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Event notifications

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Event notifications allow a plugin to subscribe to events in lightningd. lightningd will then send a push notification if an event matching the subscription occurred. A notification is defined in the JSON-RPC [specification][jsonrpc-spec] as an RPC call that does not include an id parameter:

A Notification is a Request object without an "id" member. A Request object that is a Notification signifies the Client's lack of interest in the corresponding Response object, and as such no Response object needs to be returned to the client. The Server MUST NOT reply to a Notification, including those that are within a batch request.

Notifications are not confirmable by definition, since they do not have a Response object to be returned. As such, the Client would not be aware of any errors (like e.g. "Invalid params","Internal error").

Plugins subscribe by returning an array of subscriptions as part of the getmanifest response. The result for the getmanifest call above for example subscribes to the two topics connect and disconnect. The topics that are currently defined and the corresponding payloads are listed below.

📘

This is a way of specifying that you want to subscribe to all possible event notifications. It is not recommended, but is useful for plugins which want to provide generic infrastructure for others (in future, we may add the ability to dynamically subscribe/unsubscribe).

deprecated_oneshot

(Added in v24.02)

This is a special notification, which the plugin will only receive it it set deprecated_oneshot to true in its getmanifest response. It indicates that the immeditately following command wants a different deprecation status than the global allow-deprecated-apis setting.

This is possible because of the deprecations RPC command, where individual connections can change their deprecation settings.

{
  "deprecated_oneshot": {
    "deprecated_ok": false
  }
}

channel_opened

A notification for topic channel_opened is sent if a peer successfully funded a channel with us. It contains the peer id, the funding amount (in millisatoshis), the funding transaction id, and a boolean indicating if the funding transaction has been included into a block.

{
  "channel_opened": {
    "id": "03864ef025fde8fb587d989186ce6a4a186895ee44a926bfc370e2c366597a3f8f",
    "funding_msat": 100000000,
    "funding_txid": "4a5e1e4baab89f3a32518a88c31bc87f618f76673e2cc77ab2127b7afdeda33b",
    "channel_ready": false
  }
}

channel_open_failed

A notification to indicate that a channel open attempt has been unsuccessful.
Useful for cleaning up state for a v2 channel open attempt. See plugins/funder.c for an example of how to use this.

{
  "channel_open_failed": {
    "channel_id": "a2d0851832f0e30a0cf...",
  }
}

channel_state_changed

A notification for topic channel_state_changed is sent every time a channel changes its state. The notification includes the peer_id and channel_id, the old and new channel states, the type of cause and a message.

{
    "channel_state_changed": {
        "peer_id": "03bc9337c7a28bb784d67742ebedd30a93bacdf7e4ca16436ef3798000242b2251",
        "channel_id": "a2d0851832f0e30a0cf778a826d72f077ca86b69f72677e0267f23f63a0599b4",
        "short_channel_id" : "561820x1020x1",
        "timestamp":"2023-01-05T18:27:12.145Z",
        "old_state": "CHANNELD_NORMAL",
        "new_state": "CHANNELD_SHUTTING_DOWN",
        "cause" : "remote",
        "message" : "Peer closes channel"
    }
}

A cause can have the following values:

  • "unknown" Anything other than the reasons below. Should not happen.
  • "local" Unconscious internal reasons, e.g. dev fail of a channel.
  • "user" The operator or a plugin opened or closed a channel by intention.
  • "remote" The remote closed or funded a channel with us by intention.
  • "protocol" We need to close a channel because of bad signatures and such.
  • "onchain" A channel was closed onchain, while we were offline.

Most state changes are caused subsequentially for a prior state change, e.g. "CLOSINGD_COMPLETE" is followed by "FUNDING_SPEND_SEEN". Because of this, the cause reflects the last known reason in terms of local or remote user interaction, protocol reasons, etc. More specifically, a new_state "FUNDING_SPEND_SEEN" will likely not have "onchain" as a cause but some value such as "REMOTE" or "LOCAL" depending on who initiated the closing of a channel.

