degesch: add exponential reconnect backoff

1 files changed, 29 insertions, 1 deletions

diff --git a/degesch.c b/degesch.c
index a570733..8abb53a 100644
--- a/degesch.c
+++ b/degesch.c
@@ -1116,6 +1116,7 @@ struct server
 
 	enum server_state state;            ///< Connection state
 	struct connector *connector;        ///< Connection establisher
+	unsigned reconnect_attempt;         ///< Number of reconnect attempt
 	bool manual_disconnect;             ///< Don't reconnect after disconnect
 
 	int socket;                         ///< Socket FD of the server
@@ -1613,6 +1614,17 @@ static struct config_schema g_config_behaviour[] =
 	  .type      = CONFIG_ITEM_BOOLEAN,
 	  .default_  = "off",
 	  .on_change = on_config_debug_mode_change },
+
+	{ .name      = "reconnect_delay_growing",
+	  .comment   = "Growing factor for reconnect delay",
+	  .type      = CONFIG_ITEM_INTEGER,
+	  .validate  = config_validate_nonnegative,
+	  .default_  = "2" },
+	{ .name      = "reconnect_delay_max",
+	  .comment   = "Maximum reconnect delay in seconds",
+	  .type      = CONFIG_ITEM_INTEGER,
+	  .validate  = config_validate_nonnegative,
+	  .default_  = "600" },
 	{}
 };
 
@@ -3467,7 +3479,18 @@ irc_queue_reconnect (struct server *s)
 		return;
 	int64_t delay = get_config_integer (s->config, "reconnect_delay");
 
-	// TODO: exponentional backoff
+	int64_t delay_factor = get_config_integer (s->ctx->config.root,
+		"behaviour.reconnect_delay_growing");
+	int64_t delay_max = get_config_integer (s->ctx->config.root,
+		"behaviour.reconnect_delay_max");
+
+	for (unsigned i = 0; i < s->reconnect_attempt; i++)
+		delay *= delay_factor;
+	if (delay > delay_max || delay < 0)
+		delay = delay_max;
+
+	s->reconnect_attempt++;
+
 	// XXX: maybe add a state for when a connect is queued?
 	hard_assert (s->state == IRC_DISCONNECTED);
 	log_server_status (s, s->buffer,
@@ -3671,7 +3694,10 @@ irc_disconnect (struct server *s)
 	else if (s->manual_disconnect)
 		s->manual_disconnect = false;
 	else
+	{
+		s->reconnect_attempt = 0;
 		irc_queue_reconnect (s);
+	}
 
 	refresh_prompt (s->ctx);
 }
@@ -4420,6 +4446,8 @@ irc_initiate_connect (struct server *s)
 		return;
 	}
 
+	s->reconnect_attempt = 0;
+
 	struct str_vector servers;
 	str_vector_init (&servers);
 	cstr_split_ignore_empty (addresses, ',', &servers);