Transactions

This document explains how to influence the blockchain's state by broadcasting transactions.

Transactions include:

• a list of messages
• an optional memo
• a fee
• a signature from a key

The messages included in a transaction contain the information that will be routed to a proper message handler in the node, which in turn parses the inputs and determines the next state of the blockchain.

A StdTx is a data object that represents a transaction. It contains:

• msgs: a list of state-altering messages
• fee: the transaction fee paid to network / validators
• signatures: a list of signatures from required signers (depends on messages)
• memo: a short string describing transaction (can be empty string)

Paloma SDK provides functions that help create StdTx objects.

Using a Wallet (recommended)

A Wallet allows you to create and sign a transaction in a single step by automatically fetching the latest information from the blockchain (chain ID, account number, sequence).

Use LCDClient.wallet() to create a Wallet from any Key instance. The Key provided should correspond to the account you intend to sign the transaction with.

from paloma_sdk.client.lcd import LCDClient
from paloma_sdk.key.mnemonic import MnemonicKey

mk = MnemonicKey(mnemonic=MNEMONIC)
paloma = LCDClient("https://lcd.testnet.palomaswap.com", "<paloma chain id>")
wallet = paloma.wallet(mk)

Check the available networks to choose the right chainID.

Once you have your Wallet, you can simply create a StdTx using Wallet.create_and_sign_tx.

from paloma_sdk.client.lcd.api.tx import CreateTxOptions
from paloma_sdk.core.fee import Fee
from paloma_sdk.core.bank import MsgSend

tx = wallet.create_and_sign_tx(
    CreateTxOptions(
        msgs=[MsgSend(
            wallet.key.acc_address,
            RECIPIENT,
            "1000000ugrain" # send 1 Grain
            )]
            ,
            memo="test transaction!",
            fee=Fee(200000, "120000ugrain")
    )
)

And that's it! You should now be able to broadcast your transaction to the network.

result = paloma.tx.broadcast(tx)
print(result)

Automatic fee estimation

If no fee parameter is provided for Wallet.create_and_sign_tx(), the transaction fee will be simulated against the node and populated for you. By default, Wallet will use the fee estimation parameters of the LCDClient used to create it. You can override this behavior per transaction:

tx = wallet.create_and_sign_tx(CreateTxOptions(
    msgs=[MsgSend(
        wallet.key.acc_address,
        RECIPIENT,
        "1000000ugrain" # send 1 Grain
    )],
    memo="test transaction!",
    gas_prices="0.015ugrain", # optional
    gas_adjustment="1.2", # optional
))