# Installation

### Preliminaries
  In order to work with [`lnd`](https://github.com/lightningnetwork/lnd), the
  following build dependencies are required:

  * **Go:** `lnd` is written in Go. To install, run one of the following commands:


    **Note**: The minimum version of Go supported is Go 1.9. We recommend that
    users use the latest version of Go, which at the time of writing is
    [`1.10`](https://blog.golang.org/go1.10).


    On Linux:
    ```
    sudo apt-get install golang-1.10-go
    ```
    > Note that golang-1.10-go puts binaries in /usr/lib/go-1.10/bin. If you want them on your PATH, you need to make that change yourself. Alternatively, you can run:
    ```
    sudo ln -s /usr/lib/go-1.10/bin/go /usr/local/bin/go
    ```

    On Mac OS X
    ```
    brew install go
    ```

    Alternatively, one can download the pre-compiled binaries hosted on the
    [golang download page](https://golang.org/dl/). If one seeks to install
    from source, then more detailed installation instructions can be found
    [here](http://golang.org/doc/install).

    At this point, you should set your `$GOPATH` environment variable, which
    represents the path to your workspace. By default, `$GOPATH` is set to
    `~/go`. You will also need to add `$GOPATH/bin` to your `PATH`. This ensures
    that your shell will be able to detect the binaries you install.

    ```bash
    export GOPATH=~/gocode
    export PATH=$PATH:$GOPATH/bin
    ```

    We recommend placing the above in your .bashrc or in a setup script so that
    you can avoid typing this every time you open a new terminal window.

  * **dep:** This project uses `dep` to manage dependencies as well
    as to provide *reproducible builds*.

    **Note**: `dep` is automatically installed via the `make`. To fetch `dep`
    manually, use the following command (assumes you already have Go properly
    installed):
    ```
    go get -u github.com/golang/dep/cmd/dep
    ```

### Installing lnd

With the preliminary steps completed, to install `lnd`, `lncli`, and all
related dependencies run the following commands:
```
go get -d github.com/lightningnetwork/lnd
cd $GOPATH/src/github.com/lightningnetwork/lnd
make && make install
```

Alternatively, if one doesn't wish to use `make`, then the `go` commands can be
used directly:
```
dep ensure -v
go install -v ./...
```

**Updating**

To update your version of `lnd` to the latest version run the following
commands:
```
cd $GOPATH/src/github.com/lightningnetwork/lnd
git pull
make && make install
```

Alternatively, if one doesn't wish to use `make`, then the `go` commands can be
used directly:
```
cd $GOPATH/src/github.com/lightningnetwork/lnd
git pull
dep ensure -v
go install -v ./...
```

**Tests**

To check that `lnd` was installed properly run the following command:
```
make check
```

### Installing btcd

When using the `btcd` backend, `lnd` currently requires the
[roasbeef](https://github.com/roasbeef/btcd) fork of `btcd` due to neutrino
additions that are not yet available in the master branch. To install, run the
following commands:

Install **btcd**: (must be from roasbeef fork, not from btcsuite)
```
make btcd
```

### Starting btcd

Running the following command will create `rpc.cert` and default `btcd.conf`.

```
btcd --testnet --txindex --rpcuser=REPLACEME --rpcpass=REPLACEME
```
If you want to use `lnd` on testnet, `btcd` needs to first fully sync the
testnet blockchain. Depending on your hardware, this may take up to a few
hours.

(NOTE: It may take several minutes to find segwit-enabled peers.)

While `btcd` is syncing you can check on its progress using btcd's `getinfo`
RPC command:
```
btcctl --testnet --rpcuser=REPLACEME --rpcpass=REPLACEME getinfo
{
  "version": 120000,
  "protocolversion": 70002,
  "blocks": 1114996,
  "timeoffset": 0,
  "connections": 7,
  "proxy": "",
  "difficulty": 422570.58270815,
  "testnet": true,
  "relayfee": 0.00001,
  "errors": ""
}
```

Additionally, you can monitor btcd's logs to track its syncing progress in real
time.

You can test your `btcd` node's connectivity using the `getpeerinfo` command:
```
btcctl --testnet --rpcuser=REPLACEME --rpcpass=REPLACEME getpeerinfo | more
```

### lnd

#### Simnet vs. Testnet Development

If you are doing local development, such as for the tutorial, you'll want to
start both `btcd` and `lnd` in the `simnet` mode. Simnet is similar to regtest
in that you'll be able to instantly mine blocks as needed to test `lnd`
locally. In order to start either daemon in the `simnet` mode use `simnet`
instead of `testnet`, adding the `--bitcoin.simnet` flag instead of the
`--bitcoin.testnet` flag.

