What You’ll Learn
- How to use Neutron’s custom modules (Oracle, Cron, ICQ)
- Inter-contract communication patterns
- Advanced message handling and responses
- Working with Neutron-specific message types
Prerequisites
- Completed Part 1: Minimal Smart Contract
- Basic understanding of the Cosmos SDK
- Familiarity with CosmWasm message patterns
Neutron’s Unique Modules
Neutron provides several custom modules that enable powerful DeFi functionality:Oracle
Get high-frequency price data for any asset
Cron
Schedule automated contract executions
ICQ
Query data from other IBC-connected chains
Enhanced Contract: Oracle Integration
Let’s extend our counter contract to use Neutron’s Oracle module. We’ll create a contract that tracks the price of ATOM and only allows increments when the price is above a certain threshold.1. Update Dependencies
Add to yourCargo.toml
:
2. Enhanced State
Updatesrc/state.rs
:
3. Enhanced Messages
Updatesrc/msg.rs
:
4. Oracle Integration
Updatesrc/contract.rs
:
Inter-Contract Communication
Contracts can call other contracts using theWasmMsg::Execute
message type. Here’s how to call another contract:
Using the Cron Module
Schedule automated executions using Neutron’s Cron module:Advanced Patterns
1. Contract Factory Pattern
Create contracts that can instantiate other contracts:2. Cross-Chain Operations
Use Interchain Queries to get data from other chains:Testing Your Enhanced Contract
1. Build and Deploy
2. Test Oracle Integration
Key Concepts Learned
- Module Integration: Using Neutron’s custom modules in contracts
- Inter-Contract Calls: Calling other smart contracts
- Oracle Queries: Getting real-time price data
- Cron Scheduling: Automating contract executions
- Cross-Chain Queries: Accessing data from other blockchains
- Advanced Patterns: Factory contracts and complex workflows
Best Practices
- Error Handling: Always handle Oracle query failures gracefully
- Gas Limits: Be mindful of gas costs when calling multiple contracts
- State Management: Cache frequently accessed data to reduce costs
- Security: Validate all external data and implement proper access controls
Next Steps
Continue to Part 3: Building a Web App to learn how to create a frontend that interacts with your enhanced smart contract.Troubleshooting
Oracle Query Failed
Oracle Query Failed
Ensure the Oracle module is running and the currency pair exists:
Inter-Contract Call Failed
Inter-Contract Call Failed
Verify the target contract address and message format are correct.
Cron Schedule Not Working
Cron Schedule Not Working
Check that the Cron module is enabled and your schedule is valid: