSON, XML and gob.
+	// Other encodings can be used by providing the corresponding functions,
+	// see goa.design/implement/encoding.
+	var (
+		dec = goahttp.RequestDecoder
+		enc = goahttp.ResponseEncoder
+	)
+
+	// Build the service HTTP request multiplexer and configure it to serve
+	// HTTP requests to the service endpoints.
+	var mux goahttp.Muxer
+	{
+		mux = goahttp.NewMuxer()
+	}
+
+	// Wrap the endpoints with the transport specific layers. The generated
+	// server packages contains code generated from the design which maps
+	// the service input and output data structures to HTTP requests and
+	// responses.
+	var (
+		frontServer *frontsvr.Server
+	)
+	{
+		eh := errorHandler(logger)
+		frontServer = frontsvr.New(frontEndpoints, mux, dec, enc, eh, nil, nil)
+		if debug {
+			servers := goahttp.Servers{
+				frontServer,
+			}
+			servers.Use(httpmdlwr.Debug(mux, os.Stdout))
+		}
+	}
+	// Configure the mux.
+	frontsvr.Mount(mux, frontServer)
+
+	// Wrap the multiplexer with additional middlewares. Middlewares mounted
+	// here apply to all the service endpoints.
+	var handler http.Handler = mux
+	{
+		handler = httpmdlwr.Log(adapter)(handler)
+		handler = httpmdlwr.RequestID()(handler)
+	}
+
+	// Start HTTP server using default configuration, change the code to
+	// configure the server as required by your service.
+	srv := &http.Server{Addr: u.Host, Handler: handler, ReadHeaderTimeout: time.Second * 60}
+	for _, m := range frontServer.Mounts {
+		logger.Printf("HTTP %q mounted on %s %s", m.Method, m.Verb, m.Pattern)
+	}
+
+	(*wg).Add(1)
+	go func() {
+		defer (*wg).Done()
+
+		// Start HTTP server in a separate goroutine.
+		go func() {
+			logger.Printf("HTTP server listening on %q", u.Host)
+			errc <- srv.ListenAndServe()
+		}()
+
+		<-ctx.Done()
+		logger.Printf("shutting down HTTP server at %q", u.Host)
+
+		// Shutdown gracefully with a 30s timeout.
+		ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
+		defer cancel()
+
+		err := srv.Shutdown(ctx)
+		if err != nil {
+			logger.Printf("failed to shutdown: %v", err)
+		}
+	}()
+}
+
+// errorHandler returns a function that writes and logs the given error.
+// The function also writes and logs the error unique ID so that it's possible
+// to correlate.
+func errorHandler(logger *log.Logger) func(context.Context, http.ResponseWriter, error) {
+	return func(ctx context.Context, w http.ResponseWriter, err error) {
+		id := ctx.Value(middleware.RequestIDKey).(string)
+		_, _ = w.Write([]byte("[" + id + "] encoding: " + err.Error()))
+		logger.Printf("[%s] ERROR: %s", id, err.Error())
+	}
+}

