Merge pull request #5229 from vespa-engine/vekterli/add-cluster-state-rpc-v3-support-on-content-nodes-take-2

Add cluster state RPC v3 support on content nodes - take 2

17 files changed, 559 insertions, 33 deletions

diff --git a/storage/src/tests/storageserver/CMakeLists.txt b/storage/src/tests/storageserver/CMakeLists.txt
index 95faf7e433e..c28a6102b71 100644
--- a/storage/src/tests/storageserver/CMakeLists.txt
+++ b/storage/src/tests/storageserver/CMakeLists.txt
@@ -7,6 +7,7 @@ vespa_add_library(storage_teststorageserver TEST
     communicationmanagertest.cpp
     configurable_bucket_resolver_test.cpp
     documentapiconvertertest.cpp
+    fnet_listener_test.cpp
     mergethrottlertest.cpp
     priorityconvertertest.cpp
     service_layer_error_listener_test.cpp
diff --git a/storage/src/tests/storageserver/fnet_listener_test.cpp b/storage/src/tests/storageserver/fnet_listener_test.cpp
new file mode 100644
index 00000000000..cc9c424ac28
--- /dev/null
+++ b/storage/src/tests/storageserver/fnet_listener_test.cpp
@@ -0,0 +1,194 @@
+// Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+
+#include <vespa/document/bucket/fixed_bucket_spaces.h>
+#include <vespa/storage/storageserver/fnetlistener.h>
+#include <vespa/storage/storageserver/message_enqueuer.h>
+#include <vespa/storage/storageserver/rpcrequestwrapper.h>
+#include <vespa/storage/storageserver/slime_cluster_state_bundle_codec.h>
+#include <vespa/storageapi/message/state.h>
+#include <vespa/vdslib/state/clusterstate.h>
+#include <vespa/vespalib/stllike/asciistream.h>
+#include <vespa/vdstestlib/cppunit/macros.h>
+#include <vespa/vdstestlib/cppunit/dirconfig.h>
+#include <vespa/messagebus/testlib/slobrok.h>
+#include <tests/common/testhelper.h>
+#include <vector>
+
+namespace storage {
+
+using document::FixedBucketSpaces;
+
+class FNetListenerTest : public CppUnit::TestFixture {
+public:
+    CPPUNIT_TEST_SUITE(FNetListenerTest);
+    CPPUNIT_TEST(baseline_set_distribution_states_rpc_enqueues_command_with_state_bundle);
+    CPPUNIT_TEST(set_distribution_states_rpc_with_derived_enqueues_command_with_state_bundle);
+    CPPUNIT_TEST(compressed_bundle_is_transparently_uncompressed);
+    CPPUNIT_TEST(set_distribution_rpc_is_immediately_failed_if_listener_is_closed);
+    CPPUNIT_TEST(overly_large_uncompressed_bundle_size_parameter_returns_rpc_error);
+    CPPUNIT_TEST(mismatching_uncompressed_bundle_size_parameter_returns_rpc_error);
+    CPPUNIT_TEST_SUITE_END();
+
+    void baseline_set_distribution_states_rpc_enqueues_command_with_state_bundle();
+    void set_distribution_states_rpc_with_derived_enqueues_command_with_state_bundle();
+    void compressed_bundle_is_transparently_uncompressed();
+    void set_distribution_rpc_is_immediately_failed_if_listener_is_closed();
+    void overly_large_uncompressed_bundle_size_parameter_returns_rpc_error();
+    void mismatching_uncompressed_bundle_size_parameter_returns_rpc_error();
+};
+
+CPPUNIT_TEST_SUITE_REGISTRATION(FNetListenerTest);
+
+namespace {
+
+struct MockOperationEnqueuer : MessageEnqueuer {
+    std::vector<std::shared_ptr<api::StorageMessage>> _enqueued;
+
+    void enqueue(std::shared_ptr<api::StorageMessage> msg) override {
+        _enqueued.emplace_back(std::move(msg));
+    }
+};
+
+struct DummyReturnHandler : FRT_IReturnHandler {
+    void HandleReturn() override {}
+    FNET_Connection* GetConnection() override { return nullptr; }
+};
+
+struct Fixture {
+    // TODO factor out Slobrok code to avoid need to set up live ports for unrelated tests
+    mbus::Slobrok slobrok;
+    vdstestlib::DirConfig config;
+    MockOperationEnqueuer enqueuer;
+    std::unique_ptr<FNetListener> fnet_listener;
+    SlimeClusterStateBundleCodec codec;
+    DummyReturnHandler return_handler;
+    bool request_is_detached{false};
+    FRT_RPCRequest* bound_request{nullptr};
+
+    Fixture() : config(getStandardConfig(true)) {
+        config.getConfig("stor-server").set("node_index", "1");
+        addSlobrokConfig(config, slobrok);
+        fnet_listener = std::make_unique<FNetListener>(enqueuer, config.getConfigId(), 0);
+    }
+
+    ~Fixture() {
