autoclean: allow dynamic changes to autoclean-cycle.

Slightly less trivial: reset timer unless it's currently running callback.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

doc/lightningd-config.5.md

@@ -442,7 +442,7 @@ accepted, and ignored.
 
 ### Cleanup control options:
 
-* **autoclean-cycle**=*SECONDS* [plugin `autoclean`]
+* **autoclean-cycle**=*SECONDS* [plugin `autoclean`, *dynamic*]
 
   Perform search for things to clean every *SECONDS* seconds (default
 3600, or 1 hour, which is usually sufficient).

plugins/autoclean.c

@@ -61,6 +61,7 @@ static u64 cycle_seconds = 3600;
 static struct clean_info timer_cinfo;
 static u64 total_cleaned[NUM_SUBSYSTEM];
 static struct plugin *plugin;
+/* This is NULL if it's running now. */
 static struct plugin_timer *cleantimer;
 
 static void do_clean_timer(void *unused);
@@ -439,6 +440,7 @@ static struct command_result *do_clean(struct clean_info *cinfo)
 static void do_clean_timer(void *unused)
 {
 	assert(timer_cinfo.cleanup_reqs_remaining == 0);
+	cleantimer = NULL;
 	do_clean(&timer_cinfo);
 }
 
@@ -587,6 +589,22 @@ static const char *init(struct plugin *p,
 	return NULL;
 }
 
+static char *cycle_seconds_option(struct plugin *plugin, const char *arg,
+				  void *unused)
+{
+	char *problem = u64_option(plugin, arg, &cycle_seconds);
+	if (problem)
+		return problem;
+
+	/* If timer is not running right now, reset it to new cycle_seconds */
+	if (cleantimer) {
+		tal_free(cleantimer);
+		cleantimer = plugin_timer(plugin, time_from_sec(cycle_seconds),
+					  do_clean_timer, NULL);
+	}
+	return NULL;
+}
+
 static const struct plugin_command commands[] = { {
 	"autocleaninvoice",
 	"payment",
@@ -626,11 +644,11 @@ int main(int argc, char *argv[])
 				  " invoices that have expired for at least"
 				  " this given seconds are cleaned",
 				  u64_option, &timer_cinfo.subsystem_age[EXPIREDINVOICES]),
-		    plugin_option("autoclean-cycle",
-				  "int",
-				  "Perform cleanup every"
-				  " given seconds",
-				  u64_option, &cycle_seconds),
+		    plugin_option_dynamic("autoclean-cycle",
+					  "int",
+					  "Perform cleanup every"
+					  " given seconds",
+					  cycle_seconds_option, NULL),
 		    plugin_option_dynamic("autoclean-succeededforwards-age",
 					  "int",
 					  "How old do successful forwards have to be before deletion (0 = never)",

tests/test_plugin.py

@@ -3181,8 +3181,7 @@ def test_commando_badrune(node_factory):
 
 
 def test_autoclean(node_factory):
-    l1, l2, l3 = node_factory.line_graph(3, opts={'autoclean-cycle': 10,
-                                                  'may_reconnect': True},
+    l1, l2, l3 = node_factory.line_graph(3, opts={'may_reconnect': True},
                                          wait_for_announce=True)
 
     # Under valgrind in CI, it can 50 seconds between creating invoice
@@ -3215,6 +3214,8 @@ def test_autoclean(node_factory):
     assert len(l3.rpc.listinvoices('inv2')['invoices']) == 1
     assert l3.rpc.listinvoices('inv1')['invoices'][0]['description'] == 'description1'
 
+    l3.rpc.setconfig('autoclean-cycle', 10)
+
     # First it expires.
     wait_for(lambda: only_one(l3.rpc.listinvoices('inv1')['invoices'])['status'] == 'expired')
     # Now will get autocleaned
@@ -3275,6 +3276,7 @@ def test_autoclean(node_factory):
     assert only_one(l1.rpc.listpays(inv5['bolt11'])['pays'])['status'] == 'failed'
     assert only_one(l1.rpc.listpays(inv4['bolt11'])['pays'])['status'] == 'complete'
     l1.rpc.setconfig('autoclean-failedpays-age', 1)
+    l1.rpc.setconfig('autoclean-cycle', 5)
 
     wait_for(lambda: l1.rpc.listpays(inv5['bolt11'])['pays'] == [])
     assert l1.rpc.autoclean_status()['autoclean']['failedpays']['cleaned'] == 1
@@ -3290,6 +3292,7 @@ def test_autoclean(node_factory):
     assert len(l2.rpc.listforwards()['forwards']) == 2
 
     # Clean failed ones.
+    l2.rpc.setconfig('autoclean-cycle', 5)
     l2.rpc.setconfig('autoclean-failedforwards-age', 2)
     wait_for(lambda: l2.rpc.listforwards(status='failed')['forwards'] == [])