chore: Replaced all grpc.DialContext calls with dialContextBlocking

changelog/fragments/1752567204-stop-using-deprecated-grpc-connection-functions.yaml

@@ -0,0 +1,35 @@
+# Kind can be one of:
+# - breaking-change: a change to previously-documented behavior
+# - deprecation: functionality that is being removed in a later release
+# - bug-fix: fixes a problem in a previous version
+# - enhancement: extends functionality but does not break or fix existing behavior
+# - feature: new functionality
+# - known-issue: problems that we are aware of in a given version
+# - security: impacts on the security of a product or a user's deployment.
+# - upgrade: important information for someone upgrading from a prior version
+# - other: does not fit into any of the other categories
+kind: enhancement
+
+# Change summary; a 80ish characters long description of the change.
+summary: Stop using deprecated grpc connection establishment functions
+
+# Long description; in case the summary is not enough to describe the change
+# this field accommodate a description without length limits.
+# NOTE: This field will be rendered only for breaking-change and known-issue kinds at the moment.
+description: |
+  Migrated from deprecated grpc.DialContext to grpc.NewClient while maintaining 
+  blocking connection behavior. Created custom wrapper functions to preserve 
+  the same functionality without using deprecated APIs.
+
+# Affected component; usually one of "elastic-agent", "fleet-server", "filebeat", "metricbeat", "auditbeat", "all", etc.
+component: "elastic-agent"
+
+# PR URL; optional; the PR number that added the changeset.
+# If not present is automatically filled by the tooling finding the PR where this changelog fragment has been added.
+# NOTE: the tooling supports backports, so it's able to fill the original PR number instead of the backport PR number.
+# Please provide it if you are adding a fragment for a different PR.
+#pr: https://github.com/elastic/elastic-agent/pull/XXXX
+
+# Issue URL; optional; the GitHub issue related to this changeset (either closes or is part of).
+# If not present is automatically filled by the tooling with the issue linked to the PR number.
+issue: https://github.com/elastic/elastic-agent/issues/5453

pkg/control/dial.go

@@ -0,0 +1,37 @@
+// Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+// or more contributor license agreements. Licensed under the Elastic License 2.0;
+// you may not use this file except in compliance with the Elastic License 2.0.
+
+package control
+
+import (
+	"context"
+
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/connectivity"
+)
+
+// DialContextBlocking creates a blocking connection equivalent to the deprecated grpc.DialContext.
+// It uses the new grpc.NewClient API but waits for the connection to be established before returning,
+// maintaining the same blocking behavior as the deprecated function.
+func DialContextBlocking(ctx context.Context, target string, opts ...grpc.DialOption) (*grpc.ClientConn, error) {
+	conn, err := grpc.NewClient(target, opts...)
+	if err != nil {
+		return nil, err
+	}
+
+	for {
+		state := conn.GetState()
+		if state == connectivity.Ready {
+			return conn, nil
+		}
+		if state == connectivity.TransientFailure || state == connectivity.Shutdown {
+			conn.Close()
+			return nil, ctx.Err()
+		}
+		if !conn.WaitForStateChange(ctx, state) {
+			conn.Close()
+			return nil, ctx.Err()
+		}
+	}
+}