services/front/cmd/front/main.go

@@ -0,0 +1,123 @@
+package main
+
+import (
+	"context"
+	frontapi "crossnokaye-interview-assignment/services/front"
+	front "crossnokaye-interview-assignment/services/front/gen/front"
+	"flag"
+	"fmt"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/credentials/insecure"
+	"log"
+	"net"
+	"net/url"
+	"os"
+	"os/signal"
+	"sync"
+	"syscall"
+)
+
+func main() {
+	// Define command line flags, add any other flag required to configure the
+	// service.
+	var (
+		hostF     = flag.String("host", "localhost", "Server host (valid values: localhost)")
+		domainF   = flag.String("domain", "", "Host domain name (overrides host domain specified in service design)")
+		httpPortF = flag.String("http-port", "", "HTTP port (overrides host HTTP port specified in service design)")
+		secureF   = flag.Bool("secure", false, "Use secure scheme (https or grpcs)")
+		dbgF      = flag.Bool("debug", false, "Log request and response bodies")
+		itemAddr  = flag.String("locator-addr", ":8082", "Item service address")
+		//characterAddr = flag.String("locator-addr", ":8080", "Item service address")
+		//inventoryAddr = flag.String("locator-addr", ":8081", "Item service address")
+	)
+	flag.Parse()
+
+	// Setup logger. Replace logger with your own log package of choice.
+	var (
+		logger *log.Logger
+	)
+	{
+		logger = log.New(os.Stderr, "[frontapi] ", log.Ltime)
+	}
+
+	// Init gRPC services
+	itemClientConnection, err := grpc.Dial(*itemAddr,
+		grpc.WithTransportCredentials(insecure.NewCredentials()))
+	if err != nil {
+		log.Fatalf("failed to connect to item service", err)
+		os.Exit(1)
+	}
+	defer itemClientConnection.Close()
+
+	// Initialize the services.
+	var (
+		frontSvc front.Service
+	)
+	{
+		frontSvc = frontapi.NewFront(logger, itemClientConnection)
+	}
+
+	// Wrap the services in endpoints that can be invoked from other services
+	// potentially running in different processes.
+	var (
+		frontEndpoints *front.Endpoints
+	)
+	{
+		frontEndpoints = front.NewEndpoints(frontSvc)
+	}
+
+	// Create channel used by both the signal handler and server goroutines
+	// to notify the main goroutine when to stop the server.
+	errc := make(chan error)
+
+	// Setup interrupt handler. This optional step configures the process so
+	// that SIGINT and SIGTERM signals cause the services to stop gracefully.
+	go func() {
+		c := make(chan os.Signal, 1)
+		signal.Notify(c, syscall.SIGINT, syscall.SIGTERM)
+		errc <- fmt.Errorf("%s", <-c)
+	}()
+
+	var wg sync.WaitGroup
+	ctx, cancel := context.WithCancel(context.Background())
+
+	// Start the servers and send errors (if any) to the error channel.
+	switch *hostF {
+	case "localhost":
+		{
+			addr := "http://localhost:8000"
+			u, err := url.Parse(addr)
+			if err != nil {
+				logger.Fatalf("invalid URL %#v: %s\n", addr, err)
+			}
+			if *secureF {
+				u.Scheme = "https"
+			}
+			if *domainF != "" {
+				u.Host = *domainF
+			}
+			if *httpPortF != "" {
+				h, _, err := net.SplitHostPort(u.Host)
+				if err != nil {
+					logger.Fatalf("invalid URL %#v: %s\n", u.Host, err)
+				}
+				u.Host = net.JoinHostPort(h, *httpPortF)
+			} else if u.Port() == "" {
+				u.Host = net.JoinHostPort(u.Host, "80")
+			}
+			handleHTTPServer(ctx, u, frontEndpoints, &wg, errc, logger, *dbgF)
+		}
+
+	default:
+		logger.Fatalf("invalid host argument: %q (valid hosts: localhost)\n", *hostF)
+	}
+
+	// Wait for signal.
+	logger.Printf("exiting (%v)", <-errc)
+
+	// Send cancellation signal to the goroutines.
+	cancel()
+
+	wg.Wait()
+	logger.Println("exited")
+}

services/front/design/design.go

@@ -30,10 +30,6 @@ var _ = Service("front", func() {
 			Response(StatusBadRequest)
 			Response(StatusNotFound)
 		})
-
-		GRPC(func() {
-			Response(CodeOK)
-		})
 	})
 
 	// Method("listItems", func() {
@@ -50,10 +46,6 @@ var _ = Service("front", func() {
 			Response(StatusOK)
 			Response(StatusBadRequest)
 		})
-
-		GRPC(func() {
-			Response(CodeOK)
-		})
 	})
 
 	Method("updateItem", func() {
@@ -69,10 +61,6 @@ var _ = Service("front", func() {
 			Response(StatusBadRequest)
 			Response(StatusNotFound)
 		})
-
-		GRPC(func() {
-			Response(CodeOK)
-		})
 	})
 
 	Method("deleteItem", func() {
@@ -87,12 +75,6 @@ var _ = Service("front", func() {
 			Response(StatusBadRequest)
 			Response(StatusNotFound)
 		})
-
-		GRPC(func() {
-			Response(CodeOK)
-			Response("NotFound", CodeNotFound)
-			Response("BadRequest", CodeInvalidArgument)
-		})
 	})
 
