MXS-1220: Add PUT support for servers

The server can now be modified with a PUT request of a modified server
resource. The server resource was reorganized to have the parameters as a
separate entity from the other more general entities of the resource.

The PUT/POST functions return a more appropriate error message when no
request body is provided.

Moved some of the constant names used in server.cc into the config.h
header.

include/maxscale/config.h

@@ -73,6 +73,7 @@ extern const char CN_MS_TIMESTAMP[];
 extern const char CN_NAME[];
 extern const char CN_NON_BLOCKING_POLLS[];
 extern const char CN_OPTIONS[];
+extern const char CN_PARAMETERS[];
 extern const char CN_PASSWORD[];
 extern const char CN_POLL_SLEEP[];
 extern const char CN_PORT[];

include/maxscale/jansson.hh

@@ -15,6 +15,7 @@
 #include <maxscale/cppdefs.hh>
 
 #include <string>
+#include <sstream>
 
 #include <maxscale/jansson.h>
 #include <maxscale/utils.hh>
@@ -71,4 +72,42 @@ static inline std::string json_dump(const Closer<json_t*>& json, int flags = 0)
     return json_dump(json.get(), flags);
 }
 
+/**
+ * @brief Convert JSON to string
+ *
+ * @param JSON to convert
+ *
+ * @return The JSON value converted to a string
+ */
+static inline std::string json_to_string(json_t* json)
+{
+    std::stringstream ss;
+
+    if (json_is_string(json))
+    {
+        ss << json_string_value(json);
+    }
+    else if (json_is_boolean(json))
+    {
+        ss << (json_boolean_value(json) ? "true" : "false");
+    }
+    else if (json_is_real(json))
+    {
+        ss << json_real_value(json);
+    }
+    else if (json_is_number(json))
+    {
+        ss << json_number_value(json);
+    }
+    else if (json_is_integer(json))
+    {
+        ss << json_integer_value(json);
+    }
+    else if (json_is_null(json))
+    {
+        ss << "";
+    }
+
+    return ss.str();
+}
 }

server/core/config.cc

@@ -84,6 +84,7 @@ const char CN_MS_TIMESTAMP[]                  = "ms_timestamp";
 const char CN_NAME[]                          = "name";
 const char CN_NON_BLOCKING_POLLS[]            = "non_blocking_polls";
 const char CN_OPTIONS[]                       = "options";
+const char CN_PARAMETERS[]                    = "parameters";
 const char CN_PASSWORD[]                      = "password";
 const char CN_POLL_SLEEP[]                    = "poll_sleep";
 const char CN_PORT[]                          = "port";

server/core/config_runtime.cc

@@ -10,15 +10,21 @@
  * of this software will be governed by version 2 or later of the General
  * Public License.
  */
+
+#include <maxscale/cppdefs.hh>
+
 #include "maxscale/config_runtime.h"
 
 #include <strings.h>
 #include <string>
 #include <set>
+#include <iterator>
+#include <algorithm>
 
 #include <maxscale/atomic.h>
 #include <maxscale/paths.h>
 #include <maxscale/spinlock.h>
+#include <maxscale/jansson.hh>
 
 #include "maxscale/config.h"
 #include "maxscale/monitor.h"
@@ -27,6 +33,7 @@
 
 using std::string;
 using std::set;
+using mxs::Closer;
 
 static SPINLOCK crt_lock = SPINLOCK_INIT;
 
@@ -271,7 +278,7 @@ bool runtime_enable_server_ssl(SERVER *server, const char *key, const char *cert
     return rval;
 }
 
-bool runtime_alter_server(SERVER *server, char *key, char *value)
+bool runtime_alter_server(SERVER *server, const char *key, const char *value)
 {
     spinlock_acquire(&crt_lock);
     bool valid = true;
@@ -824,6 +831,65 @@ SERVER* runtime_create_server_from_json(json_t* json)
     return rval;
 }
 
