askrene: persistent layer support.

Signed-off-by: Rusty Russell <[email protected]>

Author: rustyrussell

contrib/msggen/msggen/schema.json

@@ -457,6 +457,13 @@
             "description": [
               "The name of the layer to create."
             ]
+          },
+          "persistent": {
+            "type": "boolean",
+            "default": "False",
+            "description": [
+              "True if askrene should save and restore this layer.  As a side-effect, create-layer also succeeds if the layer already exists and persistent is true."
+            ]
           }
         }
       },
@@ -473,6 +480,7 @@
               "additionalProperties": false,
               "required": [
                 "layer",
+                "persistent",
                 "disabled_nodes",
                 "created_channels",
                 "channel_updates",
@@ -485,6 +493,12 @@
                     "The name of the layer."
                   ]
                 },
+                "persistent": {
+                  "type": "boolean",
+                  "description": [
+                    "Whether the layer is saved/restored across restarts."
+                  ]
+                },
                 "disabled_nodes": {
                   "type": "array",
                   "items": {
@@ -873,6 +887,7 @@
               "additionalProperties": false,
               "required": [
                 "layer",
+                "persistent",
                 "disabled_nodes",
                 "created_channels",
                 "channel_updates",
@@ -885,6 +900,12 @@
                     "The name of the layer."
                   ]
                 },
+                "persistent": {
+                  "type": "boolean",
+                  "description": [
+                    "Whether the layer is saved across restarts."
+                  ]
+                },
                 "disabled_nodes": {
                   "type": "array",
                   "items": {

doc/schemas/lightning-askrene-create-layer.json

@@ -19,6 +19,13 @@
         "description": [
           "The name of the layer to create."
         ]
+      },
+      "persistent": {
+        "type": "boolean",
+        "default": "False",
+        "description": [
+          "True if askrene should save and restore this layer.  As a side-effect, create-layer also succeeds if the layer already exists and persistent is true."
+        ]
       }
     }
   },
@@ -35,6 +42,7 @@
           "additionalProperties": false,
           "required": [
             "layer",
+            "persistent",
             "disabled_nodes",
             "created_channels",
             "channel_updates",
@@ -47,6 +55,12 @@
                 "The name of the layer."
               ]
             },
+            "persistent": {
+              "type": "boolean",
+              "description": [
+                "Whether the layer is saved/restored across restarts."
+              ]
+            },
             "disabled_nodes": {
               "type": "array",
               "items": {

doc/schemas/lightning-askrene-listlayers.json

@@ -33,6 +33,7 @@
           "additionalProperties": false,
           "required": [
             "layer",
+            "persistent",
             "disabled_nodes",
             "created_channels",
             "channel_updates",
@@ -45,6 +46,12 @@
                 "The name of the layer."
               ]
             },
+            "persistent": {
+              "type": "boolean",
+              "description": [
+                "Whether the layer is saved across restarts."
+              ]
+            },
             "disabled_nodes": {
               "type": "array",
               "items": {

plugins/askrene/askrene.c

@@ -175,16 +175,17 @@ static fp16_t *get_capacities(const tal_t *ctx,
  * but we won't. */
 /* FIXME: We could cache this until gossmap/layer changes... */
 static struct layer *source_free_layer(const tal_t *ctx,
-				       struct gossmap *gossmap,
+				       struct askrene *askrene,
 				       const struct node_id *source,
 				       struct gossmap_localmods *localmods)
 {
 	/* We apply existing localmods so we see *all* channels */
+	struct gossmap *gossmap = askrene->gossmap;
 	const struct gossmap_node *srcnode;
 	const struct amount_msat zero_base_fee = AMOUNT_MSAT(0);
 	const u16 zero_delay = 0;
 	const u32 zero_prop_fee = 0;
-	struct layer *layer = new_temp_layer(ctx, "auto.sourcefree");
+	struct layer *layer = new_temp_layer(ctx, askrene, "auto.sourcefree");
 
 	/* We apply this so we see any created channels */
 	gossmap_apply_localmods(gossmap, localmods);
@@ -363,7 +364,7 @@ static const char *get_routes(const tal_t *ctx,
 				/* Handled below, after other layers */
 				assert(streq(layers[i], "auto.sourcefree"));
 				plugin_log(rq->plugin, LOG_DBG, "Adding auto.sourcefree");
-				l = source_free_layer(layers, askrene->gossmap, source, localmods);
+				l = source_free_layer(layers, askrene, source, localmods);
 			}
 		}
 
@@ -732,11 +733,12 @@ listpeerchannels_done(struct command *cmd,
 		      const jsmntok_t *toks,
 		      struct getroutes_info *info)
 {
+	struct askrene *askrene = get_askrene(cmd->plugin);
 	struct gossmap_localmods *localmods;
 
-	info->local_layer = new_temp_layer(info, "auto.localchans");
+	info->local_layer = new_temp_layer(info, askrene, "auto.localchans");
 	localmods = gossmods_from_listpeerchannels(cmd,
-						   &get_askrene(cmd->plugin)->my_id,
+						   &askrene->my_id,
 						   buffer, toks,
 						   false,
 						   add_localchan,
@@ -1066,24 +1068,33 @@ static struct command_result *json_askrene_create_layer(struct command *cmd,
 	struct layer *layer;
 	const char *layername;
 	struct json_stream *response;
+	bool *persistent;
 
 	if (!param_check(cmd, buffer, params,
 			 p_req("layer", param_string, &layername),
+			 p_opt_def("persistent", param_bool, &persistent, false),
 			 NULL))
 		return command_param_failed();
 
-	if (find_layer(askrene, layername))
-		return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
-				    "Layer already exists");
-
 	if (strstarts(layername, "auto."))
 		return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
 				    "Cannot create auto layer");
 
+	/* If it's persistent, creation is a noop if it already exists */
+	layer = find_layer(askrene, layername);
+	if (layer && !*persistent) {
+		return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
+				    "Layer already exists");
+	}
+
 	if (command_check_only(cmd))
 		return command_check_done(cmd);
 
-	layer = new_layer(askrene, layername);
+	if (!layer) {
+		layer = new_layer(askrene, layername, *persistent);
+		if (*persistent)
+			save_new_layer(layer);
+	}
 
 	response = jsonrpc_stream_success(cmd);
 	json_add_layers(response, askrene, "layers", layer);
@@ -1102,7 +1113,7 @@ static struct command_result *json_askrene_remove_layer(struct command *cmd,
 		   NULL))
 		return command_param_failed();
 
-	tal_free(layer);
+	remove_layer(layer);
 
 	response = jsonrpc_stream_success(cmd);
 	return command_finished(cmd, response);
@@ -1230,6 +1241,10 @@ static const char *init(struct command *init_cmd,
 
 	plugin_set_data(plugin, askrene);
 	plugin_set_memleak_handler(plugin, askrene_markmem);
+
+	/* Layer needs its own command to access datastore */
+	askrene->layer_cmd = aux_command(init_cmd);
+	load_layers(askrene);
 	return NULL;
 }
 

plugins/askrene/askrene.h

@@ -31,6 +31,8 @@ struct askrene {
 	fp16_t *capacities;
 	/* My own id */
 	struct node_id my_id;
+	/* Aux command for layer */
+	struct command *layer_cmd;
 };
 
 /* Information for a single route query. */