 	Method("getCharacter", func() {
@@ -107,12 +89,6 @@ var _ = Service("front", func() {
 			Response(StatusBadRequest)
 			Response(StatusNotFound)
 		})
-
-		GRPC(func() {
-			Response(CodeOK)
-			Response("NotFound", CodeNotFound)
-			Response("BadRequest", CodeInvalidArgument)
-		})
 	})
 
 	// Method("listCharacters", func() {
@@ -131,12 +107,6 @@ var _ = Service("front", func() {
 			Response(StatusOK)
 			Response(StatusInternalServerError)
 		})
-
-		GRPC(func() {
-			Response(CodeOK)
-			Response("NotFound", CodeNotFound)
-			Response("BadRequest", CodeInvalidArgument)
-		})
 	})
 
 	Method("updateCharacter", func() {
@@ -152,12 +122,6 @@ var _ = Service("front", func() {
 			Response(StatusBadRequest)
 			Response(StatusNotFound)
 		})
-
-		GRPC(func() {
-			Response(CodeOK)
-			Response("NotFound", CodeNotFound)
-			Response("BadRequest", CodeInvalidArgument)
-		})
 	})
 
 	Method("deleteCharacter", func() {
@@ -172,12 +136,6 @@ var _ = Service("front", func() {
 			Response(StatusBadRequest)
 			Response(StatusNotFound)
 		})
-
-		GRPC(func() {
-			Response(CodeOK)
-			Response("NotFound", CodeNotFound)
-			Response("BadRequest", CodeInvalidArgument)
-		})
 	})
 
 	Method("addItemToInventory", func() {
@@ -191,10 +149,6 @@ var _ = Service("front", func() {
 			Response(StatusOK)
 			Response(StatusBadRequest)
 		})
-
-		GRPC(func() {
-			Response(CodeOK)
-		})
 	})
 
 	Method("removeItemFromInventory", func() {
@@ -208,12 +162,6 @@ var _ = Service("front", func() {
 			Response(StatusOK)
 			Response(StatusBadRequest)
 		})
-
-		GRPC(func() {
-			Response(CodeOK)
-			Response("NotFound", CodeNotFound)
-			Response("BadRequest", CodeInvalidArgument)
-		})
 	})
 
 	Files("/openapi.json", "./gen/http/openapi.json")

services/front/front.go

@@ -3,6 +3,8 @@ package frontapi
 import (
 	"context"
 	front "crossnokaye-interview-assignment/services/front/gen/front"
+	genClient "crossnokaye-interview-assignment/services/item/gen/grpc/item/client"
+	"google.golang.org/grpc"
 	"log"
 )
 
@@ -10,17 +12,20 @@ import (
 // The example methods log the requests and return zero values.
 type frontsrvc struct {
 	logger *log.Logger
+
+	itemClient *genClient.Client
 }
 
 // NewFront returns the front service implementation.
-func NewFront(logger *log.Logger) front.Service {
-	return &frontsrvc{logger}
+func NewFront(logger *log.Logger, itemClientConnection *grpc.ClientConn) front.Service {
+
+	return &frontsrvc{logger: logger, itemClient: genClient.NewClient(itemClientConnection)}
 }
 
 // GetItem implements getItem.
-func (s *frontsrvc) GetItem(ctx context.Context, p int) (res *front.Item, err error) {
-	res = &front.Item{}
+func (s *frontsrvc) GetItem(ctx context.Context, id int) (res *front.Item, err error) {
 	s.logger.Print("front.getItem")
+	s.logger.Print(s.itemClient.GetItem())
 	return
 }
 

services/inventory/cmd/inventory-cli/grpc.go

@@ -0,0 +1,27 @@
+package main
+
+import (
+	cli "crossnokaye-interview-assignment/services/inventory/gen/grpc/cli/inventory"
+	"fmt"
+	"os"
+
+	goa "goa.design/goa/v3/pkg"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/credentials/insecure"
+)
+
+func doGRPC(scheme, host string, timeout int, debug bool) (goa.Endpoint, any, error) {
+	conn, err := grpc.Dial(host, grpc.WithTransportCredentials(insecure.NewCredentials()))
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "could not connect to gRPC server at %s: %v\n", host, err)
+	}
+	return cli.ParseEndpoint(conn)
+}
+
+func grpcUsageCommands() string {
+	return cli.UsageCommands()
+}
+
+func grpcUsageExamples() string {
+	return cli.UsageExamples()
+}

