Simverse

This is a tool for lightning network developers. It can generate local simnet clusters of requested size and shape. It uses docker-compose to manage the cluster and provides a set of helper scripts for your convenience.

Features

• supports btcd and bitcoind as backend nodes
• supports lnd, lightningd and eclair as lightning nodes

Workflow

You use a simple DSL script (bash) as a recipe to describe your cluster. Given a recipe, Simverse will generate a bunch of dockerfiles, docker-compose config and other supporting scripts for you. Before generating the files you can tweak your configuration using env variables.

Prerequisites:

On host machine you should have recent versions of:

• bash 4+, git 2+, jq 1.6+
• docker 18+, docker-compose 1.24+

Tested on macOS and Ubuntu 18.10.

Quick start

In a terminal session:

> git clone --recursive https://github.com/darwin/simverse.git
> cd simverse
> ./sv create                                 # first time, it will ask to clone repos, answer yes
...
> ./sv enter
...
_workspace/default > ./dc build
...
_workspace/default > ./dc up                  # this gives you a nice log for whole cluster
...

In a second terminal session:

> cd simverse
> ./sv enter
_workspace/default > btcd1 getinfo
...
_workspace/default > alice getinfo
...
_workspace/default > connect alice bob           # connect Alice's lnd node to Bob's
...
_workspace/default > fund alice 10               # fund Alice with 10 BTC
...
_workspace/default > open_channel alice bob 0.1  # open a LN channel
...
_workspace/default > pay alice bob 0.01          # pay via LN

Here is the default recipe which was used for simnet generation (see recipes/default.sh):

. cookbook/cookbook.sh

prelude

add btcd

add lnd alice
add lnd bob

If you want different configuration, see recipes/readme.md to understand the naming convention of recipes. Then you can create the simverse by adding a parameter to the create script:

./sv create a1k2

This will create a bitcoind and two lightningd configuration simverse.

If you don't want to risk putting your machine on fire, here is a recording:

• note that we used pre-generated ./tmux script to launch everything in one terminal window

Generated simnet folder

A simnet folder contains generated files for your simnet based on a selected recipe.

Typical workflow is to create simnet and then enter it via ./sv enter [simnet_name], then you can

• use ./dc command to manage simnet cluster via docker compose (see generated docker-compose.yml).
• use tools from toolbox and (generated) aliases folders (they should be on $PATH).

An example simnet session

See 'quick start' section above.

Go to simverse root directory. Please open two terminal windows:

• The first one will be for logs
• The second one will be for interaction with running cluster

In the first terminal session

1. Enter simnet via ./sv enter default
2. Build simnet via ./dc build
3. Launch simnet via ./dc up

When you hit CTRL+C, docker will shutdown your simnet and you can rinse, repeat. See tips below in FAQ to learn more.

In the second terminal session

1. (assuming running simnet)
2. Enter simnet via ./sv enter default
3. you can control individual services via their names e.g. alice getinfo or btcd1 getnetworkinfo (see aliases dir). Also note that first lnd node has alias lncli and first btcd node has alias btcctl.
4. you can also use convenience commands from toolbox, for example:

# assuming you have at least one btcd node and lnd nodes alice, bob and charlie (see the recipe 'b1l3.sh')
#
# let's follow the tutorial https://dev.lightning.community/tutorial/01-lncli

fund alice 10
fund bob 10
fund charlie 10

connect alice charlie
connect bob charlie

open_channel alice charlie 0.1
open_channel charlie bob 0.05

# wait for channel discovery to kick in (circa 20s)

pay alice bob 0.01

Alternatively you can use our pre-generated ./tmux script.

Gotchas

• If in troubles, please make sure you have the latest versions tools above, especially docker and docker-compose.
• Simverse tries to enforce host's UID and GID as permissions for simnet user running the services like lnd or btcd. This is quite important for comfortable access to simnet state folders from host machine under some systems. This can fail in case when your current UID(GID) on host is already taken inside Alpine Linux container. In such cases the effective user in the container is disconnected from host user and permissions on state folder might be different. You might need root permission to remove them on host.

macOS notes

• (recommended)keep workspace on APFS-formatted filesystem to benefit from clonefile

FAQ

Is this secure?

No. This is a developer setup and should be never used on a machine connected to open internet. It is expected to be used developer machine on a local network behind NAT/firewall and should never contain sensitive info. Anyways whatever you do, you use it at your own risk.

How do I customize build/runtime parameters for individual docker containers?

By customizing your recipe before adding a node or globally via env variables. See _defaults.sh. For example you can set different DEFAULT_LND_REPO_PATH before each add lnd ... command. This would tweak effective config for following lnd nodes. Read the cookbook.sh bash script for better understanding.

How do I rebuild everything from scratch?

./dc --no-cache build

How do I determine ports mapping to my host machine?

./dc ps (assuming a running simnet)

I'd like to know IP addresses of individual machines in the simnet cluster. How?

list_docker_ips please note that you should not use hard-coded IPs, instead use service names docker assigned to individual machines

Is it possible to launch multiple simnets in parallel?

