qubes.Template*: Add --refresh option and allow DNF cache to be used.

qubes-rpc/qvm-template-repo-query

@@ -10,7 +10,8 @@ while IFS= read -r line; do
         --enablerepo=*|\
         --disablerepo=*|\
         --repoid=*|\
-        --releasever=*)
+        --releasever=*|\
+        --refresh)
             OPTS+=("$line")
             ;;
         *)
@@ -25,13 +26,22 @@ cat > "$repodir/template.repo"
 OPTS+=("--setopt=reposdir=${repodir}")
 OPTS+=("--quiet")
 
+# This creates the hashfile if it doesn't exist, and keep the ctime and mtime
+# unchanged otherwise.
+# We then copy the {c,m}time to the repo config.
+# This allows DNF caching to work properly.
+hashfile="/tmp/qvm-template-$(b2sum "$repodir/template.repo" | cut -f1 -d' ')"
+touch -a "$hashfile"
+touch -r "$hashfile" "$repodir/template.repo"
+
 RET=0
 
 if [ "$1" = "query" ]; then
     dnf repoquery "${OPTS[@]}" --qf='%{name}|%{epoch}|%{version}|%{release}|%{reponame}|%{downloadsize}|%{buildtime}|%{license}|%{url}|%{summary}|%{description}|' "$SPEC"
     RET="$?"
 elif [ "$1" = "download" ]; then
-    curl --silent -L "$(dnf download "${OPTS[@]}" --url "$SPEC" | shuf -n 1)" -o -
+    url="$(dnf download "${OPTS[@]}" --url "$SPEC" | shuf -n 1)"
+    curl --silent -L "$url" -o -
     RET="$?"
 fi