windows: Fixes following container log rotation

If we're following a file, that file will remain open, and we continue
to read data from it when new data becomes available.

On Windows, this can be an issue if the container logs needs to be rotated.
Log rotation is done by renaming the file, but this action may fail if
the file is already opened.

Setting the FILE_SHARE_DELETE flag when opening the file will prevent this
issue, as documented: "Delete access allows both delete and rename operations" [1].

In golang, there's no way to set this flag [2], the sharemode is always set to:
sharemode := uint32(FILE_SHARE_READ | FILE_SHARE_WRITE)

Thus, we need to open the file ourselves with the right flags.

[1] https://learn.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-createfilea?redirectedfrom=MSDN
[2] https://cs.opensource.google/go/go/+/refs/tags/go1.22.2:src/syscall/syscall_windows.go;l=366

pkg/kubelet/kuberuntime/logs/logs.go

@@ -291,7 +291,7 @@ func ReadLogs(ctx context.Context, path, containerID string, opts *LogOptions, r
 		return fmt.Errorf("failed to try resolving symlinks in path %q: %v", path, err)
 	}
 	path = evaluated
-	f, err := os.Open(path)
+	f, err := openFileShareDelete(path)
 	if err != nil {
 		return fmt.Errorf("failed to open log file %q: %v", path, err)
 	}
@@ -360,7 +360,7 @@ func ReadLogs(ctx context.Context, path, containerID string, opts *LogOptions, r
 					return err
 				}
 				if recreated {
-					newF, err := os.Open(path)
+					newF, err := openFileShareDelete(path)
 					if err != nil {
 						if os.IsNotExist(err) {
 							continue

pkg/kubelet/kuberuntime/logs/logs_other.go

@@ -0,0 +1,29 @@
+//go:build !windows
+// +build !windows
+
+/*
+Copyright 2024 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package logs
+
+import (
+	"os"
+)
+
+func openFileShareDelete(path string) (*os.File, error) {
+	// Noop. Only relevant for Windows.
+	return os.Open(path)
+}

pkg/kubelet/kuberuntime/logs/logs_test.go

@@ -286,6 +286,10 @@ func TestReadRotatedLog(t *testing.T) {
 		}
 	}
 
+	// Finished writing into the file, close it, so we can delete it later.
+	err = file.Close()
+	assert.NoErrorf(t, err, "could not close file.")
+
 	time.Sleep(20 * time.Millisecond)
 	// Make the function ReadLogs end.
 	fakeRuntimeService.Lock()

pkg/kubelet/kuberuntime/logs/logs_windows.go

@@ -0,0 +1,49 @@
+//go:build windows
+// +build windows
+
+/*
+Copyright 2024 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package logs
+
+import (
+	"os"
+	"syscall"
+)
+
+// Based on Windows implementation of Windows' syscall.Open
+// https://cs.opensource.google/go/go/+/refs/tags/go1.22.2:src/syscall/syscall_windows.go;l=342
+// In addition to syscall.Open, this function also adds the syscall.FILE_SHARE_DELETE flag to sharemode,
+// which will allow us to read from the file without blocking the file from being deleted or renamed.
+// This is essential for Log Rotation which is done by renaming the open file. Without this, the file rename would fail.
+func openFileShareDelete(path string) (*os.File, error) {
+	pathp, err := syscall.UTF16PtrFromString(path)
+	if err != nil {
+		return nil, err
+	}
+
+	var access uint32 = syscall.GENERIC_READ
+	var sharemode uint32 = syscall.FILE_SHARE_READ | syscall.FILE_SHARE_WRITE | syscall.FILE_SHARE_DELETE
+	var createmode uint32 = syscall.OPEN_EXISTING
+	var attrs uint32 = syscall.FILE_ATTRIBUTE_NORMAL
+
+	handle, err := syscall.CreateFile(pathp, access, sharemode, nil, createmode, attrs, 0)
+	if err != nil {
+		return nil, err
+	}
+
+	return os.NewFile(uintptr(handle), path), nil
+}