Note: If the channel is not closed or being closed yet, the cause will reflect which side "remote" or "local" opened the channel.

Note: If the cause is "onchain" this was very likely a conscious decision of the remote peer, but we have been offline.

connect

A notification for topic connect is sent every time a new connection to a peer is established. direction is either "in" or "out".

{
  "connect" :  {
    "address" : {
      "address" : "127.0.0.1",
      "port" : 38012,
      "type" : "ipv4"
  },
  "direction" : "in",
  "id" : "022d223620a359a47ff7f7ac447c85c46c923da53389221a0054c11c1e3ca31d59"
  }
}

disconnect

A notification for topic disconnect is sent every time a connection to a peer was lost.

{
  "disconnect": {
    "id": "02f6725f9c1c40333b67faea92fd211c183050f28df32cac3f9d69685fe9665432"
  }
}

custommsg

A notification for topic custommsg is sent when the node receives a custommsg. 

{
  "custommsg" : {
    "peer_id" : "02f6725f9c1c40333b67faea92fd211c183050f28df32cac3f9d69685fe9665432",
    "payload" : "1337ffffffff"
  }
}

This payload represents a custommsg that was send by the peer whose node_id matches
peer_id. The message has type 0x1337 and contents ffffffff.

To avoid conflicts with internal state-tracking, unexpected disconnections and channel-closures
the messages are currently limited to odd-numbered messages that can be safely ignored by
other nodes (see "it's ok to be odd" in the specification
for details).

The plugin must implement the parsing of the message including the type prefix.

invoice_payment

A notification for topic invoice_payment is sent every time an invoice is paid.

{
  "invoice_payment": {
    "label": "unique-label-for-invoice",
    "preimage": "0000000000000000000000000000000000000000000000000000000000000000",
    "msat": 10000,
  }
}

Before version 23.11 the msat field was a string with msat-suffix, e.g: "10000msat".

Note that there will be a string member "outpoint" ("txid:outnum") if
the payment was onchain (possible with the invoices-onchain-fallback
config option).

invoice_creation

A notification for topic invoice_creation is sent every time an invoice is created.

{
  "invoice_creation": {
    "label": "unique-label-for-invoice",
    "preimage": "0000000000000000000000000000000000000000000000000000000000000000",
    "msat": 10000
  }
}

Before version 23.11 the msat field was a string with msat-suffix, e.g: "10000msat".

warning

A notification for topic warning is sent every time a new BROKEN/UNUSUAL level(in plugins, we use error/warn) log generated, which means an unusual/borken thing happens, such as channel failed, message resolving failed...

{
  "warning": {
    "level": "warn",
    "time": "1559743608.565342521",
    "source": "lightningd(17652): 0821f80652fb840239df8dc99205792bba2e559a05469915804c08420230e23c7c chan #7854:",
    "log": "Peer permanent failure in CHANNELD_NORMAL: lightning_channeld: sent ERROR bad reestablish dataloss msg"
  }
}
  1. level is warn or error: warn means something seems bad happened and it's under control, but we'd better check it; error means something extremely bad is out of control, and it may lead to crash;
  2. time is the second since epoch;
  3. source means where the event happened, it may have the following forms:
    <node_id> chan #<db_id_of_channel>:,lightningd(<lightningd_pid>):,
    plugin-<plugin_name>:, <daemon_name>(<daemon_pid>):, jsonrpc:,
    jcon fd <error_fd_to_jsonrpc>:, plugin-manager;
  4. log is the context of the original log entry.

forward_event

A notification for topic forward_event is sent every time the status of a forward payment is set. The json format is same as the API listforwards.

