Merge pull request #21324 from vespa-engine/revert-21318-balder/allow-creating-config-context-with-provided-transport

Revert "Add support for creating ConfigContext with externally provided FNET_…"

17 files changed, 65 insertions, 105 deletions

diff --git a/config/src/tests/file_subscription/file_subscription.cpp b/config/src/tests/file_subscription/file_subscription.cpp
index 6b900876bda..b4a2b890bb5 100644
--- a/config/src/tests/file_subscription/file_subscription.cpp
+++ b/config/src/tests/file_subscription/file_subscription.cpp
@@ -58,7 +58,7 @@ TEST("requireThatFileSpecGivesCorrectSource") {
     writeFile("my.cfg", "foobar");
     FileSpec spec("my.cfg");
 
-    auto factory = spec.createSourceFactory(TimingValues());
+    SourceFactory::UP factory(spec.createSourceFactory(TimingValues()));
     ASSERT_TRUE(factory);
     auto holder = std::make_shared<ConfigHolder>();
     std::unique_ptr<Source> src = factory->createSource(holder, ConfigKey("my", "my", "bar", "foo"));
diff --git a/config/src/tests/frtconnectionpool/frtconnectionpool.cpp b/config/src/tests/frtconnectionpool/frtconnectionpool.cpp
index 46e1f698091..c2ed60370e0 100644
--- a/config/src/tests/frtconnectionpool/frtconnectionpool.cpp
+++ b/config/src/tests/frtconnectionpool/frtconnectionpool.cpp
@@ -3,9 +3,6 @@
 #include <vespa/vespalib/testkit/testapp.h>
 #include <vespa/config/frt/frtconnectionpool.h>
 #include <vespa/fnet/frt/error.h>
-#include <vespa/fnet/transport.h>
-#include <vespa/fastos/thread.h>
-#include <vespa/vespalib/util/size_literals.h>
 #include <sstream>
 #include <set>
 #include <unistd.h>
@@ -15,12 +12,8 @@ using namespace config;
 class Test : public vespalib::TestApp {
 private:
     static ServerSpec::HostSpecList _sources;
-    FastOS_ThreadPool _threadPool;
-    FNET_Transport    _transport;
     void verifyAllSourcesInRotation(FRTConnectionPool& sourcePool);
 public:
-    Test();
-    ~Test() override;
     int Main() override;
     void testBasicRoundRobin();
     void testBasicHashBasedSelection();
@@ -32,18 +25,6 @@ public:
     void testManySources();
 };
 
-Test::Test()
-    : vespalib::TestApp(),
-      _threadPool(64_Ki),
-      _transport()
-{
-    _transport.Start(&_threadPool);
-}
-
-Test::~Test() {
-    _transport.ShutDown(true);
-}
-
 TEST_APPHOOK(Test);
 
