Allow checkup logger interrupt to be called multiple times

pkg/debug/checkups/checkpoint.go

@@ -19,9 +19,10 @@ type (
 	}
 
 	checkPointer struct {
-		logger    logger
-		knapsack  types.Knapsack
-		interrupt chan struct{}
+		logger      logger
+		knapsack    types.Knapsack
+		interrupt   chan struct{}
+		interrupted bool
 	}
 )
 
@@ -53,6 +54,13 @@ func (c *checkPointer) Run() error {
 }
 
 func (c *checkPointer) Interrupt(_ error) {
+	// Only perform shutdown tasks on first call to interrupt -- no need to repeat on potential extra calls.
+	if c.interrupted {
+		return
+	}
+
+	c.interrupted = true
+
 	c.interrupt <- struct{}{}
 }
 

pkg/debug/checkups/checkpoint_test.go

@@ -0,0 +1,59 @@
+package checkups
+
+import (
+	"errors"
+	"testing"
+	"time"
+
+	"github.com/go-kit/kit/log"
+	storageci "github.com/kolide/launcher/pkg/agent/storage/ci"
+	typesmocks "github.com/kolide/launcher/pkg/agent/types/mocks"
+	"github.com/stretchr/testify/require"
+)
+
+func TestInterrupt_Multiple(t *testing.T) {
+	t.Parallel()
+
+	mockKnapsack := typesmocks.NewKnapsack(t)
+	mockKnapsack.On("UpdateChannel").Return("nightly").Maybe()
+	mockKnapsack.On("TufServerURL").Return("localhost").Maybe()
+	mockKnapsack.On("BboltDB").Return(storageci.SetupDB(t)).Maybe()
+	mockKnapsack.On("KolideHosted").Return(false).Maybe()
+	mockKnapsack.On("KolideServerURL").Return("localhost").Maybe()
+	mockKnapsack.On("ControlServerURL").Return("localhost").Maybe()
+	mockKnapsack.On("InsecureTransportTLS").Return(true).Maybe()
+	checkupLogger := NewCheckupLogger(log.NewNopLogger(), mockKnapsack)
+	mockKnapsack.AssertExpectations(t)
+
+	// Start and then interrupt
+	go checkupLogger.Run()
+	checkupLogger.Interrupt(errors.New("test error"))
+
+	// Confirm we can call Interrupt multiple times without blocking
+	interruptComplete := make(chan struct{})
+	expectedInterrupts := 3
+	for i := 0; i < expectedInterrupts; i += 1 {
+		go func() {
+			checkupLogger.Interrupt(nil)
+			interruptComplete <- struct{}{}
+		}()
+	}
+
+	receivedInterrupts := 0
+	for {
+		if receivedInterrupts >= expectedInterrupts {
+			break
+		}
+
+		select {
+		case <-interruptComplete:
+			receivedInterrupts += 1
+			continue
+		case <-time.After(5 * time.Second):
+			t.Errorf("could not call interrupt multiple times and return within 5 seconds -- received %d interrupts before timeout", receivedInterrupts)
+			t.FailNow()
+		}
+	}
+
+	require.Equal(t, expectedInterrupts, receivedInterrupts)
+}