ScalarDL Go Client SDK

This module is for developing applications that interact with ScalarDL networks.

Install

This SDK is released as a GO module. To install it, go to the root folder of your project and use

go get github.com/scalar-labs/scalardl-go-client-sdk/v3@{version}

to add this SDK to your module.

Compitablity

The SDK is compitable with ScalarDL by the aligned minor versions.

For instance, the users can use this SDK version 3.4.* to connect to ScalarDL 3.4.* networks.

HOWTO

This section explains the following main structures:

• ClientConfig
• ClientService
• ClientError

ClientConfig

ClientConfig represents the ScalarDL Client configuration.

The users need to prepare it before connect to a ScalarDL network.

ClientConfig can be created by loading either the Java Properties-format strings or the JSON-format strings.

The example of loading from Java Properties:

import "github.com/scalar-labs/scalardl-go-client-sdk/v3/client/config"

var clientConfig config.ClientConfig
var err error
var javaProperties = `
scalar.dl.client.server.host=localhost
scalar.dl.client.server.port=80
scalar.dl.client.server.privileged_port=8080
scalar.dl.client.cert_holder_id=foo
scalar.dl.client.cert_pem=-----BEGIN CERTIFICATE-----\nMIICjTCCAj...\n
scalar.dl.client.private_key_pem=-----BEGIN EC PRIVATE KEY-----\nMHc...
`

clientConfig, err = config.NewClientConfigFromJavaProperties(javaProperties);

The example of loading from JSON:

import "github.com/scalar-labs/scalardl-go-client-sdk/v3/client/config"

var clientConfig config.ClientConfig
var err error
var json = `
{
	"scalar.dl.client.server.host": "localhost",
	"scalar.dl.client.server.port": 80,
	"scalar.dl.client.server.privileged_port": 8080,
	"scalar.dl.client.cert_holder_id": "foo",
	"scalar.dl.client.cert_pem": "-----BEGIN CERTIFICATE-----\nMIICjTCCAj...\n",
	"scalar.dl.client.private_key_pem": "-----BEGIN EC PRIVATE KEY-----\nMHc...",
}
`

clientConfig, err = config.NewClientConfigFromJSON(json);

The ClientConfig variable then can be used to construct the ClientService structure.

ClientService

ClientService is the main interface to send requests to and receive responses from the ScalarDL networks.

Use a ClientConfig variable to construct ClientService.

import "github.com/scalar-labs/scalardl-go-client-sdk/v3/client/service"

var clientService service.ClientService
var err error

clientService, err = service.NewClientService(clientConfig)

As clientService is created successfully, users can use its functions to send the requests

Name	Request
RegisterCertificate	Certificate registration
RegisterContract	Contract registration
ExecuteContract	Contract execution
ValidateLedger	Ledger validation

The souce code in the example sub-folder demonstrate the details respectively.

ClientError

ClientError implements error interface and one more StatusCode function to contains ScalarDL status code returned by the ScalarDL networks.

Note that errors returned from ClientService are not always albe to be asserted to ClientError.

import (
	client_error "github.com/scalar-labs/scalardl-go-client-sdk/v3/client/error"
	"github.com/scalar-labs/scalardl-go-client-sdk/v3/client/service"
)

var clientService service.ClientService
var clientError client_error.ClientError
var err error

...

err = service.RegisterCertificate()

if clientError, ok := err.(client_error.ClientError); ok {
	// clientError.StatusCode() can be used here
}

Re-generate gRPC protobuf files

ScalarDL uses gRPC as the communication protocol.

The generated gRPC go files are placed in the rpc sub-folder.

To genearte them, check prerequsisites to install necessary tools. We also need to add option go_package = "./rpc"; to the *.proto files to specify the Golang package. Then, use the following command to generate related files.

protoc --go_out=<path-to-this-repository> --go-grpc_out=<path-to-this-repository> scalar.proto