Another relevant command line flag for local testing of new `lnd` developments
is the `--debughtlc` flag. When starting `lnd` with this flag, it'll be able to
automatically settle a special type of HTLC sent to it. This means that you
won't need to manually insert invoices in order to test payment connectivity.
To send this "special" HTLC type, include the `--debugsend` command at the end
of your `sendpayment` commands.


There are currently two primary ways to run `lnd`: one requires a local `btcd`
instance with the RPC service exposed, and the other uses a fully integrated
light client powered by [neutrino](https://github.com/lightninglabs/neutrino).

#### Running lnd in Light Client Mode

In order to run `lnd` in its light client mode, you'll need to locate a
full-node which is capable of serving this new light client mode. A [BIP
draft](https://github.com/Roasbeef/bips/blob/master/gcs_light_client.mediawiki)
exists, and will be finalized in the near future, but for now you'll need to be
running `roasbeef`'s fork of btcd. A public instance of such a node can be
found at `faucet.lightning.community`.

To run lnd in neutrino mode, run `lnd` with the following arguments, (swapping
in `--bitcoin.simnet` if needed), and also your own `btcd` node if available:
```
lnd --bitcoin.active --bitcoin.testnet --debuglevel=debug --bitcoin.node=neutrino --neutrino.connect=faucet.lightning.community
```

#### Running lnd using the btcd backend

If you are on testnet, run this command after `btcd` has finished syncing.
Otherwise, replace `--bitcoin.testnet` with `--bitcoin.simnet`. If you are
installing `lnd` in preparation for the
[tutorial](http://dev.lightning.community/tutorial), you may skip this step.
```
lnd --bitcoin.active --bitcoin.testnet --debuglevel=debug --btcd.rpcuser=kek --btcd.rpcpass=kek --externalip=X.X.X.X
```

#### Running lnd using the bitcoind or litecoind backend

The configuration for bitcoind and litecoind are nearly identical, the following
steps can be mirrored with loss of generality to enable a litecoind backend.
Setup will be described in regards to `bitcoind`, but note that `lnd` uses a
distinct `litecoin.node=litecoind` argument and analogous subconfigurations
prefixed by `litecoind`.

To configure your bitcoind backend for use with lnd, first complete and verify
the following:

- The `bitcoind` instance must be configured with `--txindex` just like `btcd`
  above
- Additionally, since `lnd` uses
  [ZeroMQ](https://github.com/bitcoin/bitcoin/blob/master/doc/zmq.md) to
  interface with `bitcoind`, *your `bitcoind` installation must be compiled with
  ZMQ*. Note that if you installed `bitcoind` from source and ZMQ was not present, 
  then ZMQ support will be disabled, and `lnd` will quit on a `connection refused` error. 
  If you installed `bitcoind` via Homebrew in the past ZMQ may not be included 
  ([this has now been fixed](https://github.com/Homebrew/homebrew-core/pull/23088) 
  in the latest Homebrew recipe for bitcoin)
- Configure the `bitcoind` instance for ZMQ with `--zmqpubrawblock` and
  `--zmqpubrawtx` (the latter is optional but allows you to see unconfirmed
  transactions in your wallet). They must be combined in the same ZMQ socket
  address (e.g. `--zmqpubrawblock=tcp://127.0.0.1:28332` and
  `--zmqpubrawtx=tcp://127.0.0.1:28332`).
- Start `bitcoind` running against testnet, and let it complete a full sync with
  the testnet chain (alternatively, use `--bitcoind.regtest` instead).