+        // Must destroy any associated message contexts that may have refs to FRT_Request
+        // instance _before_ we destroy the request itself.
+        enqueuer._enqueued.clear();
+        if (bound_request) {
+            bound_request->SubRef();
+        }
+    }
+
+    void bind_request_params(EncodedClusterStateBundle& encoded_bundle, uint32_t uncompressed_length) {
+        bound_request = new FRT_RPCRequest(); // Naked new isn't pretty, but FRT_RPCRequest has internal refcounting
+        auto* params = bound_request->GetParams();
+        params->AddInt8(static_cast<uint8_t>(encoded_bundle._compression_type));
+        params->AddInt32(uncompressed_length);
+        const auto buf_len = encoded_bundle._buffer->getDataLen();
+        params->AddData(encoded_bundle._buffer->stealBuffer(), buf_len);
+
+        bound_request->SetDetachedPT(&request_is_detached);
+        bound_request->SetReturnHandler(&return_handler);
+    }
+
+    void create_request(const lib::ClusterStateBundle& bundle) {
+        // Only 1 request allowed per fixture due to lifetime handling snags
+        assert(bound_request == nullptr);
+        auto encoded_bundle = codec.encode(bundle);
+        bind_request_params(encoded_bundle, encoded_bundle._uncompressed_length);
+    }
+
+    void assert_enqueued_operation_has_bundle(const lib::ClusterStateBundle& expectedBundle) {
+        CPPUNIT_ASSERT(bound_request != nullptr);
+        CPPUNIT_ASSERT(request_is_detached);
+        CPPUNIT_ASSERT_EQUAL(size_t(1), enqueuer._enqueued.size());
+        auto& state_request = dynamic_cast<const api::SetSystemStateCommand&>(*enqueuer._enqueued[0]);
+        CPPUNIT_ASSERT_EQUAL(expectedBundle, state_request.getClusterStateBundle());
+    }
+
+    void assert_request_received_and_propagated(const lib::ClusterStateBundle& bundle) {
+        create_request(bundle);
+        fnet_listener->RPC_setDistributionStates(bound_request);
+        assert_enqueued_operation_has_bundle(bundle);
+    }
+
+    void assert_request_returns_error_response(RPCRequestWrapper::ErrorCode error_code) {
+        fnet_listener->RPC_setDistributionStates(bound_request);
+        CPPUNIT_ASSERT(!request_is_detached);
+        CPPUNIT_ASSERT(bound_request->IsError());
+        CPPUNIT_ASSERT_EQUAL(static_cast<uint32_t>(error_code), bound_request->GetErrorCode());
+    }
+
+    lib::ClusterStateBundle dummy_baseline_bundle() const {
+        return lib::ClusterStateBundle(lib::ClusterState("version:123 distributor:3 storage:3"));
+    }
+};
+
+std::shared_ptr<const lib::ClusterState> state_of(vespalib::stringref state) {
+    return std::make_shared<const lib::ClusterState>(state);
+}
+
+vespalib::string make_compressable_state_string() {
+    vespalib::asciistream ss;
+    for (int i = 0; i < 99; ++i) {
+        ss << " ." << i << ".s:d";
+    }
+    return vespalib::make_string("version:123 distributor:100%s storage:100%s",
+                                 ss.str().c_str(), ss.str().c_str());
+}
+
+}
+
+void FNetListenerTest::baseline_set_distribution_states_rpc_enqueues_command_with_state_bundle() {
+    Fixture f;
+    auto baseline = f.dummy_baseline_bundle();
+
+    f.assert_request_received_and_propagated(baseline);
+}
+
+void FNetListenerTest::set_distribution_states_rpc_with_derived_enqueues_command_with_state_bundle() {
+    Fixture f;
+    lib::ClusterStateBundle spaces_bundle(
+            lib::ClusterState("version:123 distributor:3 storage:3"),
+            {{FixedBucketSpaces::default_space(), state_of("version:123 distributor:3 storage:3 .0.s:d")},
+             {FixedBucketSpaces::global_space(), state_of("version:123 distributor:3 .1.s:d storage:3")}});
+
+    f.assert_request_received_and_propagated(spaces_bundle);
+}
+
+void FNetListenerTest::compressed_bundle_is_transparently_uncompressed() {
+    Fixture f;
+    auto state_str = make_compressable_state_string();
+    lib::ClusterStateBundle compressable_bundle{lib::ClusterState(state_str)};
+
+    f.create_request(compressable_bundle);
+    // First verify that the bundle is sent in compressed form
+    CPPUNIT_ASSERT(f.bound_request->GetParams()->GetValue(2)._data._len < state_str.size());
