Get started with Libra: My First Transaction

Owner : https://medium.com/@techgeek628/get-started-with-libra-my-first-transaction-5b3c20352d6c

This article will guide you through executing your first transaction on the Libra Blockchain.

Clone the Libra Core Repository:

git clone https://github.com/libra/libra.git

Change to the libra directory

cd libra

Setup Libra Core:

To setup Libra Core, run the setup script to install the dependencies

./scripts/dev_setup.sh

The setup script performs these actions:

1. Installs rustup — rustup is an installer for the Rust programming language, which Libra Core is implemented in.
2. Installs the required versions of the rust-toolchain.
3. Installs CMake — to manage the build process.
4. Installs protoc — a compiler for protocol buffers.
5. Installs Go — for building protocol buffers.

Build Libra CLI Client and Connect to the Testnet

To connect to a validator node running on the Libra testnet, run the client as shown below.

./scripts/cli/start_cli_testnet.sh

Once the client connects to a node on the testnet, you will see the following output.

Check If the CLI Client Is Running on Your System:

To see the help information for the account command enter “account” as shown below:

Create Alice’s Account

To create Alice’s account, enter this command:

libra% account create

Sample output on success:

>> Creating/retrieving next account from wallet
Created/retrieved account #0 address 5993ea6f4632fb962be6e7ac019f4257c2f14fdf14e5a4ee3be0f681e54a7b5e

#0 is the index of Alice’s account, and the hex string is the address of Alice’s account.

Create Bob’s Account:

To create Bob’s account, repeat the account creation command:

libra% account create

Sample output on success:

>> Creating/retrieving next account from wallet
Created/retrieved account #1 address cff7b9ba48d423dfc04e0a7d0b7ecdd035e6df08157782fd70405430c63ca2d1

#1 is the index for Bob’s account, and the hex string is the address of Bob’s account.

List Accounts:

libra% account list

Sample output on success:

User account index: 0, address: 5993ea6f4632fb962be6e7ac019f4257c2f14fdf14e5a4ee3be0f681e54a7b5e, sequence number: 0, status: Local
User account index: 1, address: cff7b9ba48d423dfc04e0a7d0b7ecdd035e6df08157782fd70405430c63ca2d1, sequence number: 0, status: Local

The sequence number for an account indicates the number of transactions that have been sent from that account.

Add 110 Libra to Alice’s Account:

libra% account mint 0 110

1. 0 is the index of Alice’s account.
2. 110 is the amount of Libra to be added to Alice’s account.

Sample output on success:

>> Minting coins
Mint request submitted

Add 52 Libra to Bob’s Account

libra% account mint 1 52

Sample output on success:

>> Minting coins
Mint request submitted

Check the Balance:

To check the balance in Alice’s account, enter this command:

libra% query balance 0

Sample output on success:

Balance is: 110

To check the balance in Bob’s account, enter this command:

libra% query balance 1

Sample output on success:

Balance is: 52

Query the Accounts’ Sequence Numbers

libra% query sequence 0
>> Getting current sequence number
Sequence number is: 0libra% query sequence 1
>> Getting current sequence number
Sequence number is: 0

A sequence number of 0 for both Alice’s and Bob’s accounts indicates that no transactions from either Alice’s or Bob’s account have been executed so far.

Submit a Transaction

Before we submit a transaction to transfer Libra from Alice’s account to Bob’s account, we will query the sequence number of each account. This will help us understand how executing a transaction changes the sequence number of each account.

libra% query sequence 0
>> Getting current sequence number
Sequence number is: 0libra% query sequence 1
>> Getting current sequence number
Sequence number is: 0

Transfer Money

libra% transfer 0 1 10

Sample output on success:

>> Transferring
Transaction submitted to validator
To query for transaction status, run: query txn_acc_seq 0 0 <fetch_events=true|false>

0 is the index of Alice’s account. 1 is the index of Bob’s account. 10 is the number of Libra to transfer from Alice’s account to Bob’s account.

Retrieve the information about the transaction :

libra% query txn_acc_seq 0 0 true

Sample output on success:

Getting committed transaction by account and sequence number
Committed transaction: SignedTransaction { 
 raw_txn: RawTransaction { 
 sender: 5993ea6f4632fb962be6e7ac019f4257c2f14fdf14e5a4ee3be0f681e54a7b5e, 
 sequence_number: 0, 
 payload: {, 
 transaction: peer_to_peer_transaction, 
 args: [ 
 {ADDRESS: cff7b9ba48d423dfc04e0a7d0b7ecdd035e6df08157782fd70405430c63ca2d1},
 {U64: 10000000}, 
 ]
 }, 
 max_gas_amount: 10000, 
 gas_unit_price: 0, 
 expiration_time: 1560880276s, 
}, 
 public_key: 09434588784ea49844e622c023df9e1fa3c52ff7ca7e51f970fc80c2bd2e759c, 
 signature: Signature( R: CompressedEdwardsY: [202, 230, 255, 181, 94, 160, 144, 218, 61, 165, 204, 18, 156, 164, 154, 222, 187, 79, 165, 183, 153, 32, 183, 47, 187, 95, 208, 182, 159, 226, 127, 91], s: Scalar{
 bytes: [100, 247, 195, 92, 83, 157, 100, 112, 110, 203, 47, 167, 86, 75, 239, 138, 8, 119, 71, 255, 15, 87, 157, 158, 59, 154, 160, 45, 42, 24, 101, 4],
} ), 
 }
Events: 
ContractEvent { access_path: AccessPath { address: 5993ea6f4632fb962be6e7ac019f4257c2f14fdf14e5a4ee3be0f681e54a7b5e, type: Resource, hash: “217da6c6b3e19f1825cfb2676daecce3bf3de03cf26647c78df00b371b25cc97”, suffix: “/sent_events_count/” } , index: 0, event_data: AccountEvent { account: cff7b9ba48d423dfc04e0a7d0b7ecdd035e6df08157782fd70405430c63ca2d1, amount: 10000000 } }
ContractEvent { access_path: AccessPath { address: cff7b9ba48d423dfc04e0a7d0b7ecdd035e6df08157782fd70405430c63ca2d1, type: Resource, hash: “217da6c6b3e19f1825cfb2676daecce3bf3de03cf26647c78df00b371b25cc97”, suffix: “/received_events_count/” } , index: 0, event_data: AccountEvent { account: 5993ea6f4632fb962be6e7ac019f4257c2f14fdf14e5a4ee3be0f681e54a7b5e, amount: 10000000 } }
libra%

Query Sequence Number After Transfer

libra% query sequence 0
>> Getting current sequence number
Sequence number is: 1libra% query sequence 1
>> Getting current sequence number
Sequence number is: 0

The sequence number of 1 for Alice’s account (index 0) indicates that one transaction has been sent from Alice’s account so far.

Check the Balance in Both Accounts After Transfer

libra% query balance 0
Balance is: 100libra% query balance 1
Balance is: 62

Congratulations! You have successfully executed your transaction on the Libra testnet and transferred 10 Libra from Alice’s account to Bob’s account!