MXS-2379: Fix maxinfo HTTP interface

Added the missing HTTP request handlers and a new JSON conversion
function.

include/maxscale/resultset.hh

@@ -52,6 +52,13 @@ public:
      */
     void write(DCB* dcb);
 
+    /**
+     * Write the result set to a DCB as JSON
+     *
+     * @param dcb DCB where the result set is written
+     */
+    void write_as_json(DCB* dcb);
+
 private:
     std::vector<std::string>              m_columns;
     std::vector<std::vector<std::string>> m_rows;

server/core/resultset.cc

@@ -16,6 +16,7 @@
 
 #include <numeric>
 
+#include <maxscale/alloc.h>
 #include <maxscale/resultset.hh>
 #include <maxscale/buffer.h>
 #include <maxscale/dcb.h>
@@ -206,3 +207,24 @@ void ResultSet::write(DCB* dcb)
 
     mysql_send_eof(dcb, seqno);
 }
+
+void ResultSet::write_as_json(DCB* dcb)
+{
+    json_t* arr = json_array();
+
+    for (const auto& row : m_rows)
+    {
+        json_t* obj = json_object();
+
+        for (size_t i = 0; i < row.size(); i++)
+        {
+            json_object_set_new(obj, m_columns[i].c_str(), json_string(row[i].c_str()));
+        }
+
+        json_array_append_new(arr, obj);
+    }
+
+    char* js = json_dumps(arr, JSON_INDENT(4));
+    dcb_printf(dcb, "%s", js);
+    MXS_FREE(js);
+}

server/modules/routing/maxinfo/CMakeLists.txt

@@ -1,4 +1,4 @@
-add_library(maxinfo SHARED maxinfo.cc maxinfo_parse.cc maxinfo_error.cc maxinfo_exec.cc)
+add_library(maxinfo SHARED maxinfo.cc maxinfo_parse.cc maxinfo_error.cc maxinfo_exec.cc maxinfo_http.cc)
 set_target_properties(maxinfo PROPERTIES INSTALL_RPATH ${CMAKE_INSTALL_RPATH}:${MAXSCALE_LIBDIR} VERSION "1.0.0" LINK_FLAGS -Wl,-z,defs)
 target_link_libraries(maxinfo maxscale-common)
 install_module(maxinfo core)

server/modules/routing/maxinfo/maxinfo.cc

@@ -305,6 +305,7 @@ static int execute(MXS_ROUTER* rinstance, MXS_ROUTER_SESSION* router_session, GW
 
     if (GWBUF_TYPE(queue) == GWBUF_TYPE_HTTP)
     {
+        handle_url(instance, session, queue);
         gwbuf_free(queue);
         return 0;
     }

server/modules/routing/maxinfo/maxinfo.h

@@ -137,5 +137,6 @@ extern void          maxinfo_send_error(DCB*, int, const char*);
 extern void maxinfo_send_parse_error(DCB*, char*, PARSE_ERROR);
 extern std::unique_ptr<ResultSet> maxinfo_variables();
 extern std::unique_ptr<ResultSet> maxinfo_status();
+extern int                        handle_url(INFO_INSTANCE* instance, INFO_SESSION* session, GWBUF* queue);
 
 #endif

server/modules/routing/maxinfo/maxinfo_http.cc

@@ -0,0 +1,108 @@
+/*
+ * 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: 2022-01-01
+ *
+ * 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 "maxinfo.h"
+
+#include <unordered_map>
+#include <string>
+#include <functional>
+
+#include <maxscale/utils.hh>
+
+#include "../../../core/internal/poll.hh"
+#include "../../../core/internal/monitor.hh"
+#include "../../../core/internal/server.hh"
+#include "../../../core/internal/service.hh"
+#include "../../../core/internal/modules.hh"
+#include "../../../core/internal/session.hh"
+
+void serviceGetList_http(INFO_INSTANCE* instance, INFO_SESSION* session, DCB* dcb)
+{
+    serviceGetList()->write_as_json(dcb);
+}
+
+void serviceGetListenerList_http(INFO_INSTANCE* instance, INFO_SESSION* session, DCB* dcb)
+{
+    serviceGetListenerList()->write_as_json(dcb);
+}
+
+void moduleGetList_http(INFO_INSTANCE* instance, INFO_SESSION* session, DCB* dcb)
+{
+    moduleGetList()->write_as_json(dcb);
+}
+
+void monitorGetList_http(INFO_INSTANCE* instance, INFO_SESSION* session, DCB* dcb)
+{
+    monitor_get_list()->write_as_json(dcb);
+}
+
+void maxinfoSessionsAll_http(INFO_INSTANCE* instance, INFO_SESSION* session, DCB* dcb)
+{
+    sessionGetList()->write_as_json(dcb);
+}
+
+void maxinfoClientSessions_http(INFO_INSTANCE* instance, INFO_SESSION* session, DCB* dcb)
+{
+    sessionGetList()->write_as_json(dcb);
+}
+
+void serverGetList_http(INFO_INSTANCE* instance, INFO_SESSION* session, DCB* dcb)
+{
+    serverGetList()->write_as_json(dcb);
+}
+
+void eventTimesGetList_http(INFO_INSTANCE* instance, INFO_SESSION* session, DCB* dcb)
+{
+    eventTimesGetList()->write_as_json(dcb);
+}
+
+void maxinfo_variables_http(INFO_INSTANCE* instance, INFO_SESSION* session, DCB* dcb)
+{
+    maxinfo_variables()->write_as_json(dcb);
+}
+
+void maxinfo_status_http(INFO_INSTANCE* instance, INFO_SESSION* session, DCB* dcb)
+{
+    maxinfo_status()->write_as_json(dcb);
+}
+
+/**
+ * Table that maps a URI to a function to call to
+ * to obtain the result set related to that URI
+ */
+static std::unordered_map<std::string, void (*)(INFO_INSTANCE*, INFO_SESSION*, DCB*)> supported_uri
+{
+    {"/services", serviceGetList_http},
+    {"/listeners", serviceGetListenerList_http},
+    {"/modules", moduleGetList_http},
+    {"/monitors", monitorGetList_http},
+    {"/sessions", maxinfoSessionsAll_http},
+    {"/clients", maxinfoClientSessions_http},
+    {"/servers", serverGetList_http},
+    {"/variables", maxinfo_variables_http},
+    {"/status", maxinfo_status_http},
+    {"/event/times", eventTimesGetList_http}
+};
+
+int handle_url(INFO_INSTANCE* instance, INFO_SESSION* session, GWBUF* queue)
+{
+    std::string uri((char*)GWBUF_DATA(queue));
+    auto it = supported_uri.find(uri);
+
+    if (it != supported_uri.end())
+    {
+        it->second(instance, session, session->dcb);
+    }
+
+    return 1;
+}