feature/sugar: implement go-tarantool like faces for sharded tarantool

CHANGELOG.md

@@ -17,7 +17,8 @@ FEATURES:
 * All discovering logs has new prefix [DISCOVERY]
 * Introduce Replicaset.CallAsync, it is usefull to send concurrent requests to replicasets;
 	additionally, CallAsync provides new interface to interact with replicaset without cons of interface of ReplicaCall
-* Retry tarantool request only on some vshard errors (#66)
+* Retry tarantool request only on some vshard errors (#66).
+* Added call interfaces backwards compatible with go-tarantool (#31).
 
 REFACTOR:
 

sugar.go

@@ -0,0 +1,118 @@
+package vshard_router //nolint:revive
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/tarantool/go-tarantool/v2/pool"
+)
+
+// CallRequest helps you to create a call request object for execution
+// by a Connection.
+type CallRequest struct {
+	ctx      context.Context
+	fnc      string
+	args     interface{}
+	bucketID uint64
+}
+
+// CallResponse is a backwards-compatible structure with go-tarantool for easier replacement.
+type CallResponse struct {
+	rawResp     interface{}
+	getTypedFnc StorageResultTypedFunc
+	err         error
+}
+
+// NewCallRequest returns a new empty CallRequest.
+func (r *Router) NewCallRequest(function string) *CallRequest {
+	req := new(CallRequest)
+	req.fnc = function
+	return req
+}
+
+// Do perform a request synchronously on the connection.
+// It is important that the logic of this method is different from go-tarantool.
+func (r *Router) Do(req *CallRequest, userMode pool.Mode) *CallResponse {
+	ctx := req.ctx
+	bucketID := req.bucketID
+	resp := new(CallResponse)
+
+	if req.fnc == "" {
+		resp.err = fmt.Errorf("func name is empty")
+		return resp
+	}
+
+	if req.args == nil {
+		resp.err = fmt.Errorf("no request args")
+		return resp
+	}
+
+	if req.bucketID == 0 {
+		if r.cfg.BucketGetter == nil {
+			resp.err = fmt.Errorf("bucket id for request is not set")
+			return resp
+		}
+
+		bucketID = r.cfg.BucketGetter(ctx)
+	}
+
+	vshardMode := ReadMode
+
+	// If the user says he prefers to do it on the master,
+	// then he agrees that it will go to the replica, which means he will not write.
+	if userMode == pool.RW {
+		vshardMode = WriteMode
+	}
+
+	resp.rawResp, resp.getTypedFnc, resp.err = r.RouterCallImpl(ctx,
+		bucketID,
+		CallOpts{
+			Timeout:    r.cfg.RequestTimeout,
+			PoolMode:   userMode,
+			VshardMode: vshardMode,
+		},
+		req.fnc,
+		req.args)
+
+	return resp
+}
+
+// Args sets the args for the eval request.
+// Note: default value is empty.
+func (req *CallRequest) Args(args interface{}) *CallRequest {
+	req.args = args
+	return req
+}
+
+// Context sets a passed context to the request.
+func (req *CallRequest) Context(ctx context.Context) *CallRequest {
+	req.ctx = ctx
+	return req
+}
+
+// BucketID method that sets the bucketID for your request.
+// You can ignore this parameter if you have a bucketGetter.
+// However, this method has a higher priority.
+func (req *CallRequest) BucketID(bucketID uint64) *CallRequest {
+	req.bucketID = bucketID
+	return req
+}
+
+// GetTyped waits synchronously for response and calls msgpack.Decoder.Decode(result) if no error happens.
+func (resp *CallResponse) GetTyped(result interface{}) error {
+	if resp.err != nil {
+		return resp.err
+	}
+
+	return resp.getTypedFnc(result)
+}
+
+// Get implementation now works synchronously for response.
+// The interface was created purely for convenient migration to go-vshard-router from go-tarantool.
+func (resp *CallResponse) Get() ([]interface{}, error) {
+	if resp.err != nil {
+		return nil, resp.err
+	}
+
+	return []interface{}{resp.rawResp}, nil
+}

vshard.go

@@ -92,13 +92,25 @@ type Config struct {
 	TopologyProvider TopologyProvider // TopologyProvider is required provider
 
 	// Discovery
-	DiscoveryTimeout time.Duration // DiscoveryTimeout is timeout between cron discovery job; by default there is no timeout
+	// DiscoveryTimeout is timeout between cron discovery job; by default there is no timeout.
+	DiscoveryTimeout time.Duration
 	DiscoveryMode    DiscoveryMode
 
 	TotalBucketCount uint64
 	User             string
 	Password         string
 	PoolOpts         tarantool.Opts
+
+	// BucketGetter is an optional argument.
+	// You can specify a function that will receive the bucket id from the context.
+	// This is useful if you use middleware that inserts the calculated bucket id into the request context.
+	BucketGetter func(ctx context.Context) uint64
+	// RequestTimeout timeout for requests to Tarantool.
+	// Don't rely on using this timeout.
+	// This is the difference between the timeout of the library itself
+	// that is, our retry timeout if the buckets, for example, move.
+	// Currently, it only works for sugar implementations .
+	RequestTimeout time.Duration
 }
 
 type BucketStatInfo struct {