[cluster] deploy: fix destination directory

"~" is resolved by the local shell (dumb me!). We now get the
destination directory by connecting to the first alive host from the
hosts' list (using cluster-ping), and get the user's home directory.
This is not perfect because it assumes the home directory is the same on
each host.

We could add an option in the future to do the test on each host, but
this would be significantly slower. Alternatively, we could allow to use
scp instead of pscp (because scp is smart enough to get the remote
user's home directory by itself), transferring files once at time, but
again, it would be slow.

cluster/README

@@ -73,4 +73,5 @@ Please note that unlike rsync, prsync cannot handle multiple local
 files, therefore the -P option is ignored when passed along with -r or
 -R.
 
-Dependencies: parallel-scp (pscp), parallel-rsync (prsync)
+Dependencies: parallel-scp (pscp), parallel-rsync (prsync), cluster-ping
+              (see above)

cluster/cluster-deploy.sh

@@ -90,27 +90,44 @@ elif [ "$PRSYNC" = "" ] ; then
 fi
 
 # Hosts' list file
-HOSTS="$HOME/.config/cluster/$1.lst"
+HOSTS_LIST_NAME="$1"
+HOSTS="$HOME/.config/cluster/${HOSTS_LIST_NAME}.lst"
 shift
 echo "Using file '$HOSTS' as hosts' list."
 
 # Login
 if [ "$LOGIN" != "" ] ; then
   echo "Login: $LOGIN"
+  SSH_LOGIN="${LOGIN}@"
   LOGIN="-l $LOGIN"
 fi
 
+# Test the connection to the first host and get the destination
+# directory (home directory of the remote user)
+FIRST_HOST=$(cluster-ping "$HOSTS_LIST_NAME" 2>/dev/null | sed -n "s/ is alive$//p" | head -n1)
+if [ "$FIRST_HOST" = "" ] ; then
+  echo "None of the remote hosts is alive."
+  exit 6
+fi
+echo "Testing connection to $FIRST_HOST..."
+DEST_DIR="$(ssh ${SSH_LOGIN}${FIRST_HOST} 'echo $HOME' 2>/dev/null)"
+if [ "$DEST_DIR" = "" ] ; then
+  echo "Cannot connect to the first alive host. Aborting."
+  exit 7
+fi
+echo "Destination directory: $DEST_DIR"
+
 # Transfer the files in parallel...
 if [ "$PARALLEL" = "1" ] ; then
-  exec $PSCP -r $LOGIN -h "$HOSTS" -- "$@" ~
+  exec $PSCP -r $LOGIN -h "$HOSTS" -- "$@" "$DEST_DIR"
 fi
 
 # ... or one by one
 for FILE in "$@" ; do
   echo "Deploying '$FILE'..."
   if [ "$RSYNC" = "1" ] ; then
-    $PRSYNC -a $DELETE $LOGIN -h "$HOSTS" -- "$FILE" ~
+    $PRSYNC -a $DELETE $LOGIN -h "$HOSTS" -- "$FILE" "$DEST_DIR"
   else
-    $PSCP -r $LOGIN -h "$HOSTS" -- "$FILE" ~
+    $PSCP -r $LOGIN -h "$HOSTS" -- "$FILE" "$DEST_DIR"
   fi
 done