From f870f76b5b430d776d5d35cace1e5f0ae4b4aec7 Mon Sep 17 00:00:00 2001
From: Håvard Pettersen <havardpe@yahooinc.com>
Date: Thu, 10 Aug 2023 09:46:52 +0000
Subject: keep rpc target alive until pending rpc invocations complete

---
 messagebus/src/vespa/messagebus/network/rpctarget.cpp     | 9 +++++----
 messagebus/src/vespa/messagebus/network/rpctarget.h       | 8 ++++++--
 messagebus/src/vespa/messagebus/network/rpctargetpool.cpp | 2 +-
 3 files changed, 12 insertions(+), 7 deletions(-)

(limited to 'messagebus')

diff --git a/messagebus/src/vespa/messagebus/network/rpctarget.cpp b/messagebus/src/vespa/messagebus/network/rpctarget.cpp
index 9c6ca9dff69..d7f3e77c6fd 100644
--- a/messagebus/src/vespa/messagebus/network/rpctarget.cpp
+++ b/messagebus/src/vespa/messagebus/network/rpctarget.cpp
@@ -5,8 +5,8 @@
 
 namespace mbus {
 
-RPCTarget::RPCTarget(const string &spec, FRT_Supervisor &orb) :
-    _lock(),
+RPCTarget::RPCTarget(const string &spec, FRT_Supervisor &orb, ctor_tag)
+  : _lock(),
     _orb(orb),
     _name(spec),
     _target(*_orb.GetTarget(spec.c_str())),
@@ -48,6 +48,7 @@ RPCTarget::resolveVersion(duration timeout, RPCTarget::IVersionHandler &handler)
         handler.handleVersion(_version.get());
     } else if (shouldInvoke) {
         FRT_RPCRequest *req = _orb.AllocRPCRequest();
+        req->getStash().create<SP>(shared_from_this());
         req->SetMethodName("mbus.getVersion");
         _target.InvokeAsync(req, vespalib::to_s(timeout), this);
     }
@@ -67,8 +68,9 @@ RPCTarget::isValid() const
 }
 
 void
-RPCTarget::RequestDone(FRT_RPCRequest *req)
+RPCTarget::RequestDone(FRT_RPCRequest *raw_req)
 {
+    auto req = vespalib::ref_counted<FRT_RPCRequest>::internal_attach(raw_req);
     HandlerList handlers;
     {
         std::lock_guard guard(_lock);
@@ -94,7 +96,6 @@ RPCTarget::RequestDone(FRT_RPCRequest *req)
         _state = (_version.get() ? VERSION_RESOLVED : VERSION_NOT_RESOLVED);
     }
     _cond.notify_all();
-    req->internal_subref();
 }
 
 } // namespace mbus
diff --git a/messagebus/src/vespa/messagebus/network/rpctarget.h b/messagebus/src/vespa/messagebus/network/rpctarget.h
index fffffae64f7..77fcef5f48f 100644
--- a/messagebus/src/vespa/messagebus/network/rpctarget.h
+++ b/messagebus/src/vespa/messagebus/network/rpctarget.h
@@ -13,7 +13,7 @@ namespace mbus {
  * target. Instances of this class are returned by {@link RPCService}, and
  * cached by {@link RPCTargetPool}.
  */
-class RPCTarget : public FRT_IRequestWait {
+class RPCTarget : public FRT_IRequestWait, public std::enable_shared_from_this<RPCTarget> {
 public:
     /**
      * Declares a version handler used when resolving the version of a target.
@@ -58,6 +58,7 @@ private:
     Version_UP                 _version;
     HandlerList                _versionHandlers;
 
+    struct ctor_tag {};
 public:
     /**
      * Convenience typedefs.
@@ -72,7 +73,10 @@ public:
      * @param spec The connection spec of this target.
      * @param orb  The FRT supervisor to use when connecting to target.
      */
-    RPCTarget(const string &name, FRT_Supervisor &orb);
+    RPCTarget(const string &name, FRT_Supervisor &orb, ctor_tag);
+    static SP create(const string &name, FRT_Supervisor &orb) {
+        return std::make_shared<RPCTarget>(name, orb, ctor_tag{});
+    }
 
     /**
      * Destructor. Subrefs the contained FRT target.
diff --git a/messagebus/src/vespa/messagebus/network/rpctargetpool.cpp b/messagebus/src/vespa/messagebus/network/rpctargetpool.cpp
index b403c65f863..db09b127114 100644
--- a/messagebus/src/vespa/messagebus/network/rpctargetpool.cpp
+++ b/messagebus/src/vespa/messagebus/network/rpctargetpool.cpp
@@ -97,7 +97,7 @@ RPCTargetPool::getTarget(FRT_Supervisor &orb, const RPCServiceAddress &address)
     std::vector<RPCTarget::SP> targets;
     targets.reserve(_numTargetsPerSpec);
     for (size_t i(0); i < _numTargetsPerSpec; i++) {
-        targets.push_back(std::make_shared<RPCTarget>(spec, orb));
+        targets.push_back(RPCTarget::create(spec, orb));
     }
     _targets.insert(TargetMap::value_type(spec, Entry(std::move(targets), currentTime)));
     return _targets.find(spec)->second.getTarget(guard, currentTime);
-- 
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