MXS-1220: Add threads resource

The threads are now a REST API resource exposed via the /maxscale/threads
resource collection.

server/core/worker.cc

@@ -12,11 +12,15 @@
  */
 
 #include "maxscale/worker.hh"
+
 #include <errno.h>
 #include <fcntl.h>
 #include <signal.h>
 #include <stdlib.h>
 #include <unistd.h>
+#include <vector>
+#include <sstream>
+
 #include <maxscale/alloc.h>
 #include <maxscale/atomic.h>
 #include <maxscale/config.h>
@@ -24,13 +28,21 @@
 #include <maxscale/log_manager.h>
 #include <maxscale/platform.h>
 #include <maxscale/semaphore.hh>
+#include <maxscale/json_api.h>
+#include <maxscale/utils.hh>
+
 #include "maxscale/modules.h"
 #include "maxscale/poll.h"
 #include "maxscale/statistics.h"
+#include "maxscale/workertask.hh"
 
 #define WORKER_ABSENT_ID -1
 
 using maxscale::Worker;
+using maxscale::Closer;
+using maxscale::Semaphore;
+using std::vector;
+using std::stringstream;
 
 namespace
 {
@@ -767,6 +779,87 @@ MXS_SESSION* Worker::find_session(uint64_t id)
     return rval;
 }
 
+class WorkerInfoTask: public maxscale::WorkerTask
+{
+public:
+    WorkerInfoTask(const char* host, uint32_t nthreads):
+        m_host(host)
+    {
+        m_data.resize(nthreads);
+    }
+
+    void execute(Worker& worker)
+    {
+        json_t* stats = json_object();
+        const Worker::STATISTICS& s = worker.get_local_statistics();
+        json_object_set_new(stats, "reads", json_integer(s.n_read));
+        json_object_set_new(stats, "writes", json_integer(s.n_write));
+        json_object_set_new(stats, "errors", json_integer(s.n_error));
+        json_object_set_new(stats, "hangups", json_integer(s.n_hup));
+        json_object_set_new(stats, "accepts", json_integer(s.n_accept));
+        json_object_set_new(stats, "blocking_polls", json_integer(s.blockingpolls));
+        json_object_set_new(stats, "event_queue_length", json_integer(s.evq_length));
+        json_object_set_new(stats, "max_event_queue_length", json_integer(s.evq_max));
+        json_object_set_new(stats, "max_exec_time", json_integer(s.maxexectime));
+        json_object_set_new(stats, "max_queue_time", json_integer(s.maxqtime));
+
+        json_t* attr = json_object();
+        json_object_set_new(attr, "stats", stats);
+
+        int idx = worker.get_current_id();
+        stringstream ss;
+        ss << idx;
+
+        json_t* json = json_object();
+        json_object_set_new(json, CN_ID, json_string(ss.str().c_str()));
+        json_object_set_new(json, CN_TYPE, json_string(CN_THREADS));
+        json_object_set_new(json, CN_ATTRIBUTES, attr);
+
+        ss_dassert((size_t)idx < m_data.size());
+        m_data[idx] = json;
+    }
+
+    json_t* resource()
+    {
+        json_t* arr = json_array();
+
+        for (vector<json_t*>::iterator it = m_data.begin(); it != m_data.end(); it++)
+        {
+            json_array_append_new(arr, *it);
+        }
+
+        return mxs_json_resource(m_host, MXS_JSON_API_THREADS, arr);
+    }
+
+    json_t* resource(int id)
+    {
+        return mxs_json_resource(m_host, MXS_JSON_API_THREADS, m_data[id]);
+    }
+
+private:
+    vector<json_t*> m_data;
+    const char*     m_host;
+};
+
+json_t* mxs_worker_to_json(const char* host, int id)
+{
+    Worker* target = Worker::get(id);
+    WorkerInfoTask task(host, id + 1);
+    Semaphore sem;
+
+    target->post(&task, &sem);
+    sem.wait();
+
+    return task.resource(id);
+}
+
+json_t* mxs_worker_list_to_json(const char* host)
+{
+    WorkerInfoTask task(host, config_threadcount());
+    Worker::execute_concurrently(task);
+    return task.resource();
+}
+
 void Worker::run()
 {
     this_thread.current_worker_id = m_id;