{
  "forward_event": {
    "payment_hash": "f5a6a059a25d1e329d9b094aeeec8c2191ca037d3f5b0662e21ae850debe8ea2",
    "in_channel": "103x2x1",
    "out_channel": "103x1x1",
    "in_msat": 100001001,
    "out_msat": 100000000,
    "fee_msat": 1001,
    "status": "settled",
    "received_time": 1560696342.368,
    "resolved_time": 1560696342.556
  }
}

or

{
  "forward_event": {
    "payment_hash": "ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff",
    "in_channel": "103x2x1",
    "out_channel": "110x1x0",
    "in_msat": 100001001,
    "out_msat": 100000000,
    "fee_msat": 1001,
    "status": "local_failed",
    "failcode": 16392,
    "failreason": "WIRE_PERMANENT_CHANNEL_FAILURE",
    "received_time": 1560696343.052
  }
}
  • The status includes offered, settled, failed and local_failed, and they are all string type in json.
    • When the forward payment is valid for us, we'll set offered and send the forward payment to next hop to resolve;
    • When the payment forwarded by us gets paid eventually, the forward payment will change the status from offered to settled;
    • If payment fails locally(like failing to resolve locally) or the corresponding htlc with next hop fails(like htlc timeout), we will set the status as local_failed. local_failed may be set before setting offered or after setting offered. In fact, from the
      time we receive the htlc of the previous hop, all we can know the cause of the failure is treated as local_failed. local_failed only occuors locally or happens in the htlc between us and next hop;
      • If local_failed is set before offered, this means we just received htlc from the previous hop and haven't generate htlc for next hop. In this case, the json of forward_event sets the fields of out_msatoshi, out_msat,fee and out_channel as 0;
        • Note: In fact, for this case we may be not sure if this incoming htlc represents a pay to us or a payment we need to forward. We just simply treat all incoming failed to resolve as local_failed.
      • Only in local_failed case, json includes failcode and failreason fields;
    • failed means the payment forwarded by us fails in the latter hops, and the failure isn't related to us, so we aren't accessed to the fail reason. failed must be set after
      offered.
      • failed case doesn't include failcode and failreason
        fields;
  • received_time means when we received the htlc of this payment from the previous peer. It will be contained into all status case;
  • resolved_time means when the htlc of this payment between us and the next peer was resolved. The resolved result may success or fail, so only settled and failed case contain resolved_time;
  • The failcode and failreason are defined in BOLT 4.

sendpay_success

A notification for topic sendpay_success is sent every time a sendpay succeeds (with complete status). The json is the same as the return value of the commands sendpay/waitsendpay when these commands succeed.

{
  "sendpay_success": {
    "id": 1,
    "payment_hash": "5c85bf402b87d4860f4a728e2e58a2418bda92cd7aea0ce494f11670cfbfb206",
    "destination": "035d2b1192dfba134e10e540875d366ebc8bc353d5aa766b80c090b39c3a5d885d",
    "amount_msat": 100000000,
    "amount_sent_msat": 100001001,
    "created_at": 1561390572,
    "status": "complete",
    "payment_preimage": "9540d98095fd7f37687ebb7759e733934234d4f934e34433d4998a37de3733ee"
  }
}

sendpay doesn't wait for the result of sendpay and waitsendpay returns the result of sendpay in specified time or timeout, but sendpay_success will always return the result anytime when sendpay successes if is was subscribed.

sendpay_failure

A notification for topic sendpay_failure is sent every time a sendpay completes with failed status. The JSON is same as the return value of the commands sendpay/waitsendpay when these commands fail.

