MXS-1992 Allow changing the QC cache size

include/maxscale/json_api.h

@@ -35,6 +35,7 @@ MXS_BEGIN_DECLS
 #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_QC        "/maxscale/query_classifier/"
 #define MXS_JSON_API_USERS     "/users/"
 
 /**

server/core/config_runtime.cc

@@ -15,14 +15,14 @@
 
 #include "internal/config_runtime.h"
 
-#include <strings.h>
-#include <string>
-#include <sstream>
-#include <set>
-#include <iterator>
 #include <algorithm>
-#include <tuple>
 #include <functional>
+#include <iterator>
+#include <set>
+#include <sstream>
+#include <string>
+#include <strings.h>
+#include <tuple>
 #include <vector>
 
 #include <maxscale/atomic.h>
@@ -31,14 +31,15 @@
 #include <maxscale/json_api.h>
 #include <maxscale/paths.h>
 #include <maxscale/platform.h>
+#include <maxscale/router.h>
 #include <maxscale/spinlock.hh>
 #include <maxscale/users.h>
-#include <maxscale/router.h>
 
 #include "internal/config.hh"
-#include "internal/monitor.h"
-#include "internal/modules.h"
 #include "internal/filter.hh"
+#include "internal/modules.h"
+#include "internal/monitor.h"
+#include "internal/query_classifier.hh"
 
 typedef std::set<std::string> StringSet;
 typedef std::vector<std::string> StringVector;
@@ -2538,3 +2539,40 @@ bool runtime_alter_maxscale_from_json(json_t* new_json)
 
     return rval;
 }
+
+bool validate_qc_json(json_t* json)
+{
+    json_t* param = mxs_json_pointer(json, MXS_JSON_PTR_PARAMETERS);
+    bool rval = false;
+
+    if (param && json_is_object(param))
+    {
+        rval = is_count_or_null(param, "cache_size");
+    }
+
+    return rval;
+}
+
+// TODO: Expose everything needed so that this function could be
+// TODO: part of the query classifier API. 
+bool runtime_alter_qc_from_json(json_t* json)
+{
+    bool rval = false;
+
+    if (validate_qc_json(json))
+    {
+        rval = true;
+
+        json_t* param = mxs_json_pointer(json, MXS_JSON_PTR_PARAMETERS);
+        json_t* value;
+
+        if ((value = mxs_json_pointer(param, "cache_size")))
+        {
+            QC_CACHE_PROPERTIES cache_properties = { json_integer_value(value) };
+
+            qc_set_cache_properties(&cache_properties);
+        }
+    }
+
+    return rval;
+}

server/core/internal/config_runtime.h

@@ -389,3 +389,12 @@ bool runtime_remove_user(const char* id, enum user_type type);
  * @return True if the core parameters are valid and were successfully applied
  */
 bool runtime_alter_maxscale_from_json(json_t* new_json);
+
+/**
+ * @brief Alter core query classifier parameters from JSON.
+ *
+ * @param new_json  JSON defining the new parameters.
+ *
+ * @return True if the core parameters are valid and were successfully applied
+ */
+bool runtime_alter_qc_from_json(json_t* new_json);

server/core/internal/query_classifier.hh

@@ -14,6 +14,7 @@
 
 #include <maxscale/cppdefs.hh>
 #include <maxscale/query_classifier.h>
+#include <maxscale/jansson.hh>
 
 MXS_BEGIN_DECLS
 
@@ -36,4 +37,13 @@ typedef enum qc_trx_parse_using
  */
 uint32_t qc_get_trx_type_mask_using(GWBUF* stmt, qc_trx_parse_using_t use);
 
+/**
+ * Generic query classifier information.
+ *
+ * @param zHost  The MaxScale host.
+ *
+ * @return A json object containing information.
+ */
+std::unique_ptr<json_t> qc_as_json(const char* zHost);
+
 MXS_END_DECLS

server/core/resource.cc

@@ -13,29 +13,30 @@
 #include "internal/resource.hh"
 
