tabconf.md

setting up developer environment

Instructions.

Our developer environment is amazing, but it downloads a few gigabytes of data to get set up

fedimint-cli

# pull docker image
docker pull fedimint/fedimint-cli:master

# alias fedimint-cli to docker version
alias fedimint-cli="docker run -v $PWD/demo:/var/fedimint fedimint/fedimint-cli:master fedimint-cli --workdir /var/fedimint"

# join federation at https://testfed.xyz
fedimint-cli join-federation '{"members":[[0,"ws://188.166.55.8:17241/"]]}'

# look at `demo/client.json`

# see wallet balances
fedimint-cli info

# create invoice (decode, pay in faucet)
fedimint-cli ln-invoice <amount> <description>

# pay the invoice on https://testfed.xyz

# sweep funds
fedimint-cli wait-invoice <invoice>
fedimint-cli fetch

# see updated balances
fedimint-cli info

# produce ecash
fedimint-cli spend <amount> 

# see updated balances
fedimint-cli info

# sweep ecash back to wallet
fedimint-cli reissue <ecash>
fedimint-cli fetch

# see updated balances
fedimint-cli info

# play with spending different amounts to understand coin selection

# get invoice from testfed.xyz and pay it
fedimint-cli ln-pay <invoice>

What is a note?

How does lightning integration work?

What's backing all this?

Wallet Module

• consensus_proposal sends something to have hbbft get consensus on
• begin_consensus_epoch gets the "consensus items" -- the things hbbft achieved consensus on -- and can process them before transaction processing begins
  • Wallet module commits block height and fee rate to db https://github.com/fedimint/fedimint/blob/b91d528291db6a41f94eb13e137482296a5bd738/modules/fedimint-wallet/src/lib.rs#L281-#L288
  • save peg out signatures from peers
  • At the end of every epoch, we save a "pending transaction" https://github.com/fedimint/fedimint/blob/b91d528291db6a41f94eb13e137482296a5bd738/modules/fedimint-wallet/src/lib.rs#L480-#L492
  • A background task will pick this signed transaction up and broadcast it https://github.com/fedimint/fedimint/blob/b91d528291db6a41f94eb13e137482296a5bd738/modules/fedimint-wallet/src/lib.rs#L1197-#L1203
• build_verification_cache is premature optimization
  • https://github.com/fedimint/fedimint/blob/b91d528291db6a41f94eb13e137482296a5bd738/modules/fedimint-mint/src/lib.rs#L153-#L174
• validate_input
  • checks that we know the block, input is valid, and deposit hasn't already been claimed
• apply_input
  • saves a spendable utxo (including secret tweak) to the db
• validate_output
  • checks network, acceptable fee, can create tx
• apply_output
  • create tx, sign tx, delete used utxos,
• end_consensus_epic
  • finalize psbts, poller will find them ...
• output_status
  • Incoming contract preimage decryption has state transitions https://github.com/fedimint/fedimint/blob/b91d528291db6a41f94eb13e137482296a5bd738/modules/fedimint-ln/src/lib.rs#L605-#L609
    • the states https://github.com/fedimint/fedimint/blob/b91d528291db6a41f94eb13e137482296a5bd738/modules/fedimint-ln/src/contracts/mod.rs#L132-#L141

Other modules

• frost https://github.com/fedimint/fedimint/compare/master...nickfarrow:minimint:frost
• pay-to-simp-hash https://github.com/justinmoon/fedimint/pull/5/files
  • OutputOutcome here is just a simplicity program id https://github.com/justinmoon/fedimint/pull/5/files#diff-b65a2edd3dce92b73bdac2590ebde2ff1b66ef359b11eaa50200a6366fad6e67R67 ... actually this doesn't really make sense
• betting game https://github.com/elsirion/fedimint/blob/2022-10-tabconf-workshop/modules/fedimint-tabconf/src/lib.rs#L448

Module ideas

• DLC execution
• Federated statechain

Setup a federation

Run 2 servers

docker run -v $PWD/demo:/var/fedimint fedimint/fedimintd:master fedimintd /var/fedimint/mint-1.json /var/fedimint/mint-1.db 10000

docker run -v $PWD/demo:/var/fedimint fedimint/fedimintd:master fedimintd /var/fedimint/mint-2.json /var/fedimint/mint-2.db 10001

Use this for btc rpc bitcoin:bitcoin@188.166.55.8:18443

After setup, take a look at /demo

Note: this is a hack. we've merged distributed key generation. on saturday we'll probably try to hack these together.

• signet deployment https://github.com/elsirion/fedimint-signet