MXS-1992 Make preparations for REST-API

include/maxscale/json_api.h

@@ -34,6 +34,7 @@ MXS_BEGIN_DECLS
 #define MXS_JSON_API_LOGS      "/maxscale/logs/"
 #define MXS_JSON_API_TASKS     "/maxscale/tasks/"
 #define MXS_JSON_API_MODULES   "/maxscale/modules/"
+#define MXS_JSON_API_QC_STATS  "/maxscale/qc_stats/"
 #define MXS_JSON_API_USERS     "/users/"
 
 /**

server/core/internal/routingworker.hh

@@ -355,12 +355,37 @@ public:
         }
     }
 
+    /**
+     * Provides QC statistics of one workers
+     *
+     * @param id[in]       Id of worker.
+     * @param pStats[out]  The QC statistics of that worker.
+     *
+     * return True, if @c id referred to a worker, false otherwise.
+     */
+    static bool get_qc_stats(int id, QC_CACHE_STATS* pStats);
+
     /**
      * Provides QC statistics of all workers
      *
      * @param all_stats  Vector that on return will contain the statistics of all workers.
      */
-    static void get_all_qc_stats(std::vector<QC_CACHE_STATS>& all_stats);
+    static void get_qc_stats(std::vector<QC_CACHE_STATS>& all_stats);
+
+    /**
+     * Provides QC statistics of all workers as a Json object for use in the REST-API.
+     */
+    static std::unique_ptr<json_t> get_qc_stats_as_json(const char* zHost);
+
+    /**
+     * Provides QC statistics of one worker as a Json object for use in the REST-API.
+     *
+     * @param zHost  The name of the MaxScale host.
+     * @param id     An id of a worker.
+     *
+     * @return A json object if @c id refers to a worker, NULL otherwise.
+     */
+    static std::unique_ptr<json_t> get_qc_stats_as_json(const char* zHost, int id);
 
 private:
     const int    m_id;       /*< The id of the worker. */

server/core/routingworker.cc

@@ -869,7 +869,40 @@ int64_t RoutingWorker::get_one_statistic(POLL_STAT what)
 }
 
 //static
-void RoutingWorker::get_all_qc_stats(std::vector<QC_CACHE_STATS>& all_stats)
+bool RoutingWorker::get_qc_stats(int id, QC_CACHE_STATS* pStats)
+{
+    class Task : public mxs::Worker::Task
+    {
+    public:
+        Task(QC_CACHE_STATS* pStats)
+            : m_stats(*pStats)
+        {
+        }
+
+        void execute(mxs::Worker&)
+        {
+            qc_get_cache_stats(&m_stats);
+        }
+
+    private:
+        QC_CACHE_STATS& m_stats;
+    };
+
+    RoutingWorker* pWorker = RoutingWorker::get(id);
+
+    if (pWorker)
+    {
+        Semaphore sem;
+        Task task(pStats);
+        pWorker->post(&task, &sem);
+        sem.wait();
+    }
+
+    return pWorker != nullptr;
+}
+
+//static
+void RoutingWorker::get_qc_stats(std::vector<QC_CACHE_STATS>& all_stats)
 {
     class Task : public mxs::Worker::Task
     {
@@ -898,6 +931,75 @@ void RoutingWorker::get_all_qc_stats(std::vector<QC_CACHE_STATS>& all_stats)
     mxs::RoutingWorker::execute_concurrently(task);
 }
 
+namespace
+{
+
+json_t* qc_stats_to_json(const char* zHost, int id, const QC_CACHE_STATS& stats)
+{
+    json_t* pStats = json_object();
+    json_object_set_new(pStats, "size", json_integer(stats.size));
+    json_object_set_new(pStats, "inserts", json_integer(stats.inserts));
+    json_object_set_new(pStats, "hits", json_integer(stats.hits));
+    json_object_set_new(pStats, "misses", json_integer(stats.misses));
+    json_object_set_new(pStats, "evictions", json_integer(stats.evictions));
+
+    json_t* pAttributes = json_object();
+    json_object_set_new(pAttributes, "stats", pStats);
+
+    json_t* pSelf = mxs_json_self_link(zHost, "qc_stats", std::to_string(id).c_str());
+
+    json_t* pJson = json_object();
+    json_object_set_new(pJson, CN_ID, json_string(std::to_string(id).c_str()));
+    json_object_set_new(pJson, CN_TYPE, json_string("qc_stats"));
+    json_object_set_new(pJson, CN_ATTRIBUTES, pAttributes);
+    json_object_set_new(pJson, CN_LINKS, pSelf);
+
+    return pJson;
+}
+
+}
+
+//static
+std::unique_ptr<json_t> RoutingWorker::get_qc_stats_as_json(const char* zHost, int id)
+{
+    std::unique_ptr<json_t> sStats;
+
+    QC_CACHE_STATS stats;
+
+    if (get_qc_stats(id, &stats))
+    {
+        json_t* pJson = qc_stats_to_json(zHost, id, stats);
+
+        stringstream self;
+        self << MXS_JSON_API_QC_STATS << id;
+
+        sStats = std::unique_ptr<json_t>(mxs_json_resource(zHost, self.str().c_str(), pJson));
+    }
+
+    return sStats;
+}
+
+//static
+std::unique_ptr<json_t> RoutingWorker::get_qc_stats_as_json(const char* zHost)
+{
+    vector<QC_CACHE_STATS> all_stats;
+
+    get_qc_stats(all_stats);
+
+    std::unique_ptr<json_t> sAll_stats(json_array());
+
+    int id = 0;
+    for (const auto& stats : all_stats)
+    {
+        json_t* pJson = qc_stats_to_json(zHost, id, stats);
+
+        json_array_append_new(sAll_stats.get(), pJson);
+        ++id;
+    }
+
+    return std::unique_ptr<json_t>(mxs_json_resource(zHost, MXS_JSON_API_QC_STATS, sAll_stats.release()));
+}
+
 }
 
 size_t mxs_rworker_broadcast_message(uint32_t msg_id, intptr_t arg1, intptr_t arg2)

server/modules/routing/debugcli/debugcmd.cc

@@ -2436,7 +2436,7 @@ show_qc_all(DCB* dcb)
 {
     std::vector<QC_CACHE_STATS> all_stats;
 
-    mxs::RoutingWorker::get_all_qc_stats(all_stats);
+    mxs::RoutingWorker::get_qc_stats(all_stats);
 
     dcb_printf(dcb, " ID | Size       | Inserts    | Hits       | Misses     | Evictions  |\n");
     dcb_printf(dcb, "----+------------+------------+------------+------------+------------+\n");