 ServerSpec::HostSpecList Test::_sources;
@@ -98,7 +79,7 @@ void Test::verifyAllSourcesInRotation(FRTConnectionPool& sourcePool) {
  */
 void Test::testBasicRoundRobin() {
     const ServerSpec spec(_sources);
-    FRTConnectionPool sourcePool(_transport, spec, timingValues);
+    FRTConnectionPool sourcePool(spec, timingValues);
     for (int i = 0; i < 9; i++) {
         int j = i % _sources.size();
         std::stringstream s;
@@ -112,7 +93,7 @@ void Test::testBasicRoundRobin() {
  */
 void Test::testBasicHashBasedSelection() {
     const ServerSpec spec(_sources);
-    FRTConnectionPool sourcePool(_transport, spec, timingValues);
+    FRTConnectionPool sourcePool(spec, timingValues);
     sourcePool.setHostname("a.b.com");
     for (int i = 0; i < 9; i++) {
         EXPECT_EQUAL("host1", sourcePool.getNextHashBased()->getAddress());
@@ -127,7 +108,7 @@ void Test::testBasicHashBasedSelection() {
     hostnames.push_back("stroustrup-02.example.yahoo.com");
     hostnames.push_back("alexandrescu-03.example.yahoo.com");
     const ServerSpec spec2(hostnames);
-    FRTConnectionPool sourcePool2(_transport, spec2, timingValues);
+    FRTConnectionPool sourcePool2(spec2, timingValues);
     sourcePool2.setHostname("sutter-01.example.yahoo.com");
     EXPECT_EQUAL("stroustrup-02.example.yahoo.com", sourcePool2.getNextHashBased()->getAddress());
     sourcePool2.setHostname("stroustrup-02.example.yahoo.com");
@@ -142,7 +123,7 @@ void Test::testBasicHashBasedSelection() {
  */
 void Test::testSetErrorRoundRobin() {
     const ServerSpec spec(_sources);
-    FRTConnectionPool sourcePool(_transport, spec, timingValues);
+    FRTConnectionPool sourcePool(spec, timingValues);
     FRTConnection* source = sourcePool.getNextRoundRobin();
     source->setError(FRTE_RPC_CONNECTION);
     for (int i = 0; i < 9; i++) {
@@ -157,7 +138,7 @@ void Test::testSetErrorRoundRobin() {
  */
 void Test::testSetErrorAllRoundRobin() {
     const ServerSpec spec(_sources);
-    FRTConnectionPool sourcePool(_transport, spec, timingValues);
+    FRTConnectionPool sourcePool(spec, timingValues);
     for (int i = 0; i < (int)_sources.size(); i++) {
         FRTConnection* source = sourcePool.getNextRoundRobin();
         source->setError(FRTE_RPC_CONNECTION);
@@ -171,7 +152,7 @@ void Test::testSetErrorAllRoundRobin() {
  */
 void Test::testSetErrorHashBased() {
     const ServerSpec spec(_sources);
-    FRTConnectionPool sourcePool(_transport, spec, timingValues);
+    FRTConnectionPool sourcePool(spec, timingValues);
     FRTConnection* source = sourcePool.getNextHashBased();
     source->setError(FRTE_RPC_CONNECTION);
     for (int i = 0; i < (int)_sources.size(); i++) {
@@ -186,7 +167,7 @@ void Test::testSetErrorHashBased() {
  */
 void Test::testSetErrorAllHashBased() {
     const ServerSpec spec(_sources);
-    FRTConnectionPool sourcePool(_transport, spec, timingValues);
+    FRTConnectionPool sourcePool(spec, timingValues);
     FRTConnection* firstSource = sourcePool.getNextHashBased();
     auto readySources = sourcePool.getReadySources();
     for (int i = 0; i < (int)readySources.size(); i++) {
@@ -218,7 +199,7 @@ void Test::testSetErrorAllHashBased() {
  */
 void Test::testSuspensionTimeout() {
     const ServerSpec spec(_sources);
-    FRTConnectionPool sourcePool(_transport, spec, timingValues);
+    FRTConnectionPool sourcePool(spec, timingValues);
     Connection* source = sourcePool.getCurrent();
     source->setTransientDelay(1s);
     source->setError(FRTE_RPC_CONNECTION);
@@ -246,7 +227,7 @@ void Test::testManySources() {
     twoSources.push_back("host1");
 
     const ServerSpec spec(twoSources);
-    FRTConnectionPool sourcePool(_transport, spec, timingValues);
+    FRTConnectionPool sourcePool(spec, timingValues);
 
     for (int i = 0; i < (int)hostnames.size(); i++) {
         sourcePool.setHostname(hostnames[i]);
diff --git a/config/src/tests/subscriber/subscriber.cpp b/config/src/tests/subscriber/subscriber.cpp
index d7320bb6a2f..548e54e1d18 100644
--- a/config/src/tests/subscriber/subscriber.cpp
+++ b/config/src/tests/subscriber/subscriber.cpp
@@ -85,7 +85,7 @@ namespace {
 