services/inventory/cmd/inventory-cli/main.go

@@ -0,0 +1,120 @@
+package main
+
+import (
+	"context"
+	"encoding/json"
+	"flag"
+	"fmt"
+	"net/url"
+	"os"
+	"strings"
+
+	goa "goa.design/goa/v3/pkg"
+)
+
+func main() {
+	var (
+		hostF = flag.String("host", "localhost", "Server host (valid values: localhost)")
+		addrF = flag.String("url", "", "URL to service host")
+
+		verboseF = flag.Bool("verbose", false, "Print request and response details")
+		vF       = flag.Bool("v", false, "Print request and response details")
+		timeoutF = flag.Int("timeout", 30, "Maximum number of seconds to wait for response")
+	)
+	flag.Usage = usage
+	flag.Parse()
+	var (
+		addr    string
+		timeout int
+		debug   bool
+	)
+	{
+		addr = *addrF
+		if addr == "" {
+			switch *hostF {
+			case "localhost":
+				addr = "grpc://localhost:8081"
+			default:
+				fmt.Fprintf(os.Stderr, "invalid host argument: %q (valid hosts: localhost)\n", *hostF)
+				os.Exit(1)
+			}
+		}
+		timeout = *timeoutF
+		debug = *verboseF || *vF
+	}
+
+	var (
+		scheme string
+		host   string
+	)
+	{
+		u, err := url.Parse(addr)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "invalid URL %#v: %s\n", addr, err)
+			os.Exit(1)
+		}
+		scheme = u.Scheme
+		host = u.Host
+	}
+	var (
+		endpoint goa.Endpoint
+		payload  any
+		err      error
+	)
+	{
+		switch scheme {
+		case "grpc", "grpcs":
+			endpoint, payload, err = doGRPC(scheme, host, timeout, debug)
+		default:
+			fmt.Fprintf(os.Stderr, "invalid scheme: %q (valid schemes: grpc)\n", scheme)
+			os.Exit(1)
+		}
+	}
+	if err != nil {
+		if err == flag.ErrHelp {
+			os.Exit(0)
+		}
+		fmt.Fprintln(os.Stderr, err.Error())
+		fmt.Fprintln(os.Stderr, "run '"+os.Args[0]+" --help' for detailed usage.")
+		os.Exit(1)
+	}
+
+	data, err := endpoint(context.Background(), payload)
+	if err != nil {
+		fmt.Fprintln(os.Stderr, err.Error())
+		os.Exit(1)
+	}
+
+	if data != nil {
+		m, _ := json.MarshalIndent(data, "", "    ")
+		fmt.Println(string(m))
+	}
+}
+
+func usage() {
+	fmt.Fprintf(os.Stderr, `%s is a command line client for the inventory API.
+
+Usage:
+    %s [-host HOST][-url URL][-timeout SECONDS][-verbose|-v] SERVICE ENDPOINT [flags]
+
+    -host HOST:  server host (localhost). valid values: localhost
+    -url URL:    specify service URL overriding host URL (http://localhost:8080)
+    -timeout:    maximum number of seconds to wait for response (30)
+    -verbose|-v: print request and response details (false)
+
+Commands:
+%s
+Additional help:
+    %s SERVICE [ENDPOINT] --help
+
+Example:
+%s
+`, os.Args[0], os.Args[0], indent(grpcUsageCommands()), os.Args[0], indent(grpcUsageExamples()))
+}
+
+func indent(s string) string {
+	if s == "" {
+		return ""
+	}
+	return "    " + strings.Replace(s, "\n", "\n    ", -1)
+}

