lightningd/plugin_control: add a 'plugin' command

This adds a new pair of files : lightningd/plugin_control, along with a new RPC
command : 'plugin'. This command can be used to manage plugins without restarting lightningd:

lightning-cli plugin start helloworld.py
lightning-cli plugin stop helloworld.py

lightningd/Makefile

@@ -89,6 +89,7 @@ LIGHTNINGD_SRC :=				\
 	lightningd/peer_htlcs.c			\
 	lightningd/ping.c			\
 	lightningd/plugin.c			\
+	lightningd/plugin_control.c		\
 	lightningd/plugin_hook.c		\
 	lightningd/subd.c			\
 	lightningd/watch.c

lightningd/plugin.c

@@ -121,7 +121,7 @@ void PRINTF_FMT(2,3) plugin_kill(struct plugin *plugin, char *fmt, ...)
 	msg = tal_vfmt(plugin, fmt, ap);
 	va_end(ap);
 
-	log_broken(plugin->log, "Killing plugin: %s", msg);
+	log_info(plugin->log, "Killing plugin: %s", msg);
 	plugin->stop = true;
 	io_wake(plugin);
 	kill(plugin->pid, SIGKILL);
@@ -813,6 +813,12 @@ static void plugin_manifest_cb(const char *buffer,
 		plugin_kill(
 		    plugin,
 		    "Failed to register options, methods, hooks, or subscriptions.");
+
+	/* If all plugins have replied to getmanifest and this is not
+	 * the startup init, configure them */
+	if (!plugin->plugins->startup && plugin->plugins->pending_manifests == 0)
+		plugins_config(plugin->plugins);
+
 	/* Reset timer, it'd kill us otherwise. */
 	tal_free(plugin->timeout_timer);
 }

lightningd/plugin_control.c

@@ -0,0 +1,132 @@
+#include <ccan/tal/path/path.h>
+#include <common/json_command.h>
+#include <common/jsonrpc_errors.h>
+#include <common/param.h>
+#include <dirent.h>
+#include <errno.h>
+#include <lightningd/plugin_control.h>
+#include <lightningd/plugin_hook.h>
+#include <unistd.h>
+
+/**
+ * A plugin command which permits to control plugins without restarting
+ * lightningd. It takes a subcommand, and an optional subcommand parameter.
+ */
+static struct command_result *json_plugin_control(struct command *cmd,
+						const char *buffer,
+						const jsmntok_t *obj UNNEEDED,
+						const jsmntok_t *params)
+{
+	const char *subcmd;
+	subcmd = param_subcommand(cmd, buffer, params,
+				  "start", "stop", "startdir", "rescan", "list", NULL);
+	if (!subcmd)
+		return command_param_failed();
+
+	struct plugin *p;
+	struct json_stream *response;
+
+	if (streq(subcmd, "stop")) {
+		const char *plugin_name;
+		bool plugin_found;
+
+		if (!param(cmd, buffer, params,
+			   p_req("subcommand", param_ignore, cmd),
+			   p_req("plugin", param_string, &plugin_name),
+			   NULL))
+			return command_param_failed();
+
+		plugin_found = false;
+		list_for_each(&cmd->ld->plugins->plugins, p, list) {
+			if (plugin_paths_match(p->cmd, plugin_name)) {
+				plugin_found = true;
+				plugin_hook_unregister_all(p);
+				plugin_kill(p, "%s stopped by lightningd via RPC",
+						plugin_name);
+				break;
+			}
+		}
+		if (!plugin_found)
+			return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
+					   "Could not find plugin %s", plugin_name);
+	} else if (streq(subcmd, "start")) {
+		const char *plugin_path;
+
+		if (!param(cmd, buffer, params,
+			   p_req("subcommand", param_ignore, cmd),
+			   p_req("plugin", param_string, &plugin_path),
+			   NULL))
+			return command_param_failed();
+
+		if (access(plugin_path, X_OK) == 0)
+			plugin_register(cmd->ld->plugins, plugin_path);
+		else
+			return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
+						   "%s is not executable: %s",
+						   plugin_path, strerror(errno));
+	} else if (streq(subcmd, "startdir")) {
+		const char *dir_path;
+
+		if (!param(cmd, buffer, params,
+			   p_req("subcommand", param_ignore, cmd),
+			   p_req("directory", param_string, &dir_path),
+			   NULL))
+			return command_param_failed();
+
+		if (access(dir_path, F_OK) == 0)
+			add_plugin_dir(cmd->ld->plugins, dir_path, true);
+		else
+			return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
+						   "Could not open %s", dir_path);
+	} else if (streq(subcmd, "rescan")) {
+		if (!param(cmd, buffer, params,
+			   p_req("subcommand", param_ignore, cmd),
+			   NULL))
+			return command_param_failed();
+
+		plugins_add_default_dir(cmd->ld->plugins,
+				path_join(tmpctx, cmd->ld->config_dir, "plugins"));
+	} else if (streq(subcmd, "list")) {
+		if (!param(cmd, buffer, params,
+			   p_req("subcommand", param_ignore, cmd),
+			   NULL))
+			return command_param_failed();
+		/* Don't do anything as we return the plugin list anyway */
+	}
+
+	/* The config function is called once we got the manifest,
+	 * in 'plugin_manifest_cb'.*/
+	plugins_start(cmd->ld->plugins, cmd->ld->dev_debug_subprocess);
+
+	response = json_stream_success(cmd);
+	json_array_start(response, "plugins");
+	list_for_each(&cmd->ld->plugins->plugins, p, list) {
+		json_object_start(response, NULL);
+		json_add_string(response, "name", p->cmd);
+		json_add_bool(response, "active", p->configured);
+		json_object_end(response);
+	}
+	json_array_end(response);
+
+	return command_success(cmd, response);
+}
+
+static const struct json_command plugin_control_command = {
+	"plugin",
+	"plugin",
+	json_plugin_control,
+	"Control plugins (start, stop, startdir, rescan, list)",
+	.verbose = "Usage :\n"
+	"plugin start /path/to/a/plugin\n"
+	"	adds a new plugin to c-lightning\n"
+	"plugin stop plugin_name\n"
+	"	stops an already registered plugin\n"
+	"plugin startdir /path/to/a/plugin_dir/\n"
+	"	adds a new plugin directory\n"
+	"plugin rescan\n"
+	"	loads not-already-loaded plugins from the default plugins dir\n"
+	"plugin list\n"
+	"	lists all active plugins\n"
+	"\n"
+};
+AUTODATA(json_command, &plugin_control_command);

lightningd/plugin_control.h

@@ -0,0 +1,7 @@
+#ifndef LIGHTNING_LIGHTNINGD_PLUGIN_CONTROL_H
+#define LIGHTNING_LIGHTNINGD_PLUGIN_CONTROL_H
+#include "config.h"
+#include <lightningd/lightningd.h>
+
+
+#endif /* LIGHTNING_LIGHTNINGD_PLUGIN_CONTROL_H */