πObjective
The goal of this article is to help you
- Connect the lightning nodes to form a peer
- Open a payment channel between
lnd1
andlnd2
nodes - Add some confirmations to the block that the channel opening transaction was mined on
- Check the list of channels to ensure our channel is ready and funded
- Create an invoice on
lnd2
- inspect the invoice created above from
lnd1
- Pay or satisfy the invoice created by
lnd2
vialnd1
- Close the payment channels, kill both Bitcoin and lightning daemons
- Celebrate the success of this tutorial with a cold bottle of beer.
π Introduction
Hey there, welcome to the final part of this 3 part series on simulating your first lightning transaction.
If you are as happy as I am to finally wrap up the series, let's get right to it....
Prerequisites
To be successful in this tutorial in case if you haven't already gone through the previous parts leading up to this one, ensure you;
- β checkout Part 1
- β checkout Part 2
- β Have a running Bitcoin network daemon (on regtest)
- β Have two active and running lightning node instances as lnd1 and lnd2
If the above prerequisites list has been satisfied then you can proceed beyond this point.
π Connect the lightning nodes to form a peer
Now that both of our nodes are ready for some action, we need to connect them to form a peer-to-peer
network this would enable our nodes to communicate with each other on the network by opening and closing channels.
From lnd1
run
command:
lncli1 listpeers
output:
{
"peers": [] //ππΏ no peers for now...let's fix that.
}
From lnd2
run the command below to get its identity_pubkey
which we would use in connecting the node to lnd1
command:
lncli2 getinfo
output:
{
"version": "0.17.0-beta commit=fn/v1.0.1-85-ge31d15989",
"commit_hash": "e31d1598932a814c2d44b774e5110746295df711",
"identity_pubkey": "024baa5e16c118f42cddd95fd828b32fa8dfcfea55fa384e89e2da0f3b96fc4579",//ππΏ copy this
"alias": "024baa5e16c118f42cdd",
...
}
Now let's connect lnd2
to lnd1
by passing the identity_pubkey
, IP address
and port
command:
lncli1 connect 024baa5e16c118f42cddd95fd828b32fa8dfcfea55fa384e89e2da0f3b96fc4579@localhost:9734
output:
{} //ππΏ don't worry this is the correct output.
Let's check for the list of peers once again at lnd1
command:
lncli1 listpeers
output:
{
"peers": [
{
"pub_key": "024baa5e16c118f42cddd95fd828b32fa8dfcfea55fa384e89e2da0f3b96fc4579",
"address": "127.0.0.1:9734",
"bytes_sent": "394",
"bytes_recv": "394",
"sat_sent": "0",
"sat_recv": "0",
"inbound": false,
"ping_time": "-1",
"sync_type": "ACTIVE_SYNC",
.....
}]}
π Both Nodes are now successfully connected as a peer
on our local lightning network.
π Open a payment channel between lnd1
and lnd2
nodes
Now let's open up a payment channel
between lnd1
and lnd2
Quick note: A payment channel on the lightning network is a two-way connection between two parties (lightning nodes) that enables them to exchange bitcoin.
To create a payment channel between lnd1
and lnd2
, we'll be making use of the pub_key
of lnd2
and we'll then be funding the channel with 100,000 SAT
. the 100,000 SAT
is lnd1's
contribution to the channel
command:
lncli1 openchannel 024baa5e16c118f42cddd95fd828b32fa8dfcfea55fa384e89e2da0f3b96fc4579 100000
output:
{
"funding_txid": "0e5e4d4f8f793cddd9370eb81140d5bc168b0e32200a3a17177d9e4da26607b0"
}
π Mine some blocks to increase the confirmations for the Channel opening transaction
Once the channel has been created and lnd1's
BTC contribution has been added to the channel, we need to mine/generate some blocks to increase confirmations for the Channel opening transaction.
command:
bitcoin-cli -generate 10
output:
{
"address": "bcrt1q5ltxhvn3essvq5ldzpfrvlhul73auec4ekg4fk",
"blocks": [
"518ab6ab9e6e93ef03be2da8a8f728358cb0d4270126d1770cdb223df52f9f11",
"01f8a4a87c0c8c98697458e42bdb459af095ba90ad9ae165ac3c31be9addf447",
"3880fe05eaf1cff356d7b035d619704a6b93893b225fb31a938ca7275488229c",
"11e52d12e2d7547dd1f47a44d088bd59fd73c7c436b4076c03e51d78a3fba25e",
...
