Lnd rpc docs (#2896)

docs/rpc/lnd.md

@@ -0,0 +1,66 @@
+---
+id: lnd-rpc
+title: LND
+---
+
+This is an RPC client for [LND](https://github.com/LightningNetwork/lnd). It assumes that a bitcoind instance is running.
+
+Currently, this RPC client is written for [v0.12.1](https://github.com/lightningnetwork/lnd/releases/tag/v0.12.1-beta) version of LND.
+
+## Configuration of LND
+
+Please see the [sample configuration for LND](https://github.com/lightningnetwork/lnd/blob/v0.12.1-beta/sample-lnd.conf).
+
+You can find the configuration we use for our testing infrastructure for lnd [here](https://github.com/bitcoin-s/bitcoin-s/blob/656e0928bf1bf4f511f60dec625699b454f29a1f/testkit/src/main/scala/org/bitcoins/testkit/lnd/LndRpcTestUtil.scala#L90).
+
+## Starting LND
+
+You need to download the binaries from the [LND's github](https://github.com/lightningnetwork/lnd/releases/tag/v0.12.1-beta).
+
+To run lnd by unzipping the `lnd-linux-amd64-v0.12.1-beta.tar.gz` (or whichever platform you are on) and then running
+
+```bash
+$ ./lnd-linux-amd64-v0.12.1-beta/lnd
+```
+
+If you wish to start lnd from the RPC client, you can construct a [`LndRpcClient.binary`](https://github.com/bitcoin-s/bitcoin-s/blob/656e0928bf1bf4f511f60dec625699b454f29a1f/lnd-rpc/src/main/scala/org/bitcoins/lnd/rpc/LndRpcClient.scala#L35) field set
+
+We will default to using the `binary` field first when trying to start the jar, and the fallback to the default datadir (`~/.lnd`).
+
+Here is an example of how to start lnd:
+
+```scala mdoc:invisible
+import akka.actor.ActorSystem
+import org.bitcoins.lnd.rpc._
+import org.bitcoins.lnd.rpc.config._
+import java.nio.file.Paths
+```
+
+```scala mdoc:compile-only
+
+implicit val system = ActorSystem(s"lnd-rpc-${System.currentTimeMillis}")
+implicit val ec = system.dispatcher
+
+val datadirPath = Paths.get("path", "to", "datadir")
+val binaryPath = Paths.get("path", "to", "lnd-linux-amd64-v0.12.1-beta", "lnd")
+val instance = LndInstance.fromDataDir(datadirPath.toFile)
+val client = new LndRpcClient(instance, Some(binaryPath.toFile))
+
+val startedF = client.start()
+
+for {
+  lnd <- startedF
+  info <- lnd.getInfo
+} yield {
+  println(s"Lnd info: $info")
+}
+```
+
+### Updating to a new LND version
+
+The lnd rpc module uses lnd's gRPC. This means when updating to the latest version, the `.proto` files will need to be updated.
+Bitcoin-S stores them in [lnd-rpc/src/main/protobuf](https://github.com/bitcoin-s/bitcoin-s/tree/master/lnd-rpc/src/main/protobuf).
+You can find the files to copy from LND [here](https://github.com/lightningnetwork/lnd/tree/master/lnrpc).
+
+After updating the `proto` files you can run `sbt compile` and this will generate the corresponding class files, this should then give
+compile warnings for changed rpc functions.

docs/rpc/rpc-clients-intro.md

@@ -28,4 +28,4 @@ RPC calls like `getblockheader` we'll even parse the
 hexadecimal string into a complete header that you can
 interact with without goofing around with bits and bytes.
 
-We currently have RPC clients for Bitcoin Core and Eclair.
+We currently have RPC clients for Bitcoin Core, Eclair, Lnd.

website/i18n/en.json

@@ -116,6 +116,9 @@
       "rpc/rpc-eclair": {
         "title": "Eclair"
       },
+      "rpc/lnd-rpc": {
+        "title": "LND"
+      },
       "rpc/rpc-clients-intro": {
         "title": "Introduction"
       },
@@ -128,6 +131,9 @@
       "security": {
         "title": "Security"
       },
+      "testkit/testkit-core": {
+        "title": "Testkit Core"
+      },
       "testkit/testkit": {
         "title": "Testkit"
       },

website/sidebars.json

@@ -60,7 +60,8 @@
     "RPC Clients": [
       "rpc/rpc-clients-intro",
       "rpc/rpc-eclair",
-      "rpc/rpc-bitcoind"
+      "rpc/rpc-bitcoind",
+      "rpc/lnd-rpc"
     ],
     "Secp256k1": [
       "secp256k1/secp256k1",