davide/palladum-lightning
1
0
Fork 0
Code Issues Pull Requests Actions 5 Packages Projects Releases Wiki Activity

libplugin: pay now emits channel_hint as we learn about the net

Browse Source 
The `pay` plugin, as well as other plugins making use of the tree-pay
executor, will now emit their observations as they see them. The
notifications are sent on the `channel_hint_updated` topic, and any
subscriber will get them.

We also added a `timestamp` to the `struct channel_hint`, as these
observations now outlive the `pay` call, and have to be attenuated /
relaxed as they age, until we can eliminate them completely (when the
restriction is equal to the structural information gathered from the
gossip).

Changelog-Added: pay: Payments now emit `channel_hint_updated` notification to share inferred balances and observations across multiple payments.
This commit is contained in:
Christian Decker
2024-07-23 15:06:52 +02:00
committed by Rusty Russell
parent 0e99f2e718
commit 8e9f71ff85
3 changed files with 38 additions and 1 deletions
Download Patch File Download Diff File Expand all files Collapse all files

31
plugins/libplugin-pay.c
View File

@@ -387,6 +387,29 @@ void payment_start(struct payment *p)
payment_start_at_blockheight(p, INVALID_BLOCKHEIGHT);
}
/**
* Notify subscribers of the `channel_hint` topic about a changed hint
*
* We share the channel_hints across payments, and across plugins, in order to
* maximize the context they have when performing payments.
*/
/**
* Notify subscribers of the `channel_hint` topic about a changed hint
*
* We share the channel_hints across payments, and across plugins, in order
* to maximize the context they have when performing payments.
*/
static void channel_hint_notify(struct plugin *plugin,
const struct channel_hint *hint)
{
struct json_stream *js =
plugin_notification_start(plugin, "channel_hint_update");
/* The timestamp used to decay the observation over time. */
json_add_u32(js, "timestamp", hint->timestamp);
plugin_notification_end(plugin, js);
}
static void channel_hints_update(struct payment *p,
const struct short_channel_id scid,
int direction, bool enabled, bool local,
@@ -395,6 +418,7 @@ static void channel_hints_update(struct payment *p,
{
struct payment *root = payment_root(p);
struct channel_hint newhint;
u32 timestamp = time_now().ts.tv_sec;
/* If the channel is marked as enabled it must have an estimate. */
assert(!enabled || estimated_capacity != NULL);
@@ -424,7 +448,8 @@ static void channel_hints_update(struct payment *p,
modified = true;
}
if (modified)
if (modified) {
hint->timestamp = timestamp;
paymod_log(p, LOG_DBG,
"Updated a channel hint for %s: "
"enabled %s, "
@@ -434,12 +459,15 @@ static void channel_hints_update(struct payment *p,
hint->enabled ? "true" : "false",
fmt_amount_msat(tmpctx,
hint->estimated_capacity));
channel_hint_notify(p->plugin, hint);
}
return;
}
}
/* No hint found, create one. */
newhint.enabled = enabled;
newhint.timestamp = timestamp;
newhint.scid.scid = scid;
newhint.scid.dir = direction;
if (local) {
@@ -459,6 +487,7 @@ static void channel_hints_update(struct payment *p,
fmt_short_channel_id_dir(tmpctx, &newhint.scid),
newhint.enabled ? "true" : "false",
fmt_amount_msat(tmpctx, newhint.estimated_capacity));
channel_hint_notify(p->plugin, &newhint);
}
static void payment_exclude_most_expensive(struct payment *p)