From 869e541324f47132dd505b743d8db59976a4d087 Mon Sep 17 00:00:00 2001
From: Ben Langmead <ben.langmead@gmail.com>
Date: Mon, 19 Apr 2021 06:07:45 -0400
Subject: [PATCH] create new FTP connection per file; add retries

---
 scripts/rsync_from_ncbi.pl | 41 ++++++++++++++++++++++++--------------
 1 file changed, 26 insertions(+), 15 deletions(-)

diff --git a/scripts/rsync_from_ncbi.pl b/scripts/rsync_from_ncbi.pl
index 6ca239c..68375c7 100755
--- a/scripts/rsync_from_ncbi.pl
+++ b/scripts/rsync_from_ncbi.pl
@@ -79,29 +79,40 @@
   close MANIFEST;
 }
 
+sub ftp_connection {
+    my $ftp = Net::FTP->new($SERVER, Passive => 1)
+        or die "$PROG: FTP connection error: $@\n";
+    $ftp->login($FTP_USER, $FTP_PASS)
+        or die "$PROG: FTP login error: " . $ftp->message() . "\n";
+    $ftp->binary()
+        or die "$PROG: FTP binary mode error: " . $ftp->message() . "\n";
+    $ftp->cwd($SERVER_PATH)
+        or die "$PROG: FTP CD error: " . $ftp->message() . "\n";
+    return $ftp;
+}
+
 if ($use_ftp) {
   print STDERR "Step 1/2: Performing ftp file transfer of requested files\n";
-  my $ftp = Net::FTP->new($SERVER, Passive => 1)
-    or die "$PROG: FTP connection error: $@\n";
-  $ftp->login($FTP_USER, $FTP_PASS)
-    or die "$PROG: FTP login error: " . $ftp->message() . "\n";
-  $ftp->binary()
-    or die "$PROG: FTP binary mode error: " . $ftp->message() . "\n";
-  $ftp->cwd($SERVER_PATH)
-    or die "$PROG: FTP CD error: " . $ftp->message() . "\n";
   open MANIFEST, "<", "manifest.txt"
     or die "$PROG: can't open manifest: $!\n";
   mkdir "all" or die "$PROG: can't create 'all' directory: $!\n";
   chdir "all" or die "$PROG: can't chdir into 'all' directory: $!\n";
   while (<MANIFEST>) {
     chomp;
-    $ftp->get($_)
-      or do {
-        my $msg = $ftp->message();
-        if ($msg !~ /: No such file or directory$/) {
-          warn "$PROG: unable to download $_: $msg\n";
-        }
-      };
+    my $ftp = ftp_connection();
+    my $try = 0;
+    my $ntries = 5;
+    my $sleepsecs = 3;
+    while($try < $ntries) {
+        $try++;
+        last if $ftp->get($_);
+        warn "$PROG: unable to download $_ on try $try of $ntries: ".$ftp->message()."\n";
+        last if $try == $ntries;
+        sleep $sleepsecs;
+        $sleepsecs *= 3;
+    }
+    die "$PROG: unable to download ftp://${SERVER}${SERVER_PATH}/$_\n" if $try == $ntries;
+    $ftp->quit;
   }
   close MANIFEST;
   chdir ".." or die "$PROG: can't return to correct directory: $!\n";