listconfigs: add `plugin` field if config is for a plugin.

I chose the full path name, not just the basename.

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

doc/lightning-listconfigs.7.md

@@ -45,6 +45,7 @@ On success, an object is returned, containing:
   - **disable-mpp** (object, optional):
     - **set** (boolean): `true` if set in config or cmdline
     - **source** (string): source of configuration setting
+    - **plugin** (string, optional): plugin which registered this configuration setting
   - **mainnet** (object, optional):
     - **set** (boolean): `true` if set in config or cmdline
     - **source** (string): source of configuration setting
@@ -446,4 +447,4 @@ RESOURCES
 
 Main web site: <https://github.com/ElementsProject/lightning>
 
-[comment]: # ( SHA256STAMP:1702f7c62fe10d63612fbbf56eeaf043cdfef6fa874d4fdbdcb81bbbbe5c98d8)
+[comment]: # ( SHA256STAMP:2b3588b395919162c122cd386f0f4b320d906d0190e706bfa1b68db4126e7ee2)

doc/schemas/listconfigs.schema.json

@@ -65,6 +65,10 @@
             "source": {
               "type": "string",
               "description": "source of configuration setting"
+            },
+            "plugin": {
+              "type": "string",
+              "description": "plugin which registered this configuration setting"
             }
           }
         },

lightningd/options.c

@@ -2066,6 +2066,7 @@ static void json_add_config(struct lightningd *ld,
 		json_object_start(response, names[0]);
 		json_add_bool(response, "set", cv != NULL);
 		json_add_source(response, "source", cv);
+		json_add_config_plugin(response, ld->plugins, "plugin", ot);
 		json_object_end(response);
 		return;
 	}
@@ -2089,6 +2090,7 @@ static void json_add_config(struct lightningd *ld,
 			json_add_source(response, NULL, cv);
 		}
 		json_array_end(response);
+		json_add_config_plugin(response, ld->plugins, "plugin", ot);
 		json_object_end(response);
 		return;
 	}
@@ -2101,6 +2103,7 @@ static void json_add_config(struct lightningd *ld,
 	json_object_start(response, names[0]);
 	json_add_configval(response, configval_fieldname(ot), ot, val);
 	json_add_source(response, "source", cv);
+	json_add_config_plugin(response, ld->plugins, "plugin", ot);
 	json_object_end(response);
 }
 

lightningd/plugin.c

@@ -1366,6 +1366,29 @@ static struct plugin_opt *plugin_opt_find(const struct plugin *plugin,
 	return NULL;
 }
 
+void json_add_config_plugin(struct json_stream *stream,
+			    const struct plugins *plugins,
+			    const char *fieldname,
+			    const struct opt_table *ot)
+{
+	struct plugin *plugin;
+
+	/* Shortcut */
+	if (!is_plugin_opt(ot))
+		return;
+
+	/* Find the plugin that registered this RPC call */
+	list_for_each(&plugins->plugins, plugin, list) {
+		struct plugin_opt *popt = plugin_opt_find(plugin, ot->names+2);
+		if (popt) {
+			json_add_string(stream, fieldname, plugin->cmd);
+			return;
+		}
+	}
+
+	/* Reaching here is possible, if a plugin was stopped! */
+}
+
 /* Start command might have included plugin-specific parameters.
  * We make sure they *are* parameters for this plugin, then add them
  * to our configvars. */

lightningd/plugin.h

@@ -358,4 +358,11 @@ void plugins_set_builtin_plugins_dir(struct plugins *plugins,
 
 /* Is this option for a plugin? */
 bool is_plugin_opt(const struct opt_table *ot);
+
+/* Add this field if this ot is owned by a plugin */
+void json_add_config_plugin(struct json_stream *stream,
+			    const struct plugins *plugins,
+			    const char *fieldname,
+			    const struct opt_table *ot);
+
 #endif /* LIGHTNING_LIGHTNINGD_PLUGIN_H */

tests/test_misc.py

@@ -738,6 +738,7 @@ def test_listconfigs(node_factory, bitcoind, chainparams):
             c = configs[name]
             assert c['source'] == 'cmdline'
             assert c[valfield] == val
+            assert 'plugin' not in c
 
         # These are aliases, but we don't print the (unofficial!) wumbo.
         assert 'wumbo' not in configs

tests/test_plugin.py

@@ -2441,6 +2441,7 @@ def test_dynamic_args(node_factory):
 
     assert l1.rpc.call("hello") == "Test arg parsing world"
     assert l1.rpc.listconfigs('greeting')['configs']['greeting']['value_str'] == 'Test arg parsing'
+    assert l1.rpc.listconfigs('greeting')['configs']['greeting']['plugin'] == plugin_path
 
     l1.rpc.plugin_stop(plugin_path)
     assert 'greeting' not in l1.rpc.listconfigs()['configs']
@@ -4166,6 +4167,7 @@ def test_plugin_persist_option(node_factory):
     c = l1.rpc.listconfigs('greeting')['configs']['greeting']
     assert c['source'] == "cmdline"
     assert c['value_str'] == "Static option"
+    assert c['plugin'] == plugin_path
     l1.rpc.plugin_stop(plugin_path)
     assert 'greeting' not in l1.rpc.listconfigs()['configs']
 
@@ -4174,6 +4176,7 @@ def test_plugin_persist_option(node_factory):
     c = l1.rpc.listconfigs('greeting')['configs']['greeting']
     assert c['source'] == "cmdline"
     assert c['value_str'] == "Static option"
+    assert c['plugin'] == plugin_path
     assert l1.rpc.call("hello") == "Static option world"
     l1.rpc.plugin_stop(plugin_path)
     assert 'greeting' not in l1.rpc.listconfigs()['configs']
@@ -4183,6 +4186,7 @@ def test_plugin_persist_option(node_factory):
     c = l1.rpc.listconfigs('greeting')['configs']['greeting']
     assert c['source'] == "pluginstart"
     assert c['value_str'] == "Dynamic option"
+    assert c['plugin'] == plugin_path
     assert l1.rpc.call("hello") == "Dynamic option world"
     l1.rpc.plugin_stop(plugin_path)
     assert 'greeting' not in l1.rpc.listconfigs()['configs']
@@ -4192,4 +4196,5 @@ def test_plugin_persist_option(node_factory):
     c = l1.rpc.listconfigs('greeting')['configs']['greeting']
     assert c['source'] == "cmdline"
     assert c['value_str'] == "Static option"
+    assert c['plugin'] == plugin_path
     assert l1.rpc.call("hello") == "Static option world"