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Exercise-2-solutions.md

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Example Solution for Shelley Stakepool Exercise Sheet 2

LATEST NODE TAG: 1.14.2

Objectives

In the second exercise, we will make sure that you can:

  • Build simple transactions using the basic transaction mechanism;
  • Sign transactions and confirm that the transaction is complete;
  • Submit transactions to the Shelley Testnet Blockchain;
  • Verify that the transactions have been processed by inspecting the addresses that they have been sent to.

PREREQUISITES

  1. Have a node running

     cardano-node run \
 --topology relay/shelley_testnet-topology.json \
 --database-path relay/db \
 --socket-path relay/db/node.socket \
 --host-addr x.x.x.x \
 --port 3001 \
 --config relay/shelley_testnet-config.json

  2. Have funds in you payment.addr . If you don't, please register your address on the spreadsheet.

LET'S GO FOR IT !!

We are using the node socket to submit transactions, so let's set environment variable CARDANO_NODE_SOCKET_PATH to the socket-path specified in your node configuration, let's our relay node for that.

export CARDANO_NODE_SOCKET_PATH=relay/db/node.socket

Let's create a second payment key pair and address (You should have created one in Exercise 1). We need to create also a stake key pair and a stake address. The payment set, gives you control of your funds, the stake set, allows you to participate in the protocol, by delegating your stake or creating your own stake pool.

Generate Payment Key Pair

cardano-cli shelley address key-gen \
    --verification-key-file payment2.vkey \
    --signing-key-file payment2.skey

This has created two files containging our signing key and our verification key, let's take a look.

$ cat payment2.skey

> type: SigningKeyShelley
> title: Free form text
> cbor-hex:
>  18ad58202bd444b77c3149a31a59729c91691ff14dccf0a0891d6c6630668007f27e5806

$ cat payment2.vkey

> type: PaymentVerificationKeyShelley
> title: Free form text
> cbor-hex:
>  18af582024caa975f44df72753c3cc4b1bd7ca46fce12d4503d6a0bc003473dc4fd6e780

Generate Stake Key Pair

cardano-cli shelley stake-address key-gen \
--verification-key-file stake2.vkey \
--signing-key-file stake2.skey

This has created another set of keys, these ones will later allow us to delegate and/or create a stake pool. Let's see how they look

$ cat stake2.skey

> type: SigningKeyShelley
> title: Free form text
> cbor-hex:
>  18ad58205feed52eff8860d3041b523f89d41075376bbe05aebb716a1c7a3f1310c3cbb7

$ cat stake2.vkey

> type: StakingVerificationKeyShelley
> title: Free form text
> cbor-hex:
> 18b9582021ddc6229bc5e4eb00bc723492d89d1f899aad5e48cfbca57da5605c1e9b3e34

Generate Payment Address

Now we will use both payment2.vkey and stake2.vkeyto build a payment address. This will link our payment address to our stake keys and stake address.

cardano-cli shelley address build \
--payment-verification-key-file payment2.vkey \
--stake-verification-key-file stake2.vkey \
--out-file payment2.addr \
--testnet-magic 42

Generate Stake Address

And, now generate you stake address. This will collect your rewards from delegation.

cardano-cli shelley stake-address build \
--staking-verification-key-file stake2.vkey \
--out-file stake2.addr \
--testnet-magic 42

Yei!! Now we have two payment addresses, we can send a transaction.

TRANSACTIONS

To create our transaction we will need the protocl parameters, so let's query the parameters and save them in protocol.json

cardano-cli shelley query protocol-parameters \
    --testnet-magic 42 \
    --out-file protocol.json

We also need the UTXO details of the payment.addr that will send the funds.

cardano-cli shelley query utxo \
    --address $(cat payment.addr) \
    --testnet-magic 42

	                             TxHash                                 TxIx        Lovelace
----------------------------------------------------------------------------------------
65bc31936bae87240236e42a73b84d03dc7fd1cee5ac73caff051eeec7a34da0     1                 0
e757f08b856c5f12d5784f749c4fc2b1fda8b48299b520f29f6055ce94a5d8cf     0      499498404313

Sending funds to our new payment2.addrrequires five (5) simple steps.