+bool handle_alter_server_relations(SERVER* server, json_t* new_json)
+{
+    bool rval = false;
+    set<string> old_relations;
+    set<string> new_relations;
+    Closer<json_t*> old_json(server_to_json(server, ""));
+    ss_dassert(old_json.get());
+
+    if (extract_relations(old_json.get(), old_relations, server_relation_types, server_relation_is_valid) &&
+        extract_relations(new_json, new_relations, server_relation_types, server_relation_is_valid))
+    {
+        set<string> removed_relations;
+        set<string> added_relations;
+
+        std::set_difference(old_relations.begin(), old_relations.end(),
+                            new_relations.begin(), new_relations.end(),
+                            std::inserter(removed_relations, removed_relations.begin()));
+
+        std::set_difference(new_relations.begin(), new_relations.end(),
+                            old_relations.begin(), old_relations.end(),
+                            std::inserter(added_relations, added_relations.begin()));
+
+        if (link_server_relations(server, added_relations) &&
+            unlink_server_relations(server, removed_relations))
+        {
+            rval = true;
+        }
+    }
+
+    return rval;
+}
+
+bool runtime_alter_server_from_json(SERVER* server, json_t* new_json)
+{
+    bool rval = false;
+
+    if (handle_alter_server_relations(server, new_json))
+    {
+        json_t* parameters = json_object_get(new_json, CN_PARAMETERS);
+
+        if (parameters)
+        {
+            rval = true;
+            const char *key;
+            json_t *value;
+
+            json_object_foreach(parameters, key, value)
+            {
+                if (!runtime_alter_server(server, key, mxs::json_to_string(value).c_str()))
+                {
+                    rval = false;
+                }
+            }
+        }
+    }
+
+    return rval;
+}
+
 static bool monitor_contains_required_fields(json_t* json)
 {
     json_t* value;

server/core/maxscale/config_runtime.h

@@ -89,7 +89,7 @@ bool runtime_unlink_server(SERVER *server, const char *target);
  * @param value New value
  * @return True if @c key was one of the supported parameters
  */
-bool runtime_alter_server(SERVER *server, char *key, char *value);
+bool runtime_alter_server(SERVER *server, const char *key, const char *value);
 
 /**
  * @brief Enable SSL for a server
@@ -188,6 +188,16 @@ bool runtime_destroy_monitor(MXS_MONITOR *monitor);
  */
 SERVER* runtime_create_server_from_json(json_t* json);
 
+/**
+ * @brief Alter a server using JSON
+ *
+ * @param server Server to alter
+ * @param new_json JSON definition of the new server
+ *
+ * @return True if the server was successfully modified to represent @c new_json
+ */
+bool runtime_alter_server_from_json(SERVER* server, json_t* new_json);
+
 /**
  * @brief Create a new monitor from JSON
  *

server/core/resource.cc

@@ -117,7 +117,24 @@ HttpResponse cb_create_server(HttpRequest& request)
         }
     }
 
-    return HttpResponse(MHD_HTTP_INTERNAL_SERVER_ERROR);
+    return HttpResponse(MHD_HTTP_BAD_REQUEST);
+}
+
+HttpResponse cb_alter_server(HttpRequest& request)
+{
+    json_t* json = request.get_json();
+
+    if (json)
+    {
+        SERVER* server = server_find_by_unique_name(request.uri_part(1).c_str());
+
+        if (server && runtime_alter_server_from_json(server, json))
+        {
+            return HttpResponse(MHD_HTTP_OK, server_to_json(server, request.host()));
+        }
+    }
+
+    return HttpResponse(MHD_HTTP_BAD_REQUEST);
 }
 
 HttpResponse cb_create_monitor(HttpRequest& request)
@@ -134,7 +151,7 @@ HttpResponse cb_create_monitor(HttpRequest& request)
         }
     }
 
-    return HttpResponse(MHD_HTTP_INTERNAL_SERVER_ERROR);
+    return HttpResponse(MHD_HTTP_BAD_REQUEST);
 }
 
 HttpResponse cb_all_servers(HttpRequest& request)
@@ -301,6 +318,8 @@ public:
         m_post.push_back(SResource(new Resource(cb_flush, 3, "maxscale", "logs", "flush")));
         m_post.push_back(SResource(new Resource(cb_create_server, 1, "servers")));
         m_post.push_back(SResource(new Resource(cb_create_monitor, 1, "monitors")));
+
+        m_put.push_back(SResource(new Resource(cb_alter_server, 2, "servers", ":server")));
     }
 