             return std::make_shared<ConfigSubscription>(0, key, holder, std::make_unique<MySource>());
         }
-        void unsubscribe(const ConfigSubscription & subscription) override {
+        void unsubscribe(const ConfigSubscription::SP & subscription) override {
             (void) subscription;
             numCancel++;
         }
diff --git a/config/src/vespa/config/common/cancelhandler.h b/config/src/vespa/config/common/cancelhandler.h
index 694f0185e7c..8dde83ba7d9 100644
--- a/config/src/vespa/config/common/cancelhandler.h
+++ b/config/src/vespa/config/common/cancelhandler.h
@@ -13,7 +13,7 @@ struct CancelHandler
      *
      * @param subscription ConfigSubscription to cancel
      */
-    virtual void unsubscribe(const ConfigSubscription & subscription) = 0;
+    virtual void unsubscribe(const std::shared_ptr<ConfigSubscription> & subscription) = 0;
 
     virtual ~CancelHandler() = default;
 };
diff --git a/config/src/vespa/config/common/configcontext.cpp b/config/src/vespa/config/common/configcontext.cpp
index eb56202bf06..2c8c981862d 100644
--- a/config/src/vespa/config/common/configcontext.cpp
+++ b/config/src/vespa/config/common/configcontext.cpp
@@ -6,7 +6,9 @@
 namespace config {
 
 ConfigContext::ConfigContext(const SourceSpec & spec)
-    : ConfigContext(TimingValues(), spec)
+    : _timingValues(),
+      _generation(1),
+      _manager(std::make_unique<ConfigManager>(spec.createSourceFactory(_timingValues), _generation))
 { }
 
 ConfigContext::ConfigContext(const TimingValues & timingValues, const SourceSpec & spec)
diff --git a/config/src/vespa/config/common/configmanager.cpp b/config/src/vespa/config/common/configmanager.cpp
index 1417aed79ae..983cccb0b0b 100644
--- a/config/src/vespa/config/common/configmanager.cpp
+++ b/config/src/vespa/config/common/configmanager.cpp
@@ -11,7 +11,7 @@ LOG_SETUP(".config.common.configmanager");
 
 namespace config {
 
-ConfigManager::ConfigManager(std::unique_ptr<SourceFactory> sourceFactory, int64_t initialGeneration)
+ConfigManager::ConfigManager(SourceFactory::UP sourceFactory, int64_t initialGeneration)
     : _idGenerator(0),
       _sourceFactory(std::move(sourceFactory)),
       _generation(initialGeneration),
@@ -53,10 +53,10 @@ ConfigManager::subscribe(const ConfigKey & key, vespalib::duration timeout)
 }
 
 void
-ConfigManager::unsubscribe(const ConfigSubscription & subscription)
+ConfigManager::unsubscribe(const ConfigSubscription::SP & subscription)
 {
     std::lock_guard guard(_lock);
-    const SubscriptionId id(subscription.getSubscriptionId());
+    const SubscriptionId id(subscription->getSubscriptionId());
     if (_subscriptionMap.find(id) != _subscriptionMap.end())
         _subscriptionMap.erase(id);
 }
diff --git a/config/src/vespa/config/common/configmanager.h b/config/src/vespa/config/common/configmanager.h
index a622bce469e..09d263d9c25 100644
--- a/config/src/vespa/config/common/configmanager.h
+++ b/config/src/vespa/config/common/configmanager.h
@@ -21,19 +21,19 @@ struct TimingValues;
 class ConfigManager : public IConfigManager
 {
 public:
-    ConfigManager(std::unique_ptr<SourceFactory> sourceFactory, int64_t initialGeneration);
+    ConfigManager(SourceFactory::UP sourceFactory, int64_t initialGeneration);
     ~ConfigManager() override;
 
