Add RSYNC_DELETE_METHOD option to make it easier to use --delete-delay

If RSYNC_OPTIONS2 hasn't been modified, this will result in
--delete-delay being used if rsync 3.0.0 or greater is used.

Signed-off-by: Raphael Geissert <geissert@debian.org>

2 files changed, 30 insertions, 2 deletions

diff --git a/bin/ftpsync b/bin/ftpsync
index da665e5..23d7eb0 100755
--- a/bin/ftpsync
+++ b/bin/ftpsync
@@ -290,12 +290,29 @@ RSYNC=${RSYNC:-rsync}
 RSYNC_FILTER=${RSYNC_FILTER:-"--filter=protect_Archive-Update-in-Progress-${MIRRORNAME} --filter=protect_${TRACE} --filter=protect_Archive-Update-Required-${MIRRORNAME}"}
 # limit I/O bandwidth. Value is KBytes per second, unset or 0 is unlimited
 RSYNC_BW=${RSYNC_BW:-0}
+
+# Set the delete method to --delete-delay if protocol version is 30 or
+# greater (meaning rsync 3.0.0 or greater is used). Use --delete-after
+# otherwise.
+RSYNC_DELETE_METHOD=${RSYNC_DELETE_METHOD:-auto}
+if [ "xautox" = "x${RSYNC_DELETE_METHOD}x" ]; then
+    RSYNC_DELETE_METHOD=after
+
+    RSYNC_VERSION="$(${RSYNC} --version)"
+    if [[ $RSYNC_VERSION =~ (protocol[ ]+version[ ]+([0-9]+)) ]]; then
+        if [ 30 -le ${BASH_REMATCH[2]} ]; then
+            RSYNC_DELETE_METHOD=delay
+        fi
+    fi
+    unset RSYNC_VERSION
+fi
+
 # Default rsync options for *every* rsync call
 RSYNC_OPTIONS=${RSYNC_OPTIONS:-"-prltvHSB8192 --timeout 3600 --stats ${RSYNC_FILTER}"}
 # Options we only use in the first pass, where we do not want packages/sources to fly in yet and don't want to delete files
 RSYNC_OPTIONS1=${RSYNC_OPTIONS1:-"--exclude=Packages* --exclude=Sources* --exclude=Release* --exclude=InRelease --exclude=i18n/* --exclude=ls-lR*"}
 # Options for the second pass, where we do want everything, including deletion of old and now unused files
-RSYNC_OPTIONS2=${RSYNC_OPTIONS2:-"--max-delete=40000 --delay-updates --delete --delete-after --delete-excluded"}
+RSYNC_OPTIONS2=${RSYNC_OPTIONS2:-"--max-delete=40000 --delay-updates --delete --delete-excluded"}
 # Which rsync share to use on our upstream mirror?
 RSYNC_PATH=${RSYNC_PATH:-"debian"}
 
@@ -307,6 +324,11 @@ RSYNC_EXTRA=${RSYNC_EXTRA:-""}
 # 0 as unlimited, so this is safe.
 RSYNC_OPTIONS="${RSYNC_EXTRA} --bwlimit=${RSYNC_BW} ${RSYNC_OPTIONS}"
 
+# Finally, make sure RSYNC_OPTIONS2 has either --delete-after or --deleter-delay
+if ! [[ ${RSYNC_OPTIONS2} =~ --delete-(after|delay) ]]; then
+    RSYNC_OPTIONS2+=" --delete-${RSYNC_DELETE_METHOD}"
+fi
+
 # We have no default host to sync from, but will error out if its unset
 RSYNC_HOST=${RSYNC_HOST:-""}
 # Error out if we have no host to sync from
diff --git a/etc/ftpsync.conf.sample b/etc/ftpsync.conf.sample
index 4d96efb..3a8abe0 100644
--- a/etc/ftpsync.conf.sample
+++ b/etc/ftpsync.conf.sample
@@ -124,6 +124,12 @@
 ## limit I/O bandwidth. Value is KBytes per second, unset or 0 means unlimited
 #RSYNC_BW=""
 
+## Method used to delete files: "delay" or "after". "delay" is
+## recommended and is the default if no value is set and rsync 3 is
+## detected. NOTE: for this to work, neither --delete-after nor
+## --delete-delay should be set in RSYNC_OPTIONS2 (below).
+#RSYNC_DELETE_METHOD=""
+
 ## BE VERY CAREFUL WHEN YOU CHANGE THE RSYNC_OPTIONS! BETTER DON'T!
 ## BE VERY CAREFUL WHEN YOU CHANGE THE RSYNC_OPTIONS! BETTER DON'T!
 ## BE VERY CAREFUL WHEN YOU CHANGE THE RSYNC_OPTIONS! BETTER DON'T!
@@ -144,7 +150,7 @@
 ## Options the second pass gets. Now we want the Packages/Source indices too
 ## and we also want to delete files. We also want to delete files that are
 ## excluded.
-#RSYNC_OPTIONS2="--max-delete=40000 --delay-updates --delete --delete-after --delete-excluded"
+#RSYNC_OPTIONS2="--max-delete=40000 --delay-updates --delete --delete-excluded"
 
 ## You may establish the connection via a web proxy by setting the environment
 ## variable RSYNC_PROXY to a hostname:port pair pointing to your web proxy.  Note