     ~RootResource()

server/core/server.cc

@@ -14,23 +14,6 @@
 /**
  * @file server.c  - A representation of a backend server within the gateway.
  *
- * @verbatim
- * Revision History
- *
- * Date         Who                     Description
- * 18/06/13     Mark Riddoch            Initial implementation
- * 17/05/14     Mark Riddoch            Addition of unique_name
- * 20/05/14     Massimiliano Pinto      Addition of server_string
- * 21/05/14     Massimiliano Pinto      Addition of node_id
- * 28/05/14     Massimiliano Pinto      Addition of rlagd and node_ts fields
- * 20/06/14     Massimiliano Pinto      Addition of master_id, depth, slaves fields
- * 26/06/14     Mark Riddoch            Addition of server parameters
- * 30/08/14     Massimiliano Pinto      Addition of new service status description
- * 30/10/14     Massimiliano Pinto      Addition of SERVER_MASTER_STICKINESS description
- * 01/06/15     Massimiliano Pinto      Addition of server_update_address/port
- * 19/06/15     Martin Brampton         Extra code for persistent connections
- *
- * @endverbatim
  */
 #include <stdio.h>
 #include <stdlib.h>
@@ -39,6 +22,7 @@
 #include <sys/stat.h>
 #include <fcntl.h>
 
+#include <maxscale/config.h>
 #include <maxscale/service.h>
 #include <maxscale/session.h>
 #include <maxscale/server.h>
@@ -1403,14 +1387,25 @@ json_t* server_list_to_json(const char* host)
 
 json_t* server_to_json(const SERVER* server, const char* host)
 {
-    // TODO: Add error checks
     json_t* rval = json_object();
 
     json_object_set_new(rval, CN_NAME, json_string(server->unique_name));
-    json_object_set_new(rval, CN_ADDRESS, json_string(server->name));
-    json_object_set_new(rval, CN_PORT, json_integer(server->port));
-    json_object_set_new(rval, CN_PROTOCOL, json_string(server->protocol));
 
+    /** Store server parameters  */
+    json_t* params = json_object();
+
+    json_object_set_new(params, CN_ADDRESS, json_string(server->name));
+    json_object_set_new(params, CN_PORT, json_integer(server->port));
+    json_object_set_new(params, CN_PROTOCOL, json_string(server->protocol));
+
+    for (SERVER_PARAM* p = server->parameters; p; p = p->next)
+    {
+        json_object_set_new(params, p->name, json_string(p->value));
+    }
+
+    json_object_set_new(rval, CN_PARAMETERS, params);
+
+    /** Store general information about the server state */
     char* stat = server_status(server);
     json_object_set_new(rval, "status", json_string(stat));
     MXS_FREE(stat);
@@ -1452,6 +1447,7 @@ json_t* server_to_json(const SERVER* server, const char* host)
         json_object_set_new(rval, "last_heartbeat", json_string(timebuf));
     }
 
+    /** Store statistics */
     json_t* stats = json_object();
 
     json_object_set_new(stats, "connections", json_integer(server->stats.n_current));
@@ -1460,13 +1456,14 @@ json_t* server_to_json(const SERVER* server, const char* host)
 
     json_object_set_new(rval, "statictics", stats);
 
+    /** Store server relations to other objects */
     json_t* rel = json_object();
 
     json_t* arr = service_relations_to_server(server, host);
 
     if (json_array_size(arr) > 0)
     {
-        json_object_set_new(rel, "services", arr);
+        json_object_set_new(rel, CN_SERVICES, arr);
     }
     else
     {
@@ -1477,14 +1474,14 @@ json_t* server_to_json(const SERVER* server, const char* host)
 
     if (json_array_size(arr) > 0)
     {
-        json_object_set_new(rel, "monitors", arr);
+        json_object_set_new(rel, CN_MONITORS, arr);
     }
     else
     {
         json_decref(arr);
     }
 
-    json_object_set_new(rval, "relationships", rel);
+    json_object_set_new(rval, CN_RELATIONSHIPS, rel);
 
     return rval;
 }