From 16143f324c030579d447679d5741b63796a4ac9b Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Sat, 22 Apr 2017 18:32:46 +0200
Subject: Make HTTP soft error handling more robust

---
 bbot/agent.cxx   | 38 ++++++++++++++++++++++++++++++++------
 bbot/utility     |  4 +++-
 bbot/utility.txx | 31 ++++++++++++++++++++++---------
 3 files changed, 57 insertions(+), 16 deletions(-)

diff --git a/bbot/agent.cxx b/bbot/agent.cxx
index 683bd73..0840739 100644
--- a/bbot/agent.cxx
+++ b/bbot/agent.cxx
@@ -873,14 +873,30 @@ try
                        "--header", "Content-Type: text/manifest",
                        "--max-time", ops.request_timeout ());
 
-          serialize_manifest (tq, c.out, u, "task request");
+          // This is tricky/hairy: we may fail hard parsing the output before
+          // seeing that curl exited with an error and failing softly.
+          //
+          bool f (false);
+
+          try
+          {
+            serialize_manifest (tq, c.out, u, "task request", false);
+          }
+          catch (const failed&) {f = true;}
+
           c.out.close ();
 
-          tr = parse_manifest<task_response_manifest> (
-            c.in, u, "task response");
+          if (!f)
+          try
+          {
+            tr = parse_manifest<task_response_manifest> (
+              c.in, u, "task response", false);
+          }
+          catch (const failed&) {f = true;}
+
           c.in.close ();
 
-          if (!c.wait ())
+          if (!c.wait () || f)
             throw_generic_error (EIO);
         }
         catch (const system_error& e)
@@ -971,10 +987,20 @@ try
                      "--header", "Content-Type: text/manifest",
                      "--max-time", ops.request_timeout ());
 
-        serialize_manifest (rq, c.out, u, "task request");
+        // This is tricky/hairy: we may fail hard writing the input before
+        // seeing that curl exited with an error and failing softly.
+        //
+        bool f (false);
+
+        try
+        {
+          serialize_manifest (rq, c.out, u, "task request");
+        }
+        catch (const failed&) {f = true;}
+
         c.out.close ();
 
-        if (!c.wait ())
+        if (!c.wait () || f)
           throw_generic_error (EIO);
       }
       catch (const system_error& e)
diff --git a/bbot/utility b/bbot/utility
index 7fe6bfb..3424f2b 100644
--- a/bbot/utility
+++ b/bbot/utility
@@ -143,6 +143,7 @@ namespace bbot
   parse_manifest (istream&,
                   const string& name,
                   const char* what,
+                  bool fail_hard = true,
                   bool ignore_unknown = true);
 
   template <typename T>
@@ -154,7 +155,8 @@ namespace bbot
   serialize_manifest (const T&,
                       ostream&,
                       const string& name,
-                      const char* what);
+                      const char* what,
+                      bool fail_hard = true);
 }
 
 #include <bbot/utility.txx>
diff --git a/bbot/utility.txx b/bbot/utility.txx
index 4ee4c6f..231bd8f 100644
--- a/bbot/utility.txx
+++ b/bbot/utility.txx
@@ -157,7 +157,7 @@ namespace bbot
         fail << what << " manifest file " << f << " does not exist";
 
       ifdstream ifs (f);
-      return parse_manifest<T> (ifs, f.string (), what, ignore_unknown);
+      return parse_manifest<T> (ifs, f.string (), what, true, ignore_unknown);
     }
     catch (const system_error& e) // EACCES, etc.
     {
@@ -171,6 +171,7 @@ namespace bbot
   parse_manifest (istream& is,
                   const string& name,
                   const char* what,
+                  bool hard,
                   bool ignore_unknown)
   {
     using namespace butl;
@@ -182,15 +183,19 @@ namespace bbot
     }
     catch (const manifest_parsing& e)
     {
-      fail << "invalid " << what << " manifest: "
-           << name << ':' << e.line << ':' << e.column << ": " << e.description
-           << endf;
+      diag_record dr; if (hard) dr << fail; else dr << error;
+
+      dr << "invalid " << what << " manifest: "
+         << name << ':' << e.line << ':' << e.column << ": " << e.description;
     }
     catch (const io_error& e)
     {
-      fail << "unable to read " << what << " manifest " << name << ": " << e
-           << endf;
+      diag_record dr; if (hard) dr << fail; else dr << error;
+
+      dr << "unable to read " << what << " manifest " << name << ": " << e;
     }
+
+    throw failed ();
   }
 
   template <typename T>
@@ -205,7 +210,7 @@ namespace bbot
       ofdstream ofs (f, ios::binary);
       auto_rmfile arm (f); // Try to remove on failure ignoring errors.
 
-      serialize_manifest (m, ofs, f.string (), what);
+      serialize_manifest (m, ofs, f.string (), what, true);
 
       ofs.close ();
       arm.cancel ();
@@ -221,7 +226,8 @@ namespace bbot
   serialize_manifest (const T& m,
                       ostream& os,
                       const string& name,
-                      const char* what)
+                      const char* what,
+                      bool hard)
   {
     using namespace butl;
 
@@ -229,14 +235,21 @@ namespace bbot
     {
       manifest_serializer s (os, name);
       m.serialize (s);
+      return;
     }
     catch (const manifest_serialization& e)
     {
-      fail << "invalid " << what << " manifest: " << e.description;
+      diag_record dr; if (hard) dr << fail; else dr << error;
+
+      dr << "invalid " << what << " manifest: " << e.description;
     }
     catch (const io_error& e)
     {
+      diag_record dr; if (hard) dr << fail; else dr << error;
+
       fail << "unable to write " << what << " manifest " << name << ": " << e;
     }
+
+    throw failed ();
   }
 }
-- 
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