 #include <list>
-#include <sstream>
 #include <map>
+#include <sstream>
 
+#include <maxscale/adminusers.h>
 #include <maxscale/alloc.h>
-#include <maxscale/jansson.hh>
-#include <maxscale/spinlock.hh>
-#include <maxscale/json_api.h>
 #include <maxscale/housekeeper.h>
 #include <maxscale/http.hh>
-#include <maxscale/adminusers.h>
+#include <maxscale/jansson.hh>
+#include <maxscale/json_api.h>
 #include <maxscale/modulecmd.h>
 #include <maxscale/semaphore.hh>
 #include <maxscale/server.hh>
+#include <maxscale/spinlock.hh>
 
+#include "internal/config_runtime.h"
+#include "internal/filter.hh"
 #include "internal/httprequest.hh"
 #include "internal/httpresponse.hh"
-#include "internal/session.h"
-#include "internal/filter.hh"
-#include "internal/monitor.h"
-#include "internal/service.hh"
-#include "internal/config_runtime.h"
 #include "internal/modules.h"
+#include "internal/monitor.h"
+#include "internal/query_classifier.hh"
 #include "internal/routingworker.hh"
+#include "internal/service.hh"
+#include "internal/session.h"
 
 using std::list;
 using std::map;
@@ -426,6 +427,18 @@ HttpResponse cb_alter_logs(const HttpRequest& request)
     return HttpResponse(MHD_HTTP_FORBIDDEN, runtime_get_json_error());
 }
 
+HttpResponse cb_alter_qc(const HttpRequest& request)
+{
+    ss_dassert(request.get_json());
+
+    if (runtime_alter_qc_from_json(request.get_json()))
+    {
+        return HttpResponse(MHD_HTTP_NO_CONTENT);
+    }
+
+    return HttpResponse(MHD_HTTP_FORBIDDEN, runtime_get_json_error());
+}
+
 HttpResponse cb_delete_server(const HttpRequest& request)
 {
     SERVER* server = server_find_by_unique_name(request.uri_part(1).c_str());
@@ -626,6 +639,11 @@ HttpResponse cb_all_threads(const HttpRequest& request)
     return HttpResponse(MHD_HTTP_OK, mxs_rworker_list_to_json(request.host()));
 }
 
+HttpResponse cb_qc(const HttpRequest& request)
+{
+    return HttpResponse(MHD_HTTP_OK, qc_as_json(request.host()).release());
+}
+
 HttpResponse cb_thread(const HttpRequest& request)
 {
     int id = atoi(request.last_uri_part().c_str());
@@ -889,6 +907,7 @@ public:
         m_get.push_back(SResource(new Resource(cb_get_session, 2, "sessions", ":session")));
 
         m_get.push_back(SResource(new Resource(cb_maxscale, 1, "maxscale")));
+        m_get.push_back(SResource(new Resource(cb_qc, 2, "maxscale", "query_classifier")));
         m_get.push_back(SResource(new Resource(cb_all_threads, 2, "maxscale", "threads")));
         m_get.push_back(SResource(new Resource(cb_thread, 3, "maxscale", "threads", ":thread")));
         m_get.push_back(SResource(new Resource(cb_logs, 2, "maxscale", "logs")));
@@ -936,6 +955,7 @@ public:
         m_patch.push_back(SResource(new Resource(cb_alter_service, 2, "services", ":service")));
         m_patch.push_back(SResource(new Resource(cb_alter_logs, 2, "maxscale", "logs")));
         m_patch.push_back(SResource(new Resource(cb_alter_maxscale, 1, "maxscale")));
+        m_patch.push_back(SResource(new Resource(cb_alter_qc, 2, "maxscale", "query_classifier")));
 
         /** Update resource relationships directly */
         m_patch.push_back(SResource(new Resource(cb_alter_server_service_relationship, 4,