From 29588381dc714dbb3250da4ee4f172e775724257 Mon Sep 17 00:00:00 2001
From: Iain Lane <iain.lane@canonical.com>
Date: Mon, 19 Sep 2016 17:03:58 +0100
Subject: [PATCH 1/2] Retry on all curl errors, not just timeouts

Otherwise random things cause downloading to fail when it might work on
a retry.
---
 source/utils.d | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/source/utils.d b/source/utils.d
index d04af076..3fa43096 100644
--- a/source/utils.d
+++ b/source/utils.d
@@ -352,7 +352,7 @@ in { assert (url.isRemote); }
 body
 {
     import core.time;
-    import std.net.curl : CurlTimeoutException, HTTP, FTP;
+    import std.net.curl : CurlException, HTTP, FTP;
 
     size_t onReceiveCb (File f, ubyte[] data)
     {
@@ -377,7 +377,7 @@ body
             downloader.perform();
         }
         logDebug ("Downloaded %s", url);
-    } catch (CurlTimeoutException e) {
+    } catch (CurlException e) {
         if (retryCount > 0) {
             logDebug ("Failed to download %s, will retry %d more %s",
                       url,

From 469182f8ba776ecfec404c15e9e033afeb6ac27b Mon Sep 17 00:00:00 2001
From: Iain Lane <iain.lane@canonical.com>
Date: Tue, 20 Sep 2016 11:40:26 +0100
Subject: [PATCH 2/2] Synchronise downloading of files

If multiple threads try to download the same file, then one of them will
get an incomplete file since `downloadFile` will return early if the
dest exists, which is does while the download is in progress.
---
 source/backends/debian/debpkg.d      |  4 +++-
 source/backends/debian/debpkgindex.d | 22 ++++++++++++++--------
 2 files changed, 17 insertions(+), 9 deletions(-)

diff --git a/source/backends/debian/debpkg.d b/source/backends/debian/debpkg.d
index 754f6592..7c8cc36e 100644
--- a/source/backends/debian/debpkg.d
+++ b/source/backends/debian/debpkg.d
@@ -62,7 +62,9 @@ public:
     @property string filename () const {
         if (debFname.isRemote) {
             immutable path = buildNormalizedPath (tmpDir, debFname.baseName);
-            downloadFile (debFname, path);
+            synchronized (this) {
+                downloadFile (debFname, path);
+            }
             return path;
         }
         return debFname;
diff --git a/source/backends/debian/debpkgindex.d b/source/backends/debian/debpkgindex.d
index a6005f86..9830b859 100644
--- a/source/backends/debian/debpkgindex.d
+++ b/source/backends/debian/debpkgindex.d
@@ -74,15 +74,17 @@ public:
         bool[string] ret;
 
         try {
-            const inReleaseContents = getFileContents (inRelease);
+            synchronized (this) {
+                const inReleaseContents = getFileContents (inRelease);
 
-            foreach (const ref entry; inReleaseContents) {
-                auto match = entry.matchFirst (translationregex);
+                foreach (const ref entry; inReleaseContents) {
+                    auto match = entry.matchFirst (translationregex);
 
-                if (match.empty)
-                    continue;
+                    if (match.empty)
+                        continue;
 
-                ret[match[1]] = true;
+                    ret[match[1]] = true;
+                }
             }
         } catch (Exception ex) {
             logWarning ("Could not get %s, will assume 'en' is available.", inRelease);
@@ -112,7 +114,9 @@ public:
                                             "Translation-%s.%s".format(lang, "%s"));
 
             try {
-                fname = downloadIfNecessary (rootDir, tmpDir, fullPath);
+                synchronized (this) {
+                    fname = downloadIfNecessary (rootDir, tmpDir, fullPath);
+                }
             } catch (Exception ex) {
                 logDebug ("No translations for %s in %s/%s", lang, suite, section);
                 continue;
@@ -175,7 +179,9 @@ public:
     {
         immutable path = buildPath ("dists", suite, section, "binary-%s".format (arch));
 
-        return downloadIfNecessary (rootDir, tmpDir, buildPath (path, "Packages.%s"));
+        synchronized (this) {
+            return downloadIfNecessary (rootDir, tmpDir, buildPath (path, "Packages.%s"));
+        }
     }
 
     protected DebPackage newPackage (string name, string ver, string arch)