Factor out common print loop code (#25?)

Author: aidansteele

cmd/down.go

@@ -30,7 +30,6 @@ var downCmd = &cobra.Command{
 		region := viper.GetString("region")
 		profile := viper.GetString("profile")
 		stackName := viper.GetString("stack-name")
-		printer := stackit.NewTailPrinter(cmd.OutOrStderr())
 
 		events := make(chan stackit.TailStackEvent)
 
@@ -40,17 +39,7 @@ var downCmd = &cobra.Command{
 		ctx := context.Background()
 		printerCtx, printerCancel := context.WithCancel(ctx)
 		defer printerCancel()
-
-		go func() {
-			for {
-				select {
-				case <-printerCtx.Done():
-					return
-				case tailEvent := <-events:
-					printer.PrintTailEvent(tailEvent)
-				}
-			}
-		}()
+		go printUntilDone(printerCtx, events, cmd.OutOrStderr())
 
 		err := sit.Down(ctx, stackName, events)
 		if err != nil {

cmd/execute.go

@@ -29,21 +29,10 @@ func executeChangeSet(ctx context.Context, region, profile, stackName, changeSet
 	sess := awsSession(profile, region)
 	sit := stackit.NewStackit(cloudformation.New(sess), sts.New(sess))
 	events := make(chan stackit.TailStackEvent)
-	printer := stackit.NewTailPrinter(writer)
 
 	printerCtx, printerCancel := context.WithCancel(ctx)
 	defer printerCancel()
-
-	go func() {
-		for {
-			select {
-			case <-printerCtx.Done():
-				return
-			case tailEvent := <-events:
-				printer.PrintTailEvent(tailEvent)
-			}
-		}
-	}()
+	go printUntilDone(printerCtx, events, writer)
 
 	var err error
 	if len(changeSet) == 0 {

cmd/package.go

@@ -52,21 +52,10 @@ func packageTemplate(ctx context.Context, region, profile, stackName, templatePa
 	packager := stackit.NewPackager(s3api, sts.New(sess), region)
 
 	events := make(chan stackit.TailStackEvent)
-	printer := stackit.NewTailPrinter(writer)
 
 	printerCtx, printerCancel := context.WithCancel(ctx)
 	defer printerCancel()
-
-	go func() {
-		for {
-			select {
-			case <-printerCtx.Done():
-				return
-			case tailEvent := <-events:
-				printer.PrintTailEvent(tailEvent)
-			}
-		}
-	}()
+	go printUntilDone(printerCtx, events, writer)
 
 	upInput, err := packager.Package(stackName, absPath, tags, parameters)
 	if err != nil {

cmd/up.go

@@ -23,6 +23,7 @@ import (
 	"github.com/glassechidna/stackit/pkg/stackit"
 	"github.com/spf13/cobra"
 	"github.com/spf13/viper"
+	"io"
 	"io/ioutil"
 	"os"
 	"strings"
@@ -68,20 +69,9 @@ var upCmd = &cobra.Command{
 
 		ctx := context.Background()
 
-		printer := stackit.NewTailPrinter(cmd.OutOrStderr())
 		printerCtx, printerCancel := context.WithCancel(ctx)
 		defer printerCancel()
-
-		go func() {
-			for {
-				select {
-				case <-printerCtx.Done():
-					return
-				case tailEvent := <-events:
-					printer.PrintTailEvent(tailEvent)
-				}
-			}
-		}()
+		go printUntilDone(printerCtx, events, cmd.OutOrStderr())
 
 		prepared, err := sit.Prepare(ctx, parsed, events)
 		if err != nil {
@@ -106,6 +96,19 @@ var upCmd = &cobra.Command{
 	},
 }
 
+func printUntilDone(ctx context.Context, events <-chan stackit.TailStackEvent, w io.Writer) {
+	printer := stackit.NewTailPrinter(w)
+
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case tailEvent := <-events:
+			printer.PrintTailEvent(tailEvent)
+		}
+	}
+}
+
 func keyvalSliceToMap(slice []string) map[string]string {
 	theMap := map[string]string{}