sealerio · kakaZhou719 · Jul 12, 2023
diff --git a/cmd/sealer/cmd/cluster/installer.go b/cmd/sealer/cmd/cluster/installer.go
@@ -31,6 +31,7 @@ import (
 	"github.com/sealerio/sealer/pkg/imagedistributor"
 	"github.com/sealerio/sealer/pkg/imageengine"
 	"github.com/sealerio/sealer/pkg/infradriver"
+	"github.com/sealerio/sealer/pkg/preflight"
 	"github.com/sealerio/sealer/pkg/registry"
 8000
	v1 "github.com/sealerio/sealer/types/api/v1"
 	v2 "github.com/sealerio/sealer/types/api/v2"
@@ -230,6 +231,15 @@ func (k KubeInstaller) Install(kubeImageName string, options KubeInstallOptions)
 		appNames = k.infraDriver.GetClusterLaunchApps()
 	)
 
+	runners := preflight.Runner{
+		Checkers: []preflight.Checker{preflight.ClusterIsExistsCheck{}},
+	}
+
+	err := runners.Execute()
+	if err != nil {
+		return err
+	}
+
 	logrus.Infof("start to create new cluster with image: %s", kubeImageName)
 	logrus.Debugf("will create a new cluster using: %+v\n", cluster)
 

diff --git a/pkg/preflight/checker.go b/pkg/preflight/checker.go
@@ -0,0 +1,46 @@
+// Copyright © 2023 Alibaba Group Holding Ltd.
+//
+// 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 preflight
+
+import (
+	"github.com/pkg/errors"
+	"github.com/sealerio/sealer/pkg/client/k8s"
+)
+
+// Checker validates the desired value
+type Checker interface {
+	Check() (warnings, errorList []error)
+	Name() string
+}
+
+// ClusterIsExistsCheck verifies the given cluster is existed.
+type ClusterIsExistsCheck struct {
+}
+
+// Name returns label for checker.
+func (ClusterIsExistsCheck) Name() string {
+	return "ClusterExist"
+}
+
+// Check :if the given cluster is existed, return error.
+func (c ClusterIsExistsCheck) Check() (warnings, errorList []error) {
+	// check K8s client
+	client, _ := k8s.NewK8sClient()
+	if client != nil {
+		return nil, []error{errors.Errorf("cluster is exist: could new k8s client via default kubeconfig")}
+	}
+
+	return nil, nil
+}
diff --git a/pkg/preflight/runner.go b/pkg/preflight/runner.go
@@ -0,0 +1,91 @@
+// Copyright © 2023 Alibaba Group Holding Ltd.
+//
+// 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 preflight
+
+import (
+	"bytes"
+	"fmt"
+
+	"github.com/sealerio/sealer/utils/strings"
+	"github.com/sirupsen/logrus"
+)
+
+// OptionFunc configures a runner list
+type OptionFunc func(*RunOptions)
+
+type RunOptions struct {
+	// SkipList: if checker name in this list, will skip to check. default is lowercase.
+	SkipList []string
+
+	// IgnoreList: if checker name in this list, will ignore its error after run check. default is lowercase.
+	IgnoreList []string
+}
+
+func WithSkips(skips []string) OptionFunc {
+	return func(o *RunOptions) {
+		o.SkipList = skips
+	}
+}
+
+func WithIgnores(ignores []string) OptionFunc {
+	return func(o *RunOptions) {
+		o.IgnoreList = ignores
+	}
+}
+
+type Runner struct {
+	Checkers []Checker
+}
+
+// Execute checker validate and dispatch to different results
+func (r *Runner) Execute(optFunc ...OptionFunc) error {
+	var options RunOptions
+	for _, opt := range optFunc {
+		opt(&options)
+	}
+
+	var errsBuffer bytes.Buffer
+	for _, checker := range r.Checkers {
+		// run the validation
+		name := checker.Name()
+
+		// skip specified checker
+		if len(options.SkipList) > 0 && strings.IsInSlice(name, options.SkipList) {
+			continue
+		}
+
+		warnings, errs := checker.Check()
+
+		// ignore check error and append it to warnings
+		if strings.IsInSlice(name, options.IgnoreList) {
+			warnings = append(warnings, errs...)
+			errs = []error{}
+		}
+
+		for _, w := range warnings {
+			logrus.Warnf(fmt.Sprintf("\t[WARNING %s]: %v\n", name, w))
+		}
+
+		for _, i := range errs {
+			errsBuffer.WriteString(fmt.Sprintf("\t[ERROR %s]: %v\n", name, i.Error()))
+		}
+	}
+
+	if errsBuffer.Len() > 0 {
+		return fmt.Errorf("prechecked some error:%s", errsBuffer.String())
+	}
+
+	return nil
+}