Support service listeners with multiple addresses

Enhancement issue #1813

Signed-off-by: Gabor Dozsa <gabor,[email protected]>

Author: Gabor Dozsa

python/skupper_router/management/skrouter.json

@@ -1109,6 +1109,12 @@
                     "type": "string",
                     "create": true
                 },
+                "multiAddressStrategy": {
+                    "description": "Connection target address selection strategy for multi-address listener. If not 'none', the 'address' field is ignored and multiple service addresses can be specified for the listener by creating 'listenerAddress' entities. The strategy value determines how new connections select a target address. The only supported value is 'priorityFailover' currently.  Priority failover strategy always selects the address with the highest priority value from the current set of reachable addresses.",
+                    "type": "string",
+                    "default": "none",
+                    "required": false
+                },
                 "siteId": {
                     "type": "string",
                     "required": false,
@@ -1235,6 +1241,29 @@
             }
         },
 
+        "listenerAddress" : {
+           "description": "Configure a service address for a multi-address 'tcpListener'. The corresponding 'tcpListener' must specify the strategy for selecting target addresses for new connections.",
+            "extends": "configurationEntity",
+            "operations": ["CREATE", "DELETE"],
+            "attributes": {
+                "address": {
+                    "description":"Service address.",
+                    "type": "string",
+                    "create": true
+                },
+                "value": {
+                    "description":"Address selection strategy-specific numeric value (priority, etc.).",
+                    "type": "integer",
+                    "create": true
+                },
+                "listenerRef": {
+                    "description":"Name of the 'tcpListener' this address belongs to.",
+                    "type": "string",
+                    "create": true
+                }
+            }
+       },
+
         "log": {
             "description": "Configure logging for a particular module. You can use the `UPDATE` operation to change log settings while the router is running.",
             "extends": "configurationEntity",

python/skupper_router_internal/dispatch.py

@@ -112,6 +112,8 @@ def __init__(self) -> None:
         self._prototype(self.qd_dispatch_configure_tcp_listener, c_void_p, [self.qd_dispatch_p, py_object])
         self._prototype(self.qd_dispatch_delete_tcp_listener, None, [self.qd_dispatch_p, c_void_p])
         self._prototype(self.qd_dispatch_update_tcp_listener, c_void_p, [self.qd_dispatch_p, py_object, c_void_p])
+        self._prototype(self.qd_dispatch_configure_tcp_listener_address, c_void_p, [self.qd_dispatch_p, py_object, c_void_p])
+        self._prototype(self.qd_dispatch_delete_tcp_listener_address, None, [self.qd_dispatch_p, c_void_p])
         self._prototype(self.qd_dispatch_configure_listener, c_void_p, [self.qd_dispatch_p, py_object])
         self._prototype(self.qd_connection_manager_delete_listener, None, [self.qd_dispatch_p, c_void_p])
 

python/skupper_router_internal/management/agent.py

@@ -470,6 +470,21 @@ def _delete(self):
         self._qd.qd_connection_manager_delete_listener(self._dispatch, self._implementations[0].key)
 
 
+class ListenerAddressEntity(EntityAdapter):
+    def create(self):
+        config_listener_address = self._qd.qd_dispatch_configure_listener_address(self._dispatch, self)
+        return config_listener_address
+
+    def _identifier(self):
+        return _host_port_name_identifier(self)
+
+    def __str__(self):
+        return super(ListenerAddressEntity, self).__str__().replace("Entity(", "ListenerAddressEntity(")
+
+    def _delete(self):
+        self._qd.qd_dispatch_delete_listener_address(self._dispatch, self._implementations[0].key)
+
+
 class ConnectorEntity(ConnectionBaseEntity):
     def __init__(self, agent, entity_type, attributes=None, validate=True):
         super(ConnectorEntity, self).__init__(agent, entity_type, attributes,

src/adaptors/adaptor_common.c

@@ -90,6 +90,12 @@ qd_error_t qd_load_adaptor_config(qdr_core_t *core, qd_adaptor_config_t *config,
     if (config->backlog <= 0 || config->backlog > SOMAXCONN)
         config->backlog = SOMAXCONN;
 
+    config->multi_address_strategy =  qd_entity_opt_string(entity, "multiAddressStrategy", "none"); CHECK();
+    if (!strcmp(config->multi_address_strategy, "none") && !strcmp(config->multi_address_strategy, "priorityFailover")) {
+        qd_error(QD_ERROR_VALUE, "Listener multi-address strategy value is invalid");
+        goto error;
+    }
+
     int hplen = strlen(config->host) + strlen(config->port) + 2;
     config->host_port = malloc(hplen);
     snprintf(config->host_port, hplen, "%s:%s", config->host, config->port);
@@ -115,6 +121,19 @@ qd_error_t qd_load_adaptor_config(qdr_core_t *core, qd_adaptor_config_t *config,
     return qd_error_code();
 }
 
+qd_error_t qd_load_listener_address_config(qdr_core_t *core, qd_listener_address_config_t *config, qd_entity_t *entity)
+{
+    qd_error_clear();
+    config->address = qd_entity_get_string(entity, "address");           CHECK();
+    config->value         = qd_entity_get_long(entity, "value");         CHECK();
+    config->listener_name = qd_entity_get_string(entity, "listenerRef"); CHECK();
+
+    return QD_ERROR_NONE;
+
+error:
+    return qd_error_code();
+}
+
 size_t qd_raw_conn_get_address_buf(pn_raw_connection_t *pn_raw_conn, char *buf, size_t buflen)
 {
     assert(pn_raw_conn);

src/adaptors/adaptor_common.h

@@ -41,13 +41,16 @@ typedef enum {
     QD_AGGREGATION_MULTIPART
 } qd_http_aggregation_t;
 
+
+
 typedef struct qd_adaptor_config_t qd_adaptor_config_t;
 
 struct qd_adaptor_config_t
 {
     char                       *name;
     char                       *host;
     char                       *port;
+    char                       *multi_address_strategy;
     char                       *address;
     char                       *site_id;
     char                       *host_port;
@@ -62,9 +65,21 @@ struct qd_adaptor_config_t
 
 ALLOC_DECLARE(qd_adaptor_config_t);
 
+typedef struct qd_listener_address_config_t qd_listener_address_config_t;
+
+// Address config for multi-address listeners
+struct qd_listener_address_config_t {
+    char *address;
+    int   value;
+    char *listener_name;
+};
+
 qd_error_t qd_load_adaptor_config(qdr_core_t *core, qd_adaptor_config_t *config, qd_entity_t *entity);
 void qd_free_adaptor_config(qd_adaptor_config_t *config);
 
+qd_error_t qd_load_listener_address_config(qdr_core_t *core, qd_listener_address_config_t *config, qd_entity_t *entity);
+
+
 /**
  * Get the raw connections remote address.
  * Caller must free() the result when done.