Apply Last-Modified time as mtime when saving URLs

When saving the contents of a URL to a local file, attempt to set mtime
based on the response's Last-Modified header, if there is one.

Signed-off-by: Nalin Dahyabhai <nalin@redhat.com>

Closes: #58
Approved by: nalind

.travis.yml

@@ -11,4 +11,4 @@ before_install:
     - sudo apt-get -qq install bats btrfs-tools libdevmapper-dev libgpgme11-dev
 script:
     - make
-    - cd tests; sudo ./test_runner.sh
+    - cd tests; sudo PATH="$PATH" ./test_runner.sh

add.go

@@ -9,6 +9,7 @@ import (
 	"path"
 	"path/filepath"
 	"strings"
+	"time"
 
 	"github.com/Sirupsen/logrus"
 	"github.com/containers/storage/pkg/archive"
@@ -29,12 +30,23 @@ func addUrl(destination, srcurl string) error {
 	if err != nil {
 		return fmt.Errorf("error creating %q: %v", destination, err)
 	}
+	if last := resp.Header.Get("Last-Modified"); last != "" {
+		if mtime, err := time.Parse(time.RFC1123, last); err != nil {
+			logrus.Debugf("error parsing Last-Modified time %q: %v", last, err)
+		} else {
+			defer func() {
+				if err := os.Chtimes(destination, time.Now(), mtime); err != nil {
+					logrus.Debugf("error setting mtime to Last-Modified time %q: %v", last, err)
+				}
+			}()
+		}
+	}
 	defer f.Close()
 	n, err := io.Copy(f, resp.Body)
 	if resp.ContentLength >= 0 && n != resp.ContentLength {
 		return fmt.Errorf("error reading contents for %q: wrong length (%d != %d)", destination, n, resp.ContentLength)
 	}
-	if err := f.Chmod(0755); err != nil {
+	if err := f.Chmod(0600); err != nil {
 		return fmt.Errorf("error setting permissions on %q: %v", destination, err)
 	}
 	return nil

tests/copy.bats

@@ -86,3 +86,21 @@ load helpers
   cmp ${TESTDIR}/randomfile $root/randomsubdir/randomfile
   buildah rm $cid
 }
+
+@test "copy-url-mtime" {
+  createrandom ${TESTDIR}/randomfile
+
+  cid=$(buildah from --signature-policy ${TESTSDIR}/policy.json scratch)
+  buildah config --workingdir / $cid
+  starthttpd ${TESTDIR}
+  buildah copy $cid http://0.0.0.0:${HTTP_SERVER_PORT}/randomfile /urlfile
+  stophttpd
+  root=$(buildah mount $cid)
+  test -s $root/urlfile
+  cmp ${TESTDIR}/randomfile $root/urlfile
+  run test -nt ${TESTDIR}/randomfile $root/urlfile
+  [ "$status" -ne 0 ]
+  run test -ot ${TESTDIR}/randomfile $root/urlfile
+  [ "$status" -ne 0 ]
+  buildah rm $cid
+}

tests/helpers.bash

@@ -11,7 +11,27 @@ function setup() {
 	REPO=${TESTDIR}/root
 }
 
+function starthttpd() {
+	pushd ${2:-${BATS_TMPDIR}} > /dev/null
+	cp ${TESTSDIR}/serve.go .
+	go build serve.go
+	HTTP_SERVER_PORT=$((RANDOM+32768))
+	./serve ${HTTP_SERVER_PORT} ${1:-${BATS_TMPDIR}} &
+	HTTP_SERVER_PID=$!
+	popd > /dev/null
+}
+
+function stophttpd() {
+	if test -n "$HTTP_SERVER_PID" ; then
+		kill -HUP ${HTTP_SERVER_PID}
+		unset HTTP_SERVER_PID
+		unset HTTP_SERVER_PORT
+	fi
+	true
+}
+
 function teardown() {
+	stophttpd
 	rm -fr ${TESTDIR}
 }
 

tests/serve.go

@@ -0,0 +1,40 @@
+package main
+
+import (
+	"log"
+	"net/http"
+	"os"
+	"path/filepath"
+)
+
+func sendThatFile(basepath string) func(w http.ResponseWriter, r *http.Request) {
+	return func(w http.ResponseWriter, r *http.Request) {
+		filename := filepath.Join(basepath, filepath.Clean(string([]rune{filepath.Separator})+r.URL.Path))
+		f, err := os.Open(filename)
+		if err != nil {
+			if os.IsNotExist(err) {
+				http.NotFound(w, r)
+				return
+			}
+			http.Error(w, "whoops", http.StatusInternalServerError)
+			return
+		}
+		finfo, err := f.Stat()
+		if err != nil {
+			http.Error(w, "whoops", http.StatusInternalServerError)
+			return
+		}
+		http.ServeContent(w, r, filename, finfo.ModTime(), f)
+	}
+}
+
+func main() {
+	args := os.Args
+	if len(args) < 3 {
+		log.Fatal("requires listening port and subdirectory path")
+	}
+	port := args[1]
+	basedir := args[2]
+	http.HandleFunc("/", sendThatFile(basedir))
+	log.Fatal(http.ListenAndServe(":"+port, nil))
+}