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Deposit using a blueprint

A blueprint describes the inputs to spend and the outputs to create inside an open head. This example deposits 5 ADA from an ADA-only input worth at least 8 ADA and returns the remaining input value on L1.

Prerequisites​

Complete the testnet setup through opening the head. Use its node, matching Hydra scripts, funded node wallet, and credentials/alice-funds.{sk,addr}. Run these commands from that tutorial's working directory with cardano-cli, jq, and curl available.

export CARDANO_NODE_SOCKET_PATH="$PWD/node.socket"
export CARDANO_NODE_NETWORK_ID=1
export HYDRA_API=http://127.0.0.1:4001
WALLET_ADDR=$(cat credentials/alice-funds.addr)

cardano-cli query utxo --address "$WALLET_ADDR" --out-file wallet-utxo.json
jq 'to_entries | map(select((.value.value | keys) == ["lovelace"] and .value.value.lovelace >= 8000000)) | .[:1] | from_entries' \
  wallet-utxo.json > deposit-utxo.json
TX_IN=$(jq -er 'keys[0] // error("Need an ADA-only UTxO of at least 8 ADA")' deposit-utxo.json)

Build the blueprint​

The 5 ADA output below becomes an L2 output. The blueprint itself is not submitted to Cardano.

cardano-cli conway transaction build-raw \
  --tx-in "$TX_IN" \
  --tx-out "$WALLET_ADDR+5000000" \
  --fee 0 \
  --out-file blueprint.json

cardano-cli debug transaction view --tx-file blueprint.json

Check that the output contains 5,000,000 lovelace. Build the request from the files instead of copying an encoded transaction from another example:

jq -n \
  --slurpfile blueprint blueprint.json \
  --slurpfile utxo deposit-utxo.json \
  --arg changeAddress "$WALLET_ADDR" \
  '{blueprintTx: $blueprint[0], utxo: $utxo[0], changeAddress: $changeAddress}' \
  > commit-request.json

curl --fail-with-body -sS "$HYDRA_API/commit" \
  -H 'Content-Type: application/json' \
  --data-binary @commit-request.json \
  > deposit-tx.json

changeAddress asks the node to return the remainder on L1. Without it, provide a balanced blueprint whose entire output value is to be deposited. The node pays the deposit transaction's fees from its own fuel wallet.

Sign, submit, and wait​

Open a WebSocket connection in another terminal before submitting:

websocat 'ws://127.0.0.1:4001?history=no'

Add Alice's witness while preserving the node's witness and output order:

cardano-cli conway transaction sign \
  --tx-file deposit-tx.json \
  --signing-key-file credentials/alice-funds.sk \
  --out-file deposit-signed.json

cardano-cli conway transaction submit --tx-file deposit-signed.json

The head is already open. CommitRecorded means the deposit was observed on L1; it is not yet spendable on L2. After activation, snapshot approval, and settlement of the increment, CommitFinalized confirms that the deposit has settled. With default activation settings, maturation takes roughly an hour plus the transaction-validity offset. See deposit timing.

Verify the output in GET /snapshot/utxo and the change at Alice's L1 address. If the deposit expires without being claimed, follow the recovery instructions.