services/inventory/cmd/inventory/grpc.go

@@ -0,0 +1,81 @@
+package main
+
+import (
+	"context"
+	inventorypb "crossnokaye-interview-assignment/services/inventory/gen/grpc/inventory/pb"
+	inventorysvr "crossnokaye-interview-assignment/services/inventory/gen/grpc/inventory/server"
+	inventory "crossnokaye-interview-assignment/services/inventory/gen/inventory"
+	"log"
+	"net"
+	"net/url"
+	"sync"
+
+	grpcmdlwr "goa.design/goa/v3/grpc/middleware"
+	"goa.design/goa/v3/middleware"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/reflection"
+)
+
+// handleGRPCServer starts configures and starts a gRPC server on the given
+// URL. It shuts down the server if any error is received in the error channel.
+func handleGRPCServer(ctx context.Context, u *url.URL, inventoryEndpoints *inventory.Endpoints, wg *sync.WaitGroup, errc chan error, logger *log.Logger, debug bool) {
+
+	// Setup goa log adapter.
+	var (
+		adapter middleware.Logger
+	)
+	{
+		adapter = middleware.NewLogger(logger)
+	}
+
+	// Wrap the endpoints with the transport specific layers. The generated
+	// server packages contains code generated from the design which maps
+	// the service input and output data structures to gRPC requests and
+	// responses.
+	var (
+		inventoryServer *inventorysvr.Server
+	)
+	{
+		inventoryServer = inventorysvr.New(inventoryEndpoints, nil)
+	}
+
+	// Initialize gRPC server with the middleware.
+	srv := grpc.NewServer(
+		grpc.ChainUnaryInterceptor(
+			grpcmdlwr.UnaryRequestID(),
+			grpcmdlwr.UnaryServerLog(adapter),
+		),
+	)
+
+	// Register the servers.
+	inventorypb.RegisterInventoryServer(srv, inventoryServer)
+
+	for svc, info := range srv.GetServiceInfo() {
+		for _, m := range info.Methods {
+			logger.Printf("serving gRPC method %s", svc+"/"+m.Name)
+		}
+	}
+
+	// Register the server reflection service on the server.
+	// See https://grpc.github.io/grpc/core/md_doc_server-reflection.html.
+	reflection.Register(srv)
+
+	(*wg).Add(1)
+	go func() {
+		defer (*wg).Done()
+
+		// Start gRPC server in a separate goroutine.
+		go func() {
+			lis, err := net.Listen("tcp", u.Host)
+			if err != nil {
+				errc <- err
+			}
+			logger.Printf("gRPC server listening on %q", u.Host)
+			errc <- srv.Serve(lis)
+		}()
+
+		<-ctx.Done()
+		logger.Printf("shutting down gRPC server at %q", u.Host)
+		srv.Stop()
+	}()
+}