  1. Determine the appropiate TTL (Time to live)
  2. Calculate the fee
  3. Build the transaction
  4. Sign the transaction
  5. Submit the transaction

But you can't just copy-paste things from here. There are some tweaks you need to do to the examples provided to make the transaction work. It is a good idea to open a text editor and make changes there, and then go to the CLI.

DETERMINE TTL

Let's find the current slot number, and increase it in ~1000 to give us some time to submit the transaction.

$ cardano-cli shelley query tip --testnet-magic 42

> Tip (SlotNo {unSlotNo = 266201}) (ShelleyHash {unShelleyHash = HashHeader {unHashHeader = 	26f76f2345f1ef4c39df82c89c6585bced4a0e484a3087bbd4afa06cfe2bb0c9}}) (BlockNo {unBlockNo = 9818})

So we are currently on slot 266201, Let's make our transaction TTL 267500. We will use this to calculate the fee and to build the transaction.

CALCULATE FEE

Our transaction will have 1 input (tx-in-count), the UTXO from our sending address e757f0...5d8cf from above, and 2 outputs (tx-out-count), the receiving address (payment2.addr) and a second ouput to send the change (payment.addr)

$ cardano-cli shelley transaction calculate-min-fee \
    --tx-in-count 1 \
    --tx-out-count 2 \
    --ttl 267500 \
    --testnet-magic 42 \
    --signing-key-file payment.skey \
    --protocol-params-file protocol.json

> runTxCalculateMinFee: 167965

So this transaction costs 167965 lovelaces.

Now we need to make some quick math, lets say we want to send 100 tADA to payment2.addr from our UTXO containing 499498404313 lovelaces.

$ expr 499498404313 - 100000000 - 167965
499398236348

The result is the ammount we need to send back to our own payment.addr

BUILD TRANSACTION

Again, you may want to open a text editor to work on building the transaction, and then when it is ready you can go to the CLI

 cardano-cli shelley transaction build-raw \
	--tx-in e757f08b856c5f12d5784f749c4fc2b1fda8b48299b520f29f6055ce94a5d8cf#0 \
	--tx-out $(cat payment2.addr)+100000000 \
	--tx-out $(cat payment.addr)+499398236348 \
	--ttl 267500 \
	--fee 167965 \
	--out-file tx008.raw
  • tx-in --> the UTXO from where you are sending funds__#TxIx__ from above (0 in this case).
  • tx-out --> receiving address (payment2.addr)
  • tx-out --> sending the change back to payment.addr
  • ttl --> absolute slot number
  • fee --> the result from calculate-min-fee
  • out-file --> the output raw file

SIGN TRANSACTION

We use the payment.skey to sign the transaction

 cardano-cli shelley transaction sign \
    --tx-body-file tx008.raw \
    --signing-key-file payment.skey \
    --testnet-magic 42 \
    --out-file tx008.signed

SUBMIT TRANSACTION

 cardano-cli shelley transaction submit \
    --tx-file tx008.signed \
    --testnet-magic 42

QUERY THE UTXOS OF BOTH ADDRESSES Once the transaction has been submitted, we can check the balances of our two addresses:

$ cardano-cli shelley query utxo --address $(cat payment.addr) --testnet-magic 42

                          TxHash                                 TxIx        Lovelace
----------------------------------------------------------------------------------------
65bc31936bae87240236e42a73b84d03dc7fd1cee5ac73caff051eeec7a34da0     1                 0
e36927fe54b4170b60a131cb6195f4c73a2952ea7f88507777f8ee91b682e61d     1      499398236348

$ cardano-cli shelley query utxo --address $(cat payment2.addr) --testnet-magic 42

                           TxHash                                 TxIx        Lovelace
----------------------------------------------------------------------------------------

e36927fe54b4170b60a131cb6195f4c73a2952ea7f88507777f8ee91b682e61d     0         100000000

Hey, we have moved some funds !! Congratulations. You have finished exercise 2.