+    // Ensure we uncompress it to the original form
+    f.fnet_listener->RPC_setDistributionStates(f.bound_request);
+    f.assert_enqueued_operation_has_bundle(compressable_bundle);
+}
+
+void FNetListenerTest::set_distribution_rpc_is_immediately_failed_if_listener_is_closed() {
+    Fixture f;
+    f.create_request(f.dummy_baseline_bundle());
+    f.fnet_listener->close();
+    f.assert_request_returns_error_response(RPCRequestWrapper::ERR_NODE_SHUTTING_DOWN);
+}
+
+void FNetListenerTest::overly_large_uncompressed_bundle_size_parameter_returns_rpc_error() {
+    Fixture f;
+    auto encoded_bundle = f.codec.encode(f.dummy_baseline_bundle());
+    f.bind_request_params(encoded_bundle, FNetListener::StateBundleMaxUncompressedSize + 1);
+    f.assert_request_returns_error_response(RPCRequestWrapper::ERR_BAD_REQUEST);
+}
+
+void FNetListenerTest::mismatching_uncompressed_bundle_size_parameter_returns_rpc_error() {
+    Fixture f;
+    auto encoded_bundle = f.codec.encode(f.dummy_baseline_bundle());
+    f.bind_request_params(encoded_bundle, encoded_bundle._buffer->getDataLen() + 100);
+    f.assert_request_returns_error_response(RPCRequestWrapper::ERR_BAD_REQUEST);
+}
+
+}
diff --git a/storage/src/vespa/storage/storageserver/CMakeLists.txt b/storage/src/vespa/storage/storageserver/CMakeLists.txt
index 0f90a5a8afb..8c9add78fd4 100644
--- a/storage/src/vespa/storage/storageserver/CMakeLists.txt
+++ b/storage/src/vespa/storage/storageserver/CMakeLists.txt
@@ -20,6 +20,7 @@ vespa_add_library(storage_storageserver
     service_layer_error_listener.cpp
     servicelayernode.cpp
     servicelayernodecontext.cpp
+    slime_cluster_state_bundle_codec.cpp
     statemanager.cpp
     statereporter.cpp
     storagemetricsset.cpp
diff --git a/storage/src/vespa/storage/storageserver/cluster_state_bundle_codec.h b/storage/src/vespa/storage/storageserver/cluster_state_bundle_codec.h
new file mode 100644
index 00000000000..41c5db9876d
--- /dev/null
+++ b/storage/src/vespa/storage/storageserver/cluster_state_bundle_codec.h
@@ -0,0 +1,28 @@
+// Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+
+#pragma once
+
+#include "encoded_cluster_state_bundle.h"
+
+namespace storage {
+
+namespace lib { class ClusterStateBundle; }
+
+/**
+ * Provides opaque encoding and decoding of ClusterStateBundles for transmission over RPC.
+ *
+ * Implementations may choose to compress the encoded representation of the bundle.
+ *
+ * It is important that the input given to decode() is exactly equal to that given from
+ * encode() for the results to be correct. Implementations must ensure that this information
+ * is enough to losslessly reconstruct the full encoded ClusterStateBundle.
+ */
+class ClusterStateBundleCodec {
+public:
+    virtual ~ClusterStateBundleCodec() = default;
+
+    virtual EncodedClusterStateBundle encode(const lib::ClusterStateBundle&) const = 0;
+    virtual std::shared_ptr<const lib::ClusterStateBundle> decode(const EncodedClusterStateBundle&) const = 0;
+};
+
+}
diff --git a/storage/src/vespa/storage/storageserver/communicationmanager.cpp b/storage/src/vespa/storage/storageserver/communicationmanager.cpp
index 5b927d36bb5..b9721635c24 100644
--- a/storage/src/vespa/storage/storageserver/communicationmanager.cpp
+++ b/storage/src/vespa/storage/storageserver/communicationmanager.cpp
@@ -635,7 +635,7 @@ CommunicationManager::sendDirectRPCReply(
         serializeNodeState(gns, ns, true, true, false);
         request.addReturnString(ns.str().c_str());
         LOGBP(debug, "Sending getnodestate2 reply with no host info.");
-    } else if (requestName == "setsystemstate2") {
+    } else if (requestName == "setsystemstate2" || requestName == "setdistributionstates") {
         // No data to return
     } else {
         request.addReturnInt(reply->getResult().getResult());
diff --git a/storage/src/vespa/storage/storageserver/communicationmanager.h b/storage/src/vespa/storage/storageserver/communicationmanager.h
index a29f3c8c3e3..5c7d5812fdb 100644
--- a/storage/src/vespa/storage/storageserver/communicationmanager.h
+++ b/storage/src/vespa/storage/storageserver/communicationmanager.h
@@ -12,6 +12,7 @@
 