services/inventory/cmd/inventory/main.go

@@ -0,0 +1,109 @@
+package main
+
+import (
+	"context"
+	inventoryapi "crossnokaye-interview-assignment/services/inventory"
+	inventory "crossnokaye-interview-assignment/services/inventory/gen/inventory"
+	"flag"
+	"fmt"
+	"log"
+	"net"
+	"net/url"
+	"os"
+	"os/signal"
+	"sync"
+	"syscall"
+)
+
+func main() {
+	// Define command line flags, add any other flag required to configure the
+	// service.
+	var (
+		hostF     = flag.String("host", "localhost", "Server host (valid values: localhost)")
+		domainF   = flag.String("domain", "", "Host domain name (overrides host domain specified in service design)")
+		grpcPortF = flag.String("grpc-port", "", "gRPC port (overrides host gRPC port specified in service design)")
+		secureF   = flag.Bool("secure", false, "Use secure scheme (https or grpcs)")
+		dbgF      = flag.Bool("debug", false, "Log request and response bodies")
+	)
+	flag.Parse()
+
+	// Setup logger. Replace logger with your own log package of choice.
+	var (
+		logger *log.Logger
+	)
+	{
+		logger = log.New(os.Stderr, "[inventoryapi] ", log.Ltime)
+	}
+
+	// Initialize the services.
+	var (
+		inventorySvc inventory.Service
+	)
+	{
+		inventorySvc = inventoryapi.NewInventory(logger)
+	}
+
+	// Wrap the services in endpoints that can be invoked from other services
+	// potentially running in different processes.
+	var (
+		inventoryEndpoints *inventory.Endpoints
+	)
+	{
+		inventoryEndpoints = inventory.NewEndpoints(inventorySvc)
+	}
+
+	// Create channel used by both the signal handler and server goroutines
+	// to notify the main goroutine when to stop the server.
+	errc := make(chan error)
+
+	// Setup interrupt handler. This optional step configures the process so
+	// that SIGINT and SIGTERM signals cause the services to stop gracefully.
+	go func() {
+		c := make(chan os.Signal, 1)
+		signal.Notify(c, syscall.SIGINT, syscall.SIGTERM)
+		errc <- fmt.Errorf("%s", <-c)
+	}()
+
+	var wg sync.WaitGroup
+	ctx, cancel := context.WithCancel(context.Background())
+
+	// Start the servers and send errors (if any) to the error channel.
+	switch *hostF {
+	case "localhost":
+		{
+			addr := "grpc://localhost:8081"
+			u, err := url.Parse(addr)
+			if err != nil {
+				logger.Fatalf("invalid URL %#v: %s\n", addr, err)
+			}
+			if *secureF {
+				u.Scheme = "grpcs"
+			}
+			if *domainF != "" {
+				u.Host = *domainF
+			}
+			if *grpcPortF != "" {
+				h, _, err := net.SplitHostPort(u.Host)
+				if err != nil {
+					logger.Fatalf("invalid URL %#v: %s\n", u.Host, err)
+				}
+				u.Host = net.JoinHostPort(h, *grpcPortF)
+			} else if u.Port() == "" {
+				u.Host = net.JoinHostPort(u.Host, "8080")
+			}
+			handleGRPCServer(ctx, u, inventoryEndpoints, &wg, errc, logger, *dbgF)
+		}
+
+	default:
+		logger.Fatalf("invalid host argument: %q (valid hosts: localhost)\n", *hostF)
+	}
+
+	// Wait for signal.
+	logger.Printf("exiting (%v)", <-errc)
+
+	// Send cancellation signal to the goroutines.
+	cancel()
+
+	wg.Wait()
+	logger.Println("exited")
+}

services/item/cmd/item-cli/grpc.go

@@ -0,0 +1,27 @@
+package main
+
+import (
+	cli "crossnokaye-interview-assignment/services/item/gen/grpc/cli/item"
+	"fmt"
+	"os"
+
+	goa "goa.design/goa/v3/pkg"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/credentials/insecure"
+)
+
+func doGRPC(scheme, host string, timeout int, debug bool) (goa.Endpoint, any, error) {
+	conn, err := grpc.Dial(host, grpc.WithTransportCredentials(insecure.NewCredentials()))
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "could not connect to gRPC server at %s: %v\n", host, err)
+	}
+	return cli.ParseEndpoint(conn)
+}
+
+func grpcUsageCommands() string {
+	return cli.UsageCommands()
+}
+
+func grpcUsageExamples() string {
+	return cli.UsageExamples()
+}

