Demo of Stellar Smart Contract Storage

Storage on Stellar smart contracts is not simple.

This developer journey will walk you through not just the intricacies of Storage but also give you some great practical knowledge about implementing your own point system. We will take a low-level approach to really examine some of the fundamental concepts of Stellar Smart Contracts.

This tutorial is specifically designed for new Stellar developers!

While Stellar smart contract storage can seem pretty complicated at first, it offers a huge amount of opportunity for optimization and minimization of invocation fees for your users! So a little bit of work up front, will go a long way down the line for your contract!

Tests

Tests with logs enabled:

cargo test -- --nocapture

Build and Deploy Contract with Stellar CLI

Run a local stellar network, deploy contract to local, invoke set_balance_persistent(), encode LedgerKey as XDR and extend TTL of persistent storage data by key.

Run Local Stellar Network

Run local Stellar network for testing

stellar container start local --limits testnet

Use local:

stellar network use local

Deploy to local standalone:

stellar contract deploy \
    --wasm target/wasm32-unknown-unknown/release/happy_points_system.wasm \
    --source alice \
    --network local

Invoke set_balance_persistent() function:

stellar contract invoke \
    --id CAWI33QKYJ2JV42O2KQG36MHBKQO4F3IKZPKT6C2HL7OI5VNAEM2SDE7 \
    --source alice \
    -- \
    set_balance_persistent \
    --amount 1000 \
    --addr GANUUSIQOCQOGQRV5KR7CO64SATSFLLPRRWX5XDKXYFZ7Y4XWTEALQOX

Invoke get_balance_persistent() function:

stellar contract invoke \
    --id CAWI33QKYJ2JV42O2KQG36MHBKQO4F3IKZPKT6C2HL7OI5VNAEM2SDE7 \
    --source alice \
    -- \
    get_balance_persistent \
    --addr GANUUSIQOCQOGQRV5KR7CO64SATSFLLPRRWX5XDKXYFZ7Y4XWTEALQOX

Encode LedgerKey JSON ledgerkey.json as XDR:

stellar xdr encode --type LedgerKey --input json --output single-base64 ledgerkey.json

Extend TTL of persistent storage by 10,000 ledgers:

stellar contract extend \
    --source alice \
    --id CABOIXXESAYVMNXP4HBU44DUTWFZAQAZJK5A44UFOR2KSGDHD5KUCQAJ \
    --key-xdr AAAABgAAAAGwZ1dyW0P7qAx913CFhpYGupGYPd3Fd1H8ujJu+y4QygAAABAAAAABAAAAAgAAAA8AAAAHQmFsYW5jZQAAAAASAAAAAAAAAAAbSkkQcKDjQjXqo/E73JAnIq1vjG1+3Gq+C5/jl7TIBQAAAAE= \
    --ledgers-to-extend 10000 \
    --durability persistent

Check TTL

stellar contract read \
    --output xdr \
    --id CABOIXXESAYVMNXP4HBU44DUTWFZAQAZJK5A44UFOR2KSGDHD5KUCQAJ \
    --key-xdr AAAABgAAAAEC5F7kkDFWNu/hw05wdJ2LkEAZSroOcoV0dKkYZx9VQQAAABAAAAABAAAAAgAAAA8AAAAHQmFsYW5jZQAAAAASAAAAAAAAAAAbSkkQcKDjQjXqo/E73JAnIq1vjG1+3Gq+C5/jl7TIBQAAAAE= \
    --durability persistent \
    --network testnet