taekion-org / sawtooth-client-sdk-go

Sawtooth Client SDK for Go

Sawtooth Client SDK for Go

This repo contains the Sawtooth Client SDK for Go (developed by Taekion).

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.