services/item/cmd/item-cli/main.go

@@ -0,0 +1,120 @@
+package main
+
+import (
+	"context"
+	"encoding/json"
+	"flag"
+	"fmt"
+	"net/url"
+	"os"
+	"strings"
+
+	goa "goa.design/goa/v3/pkg"
+)
+
+func main() {
+	var (
+		hostF = flag.String("host", "localhost", "Server host (valid values: localhost)")
+		addrF = flag.String("url", "", "URL to service host")
+
+		verboseF = flag.Bool("verbose", false, "Print request and response details")
+		vF       = flag.Bool("v", false, "Print request and response details")
+		timeoutF = flag.Int("timeout", 30, "Maximum number of seconds to wait for response")
+	)
+	flag.Usage = usage
+	flag.Parse()
+	var (
+		addr    string
+		timeout int
+		debug   bool
+	)
+	{
+		addr = *addrF
+		if addr == "" {
+			switch *hostF {
+			case "localhost":
+				addr = "grpc://localhost:8082"
+			default:
+				fmt.Fprintf(os.Stderr, "invalid host argument: %q (valid hosts: localhost)\n", *hostF)
+				os.Exit(1)
+			}
+		}
+		timeout = *timeoutF
+		debug = *verboseF || *vF
+	}
+
+	var (
+		scheme string
+		host   string
+	)
+	{
+		u, err := url.Parse(addr)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "invalid URL %#v: %s\n", addr, err)
+			os.Exit(1)
+		}
+		scheme = u.Scheme
+		host = u.Host
+	}
+	var (
+		endpoint goa.Endpoint
+		payload  any
+		err      error
+	)
+	{
+		switch scheme {
+		case "grpc", "grpcs":
+			endpoint, payload, err = doGRPC(scheme, host, timeout, debug)
+		default:
+			fmt.Fprintf(os.Stderr, "invalid scheme: %q (valid schemes: grpc)\n", scheme)
+			os.Exit(1)
+		}
+	}
+	if err != nil {
+		if err == flag.ErrHelp {
+			os.Exit(0)
+		}
+		fmt.Fprintln(os.Stderr, err.Error())
+		fmt.Fprintln(os.Stderr, "run '"+os.Args[0]+" --help' for detailed usage.")
+		os.Exit(1)
+	}
+
+	data, err := endpoint(context.Background(), payload)
+	if err != nil {
+		fmt.Fprintln(os.Stderr, err.Error())
+		os.Exit(1)
+	}
+
+	if data != nil {
+		m, _ := json.MarshalIndent(data, "", "    ")
+		fmt.Println(string(m))
+	}
+}
+
+func usage() {
+	fmt.Fprintf(os.Stderr, `%s is a command line client for the item API.
+
+Usage:
+    %s [-host HOST][-url URL][-timeout SECONDS][-verbose|-v] SERVICE ENDPOINT [flags]
+
+    -host HOST:  server host (localhost). valid values: localhost
+    -url URL:    specify service URL overriding host URL (http://localhost:8080)
+    -timeout:    maximum number of seconds to wait for response (30)
+    -verbose|-v: print request and response details (false)
+
+Commands:
+%s
+Additional help:
+    %s SERVICE [ENDPOINT] --help
+
+Example:
+%s
+`, os.Args[0], os.Args[0], indent(grpcUsageCommands()), os.Args[0], indent(grpcUsageExamples()))
+}
+
+func indent(s string) string {
+	if s == "" {
+		return ""
+	}
+	return "    " + strings.Replace(s, "\n", "\n    ", -1)
+}

services/item/cmd/item/grpc.go

@@ -0,0 +1,81 @@
+package main
+
+import (
+	"context"
+	itempb "crossnokaye-interview-assignment/services/item/gen/grpc/item/pb"
+	itemsvr "crossnokaye-interview-assignment/services/item/gen/grpc/item/server"
+	item "crossnokaye-interview-assignment/services/item/gen/item"
+	"log"
+	"net"
+	"net/url"
+	"sync"
+
+	grpcmdlwr "goa.design/goa/v3/grpc/middleware"
+	"goa.design/goa/v3/middleware"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/reflection"
+)
+
+// handleGRPCServer starts configures and starts a gRPC server on the given
+// URL. It shuts down the server if any error is received in the error channel.
+func handleGRPCServer(ctx context.Context, u *url.URL, itemEndpoints *item.Endpoints, wg *sync.WaitGroup, errc chan error, logger *log.Logger, debug bool) {
+
+	// Setup goa log adapter.
+	var (
+		adapter middleware.Logger
+	)
+	{
+		adapter = middleware.NewLogger(logger)
+	}
+
+	// Wrap the endpoints with the transport specific layers. The generated
+	// server packages contains code generated from the design which maps
+	// the service input and output data structures to gRPC requests and
+	// responses.
+	var (
+		itemServer *itemsvr.Server
+	)
+	{
+		itemServer = itemsvr.New(itemEndpoints, nil)
+	}
+
+	// Initialize gRPC server with the middleware.
+	srv := grpc.NewServer(
+		grpc.ChainUnaryInterceptor(
+			grpcmdlwr.UnaryRequestID(),
+			grpcmdlwr.UnaryServerLog(adapter),
+		),
+	)
+
+	// Register the servers.
+	itempb.RegisterItemServer(srv, itemServer)
+
+	for svc, info := range srv.GetServiceInfo() {
+		for _, m := range info.Methods {
+			logger.Printf("serving gRPC method %s", svc+"/"+m.Name)
+		}
+	}
+
+	// Register the server reflection service on the server.
+	// See https://grpc.github.io/grpc/core/md_doc_server-reflection.html.
+	reflection.Register(srv)
+
+	(*wg).Add(1)
+	go func() {
+		defer (*wg).Done()
+
+		// Start gRPC server in a separate goroutine.
+		go func() {
+			lis, err := net.Listen("tcp", u.Host)
+			if err != nil {
+				errc <- err
+			}
+			logger.Printf("gRPC server listening on %q", u.Host)
+			errc <- srv.Serve(lis)
+		}()
+
+		<-ctx.Done()
+		logger.Printf("shutting down gRPC server at %q", u.Host)
+		srv.Stop()
+	}()
+}

