feat: add session factory

session/factory.go

@@ -0,0 +1,128 @@
+package session
+
+import (
+	"context"
+
+	"github.com/airbloc/airbloc-go/account"
+	"github.com/airbloc/airbloc-go/bind"
+	"github.com/airbloc/airbloc-go/blockchain"
+	"github.com/airbloc/logger"
+	"github.com/pkg/errors"
+)
+
+type Factory interface {
+	NewSession(ctx context.Context, opts ...FactoryOption) (Session, account.Account, error)
+}
+
+type sessionFactory struct {
+	client      *blockchain.Client
+	feePayer    account.FeePayer
+	deployments bind.Deployments
+}
+
+func NewFactory(ctx context.Context, opt BaseOption) (Factory, error) {
+	client, err := blockchain.NewClient(ctx, opt.BlockchainEndpoint)
+	if err != nil {
+		return nil, errors.Wrapf(
+			err, "initialize klaytn client. url=%s",
+			opt.BlockchainEndpoint,
+		)
+	}
+
+	var token *string = nil
+	if opt.FeePayerToken != "" {
+		token = &opt.FeePayerToken
+	}
+
+	feePayer, err := account.NewFeePayer(ctx, nil, opt.FeePayerEndpoint, token)
+	if err != nil {
+		client.Close()
+		return nil, errors.Wrapf(
+			err, "initialize fee payer client. url=%s",
+			opt.FeePayerEndpoint,
+		)
+	}
+
+	feePayerAddr, err := feePayer.Address(ctx)
+	if err != nil {
+		client.Close()
+		return nil, errors.Wrapf(err, "fetch fee payer address")
+	}
+
+	log := logger.New("session-factory")
+	log.Info("Using feePayer {}", feePayerAddr.Hex())
+
+	deployments, err := bind.GetDeploymentsFrom(opt.DeploymentPath)
+	if err != nil {
+		client.Close()
+		return nil, errors.Wrapf(
+			err, "fetch deployments from %s",
+			opt.DeploymentPath,
+		)
+	}
+	if deployments != nil {
+		log.Info("Using deployment at {}", opt.DeploymentPath)
+	}
+
+	return &sessionFactory{
+		client:      client,
+		feePayer:    feePayer,
+		deployments: deployments,
+	}, nil
+}
+
+func MustNewFactory(ctx context.Context, opt BaseOption) Factory {
+	if sf, err := NewFactory(ctx, opt); err != nil {
+		panic(err)
+	} else {
+		return sf
+	}
+}
+
+func (sf sessionFactory) NewSession(ctx context.Context, opts ...FactoryOption) (
+	Session,
+	account.Account,
+	error,
+) {
+	factoryOption := sessionFactoryOption{}
+	for _, opt := range opts {
+		opt(&factoryOption)
+	}
+	if err := factoryOption.Validate(); err != nil {
+		return Session{},
+			account.Account{},
+			errors.Wrap(err, "validate factory option")
+	}
+
+	var (
+		acc = account.NewKeyedAccount(factoryOption.key)
+		err error
+	)
+	if factoryOption.feePayer != nil {
+		acc, err = account.NewKeyedAccountWithFeePayer(
+			ctx,
+			factoryOption.key,
+			factoryOption.feePayer,
+		)
+		if err != nil {
+			return Session{},
+				account.Account{},
+				errors.Wrap(err, "new keyed account with fee payer")
+		}
+	}
+
+	deployments := sf.deployments
+	if factoryOption.deployments != nil {
+		deployments = factoryOption.deployments
+	}
+	sess, err := NewSession(Config{
+		Account:     acc,
+		Client:      sf.client,
+		Deployments: deployments,
+	})
+	return sess, acc, err
+}
+
+func (sf sessionFactory) Close() {
+	sf.client.Close()
+}

session/factory_options.go

@@ -0,0 +1,52 @@
+package session
+
+import (
+	"crypto/ecdsa"
+	"errors"
+
+	"github.com/airbloc/airbloc-go/account"
+	"github.com/airbloc/airbloc-go/bind"
+	"github.com/airbloc/airbloc-go/blockchain"
+)
+
+type BaseOption struct {
+	BlockchainEndpoint string `split_words:"true" default:"https://api.baobab.klaytn.net:8651"`
+	DeploymentPath     string `split_words:"true"`
+	FeePayerEndpoint   string `split_words:"true" default:"http://localhost:3470/api"`
+	FeePayerToken      string `split_words:"true"`
+}
+
+type sessionFactoryOption struct {
+	// required
+	key *ecdsa.PrivateKey
+
+	// optional
+	client      *blockchain.Client
+	feePayer    account.FeePayer
+	deployments bind.Deployments
+}
+
+func (opt sessionFactoryOption) Validate() error {
+	if opt.key == nil {
+		return errors.New("ecdsa privateKey required")
+	}
+	return nil
+}
+
+type FactoryOption func(*sessionFactoryOption)
+
+func WithClient(client *blockchain.Client) FactoryOption {
+	return func(opt *sessionFactoryOption) { opt.client = client }
+}
+
+func WithKey(key *ecdsa.PrivateKey) FactoryOption {
+	return func(opt *sessionFactoryOption) { opt.key = key }
+}
+
+func WithFeePayer(feePayer account.FeePayer) FactoryOption {
+	return func(opt *sessionFactoryOption) { opt.feePayer = feePayer }
+}
+
+func WithDeployments(deployments bind.Deployments) FactoryOption {
+	return func(opt *sessionFactoryOption) { opt.deployments = deployments }
+}