It is possible to create multiple simnets. But under normal circumstances you are expected to run only one simnet at a time. By default, all simnets use the same port mappings to the host machine, so you would not be able to launch them in parallel. But you can write a simple wrapper scripts which could modify all *_PORT_ON_HOST in _defaults.sh. You can allocate them so that they don't overlap for simnets you need to run in parallel.

I noticed the nodes run in regtest mode, not simnet. Why?

Simnet mode is supported only in btcd and lnd. Bitcoind and c-lightning have regtest which happens to be available in btcd/lnd as well. To allow hybrid simverse clusters we had to use regtest mode everywhere (which works like simnet for our purposes). Only we had to patch btcd to fix some minor issue, because not many people use it this way I guess.

How can I inspect a running container in shell?

./dc exec <container> bash or ./dc exec <container> fish or ./dc exec <container> sh

or ./dc exec <container> <one-off-cmd>

Pro Tip: you might want to add --user root before container name to run the command with unrestricted permissions

Is it possible to keep simverse workspace on my own path?

Yes. Look for SIMVERSE_WORKSPACE env var.

Is it possible to keep projects' repos on my own path?

Yes. Look for SIMVERSE_REPOS env var.

What is a master bitcoin node?

In a cluster of bitcoin nodes we need one which will be special. It will do some privileged tasks like mining or holding mined coins in its associated wallet. By convention, master bitcoin node is always first bitcoin node created. You can get its hostname by running lookup_host 1 role bitcoin. Simverse supports multiple bitcoin node implementations and master node might be either btcd or bitcoind "flavor". Raw cli interface might be slightly different, so we try to hide this in our commands like onchain_balance, chain_height or earn. If you looked at their implementation you would spot code branches for different bitcoin node flavors.

Where is a faucet?

This is not a testnet with faucet so we have to mine coins ourselves. Look for FAUCET_ADDR env var which contains pre-generated bitcoin address which will receive all mined coins. During bitcoin node initialization we import this address into a wallet (see setup-wallet.sh). This way btcctl --wallet sendfrom imported ... can be used to send funds to others in need. We use similar approach when your master bitcoin node is bitcoind.

Please look at toolbox/fund script which can be used for convenient funding of lnd wallets. For example run fund alice 10 to send 10 BTC to Alice's lnd node wallet. The script might decide to call toolbox/earn to mine enough coins and wait for their maturity.

What is the difference between heterogeneous and hybrid simnets?

A homogeneous simnet contains only btcd + lnd nodes or only bitcoind + c-lightning nodes. Generally, it contains only one flavor of bitcoin and one flavor of lightning nodes. Heterogeneous simnet can mix them. A hybrid simnet is a simnet with cooperating nodes running in docker and also on the host machine. This is more advanced developer setup where you want to develop/debug one specific node and have rest of the simnet running "in the background" in docker.

Cool work! How can I send some sats your way?

My pubkey starts with 03e24db0

---

simverse utility reference

Note that sv is a convenience symlink to simverse.

> ./sv help

Simverse v0.5.

A generator of simnet clusters for lnd and friends.

Usage: ./sv [command] [args...]

Commands:

  create    create a new simnet based on a recipe
  destroy   destroy existing named simnet
  list      list existing simnets
  enter     enter a named simnet
  state     perform state operations on a simnet
  repos     perform operations on code repositories
  help      this help page
  version   display version

Run `./sv help <command>` for specific usage.
Run `./sv help <topic>` to learn about general concepts.

Topics: simnet, recipes, workspace, toolbox, aliases.

Please visit 'https://github.com/darwin/simverse' for further info.

> ./sv help simnet

About simnets

Simnet is a cluster of bitcoin and lightning nodes talking to each other.
Simnets are used during development to test different scenarios/workflow
where multiple nodes are required.

Simnets can have different sizes and shapes. They can be heavily parametrized.

This tool aims to help with simnet creation and maintenance.

The goal is to:

  * easily generate a simnet based on given parameters
  * easily manage state of a simnet (e.g. for future replays)
  * somewhat isolate simnet from host machine (via docker)
  * provide cross-platform solution (macos, linux)

Typical simnet folder structure is:

  _workspace/[simnet_name]/
    _states/
      master/
        certs/
        lnd-data-alice/
        btcd-data-btcd1/
        ...
      ...
    _volumes -> _states/master
    aliases/
    docker/
    helpers/
    repos/
    toolbox/
    dc
    docker-compose.yml
    tmux

Feel free to look around. Below we discuss state management.

Simnet state

All docker containers have their state mapped to host machine into _volumes folder.
It contains btcd's data directories, lnd's data directories and similar.
When you stop docker containers and later run them again, the state will persist.

When you look at _volumes you realize that it is just a symlink somewhere into _states directory.
Typically pointing to 'master', which is the default state.

You can manage states via `./sv state ...`.
Those are just convenience commands to copy/switch _volumes symlink between states.