 #include "communicationmanagermetrics.h"
 #include "documentapiconverter.h"
+#include "message_enqueuer.h"
 #include <vespa/storage/common/storagelink.h>
 #include <vespa/storage/common/storagecomponent.h>
 #include <vespa/storage/config/config-stor-communicationmanager.h>
@@ -85,12 +86,14 @@ public:
     std::unique_ptr<RPCRequestWrapper>            _request;
 };
 
-class CommunicationManager : public StorageLink,
-                             public framework::Runnable,
-                             private config::IFetcherCallback<vespa::config::content::core::StorCommunicationmanagerConfig>,
-                             public mbus::IMessageHandler,
-                             public mbus::IReplyHandler,
-                             private framework::MetricUpdateHook
+class CommunicationManager final
+    : public StorageLink,
+      public framework::Runnable,
+      private config::IFetcherCallback<vespa::config::content::core::StorCommunicationmanagerConfig>,
+      public mbus::IMessageHandler,
+      public mbus::IReplyHandler,
+      private framework::MetricUpdateHook,
+      public MessageEnqueuer
 {
 private:
     CommunicationManager(const CommunicationManager&);
@@ -150,7 +153,7 @@ public:
                          const config::ConfigUri & configUri);
     ~CommunicationManager();
 
-    void enqueue(std::shared_ptr<api::StorageMessage> msg);
+    void enqueue(std::shared_ptr<api::StorageMessage> msg) override;
     mbus::RPCMessageBus& getMessageBus() { assert(_mbus.get()); return *_mbus; }
     const PriorityConverter& getPriorityConverter() const { return _docApiConverter.getPriorityConverter(); }
 
diff --git a/storage/src/vespa/storage/storageserver/encoded_cluster_state_bundle.h b/storage/src/vespa/storage/storageserver/encoded_cluster_state_bundle.h
new file mode 100644
index 00000000000..6f25a6b67a6
--- /dev/null
+++ b/storage/src/vespa/storage/storageserver/encoded_cluster_state_bundle.h
@@ -0,0 +1,19 @@
+// Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+
+#pragma once
+
+#include <vespa/vespalib/data/databuffer.h>
+#include <vespa/vespalib/util/compressor.h>
+
+namespace storage {
+
+/**
+ * Contains an opaque encoded (possibly compressed) representation of a ClusterStateBundle.
+ */
+struct EncodedClusterStateBundle {
+    vespalib::compression::CompressionConfig::Type _compression_type;
+    uint32_t _uncompressed_length;
+    std::unique_ptr<vespalib::DataBuffer> _buffer;
+};
+
+}
diff --git a/storage/src/vespa/storage/storageserver/fnetlistener.cpp b/storage/src/vespa/storage/storageserver/fnetlistener.cpp
index 7a0711c9f7c..32ea8982ffb 100644
--- a/storage/src/vespa/storage/storageserver/fnetlistener.cpp
+++ b/storage/src/vespa/storage/storageserver/fnetlistener.cpp
@@ -2,6 +2,7 @@
 #include "fnetlistener.h"
 #include "communicationmanager.h"
 #include "rpcrequestwrapper.h"
+#include "slime_cluster_state_bundle_codec.h"
 #include <vespa/storageapi/message/state.h>
 #include <vespa/vespalib/util/exceptions.h>
 #include <vespa/vespalib/util/host_name.h>
@@ -9,13 +10,12 @@
 #include <sstream>
 
 #include <vespa/log/log.h>
-
 LOG_SETUP(".rpc.listener");
 
 namespace storage {
 
-FNetListener::FNetListener(CommunicationManager& comManager, const config::ConfigUri & configUri, uint32_t port)
-    : _comManager(comManager),
+FNetListener::FNetListener(MessageEnqueuer& messageEnqueuer, const config::ConfigUri & configUri, uint32_t port)
+    : _messageEnqueuer(messageEnqueuer),
       _orb(std::make_unique<FRT_Supervisor>()),
       _closed(false),
       _slobrokRegister(*_orb, configUri)
@@ -86,6 +86,12 @@ FNetListener::initRPC()
     rb.MethodDesc("Set systemstate on this node");
     rb.ParamDesc("systemstate", "New systemstate to set");
     //-------------------------------------------------------------------------
+    rb.DefineMethod("setdistributionstates", "bix", "", true, FRT_METHOD(FNetListener::RPC_setDistributionStates), this);
+    rb.MethodDesc("Set distribution states for cluster and bucket spaces");
+    rb.ParamDesc("compressionType", "Compression type for payload");
+    rb.ParamDesc("uncompressedSize", "Uncompressed size for payload");
+    rb.ParamDesc("payload", "Binary Slime format payload");
+    //-------------------------------------------------------------------------
     rb.DefineMethod("getcurrenttime", "", "lis", true, FRT_METHOD(FNetListener::RPC_getCurrentTime), this);
     rb.MethodDesc("Get current time on this node");
     rb.ReturnDesc("seconds", "Current time in seconds since epoch");
@@ -113,6 +119,13 @@ FNetListener::RPC_getCurrentTime(FRT_RPCRequest *req)
     return;
 }
 
+void FNetListener::detach_and_forward_to_enqueuer(std::shared_ptr<api::StorageMessage> cmd, FRT_RPCRequest *req) {
+    // Create a request object to avoid needing a separate transport type
+    cmd->setTransportContext(std::make_unique<StorageTransportContext>(std::make_unique<RPCRequestWrapper>(req)));
+    req->Detach();
+    _messageEnqueuer.enqueue(std::move(cmd));
+}
+
 void
 FNetListener::RPC_getNodeState2(FRT_RPCRequest *req)
 {
@@ -134,10 +147,7 @@ FNetListener::RPC_getNodeState2(FRT_RPCRequest *req)
     if (req->GetParams()->GetNumValues() > 2) {
         cmd->setSourceIndex(req->GetParams()->GetValue(2)._intval32);
     }
-        // Create a request object to avoid needing a separate transport type
-    cmd->setTransportContext(std::make_unique<StorageTransportContext>(std::make_unique<RPCRequestWrapper>(req)));
-    req->Detach();
-    _comManager.enqueue(std::move(cmd));
+    detach_and_forward_to_enqueuer(std::move(cmd), req);
 }
 
 void
@@ -155,10 +165,50 @@ FNetListener::RPC_setSystemState2(FRT_RPCRequest *req)
     auto cmd(std::make_shared<api::SetSystemStateCommand>(lib::ClusterStateBundle(systemState)));
     cmd->setPriority(api::StorageMessage::VERYHIGH);
 
