Let the client send health checks periodically

cmd/clientsim/main.go

@@ -20,16 +20,16 @@ limitations under the License.
 package main
 
 import (
+	"context"
 	"fmt"
 	"log"
 	"os"
 	"sync"
 	"time"
 
+	"git.cacert.org/cacert-gosigner/pkg/messages"
 	"github.com/justincpresley/go-cobs"
 	"github.com/shamaton/msgpackgen/msgpack"
-
-	"git.cacert.org/cacert-gosigner/pkg/messages"
 )
 
 const cobsDelimiter = 0x00
@@ -37,39 +37,64 @@ const cobsDelimiter = 0x00
 var cobsConfig = cobs.Config{SpecialByte: cobsDelimiter, Delimiter: true, EndingSave: true}
 
 func main() {
+	errorLog := log.New(os.Stderr, "", log.LstdFlags)
+
+	sim := &clientSimulator{
+		errorLog: errorLog,
+	}
+
+	err := sim.Run()
+	if err != nil {
+		errorLog.Printf("simulator returned an error: %v", err)
+	}
+}
+
+type clientSimulator struct {
+	errorLog  *log.Logger
+	commands  chan messages.Command
+	responses chan []byte
+}
+
+func (c *clientSimulator) writeTestCommands(ctx context.Context) error {
+	messages.RegisterGeneratedResolver()
+
+	const healthInterval = 10 * time.Second
+
+	timer := time.NewTimer(healthInterval)
+
+	for {
+		select {
+		case <-ctx.Done():
+			_ = timer.Stop()
+
+			return nil
+		case <-timer.C:
+			c.commands <- messages.Command{
+				Code:      messages.CmdHealth,
+				TimeStamp: time.Now().UTC(),
+			}
+
+			timer.Reset(healthInterval)
+		}
+	}
+}
+
+func (c *clientSimulator) handleInput(ctx context.Context) error {
 	const (
 		bufferSize   = 1024 * 1024
 		readInterval = 50 * time.Millisecond
 	)
 
-	errors := make(chan error)
-
-	errorLog := log.New(os.Stderr, "", log.LstdFlags)
-
-	wg := sync.WaitGroup{}
-	wg.Add(1)
-
-	done := make(chan struct{})
-	frame := make(chan []byte)
-
-	go func(done chan struct{}) {
 	buf := make([]byte, bufferSize)
 
 	for {
 		select {
-			case <-done:
+		case <-ctx.Done():
-				wg.Done()
+			return nil
-
-				return
-
 		default:
 			count, err := os.Stdin.Read(buf)
 			if err != nil {
-					errors <- err
+				return err
-
-					wg.Done()
-
-					return
 			}
 
 			if count == 0 {
@@ -82,42 +107,18 @@ func main() {
 
 			err = cobs.Verify(data, cobsConfig)
 			if err != nil {
-					errors <- err
+				return err
-
-					wg.Done()
-
-					return
 			}
 
-				frame <- cobs.Decode(data, cobsConfig)
+			c.responses <- cobs.Decode(data, cobsConfig)
 		}
 	}
-	}(done)
-
-	err := writeTestCommands(frame, errorLog)
-	if err != nil {
-		errorLog.Printf("could not write test commands")
 }
 
-	err = <-errors
+func (c *clientSimulator) handleCommands(ctx context.Context) error {
-	if err != nil {
+	for {
-		errorLog.Printf("error: %v", err)
+		select {
-	}
+		case command := <-c.commands:
-
-	wg.Wait()
-}
-
-func writeTestCommands(responses chan []byte, errorLog *log.Logger) error {
-	messages.RegisterGeneratedResolver()
-
-	commands := []messages.Command{
-		{
-			Code:      messages.CmdHealth,
-			TimeStamp: time.Now().UTC(),
-		},
-	}
-
-	for _, command := range commands {
 			commandBytes, err := msgpack.Marshal(command)
 			if err != nil {
 				return fmt.Errorf("could not marshal command bytes: %w", err)
@@ -128,7 +129,7 @@ func writeTestCommands(responses chan []byte, errorLog *log.Logger) error {
 				return fmt.Errorf("write failed: %w", err)
 			}
 
-		responseBytes := <-responses
+			responseBytes := <-c.responses
 
 			var response messages.Response
 
@@ -137,8 +138,56 @@ func writeTestCommands(responses chan []byte, errorLog *log.Logger) error {
 				return fmt.Errorf("could not unmarshal msgpack data: %w", err)
 			}
 
-		errorLog.Printf("received response: %+v", response)
+			c.errorLog.Printf("received response: %+v", response)
-	}
+		case <-ctx.Done():
-
 			return nil
 		}
+	}
+}
+
+func (c *clientSimulator) Run() error {
+	ctx, cancel := context.WithCancel(context.Background())
+
+	c.commands = make(chan messages.Command)
+	c.responses = make(chan []byte)
+
+	wg := sync.WaitGroup{}
+	wg.Add(2)
+
+	var inputError, commandError error
+
+	go func(inputErr error) {
+		inputError = c.handleInput(ctx)
+
+		cancel()
+
+		wg.Done()
+	}(inputError)
+
+	go func(commandErr error) {
+		commandErr = c.handleCommands(ctx)
+
+		cancel()
+
+		wg.Done()
+	}(commandError)
+
+	var result error
+
+	if err := c.writeTestCommands(ctx); err != nil {
+		c.errorLog.Printf("test commands failed: %v", err)
+	}
+
+	cancel()
+	wg.Wait()
+
+	if inputError != nil {
+		c.errorLog.Printf("reading input failed: %v", inputError)
+	}
+
+	if commandError != nil {
+		c.errorLog.Printf("sending commands failed: %v", commandError)
+	}
+
+	return result
+}