services/item/cmd/item/main.go

@@ -0,0 +1,109 @@
+package main
+
+import (
+	"context"
+	itemapi "crossnokaye-interview-assignment/services/item"
+	item "crossnokaye-interview-assignment/services/item/gen/item"
+	"flag"
+	"fmt"
+	"log"
+	"net"
+	"net/url"
+	"os"
+	"os/signal"
+	"sync"
+	"syscall"
+)
+
+func main() {
+	// Define command line flags, add any other flag required to configure the
+	// service.
+	var (
+		hostF     = flag.String("host", "localhost", "Server host (valid values: localhost)")
+		domainF   = flag.String("domain", "", "Host domain name (overrides host domain specified in service design)")
+		grpcPortF = flag.String("grpc-port", "", "gRPC port (overrides host gRPC port specified in service design)")
+		secureF   = flag.Bool("secure", false, "Use secure scheme (https or grpcs)")
+		dbgF      = flag.Bool("debug", false, "Log request and response bodies")
+	)
+	flag.Parse()
+
+	// Setup logger. Replace logger with your own log package of choice.
+	var (
+		logger *log.Logger
+	)
+	{
+		logger = log.New(os.Stderr, "[itemapi] ", log.Ltime)
+	}
+
+	// Initialize the services.
+	var (
+		itemSvc item.Service
+	)
+	{
+		itemSvc = itemapi.NewItem(logger)
+	}
+
+	// Wrap the services in endpoints that can be invoked from other services
+	// potentially running in different processes.
+	var (
+		itemEndpoints *item.Endpoints
+	)
+	{
+		itemEndpoints = item.NewEndpoints(itemSvc)
+	}
+
+	// Create channel used by both the signal handler and server goroutines
+	// to notify the main goroutine when to stop the server.
+	errc := make(chan error)
+
+	// Setup interrupt handler. This optional step configures the process so
+	// that SIGINT and SIGTERM signals cause the services to stop gracefully.
+	go func() {
+		c := make(chan os.Signal, 1)
+		signal.Notify(c, syscall.SIGINT, syscall.SIGTERM)
+		errc <- fmt.Errorf("%s", <-c)
+	}()
+
+	var wg sync.WaitGroup
+	ctx, cancel := context.WithCancel(context.Background())
+
+	// Start the servers and send errors (if any) to the error channel.
+	switch *hostF {
+	case "localhost":
+		{
+			addr := "grpc://localhost:8082"
+			u, err := url.Parse(addr)
+			if err != nil {
+				logger.Fatalf("invalid URL %#v: %s\n", addr, err)
+			}
+			if *secureF {
+				u.Scheme = "grpcs"
+			}
+			if *domainF != "" {
+				u.Host = *domainF
+			}
+			if *grpcPortF != "" {
+				h, _, err := net.SplitHostPort(u.Host)
+				if err != nil {
+					logger.Fatalf("invalid URL %#v: %s\n", u.Host, err)
+				}
+				u.Host = net.JoinHostPort(h, *grpcPortF)
+			} else if u.Port() == "" {
+				u.Host = net.JoinHostPort(u.Host, "8080")
+			}
+			handleGRPCServer(ctx, u, itemEndpoints, &wg, errc, logger, *dbgF)
+		}
+
+	default:
+		logger.Fatalf("invalid host argument: %q (valid hosts: localhost)\n", *hostF)
+	}
+
+	// Wait for signal.
+	logger.Printf("exiting (%v)", <-errc)
+
+	// Send cancellation signal to the goroutines.
+	cancel()
+
+	wg.Wait()
+	logger.Println("exited")
+}