[#48] client: Refactor accounting.Balance()

Signed-off-by: Evgenii Stratonikov <e.stratonikov@yadro.com>

client/accounting.go

@@ -2,12 +2,16 @@ package client
 
 import (
 	"context"
+	"fmt"
 
 	v2accounting "git.frostfs.info/TrueCloudLab/frostfs-api-go/v2/accounting"
 	"git.frostfs.info/TrueCloudLab/frostfs-api-go/v2/refs"
 	rpcapi "git.frostfs.info/TrueCloudLab/frostfs-api-go/v2/rpc"
 	"git.frostfs.info/TrueCloudLab/frostfs-api-go/v2/rpc/client"
+	v2session "git.frostfs.info/TrueCloudLab/frostfs-api-go/v2/session"
+	"git.frostfs.info/TrueCloudLab/frostfs-api-go/v2/signature"
 	"git.frostfs.info/TrueCloudLab/frostfs-sdk-go/accounting"
+	apistatus "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/client/status"
 	"git.frostfs.info/TrueCloudLab/frostfs-sdk-go/user"
 )
 
@@ -26,6 +30,24 @@ func (x *PrmBalanceGet) SetAccount(id user.ID) {
 	x.accountSet = true
 }
 
+func (x *PrmBalanceGet) buildRequest(c *Client) (*v2accounting.BalanceRequest, error) {
+	if !x.accountSet {
+		return nil, errorAccountNotSet
+	}
+
+	var accountV2 refs.OwnerID
+	x.account.WriteToV2(&accountV2)
+
+	var body v2accounting.BalanceRequestBody
+	body.SetOwnerID(&accountV2)
+
+	var req v2accounting.BalanceRequest
+	req.SetBody(&body)
+
+	c.prepareRequest(&req, new(v2session.RequestMetaHeader))
+	return &req, nil
+}
+
 // ResBalanceGet groups resulting values of BalanceGet operation.
 type ResBalanceGet struct {
 	statusRes
@@ -52,57 +74,35 @@ func (x ResBalanceGet) Amount() accounting.Decimal {
 // Return statuses:
 //   - global (see Client docs).
 func (c *Client) BalanceGet(ctx context.Context, prm PrmBalanceGet) (*ResBalanceGet, error) {
-	if !prm.accountSet {
+	req, err := prm.buildRequest(c)
-		return nil, errorAccountNotSet
+	if err != nil {
+		return nil, err
 	}
 
-	// form request body
+	if err := signature.SignServiceMessage(&c.prm.key, req); err != nil {
-	var accountV2 refs.OwnerID
+		return nil, fmt.Errorf("sign request: %w", err)
-	prm.account.WriteToV2(&accountV2)
-
-	var body v2accounting.BalanceRequestBody
-	body.SetOwnerID(&accountV2)
-
-	// form request
-	var req v2accounting.BalanceRequest
-
-	req.SetBody(&body)
-
-	// init call context
-
-	var (
-		cc  contextCall
-		res ResBalanceGet
-	)
-
-	c.initCallContext(&cc)
-	cc.meta = prm.prmCommonMeta
-	cc.req = &req
-	cc.statusRes = &res
-	cc.call = func() (responseV2, error) {
-		return rpcapi.Balance(&c.c, &req, client.WithContext(ctx))
-	}
-	cc.result = func(r responseV2) {
-		resp := r.(*v2accounting.BalanceResponse)
-
-		const fieldBalance = "balance"
-
-		bal := resp.GetBody().GetBalance()
-		if bal == nil {
-			cc.err = newErrMissingResponseField(fieldBalance)
-			return
-		}
-
-		cc.err = res.amount.ReadFromV2(*bal)
-		if cc.err != nil {
-			cc.err = newErrInvalidResponseField(fieldBalance, cc.err)
-		}
 	}
 
-	// process call
+	resp, err := rpcapi.Balance(&c.c, req, client.WithContext(ctx))
-	if !cc.processCall() {
+	if err != nil {
-		return nil, cc.err
+		return nil, err
 	}
 