]
}
π Check the list of channels
Run the command below to check the list of active channels and to confirm that the channel between both nodes is well-funded and ready.
command:
lncli1 listchannels
output:
{
"channels": [
{
"active": true,
"remote_pubkey": "024baa5e16c118f42cddd95fd828b32fa8dfcfea55fa384e89e2da0f3b96fc4579",
"channel_point": "0e5e4d4f8f793cddd9370eb81140d5bc168b0e32200a3a17177d9e4da26607b0:0",
"chan_id": "735573279047680",
"capacity": "100000",
"local_balance": "96530",
"remote_balance": "0",
"commit_fee": "3140",
"commit_weight": "772",
"fee_per_kw": "2500",
"unsettled_balance": "0",
"total_satoshis_sent": "0",
"total_satoshis_received": "0",
...
}
]
}
π Create an invoice on lnd2
Now that we have confirmed that our channel is ready for transactions, let's go ahead and create a payable invoice for an amount of 50,000 SAT
on lnd2
command:
lncli2 addinvoice --amt 50000
output:
{
"r_hash": "28f35ccf79cfc8545351ae362b4fdb0f85437ddf452c1aebd399227607e0eb6e",
"payment_request": "lnbcrt500u1pja5y06pp59re4enmeely9g5634cmzkn7mp7z5xlwlg5kp467nny38vplqadhqdqqcqzzsxqyz5vqsp58p5xllcxwt76rt7hjtjwuec2n5sfgv2t9kkc6vplrhsk2edj6ndq9qyysgqs8aysfmfz60jexh03kq27cmpym5qw8hw55wac4mqmj6t684t48u89kqaw0m7y0xuyygh5uuj95643gde3vse7zxgtu4aycfwfwk5z3cqfwmtp7",
"add_index": "1", //ππΏ total amount of invoices created.
"payment_addr": "38686fff0672fda1afd792e4ee670a9d2094314b2dad8d303f1de16565b2d4da"
}
Let's quickly inspect or confirm the details of this newly created invoice from lnd1
by making use of the invoice's payment_request
command:
lncli1 decodepayreq lnbcrt500u1pja5y06pp59re4enmeely9g5634cmzkn7mp7z5xlwlg5kp467nny38vplqadhqdqqcqzzsxqyz5vqsp58p5xllcxwt76rt7hjtjwuec2n5sfgv2t9kkc6vplrhsk2edj6ndq9qyysgqs8aysfmfz60jexh03kq27cmpym5qw8hw55wac4mqmj6t684t48u89kqaw0m7y0xuyygh5uuj95643gde3vse7zxgtu4aycfwfwk5z3cqfwmtp7
output:
{
"destination": "024baa5e16c118f42cddd95fd828b32fa8dfcfea55fa384e89e2da0f3b96fc4579",
"payment_hash": "28f35ccf79cfc8545351ae362b4fdb0f85437ddf452c1aebd399227607e0eb6e",
"num_satoshis": "50000",
"timestamp": "1708790266",
"expiry": "86400",
"description": "",
"description_hash": "",
"fallback_addr": "",
"cltv_expiry": "80",
"route_hints": [],
"payment_addr": "38686fff0672fda1afd792e4ee670a9d2094314b2dad8d303f1de16565b2d4da",
"num_msat": "50000000",
"features": {
"8": {
"name": "tlv-onion",
"is_required": true,
"is_known": true
},
...
}
...
