perunnodetui

Perun Node TUI Client

Perun Node TUI is a text based UI client for trying out the perun payment channels in a graphical way. This software is completely independent from the perun-node. It uses the grpc interface to interact with it.

A video tutorial on using the perunnode tui can be found here.

To use this application, we need to start the perun node and a blockchain node (preferably using ganache-cli). Detailed steps for setting up these components are described in the project documentation.

Once you have started the perun-node and the ganache-cli nodes, you can start the perunnodetui in two different terminals. The perunnodetui binary would have been generated by the make command in the perun-node directory.

./perunnodetui -alice -deploy

go build && ./perunnodetui -bob

The alice and bob flags in the above command will load the default configuration values for the respective users into the fields in the connect screen. The deploy flag will deploy the perun contracts to ganache-cli node. The contracts will be deployed only once and will be used by all participants in the perun network.

Once in the connect screen, press connect button to connect with the perun node. After connecting with the node, the application will switch to dashboard screen.

The dashboard screen shows,

• Address and balance of the user's on-chain account in the top left.
• Time in the top right corner. This will be used as reference to see if notifications have expired.
• List of all channels in a table format in the middle of the screen.
• Command Box and Log Box in the bottom of the screen.

To interact with the application, type commands in the command box. Supported commands are show as place holder text within the box. Here is a brief tutorial.

1. To open a channel:

open <peer-name> <own-balance> <peer-balance> 

Once the command is entered, the channel shows up in the table in Open phase for sender and a request is sent to peer.

1. To accept or reject a channel:

The channel request will show up in the peer's table in Open phase along with a timeout before which the request should be responded to. Use acc or rej followed by the S.No of the channel to send the response.

acc <S.No>

If peer accepts the channel before timeout expires, it will be funded on the blockchain from the users' accounts. The decrease in balances of both the users can be seen in the top left boxes in their respective screens.

Once it is funded, the phase of the channel will change to Transact.

1. To do off-chain transactions:

Once it is in Transact phase, use send and req commands to send and request funds respectively.

send <S.No> <amount>

The updated balance will show up in the updates section of that channel in the table with the status as For Peer. It will also show up on the peer's screen with the status as For User.

Use acc and rej commands in the same way as in step 2 for responding to the update. If accepted, the current balance of the channel will be updated. If rejected, the current will remain unchanged. One can do any number of off-chain transactions this way.

1. Close the channel:

To withdraw funds as per the latest balance of the channel, use the close command.

close <S.No>

Once close command is entered, the channel phase will be marked as Register and a special finalizing update will be sent to the peer. In this update, the balances will remain unchanged, but it will be marked as final. This will be shown as F appended after the version number.

Peer can accept or reject this update. If accepted, the new final state will be registered on the blockchain. If rejected or if timeout expires, the last known state will be registered on the blockchain. The difference is that, when accepted, the final state serves as a proof that both parties have agreed to conclude a particular state on the blockchain. Hence the state will be immediately settled on the blockchain and users can withdraw their funds without any delay.

On the other hand, if a non-final state was registered, both parties will have to wait for a specific period of time to withdraw their balances. This waiting period provides an opportunity for the other participant to refute with the latest state if an older state was registered. The aspects of refuting (if required), waiting out and withdrawing the funds will be automatically taken care of by the node.

Once the channel is settled, phase will be marked as Settle on both the dashboards and balance withdrawal will be initiated by the node. Once the balances are withdrawn, it will change to Closed.