/
validator.go
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/
validator.go
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// Copyright 2019 FairwindsOps Inc
//
// 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 webhook
import (
"context"
"fmt"
"net/http"
"os"
conf "github.com/fairwindsops/polaris/pkg/config"
validator "github.com/fairwindsops/polaris/pkg/validator"
"github.com/fairwindsops/polaris/pkg/validator/controllers"
"github.com/sirupsen/logrus"
admissionregistrationv1beta1 "k8s.io/api/admissionregistration/v1beta1"
appsv1 "k8s.io/api/apps/v1"
batchv1 "k8s.io/api/batch/v1"
batchv1beta1 "k8s.io/api/batch/v1beta1"
corev1 "k8s.io/api/core/v1"
"k8s.io/apimachinery/pkg/runtime"
"sigs.k8s.io/controller-runtime/pkg/client"
"sigs.k8s.io/controller-runtime/pkg/manager"
"sigs.k8s.io/controller-runtime/pkg/runtime/inject"
"sigs.k8s.io/controller-runtime/pkg/webhook/admission"
"sigs.k8s.io/controller-runtime/pkg/webhook/admission/builder"
"sigs.k8s.io/controller-runtime/pkg/webhook/admission/types"
)
// Validator validates k8s resources.
type Validator struct {
client client.Client
decoder types.Decoder
Config conf.Configuration
}
var _ inject.Client = &Validator{}
// InjectClient injects the client.
func (v *Validator) InjectClient(c client.Client) error {
v.client = c
return nil
}
var _ inject.Decoder = &Validator{}
// InjectDecoder injects the decoder.
func (v *Validator) InjectDecoder(d types.Decoder) error {
v.decoder = d
return nil
}
var _ admission.Handler = &Validator{}
// NewWebhook creates a validating admission webhook for the apiType.
func NewWebhook(name string, mgr manager.Manager, validator Validator, apiType runtime.Object) *admission.Webhook {
name = fmt.Sprintf("%s.k8s.io", name)
path := fmt.Sprintf("/validating-%s", name)
webhook, err := builder.NewWebhookBuilder().
Name(name).
Validating().
Path(path).
Operations(admissionregistrationv1beta1.Create, admissionregistrationv1beta1.Update).
WithManager(mgr).
ForType(apiType).
Handlers(&validator).
Build()
if err != nil {
logrus.Errorf("Error building webhook: %v", err)
os.Exit(1)
} else {
logrus.Info(name + " webhook started")
}
return webhook
}
// Handle for Validator to run validation checks.
func (v *Validator) Handle(ctx context.Context, req types.Request) types.Response {
var err error
var podResult validator.PodResult
if req.AdmissionRequest.Kind.Kind == "Pod" {
pod := corev1.Pod{}
err = v.decoder.Decode(req, &pod)
podResult = validator.ValidatePod(v.Config, &pod.Spec)
} else {
var controller controllers.Interface
if yes := v.Config.CheckIfKindIsConfiguredForValidation(req.AdmissionRequest.Kind.Kind); !yes {
logrus.Warnf("Skipping, kind (%s) isn't something we are configured to scan", req.AdmissionRequest.Kind.Kind)
return admission.ValidationResponse(true, fmt.Sprintf("Skipping: (%s) isn't something we're configured to scan.", req.AdmissionRequest.Kind.Kind))
}
// We should never hit this case unless something is misconfiured in CheckIfKindIsConfiguredForValidation
controllerType, err := conf.GetSupportedControllerFromString(req.AdmissionRequest.Kind.Kind)
if err != nil {
msg := fmt.Errorf("Unexpected error occurred. Expected Kind to be a supported type (%s)", req.AdmissionRequest.Kind.Kind)
logrus.Error(msg)
return admission.ErrorResponse(http.StatusInternalServerError, err)
}
// For each type, perform the scan
// TODO: This isn't really that elegant due to the decoder and NewXXXController setup :( could use love
switch controllerType {
case conf.Deployments:
deploy := appsv1.Deployment{}
err = v.decoder.Decode(req, &deploy)
controller = controllers.NewDeploymentController(deploy)
case conf.StatefulSets:
statefulSet := appsv1.StatefulSet{}
err = v.decoder.Decode(req, &statefulSet)
controller = controllers.NewStatefulSetController(statefulSet)
case conf.DaemonSets:
daemonSet := appsv1.DaemonSet{}
err = v.decoder.Decode(req, &daemonSet)
controller = controllers.NewDaemonSetController(daemonSet)
case conf.Jobs:
job := batchv1.Job{}
err = v.decoder.Decode(req, &job)
controller = controllers.NewJobController(job)
case conf.CronJobs:
cronJob := batchv1beta1.CronJob{}
err = v.decoder.Decode(req, &cronJob)
controller = controllers.NewCronJobController(cronJob)
case conf.ReplicationControllers:
replicationController := corev1.ReplicationController{}
err = v.decoder.Decode(req, &replicationController)
controller = controllers.NewReplicationControllerController(replicationController)
}
controllerResult := validator.ValidateController(v.Config, controller)
podResult = controllerResult.PodResult
}
if err != nil {
logrus.Errorf("Error validating request: %v", err)
return admission.ErrorResponse(http.StatusBadRequest, err)
}
allowed := true
reason := ""
if podResult.Summary.Totals.Errors > 0 {
allowed = false
reason = getFailureReason(podResult)
}
logrus.Infof("%d validation errors found when validating %s", podResult.Summary.Totals.Errors, podResult.Name)
return admission.ValidationResponse(allowed, reason)
}
func getFailureReason(podResult validator.PodResult) string {
reason := "\nPolaris prevented this deployment due to configuration problems:\n"
for _, message := range podResult.Messages {
if message.Type == validator.MessageTypeError {
reason += fmt.Sprintf("- Pod: %s\n", message.Message)
}
}
for _, containerResult := range podResult.ContainerResults {
for _, message := range containerResult.Messages {
if message.Type == validator.MessageTypeError {
reason += fmt.Sprintf("- Container %s: %s\n", containerResult.Name, message.Message)
}
}
}
return reason
}