commonsteps: StepDownload timeout override

multistep/commonsteps/step_download.go

@@ -64,40 +64,59 @@ type StepDownload struct {
 // The timeout must be long enough to accommodate large/slow downloads.
 const defaultGetterReadTimeout time.Duration = 30 * time.Minute
 
-var defaultGetterClient = getter.Client{
-	// Disable writing and reading through symlinks.
-	DisableSymlinks: true,
-	// The order of the Getters in the list may affect the result
-	// depending if the Request.Src is detected as valid by multiple getters
-	Getters: []getter.Getter{
-		&getter.GitGetter{
-			Timeout: defaultGetterReadTimeout,
-			Detectors: []getter.Detector{
-				new(getter.GitHubDetector),
-				new(getter.GitDetector),
-				new(getter.BitBucketDetector),
-				new(getter.GitLabDetector),
+var getterReadTimeout = defaultGetterReadTimeout
+var defaultGetterClient = getter.Client{}
+
+func init() {
+	prepareGetterClient()
+}
+
+// prepareGetterClient is run in the init function but is actually extracted
+// to make testing easier by providing a way to re prepare the client
+func prepareGetterClient() {
+	getterReadTimeout := defaultGetterReadTimeout
+	if env, exists := os.LookupEnv("PACKER_GETTER_READ_TIMEOUT"); exists {
+		parsedDuration, err := time.ParseDuration(env)
+		if err != nil {
+			panic(err)
+		}
+		getterReadTimeout = parsedDuration
+	}
+	defaultGetterClient = getter.Client{
+		// Disable writing and reading through symlinks.
+		DisableSymlinks: true,
+		// The order of the Getters in the list may affect the result
+		// depending if the Request.Src is detected as valid by multiple getters
+		Getters: []getter.Getter{
+			&getter.GitGetter{
+				Timeout: getterReadTimeout,
+				Detectors: []getter.Detector{
+					new(getter.GitHubDetector),
+					new(getter.GitDetector),
+					new(getter.BitBucketDetector),
+					new(getter.GitLabDetector),
+				},
+			},
+			&getter.HgGetter{
+				Timeout: getterReadTimeout,
+			},
+			new(getter.SmbClientGetter),
+			new(getter.SmbMountGetter),
+			&getter.HttpGetter{
+				Netrc:                 true,
+				XTerraformGetDisabled: true,
+				HeadFirstTimeout:      getterReadTimeout,
+				ReadTimeout:           getterReadTimeout,
+			},
+			new(getter.FileGetter),
+			&gcs.Getter{
+				Timeout: getterReadTimeout,
+			},
+			&s3.Getter{
+				Timeout: getterReadTimeout,
 			},
 		},
-		&getter.HgGetter{
-			Timeout: defaultGetterReadTimeout,
-		},
-		new(getter.SmbClientGetter),
-		new(getter.SmbMountGetter),
-		&getter.HttpGetter{
-			Netrc:                 true,
-			XTerraformGetDisabled: true,
-			HeadFirstTimeout:      defaultGetterReadTimeout,
-			ReadTimeout:           defaultGetterReadTimeout,
-		},
-		new(getter.FileGetter),
-		&gcs.Getter{
-			Timeout: defaultGetterReadTimeout,
-		},
-		&s3.Getter{
-			Timeout: defaultGetterReadTimeout,
-		},
-	},
+	}
 }
 
 func (s *StepDownload) Run(ctx context.Context, state multistep.StateBag) multistep.StepAction {

multistep/commonsteps/step_download_test.go

@@ -15,7 +15,9 @@ import (
 	"path/filepath"
 	"reflect"
 	"runtime"
+	"strings"
 	"testing"
+	"time"
 
 	"github.com/google/go-cmp/cmp"
 	urlhelper "github.com/hashicorp/go-getter/v2/helper/url"
@@ -287,6 +289,50 @@ func TestStepDownload_download(t *testing.T) {
 	os.RemoveAll(step.TargetPath)
 }
 
+func TestStepDownload_short_timeout(t *testing.T) {
+	if runtime.GOOS == "windows" {
+		t.Log("skipping download test on windows right now.")
+		return
+	}
+
+	os.Setenv("PACKER_GETTER_READ_TIMEOUT", "1ns")
+	prepareGetterClient()
+
+	// we need to re prepare the getterClient with default behavior once the test
+	// is completed
+	defer prepareGetterClient()
+	defer os.Unsetenv("PACKER_GETTER_READ_TIMEOUT")
+
+	srvr := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		<-time.After(time.Microsecond * 100)
+		w.Write([]byte("should not receive this"))
+	}))
+
+	defer srvr.Close()
+	step := &StepDownload{
+		Checksum:    "sha1:f572d396fae9206628714fb2ce00f72e94f2258f",
+		Description: "ISO",
+		ResultKey:   "iso_path",
+		Url:         nil,
+	}
+	ui := &packersdk.BasicUi{
+		Reader: new(bytes.Buffer),
+		Writer: new(bytes.Buffer),
+		PB:     &packersdk.NoopProgressTracker{},
+	}
+
+	_, err := step.download(context.TODO(), ui, srvr.URL+"/root/another.txt?")
+
+	contextDeadlineErrorMsg := "context deadline exceeded"
+	if err == nil {
+		t.Fatalf("Bad: expected a '%s' error", contextDeadlineErrorMsg)
+	}
+	if !strings.Contains(err.Error(), contextDeadlineErrorMsg) {
+		t.Fatalf("Bad: expected a '%s' error, got %s", contextDeadlineErrorMsg, err.Error())
+	}
+
+}
+
 func TestStepDownload_WindowsParseSourceURL(t *testing.T) {
 	if runtime.GOOS != "windows" {
 		t.Skip("skip windows specific tests")