+	var res ResBalanceGet
+	res.st, err = c.processResponse(resp)
+	if err != nil || !apistatus.IsSuccessful(res.st) {
+		return &res, err
+	}
+
+	const fieldBalance = "balance"
+
+	bal := resp.GetBody().GetBalance()
+	if bal == nil {
+		return &res, newErrMissingResponseField(fieldBalance)
+	}
+
+	if err := res.amount.ReadFromV2(*bal); err != nil {
+		return &res, newErrInvalidResponseField(fieldBalance, err)
+	}
 	return &res, nil
 }

client/common.go

@@ -1,7 +1,6 @@
 package client
 
 import (
-	"crypto/ecdsa"
 	"errors"
 	"fmt"
 
@@ -13,21 +12,11 @@ import (
 	"git.frostfs.info/TrueCloudLab/frostfs-sdk-go/version"
 )
 
-// common interface of resulting structures with API status.
-type resCommon interface {
-	setStatus(apistatus.Status)
-}
-
 // structure is embedded to all resulting types in order to inherit status-related methods.
 type statusRes struct {
 	st apistatus.Status
 }
 
-// setStatus implements resCommon interface method.
-func (x *statusRes) setStatus(st apistatus.Status) {
-	x.st = st
-}
-
 // Status returns server's status return.
 //
 // Use apistatus package functionality to handle the status.
@@ -85,89 +74,12 @@ var (
 	errorInvalidXHeaders      = errors.New("xheaders must be presented only as key-value pairs")
 )
 
-// groups all the details required to send a single request and process a response to it.
-type contextCall struct {
-	// ==================================================
-	// state vars that do not require explicit initialization
-
-	// final error to be returned from client method
-	err error
-
-	// received response
-	resp responseV2
-
-	// ==================================================
-	// shared parameters which are set uniformly on all calls
-
-	// request signing key
-	key ecdsa.PrivateKey
-
-	// callback prior to processing the response by the client
-	callbackResp func(ResponseMetaInfo) error
-
-	// if set, protocol errors will be expanded into a final error
-	resolveAPIFailures bool
-
-	// FrostFS network magic
-	netMagic uint64
-
-	// Meta parameters
-	meta prmCommonMeta
-
-	// ==================================================
-	// custom call parameters
-
-	// structure of the call result
-	statusRes resCommon
-
-	// request to be signed with a key and sent
-	req request
-
-	// function to send a request (unary) and receive a response
-	call func() (responseV2, error)
-
-	// function to send the request (req field)
-	wReq func() error
-
-	// function to recv the response (resp field)
-	rResp func() error
-
-	// function to close the message stream
-	closer func() error
-
-	// function of writing response fields to the resulting structure (optional)
-	result func(v2 responseV2)
-}
-
 type request interface {
 	GetMetaHeader() *v2session.RequestMetaHeader
 	SetMetaHeader(*v2session.RequestMetaHeader)
 	SetVerificationHeader(*v2session.RequestVerificationHeader)
 }
 
-// sets needed fields of the request meta header.
-func (x contextCall) prepareRequest() {
-	meta := x.req.GetMetaHeader()
-	if meta == nil {
-		meta = new(v2session.RequestMetaHeader)
-		x.req.SetMetaHeader(meta)
-	}
-
-	if meta.GetTTL() == 0 {
-		meta.SetTTL(2)
-	}
-
-	if meta.GetVersion() == nil {
-		var verV2 refs.Version
-		version.Current().WriteToV2(&verV2)
-		meta.SetVersion(&verV2)
-	}
-
-	meta.SetNetworkMagic(x.netMagic)
-
-	writeXHeadersToMeta(x.meta.xHeaders, meta)
-}
-
 func (c *Client) prepareRequest(req request, meta *v2session.RequestMetaHeader) {
 	ttl := meta.GetTTL()
 	if ttl == 0 {
@@ -187,75 +99,6 @@ func (c *Client) prepareRequest(req request, meta *v2session.RequestMetaHeader)
 	req.SetMetaHeader(meta)
 }
 