Here's a sample `bitcoin.conf` for use with lnd:
```
testnet=1
txindex=1
server=1
daemon=1
zmqpubrawblock=tcp://127.0.0.1:28332
zmqpubrawtx=tcp://127.0.0.1:28332
```

Once all of the above is complete, and you've confirmed `bitcoind` is fully updated with the latest blocks on testnet, run the command below to launch `lnd` with `bitcoind` as your backend (as with `bitcoind`, you can create an `lnd.conf` to save these options, more info on that is described further below):

```
lnd --bitcoin.active --bitcoin.testnet --debuglevel=debug --bitcoin.node=bitcoind --bitcoind.rpcuser=REPLACEME --bitcoind.rpcpass=REPLACEME --bitcoind.zmqpath=tcp://127.0.0.1:28332 --externalip=X.X.X.X
```

*NOTE:*
- The auth parameters `rpcuser` and `rpcpass` parameters can typically be determined by `lnd` for a `bitcoind` instance running under the same user, including when using cookie auth. In this case, you can exclude them from the `lnd` options entirely.
- If you DO choose to explicitly pass the auth parameters in your `lnd.conf` or command line options for `lnd` (`bitcoind.rpcuser` and `bitcoind.rpcpass` as shown in example command above), you must also specify the `bitcoind.zmqpath` option. Otherwise, `lnd` will attempt to get the configuration from your `bitcoin.conf`.
- You must ensure the same address (including port) is used for the `bitcoind.zmqpath` option passed to `lnd` as for the `zmqpubrawblock` and `zmqpubrawtx` passed in the `bitcoind` options.
- When running lnd and bitcoind on the same Windows machine, ensure you use 127.0.0.1, not localhost, for all configuration options that require a TCP/IP host address.  If you use "localhost" as the host name, you may see extremely slow inter-process-communication between lnd and the bitcoind backend.  If lnd is experiencing this issue, you'll see "Waiting for chain backend to finish sync, start_height=XXXXXX" as the last entry in the console or log output, and lnd will appear to hang.  Normal lnd output will quickly show multiple messages like this as lnd consumes blocks from bitcoind.
- Don't connect more than one instance of `lnd` to `bitcoind`.  With the default `bitcoind` settings, having more than one instance of `lnd`, or `lnd` plus any application that consumes the RPC could cause `lnd` to miss crucial updates from the backend.

#### Disabling Wallet Encryption

To disable encryption of the wallet files, pass the `--noencryptwallet` argument
to `lnd`. Obviously beware the security implications of running an unencrypted
wallet - this argument must only be used for testing purposes.

#### Macaroons

`lnd`'s authentication system is called **macaroons**, which are decentralized
bearer credentials allowing for delegation, attenuation, and other cool
features. You can learn more about them in Alex Akselrod's [writeup on
Github](https://github.com/lightningnetwork/lnd/issues/20).

Running `lnd` for the first time will by default generate the `admin.macaroon`,
`read_only.macaroon`, and `macaroons.db` files that are used to authenticate
into `lnd`. They will be stored in the default `lnd` data directory. Note that
if you specified an alternative data directory (via the `--datadir` argument),
you will have to additionally pass the updated location of the `admin.macaroon`
file into `lncli` using the `--macaroonpath` argument.

To disable macaroons for testing, pass the `--no-macaroons` flag into *both*
`lnd` and `lncli`.

#### Network Reachability

If you'd like to signal to other nodes on the network that you'll accept
incoming channels (as peers need to connect inbound to initiate a channel
funding workflow), then the `--externalip` flag should be set to your publicly
reachable IP address.

# Creating an lnd.conf (Optional)

Optionally, if you'd like to have a persistent configuration between `lnd`
launches, allowing you to simply type `lnd --bitcoin.testnet --bitcoin.active`
at the command line, you can create an `lnd.conf`.

**On MacOS, located at:**
`/Users/[username]/Library/Application Support/Lnd/lnd.conf`

**On Linux, located at:**
`~/.lnd/lnd.conf`

Here's a sample `lnd.conf` for `btcd` to get you started:
```
[Application Options]
debuglevel=trace
debughtlc=true
maxpendingchannels=10

[Bitcoin]
bitcoin.active=1
```

Notice the `[Bitcoin]` section. This section houses the parameters for the
Bitcoin chain. `lnd` also supports Litecoin testnet4 (but not both BTC and LTC
at the same time), so when working with Litecoin be sure to set to parameters
for Litecoin accordingly. For node configuration, the sections are called
`[Btcd]`, `[Bitcoind]`, `[Neutrino]`, `[Ltcd]`, and `[Litecoind]` depending on
which chain and node type you're using.

# Accurate as of:
- _roasbeef/btcd commit:_ `f8c02aff4e7a807ba0c1349e2db03695d8e790e8`
- _roasbeef/btcutil commit:_ `a259eaf2ec1b54653cdd67848a41867f280797ee`
- _lightningnetwork/lnd commit:_ `08de2becf8d77fae192205172c4fb17bb09bd0dbf49e64aa323b2fcbf9fe2a35`
