MXS-1198: Add configurable listener retry interval

The maximum listener retry interval is now configurable.

Documentation/Getting-Started/Configuration-Guide.md

@@ -886,6 +886,18 @@ Example:
 max_connections=100
 ```
 
+#### `max_retry_interval`
+
+Configure the maximum interval between consecutive attempts to bind to an
+interface. The default value for this parameter is 3600 seconds. This
+parameter was introduced in MaxScale 2.2.0.
+
+When a listener fails to bind to the interface it is assigned to, it will
+attempt to bind to the interface again after 10 seconds. If the attempt fails,
+the interval is incremented by 10 seconds and the next attempt will be in 20
+seconds. The interval is incremented until the value of `max_retry_interval` is
+reached at which point the listener attempts to bind to the interface every
+`max_retry_interval` seconds.
 
 ### Server
 

include/maxscale/service.h

@@ -151,6 +151,7 @@ typedef struct service
     bool retry_start;                  /**< If starting of the service should be retried later */
     bool log_auth_warnings;            /**< Log authentication failures and warnings */
     uint64_t capabilities;             /**< The capabilities of the service. */
+    int max_retry_interval;            /**< Maximum retry interval */
 } SERVICE;
 
 typedef enum count_spec_t

server/core/config.c

@@ -124,6 +124,7 @@ static const char *service_params[] =
     "passwd", // DEPRECATE: See config_get_password.
     "password",
     "enable_root_user",
+    "max_retry_interval",
     "max_connections",
     "max_queued_connections",
     "queued_connection_timeout",
@@ -2561,6 +2562,24 @@ int create_new_service(CONFIG_CONTEXT *obj)
         serviceEnableRootUser(obj->element, config_truth_value(enable_root_user));
     }
 
+    char *max_retry_interval = config_get_value(obj->parameters, "max_retry_interval");
+
+    if (max_retry_interval)
+    {
+        char *endptr;
+        long val = strtol(max_retry_interval, &endptr, 10);
+
+        if (val && *endptr == '\0')
+        {
+            service_set_retry_interval(obj->element, val);
+        }
+        else
+        {
+            MXS_ERROR("Invalid value for 'max_retry_interval': %s", max_retry_interval);
+            error_count++;
+        }
+    }
+
     char *connection_timeout = config_get_value(obj->parameters, "connection_timeout");
     if (connection_timeout)
     {

server/core/maxscale/service.h

@@ -129,6 +129,14 @@ void  service_update(SERVICE *service, char *router, char *user, char *auth);
  */
 void service_add_parameters(SERVICE *service, const MXS_CONFIG_PARAMETER *param);
 
+/**
+ * @brief Set listener rebinding interval
+ *
+ * @param service Service to configure
+ * @param value String value o
+ */
+void service_set_retry_interval(SERVICE *service, int value);
+
 /**
  * Internal debugging diagnostics
  */

server/core/service.c

@@ -146,6 +146,7 @@ SERVICE* service_alloc(const char *name, const char *router)
     ss_dassert(module);
 
     service->capabilities = module->module_capabilities;
+    service->max_retry_interval = SERVICE_MAX_RETRY_INTERVAL;
     service->client_count = 0;
     service->n_dbref = 0;
     service->name = my_name;
@@ -405,7 +406,7 @@ int serviceStartAllPorts(SERVICE* service)
             service->stats.n_failed_starts++;
             char taskname[strlen(service->name) + strlen("_start_retry_") +
                           (int) ceil(log10(INT_MAX)) + 1];
-            int retry_after = MXS_MIN(service->stats.n_failed_starts * 10, SERVICE_MAX_RETRY_INTERVAL);
+            int retry_after = MXS_MIN(service->stats.n_failed_starts * 10, service->max_retry_interval);
             snprintf(taskname, sizeof(taskname), "%s_start_retry_%d",
                      service->name, service->stats.n_failed_starts);
             hktask_oneshot(taskname, service_internal_restart,
@@ -994,6 +995,7 @@ serviceClearRouterOptions(SERVICE *service)
     }
     spinlock_release(&service->spin);
 }
+
 /**
  * Set the service user that is used to log in to the backebd servers
  * associated with this service.
@@ -1205,6 +1207,12 @@ void serviceSetRetryOnFailure(SERVICE *service, char* value)
     }
 }
 
+void service_set_retry_interval(SERVICE *service, int value)
+{
+    ss_dassert(value > 0);
+    service->max_retry_interval = value;
+}
+
 /**
  * Set the filters used by the service
  *