     ConfigSubscription::SP subscribe(const ConfigKey & key, vespalib::duration timeout) override;
-    void unsubscribe(const ConfigSubscription & subscription) override;
+    void unsubscribe(const ConfigSubscription::SP & subscription) override;
     void reload(int64_t generation) override;
 
 private:
-    std::atomic<SubscriptionId>    _idGenerator;
-    std::unique_ptr<SourceFactory> _sourceFactory;
-    int64_t                        _generation;
+    std::atomic<SubscriptionId> _idGenerator;
+    SourceFactory::UP _sourceFactory;
+    int64_t _generation;
 
-    using SubscriptionMap = std::map<SubscriptionId, ConfigSubscription::SP>;
+    typedef std::map<SubscriptionId, ConfigSubscription::SP> SubscriptionMap;
     SubscriptionMap _subscriptionMap;
     std::mutex _lock;
 };
diff --git a/config/src/vespa/config/common/reloadhandler.h b/config/src/vespa/config/common/reloadhandler.h
index cd329e8d525..73016a2f883 100644
--- a/config/src/vespa/config/common/reloadhandler.h
+++ b/config/src/vespa/config/common/reloadhandler.h
@@ -9,7 +9,7 @@ struct ReloadHandler
      * Reload any configs with a given generation.
      */
     virtual void reload(int64_t generation) = 0;
-    virtual ~ReloadHandler() = default;
+    virtual ~ReloadHandler() { }
 };
 
 }
diff --git a/config/src/vespa/config/common/sourcefactory.h b/config/src/vespa/config/common/sourcefactory.h
index f11a070fd95..0236bea2802 100644
--- a/config/src/vespa/config/common/sourcefactory.h
+++ b/config/src/vespa/config/common/sourcefactory.h
@@ -13,6 +13,7 @@ class IConfigHolder;
  */
 class SourceFactory {
 public:
+    typedef std::unique_ptr<SourceFactory> UP;
     virtual std::unique_ptr<Source> createSource(std::shared_ptr<IConfigHolder> holder, const ConfigKey & key) const = 0;
     virtual ~SourceFactory() = default;
 };
diff --git a/config/src/vespa/config/frt/connectionfactory.h b/config/src/vespa/config/frt/connectionfactory.h
index eb7ca10fa0d..dc1eadf3cf6 100644
--- a/config/src/vespa/config/frt/connectionfactory.h
+++ b/config/src/vespa/config/frt/connectionfactory.h
@@ -12,10 +12,12 @@ class Connection;
 class ConnectionFactory
 {
 public:
+    typedef std::unique_ptr <ConnectionFactory> UP;
+    typedef std::shared_ptr<ConnectionFactory> SP;
     virtual Connection * getCurrent() = 0;
     virtual void syncTransport() = 0;
     virtual FNET_Scheduler * getScheduler() = 0;
-    virtual ~ConnectionFactory() = default;
+    virtual ~ConnectionFactory() { }
 };
 
 }
diff --git a/config/src/vespa/config/frt/frtconnectionpool.cpp b/config/src/vespa/config/frt/frtconnectionpool.cpp
index 15ba8472af0..629baf67cf8 100644
--- a/config/src/vespa/config/frt/frtconnectionpool.cpp
+++ b/config/src/vespa/config/frt/frtconnectionpool.cpp
@@ -27,8 +27,10 @@ FRTConnectionPool::FRTConnectionKey::operator==(const FRTConnectionKey& right) c
     return _hostname == right._hostname;
 }
 
-FRTConnectionPool::FRTConnectionPool(FNET_Transport & transport, const ServerSpec & spec, const TimingValues & timingValues)
-    : _supervisor(std::make_unique<FRT_Supervisor>(& transport)),
+FRTConnectionPool::FRTConnectionPool(const ServerSpec & spec, const TimingValues & timingValues)
+    :  _threadPool(std::make_unique<FastOS_ThreadPool>(60_Ki)),
+       _transport(std::make_unique<FNET_Transport>()),
+       _supervisor(std::make_unique<FRT_Supervisor>(_transport.get())),
       _selectIdx(0),
       _hostname("")
 {
@@ -37,9 +39,13 @@ FRTConnectionPool::FRTConnectionPool(FNET_Transport & transport, const ServerSpe
         _connections[key] = std::make_shared<FRTConnection>(spec.getHost(i), *_supervisor, timingValues);
     }
     setHostname();
+    _transport->Start(_threadPool.get());
 }
 