pkg/control/dial_test.go

@@ -0,0 +1,110 @@
+// Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+// or more contributor license agreements. Licensed under the Elastic License 2.0;
+// you may not use this file except in compliance with the Elastic License 2.0.
+
+package control
+
+import (
+	"context"
+	"net"
+	"testing"
+	"time"
+
+	"google.golang.org/grpc"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"google.golang.org/grpc/connectivity"
+	"google.golang.org/grpc/credentials/insecure"
+	"google.golang.org/grpc/test/bufconn"
+)
+
+func TestDialContextBlocking_Success(t *testing.T) {
+	// Create a buffer connection for testing
+	buffer := bufconn.Listen(1024 * 1024)
+	defer buffer.Close()
+
+	// Start a mock gRPC server
+	server := grpc.NewServer()
+	go func() {
+		if err := server.Serve(buffer); err != nil {
+			t.Logf("Server serve error: %v", err)
+		}
+	}()
+	defer server.Stop()
+
+	// Test successful connection
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+
+	conn, err := DialContextBlocking(ctx, "bufconn",
+		grpc.WithContextDialer(func(context.Context, string) (net.Conn, error) {
+			return buffer.Dial()
+		}),
+		grpc.WithTransportCredentials(insecure.NewCredentials()),
+	)
+
+	require.NoError(t, err, "DialContextBlocking failed")
+	defer conn.Close()
+
+	// Verify connection is ready
+	state := conn.GetState()
+	assert.Equal(t, connectivity.Ready, state, "Expected connection state to be Ready")
+}
+
+func TestDialContextBlocking_ContextCancellation(t *testing.T) {
+	// Create a context that cancels immediately
+	ctx, cancel := context.WithCancel(context.Background())
+	cancel() // Cancel immediately
+
+	// Try to establish connection with cancelled context
+	conn, err := DialContextBlocking(ctx, "unreachable:12345",
+		grpc.WithTransportCredentials(insecure.NewCredentials()),
+	)
+
+	// Should return an error due to context cancellation
+	if err == nil {
+		conn.Close()
+		t.Fatal("Expected DialContextBlocking to fail with cancelled context")
+	}
+
+	if err != context.Canceled {
+		t.Errorf("Expected context.Canceled error, got %v", err)
+	}
+}
+
+func TestDialContextBlocking_InvalidTarget(t *testing.T) {
+	ctx, cancel := context.WithTimeout(context.Background(), 1*time.Second)
+	defer cancel()
+
+	// Try to connect to an invalid target
+	conn, err := DialContextBlocking(ctx, "invalid-scheme://invalid-target",
+		grpc.WithTransportCredentials(insecure.NewCredentials()),
+	)
+
+	// Should return an error
+	if err == nil {
+		conn.Close()
+		t.Fatal("Expected DialContextBlocking to fail with invalid target")
+	}
+}
+
+func TestDialContextBlocking_Timeout(t *testing.T) {
+	// Create a very short timeout
+	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Millisecond)
+	defer cancel()
+
+	// Try to connect to a non-existent service
+	conn, err := DialContextBlocking(ctx, "127.0.0.1:1",
+		grpc.WithTransportCredentials(insecure.NewCredentials()),
+	)
+
+	// Should return an error due to timeout
+	if err == nil {
+		conn.Close()
+		t.Fatal("Expected DialContextBlocking to fail with timeout")
+	}
+
+	if err != context.DeadlineExceeded {
+		t.Errorf("Expected context.DeadlineExceeded error, got %v", err)
+	}
+}

pkg/control/v1/client/dial.go

@@ -18,7 +18,7 @@ import (
 )
 
 func dialContext(ctx context.Context) (*grpc.ClientConn, error) {
-	return grpc.DialContext( //nolint:staticcheck // Only the deprecated version allows this call to be blocking
+	return control.DialContextBlocking(
 		ctx,
 		strings.TrimPrefix(control.Address(), "unix://"),
 		grpc.WithTransportCredentials(insecure.NewCredentials()),

pkg/control/v1/client/dial_windows.go

@@ -19,7 +19,7 @@ import (
 )
 
 func dialContext(ctx context.Context) (*grpc.ClientConn, error) {
-	return grpc.DialContext( //nolint:staticcheck // Only the deprecated version allows this call to be blocking
+	return control.DialContextBlocking(
 		ctx,
 		control.Address(),
 		grpc.WithTransportCredentials(insecure.NewCredentials()),

pkg/control/v2/client/dial.go

@@ -11,6 +11,8 @@ import (
 	"net"
 	"strings"
 
+	"github.com/elastic/elastic-agent/pkg/control"
+
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/credentials/insecure"
 )
@@ -21,7 +23,7 @@ func dialContext(ctx context.Context, address string, maxMsgSize int, opts ...gr
 		grpc.WithContextDialer(dialer),
 		grpc.WithDefaultCallOptions(grpc.MaxCallRecvMsgSize(maxMsgSize)),
 	)
-	return grpc.DialContext(ctx, address, opts...) //nolint:staticcheck // Only the deprecated version allows this call to be blocking
+	return control.DialContextBlocking(ctx, address, opts...)
 }
 
 func dialer(ctx context.Context, addr string) (net.Conn, error) {

pkg/control/v2/client/dial_windows.go

@@ -11,6 +11,8 @@ import (
 	"net"
 	"strings"
 
+	"github.com/elastic/elastic-agent/pkg/control"
+
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/credentials/insecure"
 
@@ -23,7 +25,7 @@ func dialContext(ctx context.Context, address string, maxMsgSize int, opts ...gr
 		grpc.WithContextDialer(dialer),
 		grpc.WithDefaultCallOptions(grpc.MaxCallRecvMsgSize(maxMsgSize)),
 	)
-	return grpc.DialContext(ctx, address, opts...) //nolint:staticcheck // Only the deprecated version allows this call to be blocking
+	return control.DialContextBlocking(ctx, address, opts...)
 }
 
 func dialer(ctx context.Context, addr string) (net.Conn, error) {