lightningd: maintain a status billboard for each channel.

Each state (effectively, each daemon) has two slots: a permanent slot
if something permanent happens (usually, a failure), and a transient
slot which summarizes what's happening right now.

Uncommitted channels only have a transient slot, by their very nature.

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

lightningd/channel.c

@@ -103,6 +103,7 @@ struct channel *new_channel(struct peer *peer, u64 dbid,
 			    enum side funder,
 			    /* NULL or stolen */
 			    struct log *log,
+			    const char *transient_billboard TAKES,
 			    u8 channel_flags,
 			    const struct channel_config *our_config,
 			    u32 minimum_depth,
@@ -147,6 +148,9 @@ struct channel *new_channel(struct peer *peer, u64 dbid,
 	channel->state = state;
 	channel->funder = funder;
 	channel->owner = NULL;
+	memset(&channel->billboard, 0, sizeof(channel->billboard));
+	channel->billboard.transient = tal_strdup(channel, transient_billboard);
+
 	if (!log) {
 		/* FIXME: update log prefix when we get scid */
 		/* FIXME: Use minimal unique pubkey prefix for logs! */
@@ -314,6 +318,21 @@ void channel_internal_error(struct channel *channel, const char *fmt, ...)
 	tal_free(why);
 }
 
+void channel_set_billboard(struct channel *channel, bool perm, const char *str)
+{
+	const char **p;
+
+	if (perm)
+		p = &channel->billboard.permanent[channel->state];
+	else
+		p = &channel->billboard.transient;
+	tal_free(*p);
+
+	*p = tal_fmt(channel, "%s:%s", channel_state_name(channel), str);
+	if (taken(str))
+		tal_free(str);
+}
+
 void channel_fail_transient(struct channel *channel, const char *fmt, ...)
 {
 	va_list ap;

lightningd/channel.h

@@ -8,6 +8,12 @@
 
 struct uncommitted_channel;
 
+struct billboard {
+	/* Status information to display on listpeers */
+	const char *permanent[CHANNEL_STATE_MAX+1];
+	const char *transient;
+};
+
 struct channel {
 	/* Inside peer->channels. */
 	struct list_node list;
@@ -35,6 +41,7 @@ struct channel {
 
 	/* History */
 	struct log *log;
+	struct billboard billboard;
 
 	/* Channel flags from opening message. */
 	u8 channel_flags;
@@ -92,6 +99,7 @@ struct channel *new_channel(struct peer *peer, u64 dbid,
 			    enum side funder,
 			    /* NULL or stolen */
 			    struct log *log,
+			    const char *transient_billboard TAKES,
 			    u8 channel_flags,
 			    const struct channel_config *our_config,
 			    u32 minimum_depth,
@@ -199,4 +207,7 @@ static inline bool channel_wants_reconnect(const struct channel *channel)
 void derive_channel_seed(struct lightningd *ld, struct privkey *seed,
 			 const struct pubkey *peer_id,
 			 const u64 dbid);
+
+void channel_set_billboard(struct channel *channel, bool perm,
+			   const char *str TAKES);
 #endif /* LIGHTNING_LIGHTNINGD_CHANNEL_H */

lightningd/opening_control.c

@@ -173,6 +173,7 @@ wallet_commit_channel(struct lightningd *ld,
 			      CHANNELD_AWAITING_LOCKIN,
 			      uc->fc ? LOCAL : REMOTE,
 			      uc->log,
+			      "Eat at Joes!",
 			      channel_flags,
 			      &uc->our_config,
 			      uc->minimum_depth,

wallet/wallet.c

@@ -573,6 +573,7 @@ static struct channel *wallet_stmt2channel(const tal_t *ctx, struct wallet *w, s
 			   sqlite3_column_int(stmt, 5),
 			   sqlite3_column_int(stmt, 6),
 			   NULL, /* Set up fresh log */
+			   "Loaded from database",
 			   sqlite3_column_int(stmt, 7),
 			   &our_config,
 			   sqlite3_column_int(stmt, 8),