}
π Pay or satisfy the invoice created by lnd2
via lnd1
Time for lnd1
to pay up π§Ύ
Run the command below and follow the prompts to confirm payment
command:
lncli1 payinvoice lnbcrt500u1pja5y06pp59re4enmeely9g5634cmzkn7mp7z5xlwlg5kp467nny38vplqadhqdqqcqzzsxqyz5vqsp58p5xllcxwt76rt7hjtjwuec2n5sfgv2t9kkc6vplrhsk2edj6ndq9qyysgqs8aysfmfz60jexh03kq27cmpym5qw8hw55wac4mqmj6t684t48u89kqaw0m7y0xuyygh5uuj95643gde3vse7zxgtu4aycfwfwk5z3cqfwmtp7
output:
Payment hash: 28f35ccf79cfc8545351ae362b4fdb0f85437ddf452c1aebd399227607e0eb6e
Description:
Amount (in satoshis): 50000
Fee limit (in satoshis): 2500
Destination: 024baa5e16c118f42cddd95fd828b32fa8dfcfea55fa384e89e2da0f3b96fc4579
Confirm payment (yes/no): yes
+------------+--------------+--------------+--------------+-----+----------+-----------------+----------------------+
| HTLC_STATE | ATTEMPT_TIME | RESOLVE_TIME | RECEIVER_AMT | FEE | TIMELOCK | CHAN_OUT | ROUTE |
+------------+--------------+--------------+--------------+-----+----------+-----------------+----------------------+
| SUCCEEDED | 0.086 | 0.565 | 50000 | 0 | 761 | 735573279047680 | 024baa5e16c118f42cdd |
+------------+--------------+--------------+--------------+-----+----------+-----------------+----------------------+
Amount + fee: 50000 + 0 sat
Payment hash: 28f35ccf79cfc8545351ae362b4fdb0f85437ddf452c1aebd399227607e0eb6e
Payment status: SUCCEEDED, preimage: 071ae531770166a26d7b42a82a6215776a4f90f1e9935c1f225077158b3782c9
Now that we have made payment, let's look up the invoice on lnd2
we'll be using the payment hash
above
command:
lncli2 lookupinvoice 28f35ccf79cfc8545351ae362b4fdb0f85437ddf452c1aebd399227607e0eb6e
output:
{
"memo": "",
"r_preimage": "071ae531770166a26d7b42a82a6215776a4f90f1e9935c1f225077158b3782c9",
"r_hash": "28f35ccf79cfc8545351ae362b4fdb0f85437ddf452c1aebd399227607e0eb6e",
"value": "50000",
"value_msat": "50000000",
"settled": true,// ππΏ the invoice has been fulfilled β
"creation_date": "1708790266",
"settle_date": "1708793723",
"payment_request": "lnbcrt500u1pja5y06pp59re4enmeely9g5634cmzkn7mp7z5xlwlg5kp467nny38vplqadhqdqqcqzzsxqyz5vqsp58p5xllcxwt76rt7hjtjwuec2n5sfgv2t9kkc6vplrhsk2edj6ndq9qyysgqs8aysfmfz60jexh03kq27cmpym5qw8hw55wac4mqmj6t684t48u89kqaw0m7y0xuyygh5uuj95643gde3vse7zxgtu4aycfwfwk5z3cqfwmtp7",
"description_hash": "",
"expiry": "86400",
"fallback_addr": "",
"cltv_expiry": "80",
"route_hints": [],
...
}
π Close the payment channel, kill both Bitcoin and lightning daemons
"Eventually, all good things must come to an end"
We are finally done with all lightning transactions so let's go ahead and close the payment channel and kill all running lightning and Bitcoin daemons as we close for the day.
Run the command below from any of the two nodes
command:
lncli2 closeallchannels
output:
{
"remote_pub_key": "02e0810d836946eebaeb9186c45ebb0c2d17294890ec67f488c9127de4d51dd3cd",
"channel_point": "0e5e4d4f8f793cddd9370eb81140d5bc168b0e32200a3a17177d9e4da26607b0:0",
"closing_txid": "9b9e88eec1d3708d97588088e6e40cd0d3cc65163baabb5215445785268f5b78",
"error": ""
}
Check the list of channels
command:
lncli2 listchannels
output:
{
"channels": [] //ππΏ no active channel
}
Run the command below to kill all running daemons
command:
lncli1 stop && lncli2 stop && bitcoin-cli stop
output:
Bitcoin Core stopping
π Conclusion
Finally, an amazing end to a three part journey.
I hope this article helped you gain some hands-on experience in working with the lightning network. Remember, Lightning payments are faster, cheaper and less complex than the conventional bitcoin transaction. see you in the next one ππΏ
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