plugin: Add plugins to lightningd and register arguments

doc/lightningd-config.5

@@ -176,6 +176,11 @@ Sets configuration file (default:
 \fIPATH\fR
 must exist and be readable (we allow missing files in the default case)\&. Using this inside a configuration file is meaningless\&.
 .RE
+.PP
+\fBplugin\fR=\fIPATH\fR
+.RS 4
+Specify a plugin to run as part of c\-lightning\&. This can be specified multiple times and may enable additional configuration options and JSON\-RPC methods, depending on the plugin\&.
+.RE
 .sp
 Lightning node customization options:
 .PP

doc/lightningd-config.5.txt

@@ -124,6 +124,11 @@ Lightning daemon options:
     (we allow missing files in the default case).
     Using this inside a configuration file is meaningless.
 
+*plugin*='PATH'::
+    Specify a plugin to run as part of c-lightning. This can be specified
+    multiple times and may enable additional configuration options and JSON-RPC
+    methods, depending on the plugin.
+
 Lightning node customization options:
 
 *rgb*='RRGGBB'::

lightningd/lightningd.c

@@ -211,6 +211,14 @@ static struct lightningd *new_lightningd(const tal_t *ctx)
 	ld->tor_service_password = NULL;
 	ld->max_funding_unconfirmed = 2016;
 
+	/*~ We run a number of plugins (subprocesses that we talk JSON-RPC with)
+	 *alongside this process. This allows us to have an easy way for users
+	 *to add their own tools without having to modify the c-lightning source
+	 *code. Here we initialize the context that will keep track and control
+	 *the plugins.
+	 */
+	ld->plugins = plugins_new(ld);
+
 	return ld;
 }
 

lightningd/lightningd.h

@@ -7,6 +7,7 @@
 #include <ccan/time/time.h>
 #include <ccan/timer/timer.h>
 #include <lightningd/htlc_end.h>
+#include <lightningd/plugin.h>
 #include <stdio.h>
 #include <wallet/txfilter.h>
 #include <wallet/wallet.h>
@@ -203,6 +204,8 @@ struct lightningd {
 	bool use_proxy_always;
 	char *tor_service_password;
 	bool pure_tor_setup;
+
+	struct plugins *plugins;
 };
 
 const struct chainparams *get_chainparams(const struct lightningd *ld);

lightningd/options.c

@@ -26,6 +26,7 @@
 #include <lightningd/log.h>
 #include <lightningd/options.h>
 #include <lightningd/param.h>
+#include <lightningd/plugin.h>
 #include <lightningd/subd.h>
 #include <stdio.h>
 #include <string.h>
@@ -286,11 +287,23 @@ static char *opt_add_proxy_addr(const char *arg, struct lightningd *ld)
 	return NULL;
 }
 
+static char *opt_add_plugin(const char *arg, struct lightningd *ld)
+{
+	plugin_register(ld->plugins, arg);
+	return NULL;
+}
+
 static void config_register_opts(struct lightningd *ld)
 {
 	opt_register_early_arg("--conf=<file>", opt_set_talstr, NULL,
 		&ld->config_filename,
 		"Specify configuration file. Relative paths will be prefixed by lightning-dir location. (default: config)");
+
+	/* Register plugins as an early argc, so we can initialize them and have
+	 * them register more command line options */
+	opt_register_early_arg("--plugin", opt_add_plugin, NULL, ld,
+			       "Add a plugin to be run.");
+
 	opt_register_noarg("--daemon", opt_set_bool, &ld->daemon,
 			 "Run in the background, suppress stdout/stderr");
 	opt_register_arg("--ignore-fee-limits", opt_set_bool_arg, opt_show_bool,
@@ -957,6 +970,8 @@ static void add_config(struct lightningd *ld,
 		} else if (opt->cb_arg == (void *)opt_add_proxy_addr) {
 			if (ld->proxyaddr)
 				answer = fmt_wireaddr(name0, ld->proxyaddr);
+		} else if (opt->cb_arg == (void *)opt_add_plugin) {
+			/* FIXME: Actually add the plugin options */
 #if DEVELOPER
 		} else if (strstarts(name, "dev-")) {
 			/* Ignore dev settings */

lightningd/test/run-find_my_abspath.c

@@ -119,6 +119,9 @@ struct chain_topology *new_topology(struct lightningd *ld UNNEEDED, struct log *
 /* Generated stub for onchaind_replay_channels */
 void onchaind_replay_channels(struct lightningd *ld UNNEEDED)
 { fprintf(stderr, "onchaind_replay_channels called!\n"); abort(); }
+/* Generated stub for plugins_new */
+struct plugins *plugins_new(const tal_t *ctx UNNEEDED)
+{ fprintf(stderr, "plugins_new called!\n"); abort(); }
 /* Generated stub for register_opts */
 void register_opts(struct lightningd *ld UNNEEDED)
 { fprintf(stderr, "register_opts called!\n"); abort(); }