Add skeleton hint router

The hint router will perform its scheduling solely based upon hints
provided by a filter (e.g. namedserverfilter) placed before it.

server/modules/routing/CMakeLists.txt

@@ -7,6 +7,7 @@ endif()
 
 add_subdirectory(cli)
 add_subdirectory(debugcli)
+add_subdirectory(hintrouter)
 add_subdirectory(maxinfo)
 add_subdirectory(readconnroute)
 add_subdirectory(readwritesplit)

server/modules/routing/hintrouter/CMakeLists.txt

@@ -0,0 +1,8 @@
+add_library(hintrouter SHARED
+  hintrouter.cc
+  hintroutersession.cc
+  )
+
+target_link_libraries(hintrouter maxscale-common)
+set_target_properties(hintrouter PROPERTIES VERSION "1.0.0")
+install_module(hintrouter core)

server/modules/routing/hintrouter/hintrouter.cc

@@ -0,0 +1,68 @@
+/*
+ * Copyright (c) 2016 MariaDB Corporation Ab
+ *
+ * Use of this software is governed by the Business Source License included
+ * in the LICENSE.TXT file and at www.mariadb.com/bsl11.
+ *
+ * Change Date: 2019-07-01
+ *
+ * On the date above, in accordance with the Business Source License, use
+ * of this software will be governed by version 2 or later of the General
+ * Public License.
+ */
+
+#define MXS_MODULE_NAME "hintrouter"
+#include "hintrouter.hh"
+#include <maxscale/log_manager.h>
+
+
+HintRouter::HintRouter(SERVICE* pService)
+    : maxscale::Router<HintRouter, HintRouterSession>(pService)
+{
+    MXS_NOTICE("Hint router [%s] created.", pService->name);
+}
+
+
+//static
+HintRouter* HintRouter::create(SERVICE* pService, char** pzOptions)
+{
+    return new HintRouter(pService);
+}
+
+
+HintRouterSession* HintRouter::newSession(MXS_SESSION *pSession)
+{
+    return new HintRouterSession(pSession, this);
+}
+
+void HintRouter::diagnostics(DCB* pOut)
+{
+}
+
+uint64_t HintRouter::getCapabilities()
+{
+    return 0;
+}
+
+
+extern "C" MXS_MODULE* MXS_CREATE_MODULE()
+{
+    static MXS_MODULE module =
+    {
+        MXS_MODULE_API_ROUTER,   /* Module type */
+        MXS_MODULE_BETA_RELEASE, /* Release status */
+        MXS_ROUTER_VERSION,      /* Implemented module API version */
+        "A hint router", /* Description */
+        "V1.0.0", /* Module version */
+        &HintRouter::s_object,
+        NULL, /* Process init, can be null */
+        NULL, /* Process finish, can be null */
+        NULL, /* Thread init */
+        NULL, /* Thread finish */
+        {
+            {MXS_END_MODULE_PARAMS}
+        }
+    };
+
+    return &module;
+}

server/modules/routing/hintrouter/hintrouter.hh

@@ -0,0 +1,36 @@
+#pragma once
+/*
+ * Copyright (c) 2016 MariaDB Corporation Ab
+ *
+ * Use of this software is governed by the Business Source License included
+ * in the LICENSE.TXT file and at www.mariadb.com/bsl11.
+ *
+ * Change Date: 2019-07-01
+ *
+ * On the date above, in accordance with the Business Source License, use
+ * of this software will be governed by version 2 or later of the General
+ * Public License.
+ */
+
+#include <maxscale/cppdefs.hh>
+#include <maxscale/router.hh>
+#include "hintroutersession.hh"
+
+class HintRouter : public maxscale::Router<HintRouter, HintRouterSession>
+{
+public:
+    static HintRouter* create(SERVICE* pService, char** pzOptions);
+
+    HintRouterSession* newSession(MXS_SESSION *pSession);
+
+    void diagnostics(DCB* pOut);
+
+    uint64_t getCapabilities();
+
+private:
+    HintRouter(SERVICE* pService);
+
+private:
+    HintRouter(const HintRouter&);
+    HintRouter& operator = (const HintRouter&);
+};

server/modules/routing/hintrouter/hintroutersession.cc

@@ -0,0 +1,55 @@
+/*
+ * Copyright (c) 2016 MariaDB Corporation Ab
+ *
+ * Use of this software is governed by the Business Source License included
+ * in the LICENSE.TXT file and at www.mariadb.com/bsl11.
+ *
+ * Change Date: 2019-07-01
+ *
+ * On the date above, in accordance with the Business Source License, use
+ * of this software will be governed by version 2 or later of the General
+ * Public License.
+ */
+
+#define MXS_MODULE_NAME "hintrouter"
+#include "hintroutersession.hh"
+#include <maxscale/log_manager.h>
+
+
+HintRouterSession::HintRouterSession(MXS_SESSION* pSession, HintRouter* pRouter)
+    : maxscale::RouterSession(pSession)
+    , m_pRouter(pRouter)
+{
+}
+
+
+HintRouterSession::~HintRouterSession()
+{
+}
+
+
+void HintRouterSession::close()
+{
+}
+
+
+int32_t HintRouterSession::routeQuery(GWBUF* pPacket)
+{
+    MXS_ERROR("routeQuery not implemented yet.");
+    return 0;
+}
+
+
+void HintRouterSession::clientReply(GWBUF* pPacket, DCB* pBackend)
+{
+    MXS_ERROR("clientReply not implemented yet.");
+}
+
+
+void HintRouterSession::handleError(GWBUF*             pMessage,
+                                    DCB*               pProblem,
+                                    mxs_error_action_t action,
+                                    bool*              pSuccess)
+{
+    MXS_ERROR("handleError not implemented yet.");
+}

server/modules/routing/hintrouter/hintroutersession.hh

@@ -0,0 +1,45 @@
+#pragma once
+/*
+ * Copyright (c) 2016 MariaDB Corporation Ab
+ *
+ * Use of this software is governed by the Business Source License included
+ * in the LICENSE.TXT file and at www.mariadb.com/bsl11.
+ *
+ * Change Date: 2019-07-01
+ *
+ * On the date above, in accordance with the Business Source License, use
+ * of this software will be governed by version 2 or later of the General
+ * Public License.
+ */
+
+#include <maxscale/cppdefs.hh>
+#include <maxscale/router.hh>
+
+class HintRouter;
+
+class HintRouterSession : public maxscale::RouterSession
+{
+public:
+    HintRouterSession(MXS_SESSION* pSession,
+                      HintRouter*  pRouter);
+
+    ~HintRouterSession();
+
+    void close();
+
+    int32_t routeQuery(GWBUF* pPacket);
+
+    void clientReply(GWBUF* pPacket, DCB* pBackend);
+
+    void handleError(GWBUF*             pMessage,
+                     DCB*               pProblem,
+                     mxs_error_action_t action,
+                     bool*              pSuccess);
+
+private:
+    HintRouterSession(const HintRouterSession&);
+    HintRouterSession& operator = (const HintRouterSession&);
+
+private:
+    HintRouter* m_pRouter;
+};