[#126] sdk: add sdk client for all available api requests

Signed-off-by: Alex Vanin <alexey@nspcc.ru>

pkg/accounting/decimal.go

@@ -0,0 +1,9 @@
+package accounting
+
+import (
+	"github.com/nspcc-dev/neofs-api-go/v2/accounting"
+)
+
+type Decimal struct {
+	accounting.Decimal
+}

pkg/client/client.go

@@ -0,0 +1,50 @@
+package client
+
+import (
+	"crypto/ecdsa"
+	"errors"
+
+	"github.com/nspcc-dev/neofs-api-go/pkg"
+)
+
+type (
+	Client struct {
+		key        *ecdsa.PrivateKey
+		remoteNode TransportInfo
+
+		opts *clientOptions
+	}
+
+	TransportProtocol uint32
+
+	TransportInfo struct {
+		Version  pkg.Version
+		Protocol TransportProtocol
+	}
+)
+
+const (
+	Unknown TransportProtocol = iota
+	GRPC
+)
+
+var (
+	unsupportedProtocolErr = errors.New("unsupported transport protocol")
+)
+
+func New(key *ecdsa.PrivateKey, opts ...ClientOption) (*Client, error) {
+	clientOptions := defaultClientOptions()
+	for i := range opts {
+		opts[i].apply(clientOptions)
+	}
+
+	// todo: make handshake to check latest version
+	return &Client{
+		key: key,
+		remoteNode: TransportInfo{
+			Version:  pkg.SDKVersion,
+			Protocol: GRPC,
+		},
+		opts: clientOptions,
+	}, nil
+}

pkg/client/opts.go

@@ -0,0 +1,137 @@
+package client
+
+import (
+	"github.com/nspcc-dev/neofs-api-go/pkg"
+	v2accounting "github.com/nspcc-dev/neofs-api-go/v2/accounting"
+	v2container "github.com/nspcc-dev/neofs-api-go/v2/container"
+	v2session "github.com/nspcc-dev/neofs-api-go/v2/session"
+	"google.golang.org/grpc"
+)
+
+type (
+	CallOption interface {
+		apply(*callOptions)
+	}
+
+	ClientOption interface {
+		apply(*clientOptions)
+	}
+
+	xHeader struct {
+		v2session.XHeader
+	}
+
+	callOptions struct {
+		version  pkg.Version
+		xHeaders []xHeader
+		ttl      uint32
+		epoch    uint64
+		// add session token
+		// add bearer token
+	}
+
+	clientOptions struct {
+		addr string
+
+		grpcOpts *grpcOptions
+	}
+
+	grpcOptions struct {
+		conn               *grpc.ClientConn
+		v2ContainerClient  *v2container.Client
+		v2AccountingClient *v2accounting.Client
+	}
+)
+
+func defaultCallOptions() callOptions {
+	return callOptions{
+		ttl:     2,
+		version: pkg.SDKVersion,
+	}
+}
+
+type funcCallOption struct {
+	f func(*callOptions)
+}
+
+func (fco *funcCallOption) apply(co *callOptions) {
+	fco.f(co)
+}
+
+func newFuncCallOption(f func(option *callOptions)) *funcCallOption {
+	return &funcCallOption{
+		f: f,
+	}
+}
+
+func WithXHeader(key, value string) CallOption {
+	return newFuncCallOption(func(option *callOptions) {
+		xhdr := new(v2session.XHeader)
+		xhdr.SetKey(key)
+		xhdr.SetValue(value)
+
+		option.xHeaders = append(option.xHeaders, xHeader{
+			XHeader: *xhdr,
+		})
+	})
+}
+
+func WithTTL(ttl uint32) CallOption {
+	return newFuncCallOption(func(option *callOptions) {
+		option.ttl = ttl
+	})
+}
+
+func WithEpoch(epoch uint64) CallOption {
+	return newFuncCallOption(func(option *callOptions) {
+		option.epoch = epoch
+	})
+}
+
+func v2MetaHeaderFromOpts(options callOptions) *v2session.RequestMetaHeader {
+	meta := new(v2session.RequestMetaHeader)
+	meta.SetVersion(options.version.ToV2Version())
+	meta.SetTTL(options.ttl)
+	meta.SetEpoch(options.epoch)
+
+	xhdrs := make([]*v2session.XHeader, len(options.xHeaders))
+	for i := range options.xHeaders {
+		xhdrs[i] = &options.xHeaders[i].XHeader
+	}
+
+	meta.SetXHeaders(xhdrs)
+
+	return meta
+}
+
+func defaultClientOptions() *clientOptions {
+	return &clientOptions{
+		grpcOpts: new(grpcOptions),
+	}
+}
+
+type funcClientOption struct {
+	f func(*clientOptions)
+}
+
+func (fco *funcClientOption) apply(co *clientOptions) {
+	fco.f(co)
+}
+
+func newFuncClientOption(f func(option *clientOptions)) *funcClientOption {
+	return &funcClientOption{
+		f: f,
+	}
+}
+
+func WithAddress(addr string) ClientOption {
+	return newFuncClientOption(func(option *clientOptions) {
+		option.addr = addr
+	})
+}
+
+func WithGRPCConnection(grpcConn *grpc.ClientConn) ClientOption {
+	return newFuncClientOption(func(option *clientOptions) {
+		option.grpcOpts.conn = grpcConn
+	})
+}