Adds retry instead of immediate failure

Signed-off-by: Dan Finneran <dan@thebsdbox.co.uk>

Author: thebsdbox

tink-docker/main.go

@@ -79,11 +79,28 @@ func parseCmdLine(cmdLines []string) (cfg tinkConfig) {
 // downloadFile will download a url to a local file. It's efficient because it will
 // write as it downloads and not load the whole file into memory.
 func downloadFile(filepath string, url string) error {
+	// As all functions in the LinuxKit services run in parallel, ensure that we can fail
+	// successfully until we accept that networking is actually broken
+
+	var maxRetryCount int
+	var timeOut time.Duration
+	maxRetryCount = 10
+	timeOut = time.Millisecond * 500 // 0.5 seconds
+	var resp *http.Response
+	var err error
+
+	// Retry this task
+	for retries := 0; retries < maxRetryCount; retries++ {
 	// Get the data
-	resp, err := http.Get(url)
-	if err != nil {
+	resp, err = http.Get(url)
+	if err == nil {
+		break
+	}
+	if retries == maxRetryCount - 1 {
 		return err
 	}
+		time.Sleep(timeOut)
+}
 	defer resp.Body.Close()
 
 	// Create the file