{
  "sendpay_failure": {
    "code": 204,
    "message": "failed: WIRE_UNKNOWN_NEXT_PEER (reply from remote)",
    "data": {
      "id": 2,
      "payment_hash": "9036e3bdbd2515f1e653cb9f22f8e4c49b73aa2c36e937c926f43e33b8db8851",
      "destination": "035d2b1192dfba134e10e540875d366ebc8bc353d5aa766b80c090b39c3a5d885d",
      "amount_msat": 100000000,
      "amount_sent_msat": 100001001,
      "created_at": 1561395134,
      "status": "failed",
      "erring_index": 1,
      "failcode": 16394,
      "failcodename": "WIRE_UNKNOWN_NEXT_PEER",
      "erring_node": "022d223620a359a47ff7f7ac447c85c46c923da53389221a0054c11c1e3ca31d59",
      "erring_channel": "103x2x1",
      "erring_direction": 0
    }
  }
}

sendpay doesn't wait for the result of sendpay and waitsendpay returns the result of sendpay in specified time or timeout, but sendpay_failure will always return the result anytime when sendpay fails if is was subscribed.

coin_movement

A notification for topic coin_movement is sent to record the movement of coins. It is only triggered by finalized ledger updates, i.e. only definitively resolved HTLCs or confirmed bitcoin transactions.

{
	"coin_movement": {
		"version":2,
		"node_id":"03a7103a2322b811f7369cbb27fb213d30bbc0b012082fed3cad7e4498da2dc56b",
		"type":"chain_mvt",
		"account_id":"wallet",
		"originating_account": "wallet", // (`chain_mvt` only, optional)
		"txid":"0159693d8f3876b4def468b208712c630309381e9d106a9836fa0a9571a28722", // (`chain_mvt` only, optional)
		"utxo_txid":"0159693d8f3876b4def468b208712c630309381e9d106a9836fa0a9571a28722", // (`chain_mvt` only)
		"vout":1, // (`chain_mvt` only)
		"payment_hash": "xxx", // (either type, optional on both)
		"part_id": 0, // (`channel_mvt` only, optional)
		"credit_msat":2000000000,
		"debit_msat":0,
		"output_msat": 2000000000, // ('chain_mvt' only)
		"output_count": 2, // ('chain_mvt' only, typically only channel closes)
		"fees_msat": 382, // ('channel_mvt' only)
		"tags": ["deposit"],
		"blockheight":102, // 'chain_mvt' only
		"timestamp":1585948198,
		"coin_type":"bc"
	}
}

version indicates which version of the coin movement data struct this notification adheres to.

node_id specifies the node issuing the coin movement.

type marks the underlying mechanism which moved these coins. There are two 'types' of coin_movements:

  • channel_mvts, which occur as a result of htlcs being resolved and,
  • chain_mvts, which occur as a result of bitcoin txs being mined.

account_id is the name of this account. The node's wallet is named 'wallet', all channel funds' account are the channel id.

originating_account is the account that this movement originated from.
Only tagged on external events (deposits/withdrawals to an external party).

txid is the transaction id of the bitcoin transaction that triggered this ledger event. utxo_txid and vout identify the bitcoin output which triggered this notification. (chain_mvt only). Notifications tagged journal_entry do not have a utxo_txid as they're not represented in the utxo set.

payment_hash is the hash of the preimage used to move this payment. Only present for HTLC mediated moves (both chain_mvt and channel_mvt) A chain_mvt will have a payment_hash iff it's recording an htlc that was fulfilled onchain.

part_id is an identifier for parts of a multi-part payment. useful for aggregating payments for an invoice or to indicate why a payment hash appears multiple times. channel_mvt only

credit and debit are millisatoshi denominated amounts of the fund movement. A
'credit' is funds deposited into an account; a debit is funds withdrawn.

output_value is the total value of the on-chain UTXO. Note that for channel opens/closes the total output value will not necessarily correspond to the amount that's credited/debited.

output_count is the total outputs to expect for a channel close. Useful for figuring out when every onchain output for a close has been resolved.

fees is an HTLC annotation for the amount of fees either paid or earned. For "invoice" tagged events, the fees are the total fees paid to send that payment. The end amount can be found by subtracting the total fees from the debited amount. For "routed" tagged events, both the debit/credit contain fees. Technically routed debits are the 'fee generating' event, however we include them on routed credits as well.