-    // Create a request object to avoid needing a separate transport type
-    cmd->setTransportContext(std::make_unique<StorageTransportContext>(std::make_unique<RPCRequestWrapper>(req)));
-    req->Detach();
-    _comManager.enqueue(std::move(cmd));
+    detach_and_forward_to_enqueuer(std::move(cmd), req);
+}
+
+namespace {
+
+std::shared_ptr<const lib::ClusterStateBundle> decode_bundle_from_params(const FRT_Values& params) {
+    const uint32_t uncompressed_length = params[1]._intval32;
+    if (uncompressed_length > FNetListener::StateBundleMaxUncompressedSize) {
+        throw std::range_error(vespalib::make_string("RPC ClusterStateBundle uncompressed size (%u) is "
+                                                     "greater than max size (%u)", uncompressed_length,
+                                                     FNetListener::StateBundleMaxUncompressedSize));
+    }
+    SlimeClusterStateBundleCodec codec;
+    EncodedClusterStateBundle encoded_bundle;
+    encoded_bundle._compression_type = vespalib::compression::CompressionConfig::toType(params[0]._intval8);
+    encoded_bundle._uncompressed_length = uncompressed_length;
+    // Caution: type cast to const ptr is essential or DataBuffer behavior changes!
+    encoded_bundle._buffer = std::make_unique<vespalib::DataBuffer>(
+            static_cast<const char*>(params[2]._data._buf), params[2]._data._len);
+    return codec.decode(encoded_bundle);
+}
+
+}
+
+void FNetListener::RPC_setDistributionStates(FRT_RPCRequest* req) {
+    if (_closed) {
+        LOG(debug, "Not handling RPC call setDistributionStates() as we have closed");
+        req->SetError(RPCRequestWrapper::ERR_NODE_SHUTTING_DOWN, "Node shutting down");
+        return;
+    }
+    std::shared_ptr<const lib::ClusterStateBundle> state_bundle;
+    try {
+        state_bundle = decode_bundle_from_params(*req->GetParams());
+    } catch (std::exception& e) {
+        LOG(error, "setDistributionStates RPC failed decoding: %s", e.what());
+        req->SetError(RPCRequestWrapper::ERR_BAD_REQUEST, e.what());
+        return;
+    }
+
+    // TODO add constructor taking in shared_ptr directly instead?
+    auto cmd = std::make_shared<api::SetSystemStateCommand>(*state_bundle);
+    cmd->setPriority(api::StorageMessage::VERYHIGH);
+
+    detach_and_forward_to_enqueuer(std::move(cmd), req);
 }
 
 }
diff --git a/storage/src/vespa/storage/storageserver/fnetlistener.h b/storage/src/vespa/storage/storageserver/fnetlistener.h
index 05d2d275838..bf004a3eb2b 100644
--- a/storage/src/vespa/storage/storageserver/fnetlistener.h
+++ b/storage/src/vespa/storage/storageserver/fnetlistener.h
@@ -2,37 +2,43 @@
 #pragma once
 
 #include <vespa/slobrok/sbregister.h>
+#include <atomic>
 
 namespace storage {
 
-class CommunicationManager;
+namespace api { class StorageMessage; }
+
+class MessageEnqueuer;
 class StorageServerInterface;
 
 class FNetListener :  public FRT_Invokable
 {
 public:
-    FNetListener(CommunicationManager& comManager,
-                 const config::ConfigUri & configUri, uint32_t port);
-    ~FNetListener();
+    static constexpr uint32_t StateBundleMaxUncompressedSize = 1024 * 1024 * 16;
+
+    FNetListener(MessageEnqueuer& messageEnqueuer,
+                 const config::ConfigUri & configUri,
+                 uint32_t port);
+    ~FNetListener() override;
 
     void initRPC();
     void RPC_getNodeState2(FRT_RPCRequest *req);
     void RPC_setSystemState2(FRT_RPCRequest *req);
     void RPC_getCurrentTime(FRT_RPCRequest *req);
+    void RPC_setDistributionStates(FRT_RPCRequest* req);
 
     void registerHandle(const vespalib::stringref & handle);
     void close();
     int getListenPort() const;
 
-    // Used by unit tests.
-    bool serviceExists(const vespalib::stringref & connectionSpec);
-
 private:
-    CommunicationManager&           _comManager;
+    MessageEnqueuer&                _messageEnqueuer;
     std::unique_ptr<FRT_Supervisor> _orb;
-    bool                            _closed;
+    std::atomic<bool>               _closed;
     slobrok::api::RegisterAPI       _slobrokRegister;
     vespalib::string                _handle;
+
+    void detach_and_forward_to_enqueuer(std::shared_ptr<api::StorageMessage> cmd, FRT_RPCRequest *req);
 };
 