-// prepares, signs and writes the request. Result means success.
-// If failed, contextCall.err contains the reason.
-func (x *contextCall) writeRequest() bool {
-	x.prepareRequest()
-
-	x.req.SetVerificationHeader(nil)
-
-	// sign the request
-	x.err = signature.SignServiceMessage(&x.key, x.req)
-	if x.err != nil {
-		x.err = fmt.Errorf("sign request: %w", x.err)
-		return false
-	}
-
-	x.err = x.wReq()
-	if x.err != nil {
-		x.err = fmt.Errorf("write request: %w", x.err)
-		return false
-	}
-
-	return true
-}
-
-// performs common actions of response processing and writes any problem as a result status or client error
-// (in both cases returns false).
-//
-// Actions:
-//   - verify signature (internal);
-//   - call response callback (internal);
-//   - unwrap status error (optional).
-func (x *contextCall) processResponse() bool {
-	// call response callback if set
-	if x.callbackResp != nil {
-		x.err = x.callbackResp(ResponseMetaInfo{
-			key:   x.resp.GetVerificationHeader().GetBodySignature().GetKey(),
-			epoch: x.resp.GetMetaHeader().GetEpoch(),
-		})
-		if x.err != nil {
-			x.err = fmt.Errorf("response callback error: %w", x.err)
-			return false
-		}
-	}
-
-	// note that we call response callback before signature check since it is expected more lightweight
-	// while verification needs marshaling
-
-	// verify response signature
-	x.err = signature.VerifyServiceMessage(x.resp)
-	if x.err != nil {
-		x.err = fmt.Errorf("invalid response signature: %w", x.err)
-		return false
-	}
-
-	// get result status
-	st := apistatus.FromStatusV2(x.resp.GetMetaHeader().GetStatus())
-
-	// unwrap unsuccessful status and return it
-	// as error if client has been configured so
-	successfulStatus := apistatus.IsSuccessful(st)
-
-	if x.resolveAPIFailures {
-		x.err = apistatus.ErrFromStatus(st)
-	} else {
-		x.statusRes.setStatus(st)
-	}
-
-	return successfulStatus
-}
-
 // processResponse verifies response signature and converts status to an error if needed.
 func (c *Client) processResponse(resp responseV2) (apistatus.Status, error) {
 	if c.prm.cbRespInfo != nil {
@@ -280,78 +123,6 @@ func (c *Client) processResponse(resp responseV2) (apistatus.Status, error) {
 	return st, nil
 }
 
-// reads response (if rResp is set) and processes it. Result means success.
-// If failed, contextCall.err (or statusRes if resolveAPIFailures is set) contains the reason.
-func (x *contextCall) readResponse() bool {
-	if x.rResp != nil {
-		x.err = x.rResp()
-		if x.err != nil {
-			x.err = fmt.Errorf("read response: %w", x.err)
-			return false
-		}
-	}
-
-	return x.processResponse()
-}
-
-// closes the message stream (if closer is set) and writes the results (if result is set).
-// Return means success. If failed, contextCall.err contains the reason.
-func (x *contextCall) close() bool {
-	if x.closer != nil {
-		x.err = x.closer()
-		if x.err != nil {
-			x.err = fmt.Errorf("close RPC: %w", x.err)
-			return false
-		}
-	}
-
-	// write response to resulting structure
-	if x.result != nil {
-		x.result(x.resp)
-	}
-
-	return x.err == nil
-}
-
-// goes through all stages of sending a request and processing a response. Returns true if successful.
-// If failed, contextCall.err contains the reason.
-func (x *contextCall) processCall() bool {
-	// set request writer
-	x.wReq = func() error {
-		var err error
-		x.resp, err = x.call()
-		return err
-	}
-
-	// write request
-	ok := x.writeRequest()
-	if !ok {
-		return false
-	}
-
-	// read response
-	ok = x.readResponse()
-	if !ok {
-		return x.err == nil
-	}
-
-	// close and write response to resulting structure
-	ok = x.close()
-	if !ok {
-		return false
-	}
-
-	return x.err == nil
-}
-
-// initializes static cross-call parameters inherited from client.
-func (c *Client) initCallContext(ctx *contextCall) {
-	ctx.key = c.prm.key
-	ctx.resolveAPIFailures = c.prm.resolveFrostFSErrors
-	ctx.callbackResp = c.prm.cbRespInfo
-	ctx.netMagic = c.prm.netMagic
-}
-
 // ExecRaw executes f with underlying git.frostfs.info/TrueCloudLab/frostfs-api-go/v2/rpc/client.Client
 // instance. Communicate over the Protocol Buffers protocol in a more flexible way:
 // most often used to transmit data over a fixed version of the FrostFS protocol, as well