introduce podman machine

podman machine allows podman to create, manage, and interact with a vm
running some form of linux (default is fcos).  podman is then configured
to be able to interact with the vm automatically.

while this is usable on linux, the real push is to get this working on
both current apple architectures in macos.

Ashley Cui contributed to this PR and was a great help.

[NO TESTS NEEDED]

Signed-off-by: baude <bbaude@redhat.com>

pkg/machine/pull.go

@@ -0,0 +1,97 @@
+package machine
+
+import (
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+	"os/exec"
+	"strings"
+	"time"
+
+	"github.com/sirupsen/logrus"
+	"github.com/vbauerster/mpb/v6"
+	"github.com/vbauerster/mpb/v6/decor"
+)
+
+// DownloadVMImage downloads a VM image from url to given path
+// with download status
+func DownloadVMImage(downloadURL fmt.Stringer, localImagePath string) error {
+	out, err := os.Create(localImagePath)
+	if err != nil {
+		return err
+	}
+	defer func() {
+		if err := out.Close(); err != nil {
+			logrus.Error(err)
+		}
+	}()
+
+	resp, err := http.Get(downloadURL.String())
+	if err != nil {
+		return err
+	}
+	defer func() {
+		if err := resp.Body.Close(); err != nil {
+			logrus.Error(err)
+		}
+	}()
+
+	if resp.StatusCode != http.StatusOK {
+		return fmt.Errorf("error downloading VM image: %s", resp.Status)
+	}
+	size := resp.ContentLength
+	urlSplit := strings.Split(downloadURL.String(), "/")
+	prefix := "Downloading VM image: " + urlSplit[len(urlSplit)-1]
+	onComplete := prefix + ": done"
+
+	p := mpb.New(
+		mpb.WithWidth(60),
+		mpb.WithRefreshRate(180*time.Millisecond),
+	)
+
+	bar := p.AddBar(size,
+		mpb.BarFillerClearOnComplete(),
+		mpb.PrependDecorators(
+			decor.OnComplete(decor.Name(prefix), onComplete),
+		),
+		mpb.AppendDecorators(
+			decor.OnComplete(decor.CountersKibiByte("%.1f / %.1f"), ""),
+		),
+	)
+
+	proxyReader := bar.ProxyReader(resp.Body)
+	defer func() {
+		if err := proxyReader.Close(); err != nil {
+			logrus.Error(err)
+		}
+	}()
+
+	if _, err := io.Copy(out, proxyReader); err != nil {
+		return err
+	}
+
+	p.Wait()
+	return nil
+}
+
+// Will error out if file without .xz already exists
+// Maybe extracting then renameing is a good idea here..
+// depends on xz: not pre-installed on mac, so it becomes a brew dependecy
+func decompressXZ(src string, output io.Writer) error {
+	fmt.Println("Extracting compressed file")
+	cmd := exec.Command("xzcat", "-k", src)
+	//cmd := exec.Command("xz", "-d", "-k", "-v", src)
+	stdOut, err := cmd.StdoutPipe()
+	if err != nil {
+		return err
+	}
+	//cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+	go func() {
+		if _, err := io.Copy(output, stdOut); err != nil {
+			logrus.Error(err)
+		}
+	}()
+	return cmd.Run()
+}