 }
diff --git a/storage/src/vespa/storage/storageserver/message_enqueuer.h b/storage/src/vespa/storage/storageserver/message_enqueuer.h
new file mode 100644
index 00000000000..921328a054b
--- /dev/null
+++ b/storage/src/vespa/storage/storageserver/message_enqueuer.h
@@ -0,0 +1,17 @@
+// Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+
+#pragma once
+
+#include <memory>
+
+namespace storage {
+namespace api { class StorageMessage; }
+
+// Interface for enqueuing a StorageMessage for further processing
+class MessageEnqueuer {
+public:
+    virtual ~MessageEnqueuer() = default;
+    virtual void enqueue(std::shared_ptr<api::StorageMessage> msg) = 0;
+};
+
+}
diff --git a/storage/src/vespa/storage/storageserver/rpcrequestwrapper.h b/storage/src/vespa/storage/storageserver/rpcrequestwrapper.h
index 40a5470ebb9..8412e911601 100644
--- a/storage/src/vespa/storage/storageserver/rpcrequestwrapper.h
+++ b/storage/src/vespa/storage/storageserver/rpcrequestwrapper.h
@@ -12,12 +12,13 @@ namespace storage {
  **/
 class RPCRequestWrapper {
 public:
-    enum {
+    enum ErrorCode {
         ERR_HANDLE_NOT_CONNECTED = 75000, // > 0xffff
         ERR_HANDLE_GONE          = 75001,
         ERR_REQUEST_DELETED      = 75002,
         ERR_HANDLE_DISABLED      = 75003,
-        ERR_NODE_SHUTTING_DOWN   = 75004
+        ERR_NODE_SHUTTING_DOWN   = 75004,
+        ERR_BAD_REQUEST          = 75005
     };
 
