➡️ Rust Dev's Pallas Journey: Cardano in Rust Intro

Source: Dev.to

Dive into Pallas, TxPipe’s Rust toolkit for Cardano.
Modular Rust for blockchain without Haskell.

Summary of Pallas

pallas-codec – CBOR serialization/deserialization foundation

use pallas_codec::{Encode, Decode};
use pallas_codec::minicbor::Decoder;

#[derive(Encode, Decode)]
enum MyEnum {
    Value(u64),
}

fn main() {
    let val = MyEnum::Value(42);
    let encoded = val.encode_to_vec().unwrap();
    let mut decoder = Decoder::new(&encoded);
    let decoded: MyEnum = decoder.decode().unwrap();
    if let MyEnum::Value(n) = decoded {
        println!("Decoded: {}", n);
    }
}

pallas-primitives – Ledger data structs across eras

use pallas_primitives::MultiEraTx;

fn main() {
    let tx_bytes = vec![]; // CBOR bytes
    let tx = MultiEraTx::from_cbor_bytes(&tx_bytes).unwrap();
    println!("Fee: {:?}", tx.fees());
}

pallas-crypto – Hashes, signatures, VRF for security

use pallas_crypto::{Blake2b256, Ed25519Bip32SecretKey, Ed25519Signature};
use rand::rngs::OsRng;
use rand::RngCore;

fn main() {
    let mut sk_bytes = [0u8; 32];
    OsRng.fill_bytes(&mut sk_bytes);
    let sk = Ed25519Bip32SecretKey::from_bytes(sk_bytes).unwrap();
    let data = b"test";
    let sig = Ed25519Signature::sign(&sk, data);
    println!("Sig valid: {}", sig.verify(&sk.public_key(), data));
}

pallas-addresses – Address encoding/decoding

use pallas_addresses::Address;

fn main() {
    let addr = Address::from_bech32("addr1q...").unwrap();
    if let Address::Shelley(s) = addr {
        println!("Payment: {:?}", s.payment);
    }
}

pallas-txbuilder – Transaction construction builder

use pallas_txbuilder::Builder;
use pallas_primitives::ProtocolParameters;

fn main() {
    let params = ProtocolParameters::default();
    let mut builder = Builder::new(params);
    let min_fee = builder.min_fee().unwrap();
    println!("Min fee: {}", min_fee);
}

pallas-traverse – Data analysis / traversal

use pallas_traverse::MultiEraBlock;

fn main() {
    let block_bytes = vec![]; // Bytes
    let block = MultiEraBlock::decode(&block_bytes).unwrap();
    for tx in block.txs() {
        println!("Inputs: {:?}", tx.inputs().len());
    }
}

pallas-network – Node communication stack

use pallas_network::n2c::connect;

#[tokio::main]
async fn main() {
    let _mux = connect("relay.example:3001").await.unwrap();
}

pallas-hardano – Haskell node artifact interop

use pallas_hardano::ImmutableFile;
use std::path::PathBuf;

fn main() {
    let path = PathBuf::from("chunk.file");
    let mut reader = ImmutableFile::open(&path).unwrap();
    if let Some(block) = reader.next() {
        println!("Block: {:?}", block.unwrap().header);
    }
}

pallas-math – Math utilities for ledger / consensus

use pallas_math::slot_to_epoch;

fn main() {
    let epoch = slot_to_epoch(1_000_000, 432_000);
    println!("Epoch: {}", epoch); // ~2
}

pallas-utxorpc – UTxO‑RPC querying

use pallas_utxorpc::Client;

#[tokio::main]
async fn main() {
    let client = Client::connect("grpc://node:50051").await.unwrap();
    let tip = client.get_chain_tip().await.unwrap();
    println!("Tip: {:?}", tip);
}

Conceptual Layers

Layer 1 – The Atoms

Low‑level rules of the universe: math, serialization, cryptography.

• pallas-codec – CBOR (Concise Binary Object Representation) serialization. Cardano stores data in binary CBOR, not JSON.
• pallas-crypto – Blake2b‑256 hashing and Ed25519 signatures. Cardano prefers Blake2b‑256 for speed and security.
• pallas-math – Fixed‑point arithmetic. Consensus must avoid floating‑point errors (e.g., 0.1 + 0.2 != 0.3).

Layer 2 – The Data

Data structures that populate the blockchain.

• pallas-primitives – Rust structs for TransactionBody, Block, Header, etc. Handles eras (Byron, Shelley, Alonzo, Babbage) where block shapes differ.
• pallas-addresses – Parses Bech32 addresses (addr1…) into payment and stake keys, validating checksums.

Layer 3 – The Tools

Libraries you use to read and write data.

• pallas-traverse – Essential for reading chain data. Provides MultiEraBlock, enabling queries like block.tx_count().
• pallas-txbuilder, pallas-network, pallas-utxorpc, pallas-hardano, etc., give you the building blocks for constructing transactions, communicating with nodes, and interoperating with Haskell artifacts.

Easy to remember, powerful to use.

pallas-txbuilder

What: A helper to construct valid transaction binaries.
Why: It manages the complexity of UTXO inputs, fee calculation, and change addresses.

Layer 4 – The Infrastructure

These modules connect your code to the physical network.

The Transaction Lifecycle

The life of a transaction on the Cardano Mainnet.

1. Creation – A wallet builds a transaction using pallas-txbuilder (logic) and pallas-primitives (structs).
2. Submission – The wallet pushes the transaction to a local relay node using pallas-network (TxSubmission protocol).
3. Propagation (Gossip) – Relay nodes check validity and “gossip” the transaction to the Slot Leader’s mempool.
4. Consensus – The slot leader checks its VRF (Verifiable Random Function). If it wins the lottery, it mints a block.
5. Distribution – The slot leader broadcasts the new block using pallas-network (ChainSync protocol).
6. Observation – Your Pallas client downloads the block and decodes it using pallas-traverse.