-FRTConnectionPool::~FRTConnectionPool() = default;
+FRTConnectionPool::~FRTConnectionPool()
+{
+    _transport->ShutDown(true);
+}
 
 void
 FRTConnectionPool::syncTransport()
@@ -144,19 +150,4 @@ FRTConnectionPool::getScheduler() {
     return _supervisor->GetScheduler();
 }
 
-FRTConnectionPoolWithTransport::FRTConnectionPoolWithTransport(std::unique_ptr<FastOS_ThreadPool> threadPool,
-                                                               std::unique_ptr<FNET_Transport> transport,
-                                                               const ServerSpec & spec, const TimingValues & timingValues)
-    :  FRTConnectionPool(*transport, spec, timingValues),
-       _threadPool(std::move(threadPool)),
-       _transport(std::move(transport))
-{
-    _transport->Start(_threadPool.get());
-}
-
-FRTConnectionPoolWithTransport::~FRTConnectionPoolWithTransport()
-{
-    _transport->ShutDown(true);
-}
-
 }
diff --git a/config/src/vespa/config/frt/frtconnectionpool.h b/config/src/vespa/config/frt/frtconnectionpool.h
index b7530f8536e..6b387fbf67f 100644
--- a/config/src/vespa/config/frt/frtconnectionpool.h
+++ b/config/src/vespa/config/frt/frtconnectionpool.h
@@ -13,6 +13,7 @@ class FastOS_ThreadPool;
 namespace config {
 
 class FRTConnectionPool : public ConnectionFactory {
+
 private:
 
     /**
@@ -31,6 +32,8 @@ private:
         int operator==(const FRTConnectionKey& right) const;
     };
 
+    std::unique_ptr<FastOS_ThreadPool> _threadPool;
+    std::unique_ptr<FNET_Transport> _transport;
     std::unique_ptr<FRT_Supervisor> _supervisor;
     int _selectIdx;
     vespalib::string _hostname;
@@ -38,7 +41,7 @@ private:
     ConnectionMap _connections;
 
 public:
-    FRTConnectionPool(FNET_Transport & transport, const ServerSpec & spec, const TimingValues & timingValues);
+    FRTConnectionPool(const ServerSpec & spec, const TimingValues & timingValues);
     FRTConnectionPool(const FRTConnectionPool&) = delete;
     FRTConnectionPool& operator=(const FRTConnectionPool&) = delete;
     ~FRTConnectionPool() override;
@@ -127,18 +130,5 @@ public:
     static int hashCode(const vespalib::string & s);
 };
 
-class FRTConnectionPoolWithTransport : public FRTConnectionPool {
-public:
-    FRTConnectionPoolWithTransport(std::unique_ptr<FastOS_ThreadPool> threadPool,
-                                   std::unique_ptr<FNET_Transport> transport,
-                                   const ServerSpec & spec, const TimingValues & timingValues);
-    FRTConnectionPoolWithTransport(const FRTConnectionPoolWithTransport&) = delete;
-    FRTConnectionPoolWithTransport& operator=(const FRTConnectionPoolWithTransport&) = delete;
-    ~FRTConnectionPoolWithTransport() override;
-private:
-    std::unique_ptr<FastOS_ThreadPool> _threadPool;
-    std::unique_ptr<FNET_Transport>    _transport;
-};
-
 } // namespace config
 
diff --git a/config/src/vespa/config/frt/frtsourcefactory.cpp b/config/src/vespa/config/frt/frtsourcefactory.cpp
index 1c740534730..9706e3bbd5e 100644
--- a/config/src/vespa/config/frt/frtsourcefactory.cpp
+++ b/config/src/vespa/config/frt/frtsourcefactory.cpp
@@ -1,21 +1,17 @@
 // Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
-
 #include "frtsourcefactory.h"
 #include "frtsource.h"
 #include "frtconfigagent.h"
-#include "connectionfactory.h"
 
