Try to get more atomic syncing for serving content.

Signed-off-by: Alec Warner <antarus@gentoo.org>

1 files changed, 18 insertions, 12 deletions

diff --git a/src/infra.gentoo.org/rsync-node/wrap_rsync.sh b/src/infra.gentoo.org/rsync-node/wrap_rsync.sh
index f92934c..b4a6857 100755
--- a/src/infra.gentoo.org/rsync-node/wrap_rsync.sh
+++ b/src/infra.gentoo.org/rsync-node/wrap_rsync.sh
@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/bin/bash -x
 
 # On container start, run an rsync to get a good copy of the tree.
 # Then execute rsyncd; we will start serving once the sync completes.
@@ -22,22 +22,28 @@ function sync() {
 	logger -t rsync "re-rsyncing the gentoo-portage tree"
 	/usr/bin/rsync ${OPTS[@]} "${SRC}" "${DST}" >> $0.log 2>&1
 	echo "End: "$(date) >> $0.log 2>&1
+	return 0
 }
 
-sync "${DEST_DIR}/serving" "${SOURCE_MIRROR}" # this is synchronous.
+tmp=$(mktemp -d -p "${DEST_DIR}" XXXXXX)
+sync "${tmp}" "${SOURCE_MIRROR}" # this is synchronous.
 
-# Then launch rsyncd; it will detach into the background.
+# We serve out of ${DEST_DIR}/serving
+ln -s "${tmp}" "serving"
+
+# Then launch rsyncd; it will detach into the background and serve from serving.
 rsync --daemon --config="/opt/rsync/rsyncd.conf"
 
 while true
 do
-				sleep "${WAIT_TIME}"
-				tmp=$(mktemp -d -p "${DEST_DIR}" XXXXXX)
-				# If we fail to sync, just try again.
-				if ! sync "${tmp}" "${SOURCE_MIRROR}"; then
-					rm -rf "${tmp}"
-					continue
-				fi
-				# Atomically rename
-				mv -f "${tmp}" "${DEST_DIR}/serving"
+	sleep "${WAIT_TIME}"
+	tmp=$(mktemp -d -p "${DEST_DIR}" XXXXXX)
+	# If we fail to sync, just try again.
+	if ! sync "${tmp}" "${SOURCE_MIRROR}"; then
+		rm -rf "${tmp}"
+		continue
+	fi
+	# Atomically rename
+	ln -sf "${tmp}" "staging" && \
+		mv -fT "${DEST_DIR}/staging" "${DEST_DIR}/serving"
 done