Chaincode is usually written in Golang or Java.
Chaincode can be public (visible to all on the network), confidential, or access controlled.
Writing and Deploying Smart Contracts on Fabric (Part 2)
These code files serve as a smart contract that users can interact with via APIs.
Users can call functions in the chaincode that result in a state change, and consequently updates the ledger.
There are also functions that are only used to query the ledger and do not result in any state change.
Chaincode implementation is performed by first creating the chaincode shim interface in the code.
Shim provides APIs for accessing state variables and transaction context of chain code.
The following four functions are required in order to implement the chaincode: Init(): This function is invoked when chaincode is deployed onto the ledger.
Why This Matters for Blockchain Technology
This initializes the chaincode and results in making a state change, which accordingly updates the ledger.
It takes a function name as parameters along with an array of arguments.
This function results in a state change and writes to the ledger.
Query(): This function is used to query the current state of a deployed chaincode.
Key Points to Remember
- Chaincode implementation Chaincode is usually written in Golang or Java.
- Chaincode can be public (visible to all on the network), confidential, or access controlled.
- These code files serve as a smart contract that users can interact with via APIs.
- Users can call functions in the chaincode that result in a state change, and consequently updates the ledger.
Going Deeper: Advanced Concepts
The chaincode is registered with the peer using this function.
The following diagram illustrates the general overview of Hyperledger Fabric, note that peers cluster at the top includes all types of nodes such as endorsers, committers, Orderers, and so on.
Chaincode implementation Chaincode is usually written in Golang or Java. Chaincode can be public (visible to all on the network), confidential, or access controlled. These code files serve as a smart contract that users can interact with via APIs. Users can call functions in the chaincode that result in a state change, and consequently updates the ledger. There are also functions that are only used to query the ledger and do not result in any state change. Chaincode implementation is performed by first creating the chaincode shim interface in the code. Shim provides APIs for accessing state variables and transaction context of chain code. It can either be in Java or Golang code. The following four functions are required in order to implement the chaincode: Init(): This function is invoked when chaincode is deployed onto the ledger. This initializes the chaincode and results in making a state change, which accordingly updates the ledger. Invoke(): This function is used when contracts are executed. It takes a function name as parameters along with an array of arguments. This function results in a state change and writes to the ledger. Query(): This function is used to query the current state of a deployed chaincode. This function does not make any changes to the ledger. 4(): This function is executed when a peer deploys its own copy of the chaincode. The chaincode is registered with the peer using this function. The following diagram illustrates the general overview of Hyperledger Fabric, note that peers cluster at the top includes all types of nodes such as endorsers, committers, Orderers, and so on. A high-level overview of Hyperledger Fabric
Conclusion
Chaincode implementation represents one of the many innovative layers that make blockchain technology so powerful and transformative. As distributed systems continue to evolve, a solid understanding of these core concepts becomes increasingly valuable — not just for developers, but for anyone building, investing in, or working alongside blockchain-powered systems.
Whether you are just starting your blockchain journey or deepening existing expertise, mastering these fundamentals gives you the tools to think clearly about decentralized systems and make smarter decisions in this rapidly evolving space.