wallet, payalgo: Save detail of payment failures for later reporting. (#1345)

Pointless for remote failures as those are never sent by
the erring node, but for local failures we can give more
detail.

lightningd/pay.c

@@ -515,7 +515,8 @@ void payment_failed(struct lightningd *ld, const struct htlc_out *hout,
 				    fail ? fail->failcode : 0,
 				    fail ? &fail->erring_node : NULL,
 				    fail ? &fail->erring_channel : NULL,
-				    fail ? fail->channel_update : NULL);
+				    fail ? fail->channel_update : NULL,
+				    failmsg);
 
 	/* Report to gossipd if we decided we should. */
 	if (report_to_gossipd)
@@ -549,6 +550,7 @@ bool wait_payment(const tal_t *cxt,
 	struct pubkey *failnode;
 	struct short_channel_id *failchannel;
 	u8 *failupdate;
+	char *faildetail;
 	struct routing_failure *fail;
 
 	payment = wallet_payment_by_hash(tmpctx, ld->wallet, payment_hash);
@@ -588,7 +590,8 @@ bool wait_payment(const tal_t *cxt,
 					    &failcode,
 					    &failnode,
 					    &failchannel,
-					    &failupdate);
+					    &failupdate,
+					    &faildetail);
 		/* Old DB might not save failure information */
 		if (!failonionreply && !failnode)
 			result = sendpay_result_simple_fail(tmpctx,
@@ -596,7 +599,7 @@ bool wait_payment(const tal_t *cxt,
 							    "Payment failure reason unknown");
 		else if (failonionreply) {
 			/* failed to parse returned onion error */
-			result = sendpay_result_route_failure(tmpctx, true, NULL, failonionreply, "reply from remote");
+			result = sendpay_result_route_failure(tmpctx, true, NULL, failonionreply, faildetail);
 		} else {
 			/* Parsed onion error, get its details */
 			assert(failnode);
@@ -607,7 +610,7 @@ bool wait_payment(const tal_t *cxt,
 			fail->erring_node = *failnode;
 			fail->erring_channel = *failchannel;
 			fail->channel_update = failupdate;
-			result = sendpay_result_route_failure(tmpctx, !faildestperm, fail, NULL, "route failure");
+			result = sendpay_result_route_failure(tmpctx, !faildestperm, fail, NULL, faildetail);
 		}
 
 		cb(result, cbarg);

lightningd/payalgo.c

@@ -39,6 +39,9 @@ struct pay_failure {
 	/* The routing failure, if TYPE_PAYMENT_REPLY, a tal
 	 * object whose parent is this struct */
 	struct routing_failure *routing_failure;
+	/* The detail of the routing failure. A tal_arr
+	 * string whose parent is this struct. */
+	char *details;
 };
 
 /* Output a pay failure */
@@ -48,12 +51,12 @@ json_add_failure(struct json_result *r, char const *n,
 {
 	struct routing_failure *rf;
 	json_object_start(r, n);
+	json_add_string(r, "message", f->details);
 	switch (f->type) {
 	case FAIL_UNPARSEABLE_ONION:
 		json_add_string(r, "type", "FAIL_UNPARSEABLE_ONION");
 		json_add_hex(r, "onionreply", f->onionreply,
 			     tal_len(f->onionreply));
-		json_add_route(r, "route", f->route, tal_count(f->route));
 		break;
 
 	case FAIL_PAYMENT_REPLY:
@@ -68,9 +71,9 @@ json_add_failure(struct json_result *r, char const *n,
 			json_add_hex(r, "channel_update",
 				     rf->channel_update,
 				     tal_len(rf->channel_update));
-		json_add_route(r, "route", f->route, tal_count(f->route));
 		break;
 	}
+	json_add_route(r, "route", f->route, tal_count(f->route));
 	json_object_end(r);
 }
 
