Sawtooth Client SDK for Go

This repo contains the Sawtooth Client SDK for Go (developed by Taekion). The Taekion Blockchain supports dynamic consensus via plug-ins. Our TFS Lite Client uses a customized consensus algorithm to integrated with the Hedera Consensus Service (HCS).

What is it for?

Client libraries that interface with Sawtooth transaction processors tend to repeat a lot of boilerplate code for transaction/batch construction and handling, as well as for performing queries against the data already committed to the blockchain. This library attempts to generalize much of that code in such a way that lets application-specific client libraries avoid handling many of these implementation details.

What does it do?

• Handles transaction/batch/batchlist construction and signing.
• Provides a complete abstraction of the Sawtooth Validator interface.
  • Implements this as a generalized "transport" abstraction.
  • Two implementations of transport provided:
    • REST API
    • Direct ZMQ (0MQ) to the validator

Getting Started

A application-specific client library needs to implement the following interface:

type SawtoothClientImpl interface {
    GetFamilyName() string
    GetFamilyVersion() string

    EncodePayload(interface{}) ([]byte, error)
    DecodePayload([]byte, interface{}) error

    EncodeData(interface{}) ([]byte, error)
    DecodeData([]byte, interface{}) error

    GetPayloadInputAddresses(payload interface{}) []string
    GetPayloadOutputAddresses(payload interface{}) []string
    GetPayloadDependencies(payload interface{}) []string
}

Once this is done, the library code can then construct an instance of the general library like so:

import (
    "github.com/taekion-org/sawtooth-client-sdk-go"
    "github.com/taekion-org/sawtooth-client-sdk-go/transport"
)

type AppSpecificClient struct {
    *sawtooth-client-sdk-go.SawtoothClient
}

// Assume that this type implements the SawtoothClientImpl interface
type AppSpecificClientImpl struct {}

func NewAppSpecificClient(url string, keyFile string) (*AppSpecificClient, error) {
    args := &sawtooth_client_sdk_go.SawtoothClientArgs{
        URL: url,
        KeyFile: keyFile,
        TransportType: transport.TRANSPORT_REST,  // This can also be transport.TRANSPORT_ZMQ
        Impl: &AppSpecificClientImpl{},
    }

    sawtoothClient, err := sawtooth_client_sdk_go.NewClient(args)
    if err != nil {
        return nil, err
    }

    appSpecificClient := &AppSpecificClientImpl{
        SawtoothClient: sawtoothClient,
    }

    return appSpecificClient, nil
}

At this point, the basic structure of the client is in place. Application-specific logic and functionality can be implemented using the functions that the general library provides for executing transactions and queries.

Example

For a more complete example, see the examples/intkey example. This provides a more-or-less complete re-implementation of the intkey client utility using this SDK.