 namespace config {
 
-FRTSourceFactory::FRTSourceFactory(std::unique_ptr<ConnectionFactory> connectionFactory, const TimingValues & timingValues, int traceLevel, const VespaVersion & vespaVersion, const CompressionType & compressionType)
+FRTSourceFactory::FRTSourceFactory(ConnectionFactory::UP connectionFactory, const TimingValues & timingValues, int traceLevel, const VespaVersion & vespaVersion, const CompressionType & compressionType)
     : _connectionFactory(std::move(connectionFactory)),
       _requestFactory(traceLevel, vespaVersion, compressionType),
       _timingValues(timingValues)
 {
 }
 
-FRTSourceFactory::~FRTSourceFactory() = default;
-
 std::unique_ptr<Source>
 FRTSourceFactory::createSource(std::shared_ptr<IConfigHolder> holder, const ConfigKey & key) const
 {
diff --git a/config/src/vespa/config/frt/frtsourcefactory.h b/config/src/vespa/config/frt/frtsourcefactory.h
index 19cf6241481..4331c6411dc 100644
--- a/config/src/vespa/config/frt/frtsourcefactory.h
+++ b/config/src/vespa/config/frt/frtsourcefactory.h
@@ -1,32 +1,28 @@
 // Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 #pragma once
 
+#include "connectionfactory.h"
 #include "frtconfigrequestfactory.h"
 #include <vespa/config/common/sourcefactory.h>
 #include <vespa/config/common/timingvalues.h>
 
 namespace config {
 
-class ConnectionFactory;
-
 /**
  * Class for sending and receiving config requests via FRT.
  */
 class FRTSourceFactory : public SourceFactory
 {
 public:
-    FRTSourceFactory(const FRTSourceFactory &) = delete;
-    FRTSourceFactory & operator =(const FRTSourceFactory &) = delete;
-    FRTSourceFactory(std::unique_ptr<ConnectionFactory> connectionFactory, const TimingValues & timingValues,
-                     int traceLevel, const VespaVersion & vespaVersion, const CompressionType & compressionType);
-    ~FRTSourceFactory() override;
+    FRTSourceFactory(ConnectionFactory::UP connectionFactory, const TimingValues & timingValues, int traceLevel, const VespaVersion & vespaVersion, const CompressionType & compressionType);
+
     /**
      * Create source handling config described by key.
      */
     std::unique_ptr<Source> createSource(std::shared_ptr<IConfigHolder> holder, const ConfigKey & key) const override;
 
 private:
-    std::shared_ptr<ConnectionFactory> _connectionFactory;
+    ConnectionFactory::SP _connectionFactory;
     FRTConfigRequestFactory _requestFactory;
     const TimingValues _timingValues;
 };
diff --git a/config/src/vespa/config/subscription/configsubscriptionset.cpp b/config/src/vespa/config/subscription/configsubscriptionset.cpp
index 40dc40d11ef..0b3944acc4e 100644
--- a/config/src/vespa/config/subscription/configsubscriptionset.cpp
+++ b/config/src/vespa/config/subscription/configsubscriptionset.cpp
@@ -112,7 +112,7 @@ ConfigSubscriptionSet::close()
 {
     _state = CLOSED;
     for (const auto & subscription : _subscriptionList) {
-        _mgr.unsubscribe(*subscription);
+        _mgr.unsubscribe(subscription);
         subscription->close();
     }
 }
diff --git a/config/src/vespa/config/subscription/sourcespec.cpp b/config/src/vespa/config/subscription/sourcespec.cpp
index ec70f921179..6af981807de 100644
--- a/config/src/vespa/config/subscription/sourcespec.cpp
+++ b/config/src/vespa/config/subscription/sourcespec.cpp
@@ -11,9 +11,6 @@
 #include <vespa/config/set/configinstancesourcefactory.h>
 #include <vespa/vespalib/text/stringtokenizer.h>
 #include <vespa/config/print/asciiconfigwriter.h>
-#include <vespa/vespalib/util/size_literals.h>
-#include <vespa/fnet/transport.h>
-#include <vespa/fastos/thread.h>
 #include <cassert>
 
 namespace config {
@@ -28,7 +25,7 @@ RawSpec::RawSpec(const vespalib::string & config)
 {
 }
 