     RPCRequestWrapper(FRT_RPCRequest *req);
diff --git a/storage/src/vespa/storage/storageserver/slime_cluster_state_bundle_codec.cpp b/storage/src/vespa/storage/storageserver/slime_cluster_state_bundle_codec.cpp
new file mode 100644
index 00000000000..5b7e0ab4621
--- /dev/null
+++ b/storage/src/vespa/storage/storageserver/slime_cluster_state_bundle_codec.cpp
@@ -0,0 +1,125 @@
+// Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+
+#include "slime_cluster_state_bundle_codec.h"
+#include <vespa/document/bucket/fixed_bucket_spaces.h>
+#include <vespa/vdslib/state/clusterstate.h>
+#include <vespa/vdslib/state/cluster_state_bundle.h>
+#include <vespa/vespalib/data/slime/slime.h>
+#include <vespa/vespalib/stllike/asciistream.h>
+
+using document::FixedBucketSpaces;
+using vespalib::slime::Cursor;
+using vespalib::slime::BinaryFormat;
+using vespalib::DataBuffer;
+using vespalib::ConstBufferRef;
+using vespalib::compression::CompressionConfig;
+using vespalib::compression::decompress;
+using vespalib::compression::compress;
+using vespalib::Memory;
+using namespace vespalib::slime;
+
+namespace storage {
+
+// TODO find a suitable home for this class to avoid dupes with rpcsendv2.cpp
+namespace {
+class OutputBuf : public vespalib::Output {
+public:
+    explicit OutputBuf(size_t estimatedSize) : _buf(estimatedSize) { }
+    vespalib::DataBuffer & getBuf() { return _buf; }
+private:
+    vespalib::WritableMemory reserve(size_t bytes) override {
+        _buf.ensureFree(bytes);
+        return vespalib::WritableMemory(_buf.getFree(), _buf.getFreeLen());
+    }
+    Output &commit(size_t bytes) override {
+        _buf.moveFreeToData(bytes);
+        return *this;
+    }
+    vespalib::DataBuffer _buf;
+};
+
+vespalib::string serialize_state(const lib::ClusterState& state) {
+    vespalib::asciistream as;
+    state.serialize(as, false);
+    return as.str();
+}
+
+}
+
+// Only used from unit tests; the cluster controller encodes all bundles
+// we decode in practice.
+EncodedClusterStateBundle SlimeClusterStateBundleCodec::encode(
+        const lib::ClusterStateBundle& bundle) const
+{
+    vespalib::Slime slime;
+    Cursor& root = slime.setObject();
+    Cursor& states = root.setObject("states");
+    states.setString("baseline", serialize_state(*bundle.getBaselineClusterState()));
+    Cursor& spaces = states.setObject("spaces");
+    for (const auto& sp : bundle.getDerivedClusterStates()) {
+        spaces.setString(FixedBucketSpaces::to_string(sp.first), serialize_state(*sp.second));
+    }
+
+    OutputBuf out_buf(4096);
+    BinaryFormat::encode(slime, out_buf);
+    ConstBufferRef to_compress(out_buf.getBuf().getData(), out_buf.getBuf().getDataLen());
+    auto buf = std::make_unique<DataBuffer>(vespalib::roundUp2inN(out_buf.getBuf().getDataLen()));
+    auto actual_type = compress(CompressionConfig::LZ4, to_compress, *buf, false);
+
+    EncodedClusterStateBundle encoded_bundle;
+    encoded_bundle._compression_type = actual_type;
+    assert(to_compress.size() <= INT32_MAX);
+    encoded_bundle._uncompressed_length = to_compress.size();
+    encoded_bundle._buffer = std::move(buf);
+    return encoded_bundle;
+}
+
+namespace {
+
+static const Memory StatesField("states");
+static const Memory BaselineField("baseline");
+static const Memory SpacesField("spaces");
+
+struct StateInserter : vespalib::slime::ObjectTraverser {
+    lib::ClusterStateBundle::BucketSpaceStateMapping& _space_states;
+
+    explicit StateInserter(lib::ClusterStateBundle::BucketSpaceStateMapping& space_states)
+        : _space_states(space_states) {}
+
+    void field(const Memory& symbol, const Inspector& inspector) override {
+        _space_states.emplace(FixedBucketSpaces::from_string(symbol.make_stringref()),
+                              std::make_shared<const lib::ClusterState>(inspector.asString().make_string()));
+    }
+};
+
+}
+
+std::shared_ptr<const lib::ClusterStateBundle> SlimeClusterStateBundleCodec::decode(
+        const EncodedClusterStateBundle& encoded_bundle) const
+{
+    ConstBufferRef blob(encoded_bundle._buffer->getData(), encoded_bundle._buffer->getDataLen());
+    DataBuffer uncompressed;
+    decompress(encoded_bundle._compression_type, encoded_bundle._uncompressed_length,
+               blob, uncompressed, false);
+    if (encoded_bundle._uncompressed_length != uncompressed.getDataLen()) {
+        throw std::range_error(vespalib::make_string("ClusterStateBundle indicated uncompressed size (%u) is "
+                                                     "not equal to actual uncompressed size (%zu)",
+                                                     encoded_bundle._uncompressed_length,
+                                                     uncompressed.getDataLen()));
+    }
+
+    vespalib::Slime slime;
+    BinaryFormat::decode(Memory(uncompressed.getData(), uncompressed.getDataLen()), slime);
+    Inspector& root = slime.get();
+    Inspector& states = root[StatesField];
+    lib::ClusterState baseline(states[BaselineField].asString().make_string());
+
+    Inspector& spaces = states[SpacesField];
+    lib::ClusterStateBundle::BucketSpaceStateMapping space_states;
+    StateInserter inserter(space_states);
+    spaces.traverse(inserter);
+    // TODO add shared_ptr constructor for baseline?
+    return std::make_shared<lib::ClusterStateBundle>(baseline, std::move(space_states));
+}
+
+}
diff --git a/storage/src/vespa/storage/storageserver/slime_cluster_state_bundle_codec.h b/storage/src/vespa/storage/storageserver/slime_cluster_state_bundle_codec.h
new file mode 100644
index 00000000000..1fb95134059
--- /dev/null
+++ b/storage/src/vespa/storage/storageserver/slime_cluster_state_bundle_codec.h
@@ -0,0 +1,24 @@
+// Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+
+#pragma once
+
+#include "cluster_state_bundle_codec.h"
+#include <memory>
+
+namespace storage {
+
+/**
+ * Implementation of ClusterStateBundleCodec which uses structured Slime binary encoding
+ * to implement (de-)serialization of ClusterStateBundle instances. Encoding format is
+ * intentionally extensible so that we may add other information to it later.
+ *
+ * LZ4 compression is transparently applied during encoding and decompression is
+ * subsequently applied during decoding.
+ */
+class SlimeClusterStateBundleCodec : public ClusterStateBundleCodec {
+public:
+    EncodedClusterStateBundle encode(const lib::ClusterStateBundle&) const override;
+    std::shared_ptr<const lib::ClusterStateBundle> decode(const EncodedClusterStateBundle&) const override;
+};
+
+}
diff --git a/vdslib/src/vespa/vdslib/state/cluster_state_bundle.cpp b/vdslib/src/vespa/vdslib/state/cluster_state_bundle.cpp
index a2bbba5e52c..cf9c0ba6dff 100644
--- a/vdslib/src/vespa/vdslib/state/cluster_state_bundle.cpp
+++ b/vdslib/src/vespa/vdslib/state/cluster_state_bundle.cpp
@@ -1,7 +1,9 @@
 // Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 
+#include <vespa/document/bucket/fixed_bucket_spaces.h>
 #include "cluster_state_bundle.h"
 #include "clusterstate.h"
+#include <iostream>
 
 namespace storage::lib {
 
@@ -10,6 +12,13 @@ ClusterStateBundle::ClusterStateBundle(const ClusterState &baselineClusterState)
 {
 }
 
+ClusterStateBundle::ClusterStateBundle(const ClusterState& baselineClusterState,
+                                       BucketSpaceStateMapping derivedBucketSpaceStates)
+    : _baselineClusterState(std::make_shared<const ClusterState>(baselineClusterState)),
+      _derivedBucketSpaceStates(std::move(derivedBucketSpaceStates))
+{
+}
+
 ClusterStateBundle::~ClusterStateBundle() = default;
 
 const std::shared_ptr<const lib::ClusterState> &
@@ -22,6 +31,7 @@ const std::shared_ptr<const lib::ClusterState> &
 ClusterStateBundle::getDerivedClusterState(document::BucketSpace) const
 {
     // For now, just return the baseline cluster state.
+    // TODO use _derivedBucketSpaceStates
     return _baselineClusterState;
 }
 
