plugin: Give each plugin their own log-prefix

There is no good naming just yet, so we just number them 1 to n.

lightningd/lightningd.c

@@ -217,7 +217,7 @@ static struct lightningd *new_lightningd(const tal_t *ctx)
 	 *code. Here we initialize the context that will keep track and control
 	 *the plugins.
 	 */
-	ld->plugins = plugins_new(ld, ld->log);
+	ld->plugins = plugins_new(ld, ld->log_book);
 
 	return ld;
 }

lightningd/plugin.c

@@ -56,6 +56,7 @@ struct plugins {
 	/* Currently pending requests by their request ID */
 	UINTMAP(struct plugin_request *) pending_requests;
 	struct log *log;
+	struct log_book *log_book;
 };
 
 struct json_output {
@@ -72,21 +73,29 @@ struct plugin_opt {
 	char *value;
 };
 
-struct plugins *plugins_new(const tal_t *ctx, struct log *log){
+struct plugins *plugins_new(const tal_t *ctx, struct log_book *log_book){
 	struct plugins *p;
 	p = tal(ctx, struct plugins);
 	list_head_init(&p->plugins);
-	p->log = log;
+	p->log_book = log_book;
+	p->log = new_log(p, log_book, "plugin-manager");
 	return p;
 }
 
 void plugin_register(struct plugins *plugins, const char* path TAKES)
 {
 	struct plugin *p;
+	static size_t plugin_count = 0;
 	p = tal(plugins, struct plugin);
 	list_add_tail(&plugins->plugins, &p->list);
 	p->plugins = plugins;
 	p->cmd = tal_strdup(p, path);
+
+	/* FIXME(cdecker): Referring to plugin by their registration
+	number might not be that useful, come up with a naming scheme
+	that makes more sense. */
+	plugin_count++;
+	p->log = new_log(p, plugins->log_book, "plugin-%zu", plugin_count);
 	p->log = plugins->log;
 	list_head_init(&p->plugin_opts);
 }

lightningd/plugin.h

@@ -16,7 +16,7 @@ struct plugins;
 /**
  * Create a new plugins context.
  */
-struct plugins *plugins_new(const tal_t *ctx, struct log *log);
+struct plugins *plugins_new(const tal_t *ctx, struct log_book *log_book);
 
 /**
  * Initialize the registered plugins.

lightningd/test/run-find_my_abspath.c

@@ -129,7 +129,7 @@ void plugins_config(struct plugins *plugins UNNEEDED)
 void plugins_init(struct plugins *plugins UNNEEDED)
 { fprintf(stderr, "plugins_init called!\n"); abort(); }
 /* Generated stub for plugins_new */
-struct plugins *plugins_new(const tal_t *ctx UNNEEDED, struct log *log UNNEEDED)
+struct plugins *plugins_new(const tal_t *ctx UNNEEDED, struct log_book *log_book UNNEEDED)
 { fprintf(stderr, "plugins_new called!\n"); abort(); }
 /* Generated stub for register_opts */
 void register_opts(struct lightningd *ld UNNEEDED)