-std::unique_ptr<SourceFactory>
+SourceFactory::UP
 RawSpec::createSourceFactory(const TimingValues &) const
 {
     return std::make_unique<RawSourceFactory>(_config);
@@ -52,7 +49,7 @@ FileSpec::verifyName(const vespalib::string & fileName)
     }
 }
 
-std::unique_ptr<SourceFactory>
+SourceFactory::UP
 FileSpec::createSourceFactory(const TimingValues & ) const
 {
     return std::make_unique<FileSourceFactory>(*this);
@@ -63,7 +60,7 @@ DirSpec::DirSpec(const vespalib::string & dirName)
 {
 }
 
-std::unique_ptr<SourceFactory>
+SourceFactory::UP
 DirSpec::createSourceFactory(const TimingValues & ) const
 {
     return std::make_unique<DirSourceFactory>(*this);
@@ -120,15 +117,12 @@ ServerSpec::ServerSpec(const vespalib::string & hostSpec)
     initialize(hostSpec);
 }
 
-std::unique_ptr<SourceFactory>
+SourceFactory::UP
 ServerSpec::createSourceFactory(const TimingValues & timingValues) const
 {
     const auto vespaVersion = VespaVersion::getCurrentVersion();
-    return std::make_unique<FRTSourceFactory>(
-            std::make_unique<FRTConnectionPoolWithTransport>(std::make_unique<FastOS_ThreadPool>(64_Ki),
-                                                             std::make_unique<FNET_Transport>(),
-                                                             *this, timingValues),
-            timingValues, _traceLevel, vespaVersion, _compressionType);
+    return std::make_unique<FRTSourceFactory>(std::make_unique<FRTConnectionPool>(*this, timingValues), timingValues,
+                                              _traceLevel, vespaVersion, _compressionType);
 }
 
 
@@ -137,7 +131,7 @@ ConfigSet::ConfigSet()
 {
 }
 
-std::unique_ptr<SourceFactory>
+SourceFactory::UP
 ConfigSet::createSourceFactory(const TimingValues & ) const
 {
     return std::make_unique<ConfigSetSourceFactory>(_builderMap);
diff --git a/config/src/vespa/config/subscription/sourcespec.h b/config/src/vespa/config/subscription/sourcespec.h
index 3c23233e3ab..a57b22ca322 100644
--- a/config/src/vespa/config/subscription/sourcespec.h
+++ b/config/src/vespa/config/subscription/sourcespec.h
@@ -157,6 +157,13 @@ public:
     SourceFactorySP createSourceFactory(const TimingValues & timingValues) const override;
 
     /**
+     * Add another host to this source spec, allowing failover.
+     *
+     * @param host hostname formatted as tcp/hostname:port
+     */
+    void addHost(const vespalib::string & host) { _hostList.push_back(host); }
+
+    /**
      * Inspect how many hosts this source refers to.
      *
      * @return the number of hosts referred.
@@ -186,9 +193,9 @@ public:
     CompressionType compressionType() const { return _compressionType; }
 private:
     void initialize(const vespalib::string & hostSpec);
-    HostSpecList          _hostList;
-    const int             _protocolVersion;
-    const int             _traceLevel;
+    HostSpecList _hostList;
+    const int _protocolVersion;
+    const int _traceLevel;
     const CompressionType _compressionType;
     const static int DEFAULT_PROXY_PORT = 19090;
 };