@@ -34,7 +44,36 @@ ClusterStateBundle::getVersion() const
 bool
 ClusterStateBundle::operator==(const ClusterStateBundle &rhs) const
 {
-    return *_baselineClusterState == *rhs._baselineClusterState;
+    if (!(*_baselineClusterState == *rhs._baselineClusterState)) {
+        return false;
+    }
+    if (_derivedBucketSpaceStates.size() != rhs._derivedBucketSpaceStates.size()) {
+        return false;
+    }
+    // Can't do a regular operator== comparison since we must check equality
+    // of cluster state _values_, not their _pointers_.
+    for (auto& lhs_ds : _derivedBucketSpaceStates) {
+        auto rhs_iter = rhs._derivedBucketSpaceStates.find(lhs_ds.first);
+        if ((rhs_iter == rhs._derivedBucketSpaceStates.end())
+            || !(*lhs_ds.second == *rhs_iter->second)) {
+            return false;
+        }
+    }
+    return true;
+}
+
+std::ostream& operator<<(std::ostream& os, const ClusterStateBundle& bundle) {
+    os << "ClusterStateBundle('" << *bundle.getBaselineClusterState();
+    if (!bundle.getDerivedClusterStates().empty()) {
+        // Output ordering is undefined for of per-space states.
+        for (auto& ds : bundle.getDerivedClusterStates()) {
+            os << "', ";
+            os << document::FixedBucketSpaces::to_string(ds.first);
+            os << " '" << *ds.second;
+        }
+    }
+    os << "')";
+    return os;
 }
 
 }
diff --git a/vdslib/src/vespa/vdslib/state/cluster_state_bundle.h b/vdslib/src/vespa/vdslib/state/cluster_state_bundle.h
index 77d26092f4e..a8ee0b54713 100644
--- a/vdslib/src/vespa/vdslib/state/cluster_state_bundle.h
+++ b/vdslib/src/vespa/vdslib/state/cluster_state_bundle.h
@@ -3,6 +3,8 @@
 #pragma once
 
 #include <vespa/document/bucket/bucketspace.h>
+#include <unordered_map>
+#include <iosfwd>
 
 namespace storage::lib {
 
@@ -14,14 +16,28 @@ class ClusterState;
  */
 class ClusterStateBundle
 {
+public:
+    using BucketSpaceStateMapping = std::unordered_map<
+        document::BucketSpace,
+        std::shared_ptr<const ClusterState>,
+        document::BucketSpace::hash
+    >;
     std::shared_ptr<const ClusterState> _baselineClusterState;
+    BucketSpaceStateMapping _derivedBucketSpaceStates;
 public:
     explicit ClusterStateBundle(const ClusterState &baselineClusterState);
+    ClusterStateBundle(const ClusterState& baselineClusterState,
+                       BucketSpaceStateMapping derivedBucketSpaceStates);
     ~ClusterStateBundle();
     const std::shared_ptr<const ClusterState> &getBaselineClusterState() const;
     const std::shared_ptr<const ClusterState> &getDerivedClusterState(document::BucketSpace bucketSpace) const;
+    const BucketSpaceStateMapping& getDerivedClusterStates() const noexcept {
+        return _derivedBucketSpaceStates;
+    }
     uint32_t getVersion() const;
     bool operator==(const ClusterStateBundle &rhs) const;
 };
 
+std::ostream& operator<<(std::ostream&, const ClusterStateBundle&);
+
 }
diff --git a/vdslib/src/vespa/vdslib/state/clusterstate.cpp b/vdslib/src/vespa/vdslib/state/clusterstate.cpp
index 9a69ed98c79..fbc9943e22d 100644
--- a/vdslib/src/vespa/vdslib/state/clusterstate.cpp
+++ b/vdslib/src/vespa/vdslib/state/clusterstate.cpp
@@ -55,7 +55,7 @@ struct NodeData {
     }
 };
 
-ClusterState::ClusterState(const vespalib::stringref & serialized)
+ClusterState::ClusterState(const vespalib::string& serialized)
     : Printable(),
       _version(0),
       _clusterState(&State::UP),
diff --git a/vdslib/src/vespa/vdslib/state/clusterstate.h b/vdslib/src/vespa/vdslib/state/clusterstate.h
index b60f2f6f1cc..9e8dd0f292a 100644
--- a/vdslib/src/vespa/vdslib/state/clusterstate.h
+++ b/vdslib/src/vespa/vdslib/state/clusterstate.h
@@ -36,7 +36,9 @@ public:
 
     ClusterState();
     ClusterState(const ClusterState&);
-    explicit ClusterState(const vespalib::stringref & serialized);
+    // FIXME make ClusterState parsing not require null termination of string,
+    // then move to vespalib::stringref
+    explicit ClusterState(const vespalib::string& serialized);
     ~ClusterState();
 
     std::string getTextualDifference(const ClusterState& other) const;