@@ -173,6 +176,7 @@ add_pay_failure(struct pay *pay,
 	default:
 		abort();
 	}
+	f->details = tal_strdup(f, r->details);
 	/* Grab the route */
 	f->route = tal_steal(f, pay->route);
 	pay->route = NULL;

wallet/db.c

@@ -300,6 +300,12 @@ char *dbmigrations[] = {
     ", rawtx BLOB"
     ", PRIMARY KEY (id)"
     ");",
+    /* -- Detailed payment failure -- */
+    "ALTER TABLE payments ADD faildetail TEXT;",
+    "UPDATE payments"
+    "   SET faildetail = 'unspecified payment failure reason'"
+    " WHERE status = 2;", /* PAYMENT_FAILED */
+    /* -- Detailed payment faiure ends -- */
     NULL,
 };
 

wallet/wallet.c

@@ -11,6 +11,7 @@
 #include <lightningd/log.h>
 #include <lightningd/peer_control.h>
 #include <lightningd/peer_htlcs.h>
+#include <string.h>
 
 #define SQLITE_MAX_UINT 0x7FFFFFFFFFFFFFFF
 #define DIRECTION_INCOMING 0
@@ -1770,7 +1771,8 @@ void wallet_payment_get_failinfo(const tal_t *ctx,
 				 enum onion_type *failcode,
 				 struct pubkey **failnode,
 				 struct short_channel_id **failchannel,
-				 u8 **failupdate)
+				 u8 **failupdate,
+				 char **faildetail)
 {
 	sqlite3_stmt *stmt;
 	int res;
@@ -1781,7 +1783,7 @@ void wallet_payment_get_failinfo(const tal_t *ctx,
 			  "SELECT failonionreply, faildestperm"
 			  "     , failindex, failcode"
 			  "     , failnode, failchannel"
-			  "     , failupdate"
+			  "     , failupdate, faildetail"
 			  "  FROM payments"
 			  " WHERE payment_hash=?;");
 	sqlite3_bind_sha256(stmt, 1, payment_hash);
@@ -1818,6 +1820,8 @@ void wallet_payment_get_failinfo(const tal_t *ctx,
 		*failupdate = tal_arr(ctx, u8, len);
 		memcpy(*failupdate, sqlite3_column_blob(stmt, 6), len);
 	}
+	*faildetail = tal_strndup(ctx, sqlite3_column_blob(stmt, 7),
+				  sqlite3_column_bytes(stmt, 7));
 
 	sqlite3_finalize(stmt);
 }
@@ -1830,7 +1834,8 @@ void wallet_payment_set_failinfo(struct wallet *wallet,
 				 enum onion_type failcode,
 				 const struct pubkey *failnode,
 				 const struct short_channel_id *failchannel,
-				 const u8 *failupdate /*tal_arr*/)
+				 const u8 *failupdate /*tal_arr*/,
+				 const char *faildetail)
 {
 	sqlite3_stmt *stmt;
 
@@ -1843,6 +1848,7 @@ void wallet_payment_set_failinfo(struct wallet *wallet,
 			  "     , failnode=?"
 			  "     , failchannel=?"
 			  "     , failupdate=?"
+			  "     , faildetail=?"
 			  " WHERE payment_hash=?;");
 	if (failonionreply)
 		sqlite3_bind_blob(stmt, 1,
@@ -1871,8 +1877,11 @@ void wallet_payment_set_failinfo(struct wallet *wallet,
 				  SQLITE_TRANSIENT);
 	else
 		sqlite3_bind_null(stmt, 7);
+	sqlite3_bind_blob(stmt, 8,
+			  faildetail, strlen(faildetail),
+			  SQLITE_TRANSIENT);
 
-	sqlite3_bind_sha256(stmt, 8, payment_hash);
+	sqlite3_bind_sha256(stmt, 9, payment_hash);
 
 	db_exec_prepared(wallet->db, stmt);
 }

wallet/wallet.h

@@ -735,7 +735,8 @@ void wallet_payment_get_failinfo(const tal_t *ctx,
 				 enum onion_type *failcode,
 				 struct pubkey **failnode,
 				 struct short_channel_id **failchannel,
-				 u8 **failupdate);
+				 u8 **failupdate,
+				 char **faildetail);
 /**
  * wallet_payment_set_failinfo - Set failure information for a given
  * `payment_hash`.
@@ -748,7 +749,8 @@ void wallet_payment_set_failinfo(struct wallet *wallet,
 				 enum onion_type failcode,
 				 const struct pubkey *failnode,
 				 const struct short_channel_id *failchannel,
-				 const u8 *failupdate);
+				 const u8 *failupdate,
+				 const char *faildetail);
 
 /**
  * wallet_payment_list - Retrieve a list of payments