This is an advanced feature for people who want to snapshot a state for further rollbacks.
It can be also used for replays during automated testing.


A note on hybrid simnets

By default, simnet is generated in a way that all nodes live inside docker containers
managed by docker-compose. For convenience we map all relevant ports to host machine.
This allows running another node directly on host machine and interact with nodes in
the cluster inside the docker.

This is expected workflow for someone who wants to develop particular feature and
needs supporting simnet "in the background".

> ./sv help workspace

About workspace

Workspace is a working folder where your generated simnets get stored.
By default it is under `_workspace` but you can control it
via SIMVERSE_WORKSPACE environmental variable.

Each simnet has a name given to it during `./sv create [recipe] [name]` call.
Workspace contains a folder for each simnet named after it.

You can enter your simnet via `./sv enter [name]`.

> ./sv help create

Usage: ./sv create [-f] [recipe] [name]

Creates a new simnet with `name` (default) based on `recipe` (default).
On success, prints a path to generated simnet working folder in your workspace.

Flags:
  -f,--force    force creation by destroying previous simnet

Recipe should be name of a script in `recipes` folder. It specifies requested simnet
parameters and drives the generator.

Read more about recipes via `./sv help recipes`

> ./sv help recipe

About recipes

Simnets can have different sizes and shapes. They can be heavily parametrized.
Recipe is a script describing how to build a given simnet.

An example of a simple recipe:

    . cookbook/cookbook.sh

    prelude

    add btcd btcd

    add lnd alice
    add lnd bob

Recipes are located under `recipes` folder.
Say, we stored the above recipe as `recipes/example.sh`.

By running `./sv create example mysn`, we create a new simnet named `mysn`
which has one btcd node and two lnd nodes, all with default settings.

Recipes are bash scripts executed as the last step in simnet creation.
That means you can do anything bash can do to tweak given simnet.
To make your life easier, we provide a simple library "cookbook" for building
simnet on step-by-step basis with sane defaults.

We are not going to document the cookbook here. Please refer to its sources.

Please look around in `recipes` folder and see how existing recipes are done.

> ./sv help toolbox

About toolbox

Toolbox is a set of convenience scripts for typical interaction with simnet.

When you enter a simnet via `./sv enter [name]`, toolbox folder is added to your PATH.

Explore `toolbox` folder for the details:

  attach_dlv
  brief
  chain_height
  connect
  earn
  faucet_balance
  fund
  generate
  get_route
  inspect_container
  list_docker_ips
  ln_balance
  lookup_container
  lookup_service
  newaddr
  onchain_balance
  open_channel
  pay
  pubkey
  req_pay
  simnet_ready

> ./sv help aliases

About aliases

Aliases are scripts generated depending on shape/parameters of your simnet.

When you enter a simnet via `./sv enter [name]`. Aliases folder is added to your PATH.

For example default simnet will generate following aliases for you:

  alice
  bob
  btcd1
  btcctl -> btcd1
  lncli -> alice

Aliases are convenience shortcuts to control tools for individual nodes (named by simnet recipe).

Additionally there will be generated `btcctl` symlink pointing to first btcd node. And `lncli`
symlink pointing to the first lnd node. This comes handy for asking general questions about networks
not specific to exact node.

> ./sv help destroy

Usage: ./sv destroy [name]

Deletes a simnet with `name` (default).

> ./sv help enter

Usage: ./sv enter [name]

Enters into a sub-shell with environment prepared for simnet with `name` (default).

You typically use this command to start working with a given simnet. In the sub-shell we:

  * switch working directory into simnet's folder
  * set PATH to additionally contain toolbox and aliases

> ./sv help list

Usage: ./sv list [filter]

Lists all available simnets by name. Optionally you can filter the list using a case-insensitive substring.

Run `./sv help simnet` to learn what is a simnet.

> ./sv help state

Usage: ./sv state [sub-command] ...

Manipulates simnet state.

Sub-commands:

  show     show currently selected state in a given simnet
  clone    clone existing state in a given simnet
  switch   switch selection to a named state in a given simnet
  list     list states for a given simnet
  rm       remove a named state in a given simnet

./sv state show [simnet_name]
./sv state clone [--force] [--switch] [simnet_name] <new_state_name> [old_state_name]
./sv state switch [simnet_name] [state_name]
./sv state list [simnet_name] [filter]
./sv state rm [simnet_name] <state_name>

Run `./sv help simnet` to learn about simnet states.

> ./sv help repos

Usage: ./sv repos [sub-command] ...

Manipulates code repositories.

Sub-commands:

  init       init default repos (git clone)
  update     update default repos (git pull)
  clone      clone existing repo under a new name
  list       list repos
  rm         remove repo(s)
  report     report current tips
  unshallow  unshallow repos

./sv repos init [repo_name] [...]
./sv repos update [repo_name] [...]
./sv repos clone [--force] <repo_name> <new_repo_name>
./sv repos list [filter]
./sv repos rm [repo_name] [...]
./sv repos report [filter]
./sv repos unshallow [filter]