RPC calls to LND using curl?

Question

I have a bitcoind and LND server running. I can make RPC calls to bitcoind using curl, like this:

curl http://XXX:YYY@localhost:8332 -H 'content-type:text/plain;' --data-binary '{"jsonrpc":"1.0","id":"curltext","method":"getblockchaininfo","params":[]}'

However I can't find out how to make RPC calls to LND using curl.

My lnd.conf contains a [Bitcoind] section like this:

[Bitcoind]
bitcoind.rpchost=127.0.0.1:8332
bitcoind.rpcuser=XXX
bitcoind.rpcpass=YYY
bitcoind.zmqpubrawblock=127.0.0.1:28332
bitcoind.zmqpubrawtx=127.0.0.1:28333

However, what I'm struggling with is finding out or configuring how to actually connect to LND itself with RPC.

Can't find clear documentation about this. I figured out that apparently I need to use port 10009, but this doesn't work:

curl http://XXX:YYY@localhost:10009 -H 'content-type:text/plain;' --data-binary '{"jsonrpc":"1.0","id":"curltext","method":"getinfo","params":[]}'

(result is empty, no error, nothing)

I guessed perhaps I need to set a separate RPC username and password for LND, but I can't find out how or where, i.e. what the settings are in lnd.conf?

Also, do I have to add a config line to make sure the LND daemon is listening to RPC calls?

Also, do I have to add a config line to make sure the LND daemon is accepting RPC calls from specific IPs? (localhost in this case, or adding external IPs later)

Answer 1

The lnd.conf information you shared above is required for the LND instance to query your local bitcoind node (to detect or follow on-chain/mempool events), and does not represent the LND user interface.

LND has a REST API which you can query with curl: https://api.lightning.community/rest/index.html#lnd-rest-api-reference

The REST interface listening port can be configured here: https://github.com/lightningnetwork/lnd/blob/master/config.go

The LND documentation describes it in more detail, but you will need to generate valid macaroons for LND https calls.

Answer 2

LND has two API interfaces:

1. On port 8080 is a REST RPC interface
2. On port 10009 is a GRPC interface.

The REST interface on 8080 needs a macaroon file and an optional tls certificate.
You can use CURL like this:

MACAROON_HEADER="Grpc-Metadata-macaroon: $(xxd -ps -u -c 1000 ~/.lnd/admin.macaroon)" 
curl -X GET --cacert ~/.lnd/tls.cert --header "$MACAROON_HEADER" https://192.168.0.7:8080/v1/getinfo

if you want to ignore tlc.cert add -k option to the curl call.

The parameters above are:

1. ~./lnd/admin.macaroon: is the path to your nodes macaroon file (generated by your lnd node)
2. ~/.lnd/tls.cert: is the path to the tls cert file (generated by your lnd node)
3. 192.168.0.7:8080 is the IP and port of the RPC of your LND node, if its on the same machine you can just use localhost:8080

You need the following settings in your lnd.conf:

• restlisten=0.0.0.0:8080 this tells LND to listen to RPC requests on port 8080
• no-rest-tls=true - this allows you to disable tls certificates