[#343] client: Accept context parameter in Dial

In previous implementation of `Client.Dial` there was no ability to
specify parent context (e.g. global application context).

Add `PrmDial.SetContext` method which accepts optional base dial
context. Use the context to open client connection or fall back to using
`context.Background()`.

Upgraded version of `github.com/nspcc-dev/neofs-api-go/v2` module
also fixes the problem when dial timeout didn't work properly.

Signed-off-by: Leonard Lyubich <ctulhurider@gmail.com>

client/client.go

@@ -1,8 +1,10 @@
 package client
 
 import (
+	"context"
 	"crypto/ecdsa"
 	"crypto/tls"
+	"errors"
 	"time"
 
 	v2accounting "github.com/nspcc-dev/neofs-api-go/v2/accounting"
@@ -63,6 +65,10 @@ func (c *Client) Init(prm PrmInit) {
 // Returns an error describing failure reason. If failed, the Client
 // SHOULD NOT be used.
 //
+// Uses the context specified by SetContext if it was called with non-nil
+// argument, otherwise context.Background() is used. Dial returns context
+// errors, see context package docs for details.
+//
 // Panics if required parameters are set incorrectly, look carefully
 // at the method documentation.
 //
@@ -100,7 +106,13 @@ func (c *Client) Dial(prm PrmDial) error {
 	c.setNeoFSAPIServer((*coreServer)(&c.c))
 
 	// TODO: (neofs-api-go#382) perform generic dial stage of the client.Client
-	_, _ = rpc.Balance(&c.c, new(v2accounting.BalanceRequest))
+	_, err := rpc.Balance(&c.c, new(v2accounting.BalanceRequest),
+		client.WithContext(prm.parentCtx),
+	)
+	// return context errors since they signal about dial problem
+	if errors.Is(err, context.Canceled) || errors.Is(err, context.DeadlineExceeded) {
+		return err
+	}
 
 	return nil
 }
@@ -174,6 +186,8 @@ type PrmDial struct {
 
 	streamTimeoutSet bool
 	streamTimeout    time.Duration
+
+	parentCtx context.Context
 }
 
 // SetServerURI sets server URI in the NeoFS network.
@@ -214,3 +228,11 @@ func (x *PrmDial) SetStreamTimeout(timeout time.Duration) {
 	x.streamTimeoutSet = true
 	x.streamTimeout = timeout
 }
+
+// SetContext allows to specify optional base context within which connection
+// should be established.
+//
+// Context SHOULD NOT be nil.
+func (x *PrmDial) SetContext(ctx context.Context) {
+	x.parentCtx = ctx
+}

client/client_test.go

@@ -1,6 +1,7 @@
 package client
 
 import (
+	"context"
 	"crypto/ecdsa"
 	"crypto/elliptic"
 	"crypto/rand"
@@ -37,3 +38,31 @@ func newClient(server neoFSAPIServer) *Client {
 
 	return &c
 }
+
+func TestClient_DialContext(t *testing.T) {
+	var c Client
+
+	// try to connect to any host
+	var prm PrmDial
+	prm.SetServerURI("localhost:8080")
+
+	assert := func(ctx context.Context, errExpected error) {
+		// use the particular context
+		prm.SetContext(ctx)
+
+		// expect particular context error according to Dial docs
+		require.ErrorIs(t, c.Dial(prm), errExpected)
+	}
+
+	// create pre-abandoned context
+	ctx, cancel := context.WithCancel(context.Background())
+	cancel()
+
+	assert(ctx, context.Canceled)
+
+	// create "pre-deadlined" context
+	ctx, cancel = context.WithTimeout(context.Background(), 0)
+	defer cancel()
+
+	assert(ctx, context.DeadlineExceeded)
+}

go.mod

@@ -9,7 +9,7 @@ require (
 	github.com/mr-tron/base58 v1.2.0
 	github.com/nspcc-dev/hrw v1.0.9
 	github.com/nspcc-dev/neo-go v0.99.2
-	github.com/nspcc-dev/neofs-api-go/v2 v2.13.2-0.20221004142957-5fc2644c680d
+	github.com/nspcc-dev/neofs-api-go/v2 v2.13.2-0.20221005093543-3a91383f24a9
 	github.com/nspcc-dev/neofs-contract v0.15.3
 	github.com/nspcc-dev/tzhash v1.6.1
 	github.com/stretchr/testify v1.7.0