tag is a movement descriptor. Current tags are as follows:

  • deposit: funds deposited
  • withdrawal: funds withdrawn
  • penalty: funds paid or gained from a penalty tx.
  • invoice: funds paid to or received from an invoice.
  • routed: funds routed through this node.
  • pushed: funds pushed to peer.
  • channel_open : channel is opened, initial channel balance
  • channel_close: channel is closed, final channel balance
  • delayed_to_us: on-chain output to us, spent back into our wallet
  • htlc_timeout: on-chain htlc timeout output
  • htlc_fulfill: on-chian htlc fulfill output
  • htlc_tx: on-chain htlc tx has happened
  • to_wallet: output being spent into our wallet
  • ignored: output is being ignored
  • anchor: an anchor output
  • to_them: output intended to peer's wallet
  • penalized: output we've 'lost' due to a penalty (failed cheat attempt)
  • stolen: output we've 'lost' due to peer's cheat
  • to_miner: output we've burned to miner (OP_RETURN)
  • opener: tags channel_open, we are the channel opener
  • lease_fee: amount paid as lease fee
  • leased: tags channel_open, channel contains leased funds

blockheight is the block the txid is included in. channel_mvts will be null, so will the blockheight for withdrawals to external parties (we issue these events when we send the tx containing them, before they're included in the chain).

The timestamp is seconds since Unix epoch of the node's machine time at the time lightningd broadcasts the notification.

coin_type is the BIP173 name for the coin which moved.

balance_snapshot

Emitted after we've caught up to the chain head on first start. Lists all current accounts (account_id matches the account_id emitted from coin_movement). Useful for checkpointing account balances.

{
    "balance_snapshot": [
	{
	    'node_id': '035d2b1192dfba134e10e540875d366ebc8bc353d5aa766b80c090b39c3a5d885d',
	    'blockheight': 101,
	    'timestamp': 1639076327,
	    'accounts': [
		{
		    'account_id': 'wallet',
		    'balance': '0msat',
		    'coin_type': 'bcrt'
		}
	    ]
	},
	{
	    'node_id': '035d2b1192dfba134e10e540875d366ebc8bc353d5aa766b80c090b39c3a5d885d',
	    'blockheight': 110,
	    'timestamp': 1639076343,
	    'accounts': [
		{
		    'account_id': 'wallet',
		    'balance': '995433000msat',
		    'coin_type': 'bcrt'
		}, {
		    'account_id': '5b65c199ee862f49758603a5a29081912c8816a7c0243d1667489d244d3d055f',
		     'balance': '500000000msat',
		    'coin_type': 'bcrt'
		}
	    ]
	}
    ]
}

block_added

Emitted after each block is received from bitcoind, either during the initial sync or throughout the node's life as new blocks appear.

{
 "block_added": {
   		"hash": "000000000000000000034bdb3c01652a0aa8f63d32f949313d55af2509f9d245",
      "height": 753304
    }
}

openchannel_peer_sigs

When opening a channel with a peer using the collaborative transaction protocol opt_dual_fund), this notification is fired when the peer sends us their funding transaction signatures, tx_signatures. We update the in-progress PSBT and return it here, with the peer's signatures attached.

{
  "openchannel_peer_sigs": {
    "channel_id": "252d1b0a1e5789...",
    "signed_psbt": "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"
  }
}

shutdown

Send in two situations: lightningd is (almost completely) shutdown, or the plugin stop command has been called for this plugin. In both cases the plugin has 30 seconds to exit itself, otherwise it's killed.

In the shutdown case, plugins should not interact with lightnind except via (id-less) logging or notifications. New rpc calls will fail with error code -5 and (plugin's) responses will be ignored. Because lightningd can crash or be killed, a plugin cannot rely on the shutdown notification always been send.

{
    "shutdown": {
    }
}

Updated about 1 month ago