repo_description: Kubernetes-based, scale-to-zero, request-driven compute
repo_topics: app autoscaler container developer-productivity function knative kubernetes networking scale serverless serverless-containers
code: /*
  Copyright 2024 The Knative 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 main
  
  import (
  	"fmt"
  	"reflect"
  	"strings"
  
  	"k8s.io/apimachinery/pkg/util/sets"
  	"knative.dev/serving/pkg/apis/config"
  	v1 "knative.dev/serving/pkg/apis/serving/v1"
  )
  
  type override struct {
  	crdName string
  	entries []entry
  }
  
  type entry struct {
  	path              string
  	description       string
  	allowedFields     sets.Set[string]
  	featureFlagFields []flagField
  	dropRequired      sets.Set[string]
  
  	// Drops list-type
  	//   x-kubernetes-list-map-keys:
  	//     - name
  	//   x-kubernetes-list-type: map
  	dropListType bool
  }
  
  type flagField struct {
  	name string
  	flag string
  }
  
  var overrides = []override{{
  	crdName: "services.serving.knative.dev",
  	entries: revSpecOverrides("spec.template.spec"),
  }, {
  	crdName: "configurations.serving.knative.dev",
  	entries: revSpecOverrides("spec.template.spec"),
  }, {
  	crdName: "revisions.serving.knative.dev",
  	entries: revSpecOverrides("spec"),
  }, {
  	crdName: "podautoscalers.autoscaling.internal.knative.dev",
  	entries: []entry{{
  		path: "spec.scaleTargetRef",
  		allowedFields: sets.New(
  			"apiVersion",
  			"kind",
  			"name",
  		),
  	}},
  }}
  
  func revSpecOverrides(prefixPath string) []entry {
  	entries := []entry{{
  		allowedFields: sets.New(
  			"automountServiceAccountToken",
  			"containers",
  			"enableServiceLinks",
  			"imagePullSecrets",
  			"serviceAccountName",
  			"volumes",
  		).Insert(revisionSpecFields()...),
  		featureFlagFields: []flagField{
  			{name: "affinity", flag: config.FeaturePodSpecAffinity},
  			{name: "dnsConfig", flag: config.FeaturePodSpecDNSConfig},
  			{name: "dnsPolicy", flag: config.FeaturePodSpecDNSPolicy},
  			{name: "hostAliases", flag: config.FeaturePodSpecHostAliases},
  			{name: "hostIPC", flag: config.FeaturePodSpecHostIPC},
  			{name: "hostNetwork", flag: config.FeaturePodSpecHostNetwork},
  			{name: "hostPID", flag: config.FeaturePodSpecHostPID},
  			{name: "initContainers", flag: config.FeaturePodSpecInitContainers},
  			{name: "nodeSelector", flag: config.FeaturePodSpecNodeSelector},
  			{name: "priorityClassName", flag: config.FeaturePodSpecPriorityClassName},
  			{name: "runtimeClassName", flag: config.FeaturePodSpecRuntimeClassName},
  			{name: "schedulerName", flag: config.FeaturePodSpecSchedulerName},
  			{name: "securityContext", flag: config.FeaturePodSpecSecurityContext},
  			{name: "shareProcessNamespace", flag: config.FeaturePodSpecShareProcessNamespace},
  			{name: "tolerations", flag: config.FeaturePodSpecTolerations},
  			{name: "topologySpreadConstraints", flag: config.FeaturePodSpecTopologySpreadConstraints},
  		},
  	}, {
  		path:         "containers",
  		dropListType: true,
  		dropRequired: sets.New("name"),
  		allowedFields: sets.New(
  			"args",
  			"command",
  			"env",
  			"envFrom",
  			"image",
  			"imagePullPolicy",
  			"livenessProbe",
  			"name",
  			"ports",
  			"readinessProbe",
  			"resources",
  			"securityContext",
  			"startupProbe",
  			"terminationMessagePath",
  			"terminationMessagePolicy",
  			"volumeMounts",
  			"workingDir",
  		),
  	}, {
  		path:         "containers.ports",
  		dropListType: true,
  		dropRequired: sets.New("containerPort"),
  		allowedFields: sets.New(
  			"containerPort",
  			"name",
  			"protocol",
  		),
  	}, {
  		path: "containers.securityContext",
  		allowedFields: sets.New(
  			"allowPrivilegeEscalation",
  			"capabilities",
  			"privileged",
  			"readOnlyRootFilesystem",
  			"runAsGroup",
  			"runAsNonRoot",
  			"runAsUser",
  			"seccompProfile",
  		),
  	}, {
  		path:        "containers.securityContext.privileged",
  		description: "Run container in privileged mode. This can only be set to explicitly to 'false'",
  	}, {
  		path: "containers.securityContext.capabilities",
  		allowedFields: sets.New(
  			"add",
  			"drop",
  		),
  	}, {
  		path:        "containers.securityContext.capabilities.add",
  		description: "This is accessible behind a feature flag - " + config.FeatureContainerSpecAddCapabilities,
  	}, {
  		path: "containers.resources",
  		allowedFields: sets.New(
  			"limits",
  			"requests",
  		),
  	}, {
  		path: "containers.env",
  		allowedFields: sets.New(
  			"name",
  			"value",
  			"valueFrom",
  		),
  	}, {
  		path: "containers.env.valueFrom",
  		allowedFields: sets.New(
  			"configMapKeyRef",
  			"secretKeyRef",
  		),
  		featureFlagFields: []flagField{{
  			name: "fieldRef",
  			flag: config.FeaturePodSpecFieldRef,
  		}, {
  			name: "resourceFieldRef",
  			flag: config.FeaturePodSpecFieldRef,
  		}},
  	}, {
  		path: "containers.env.valueFrom.configMapKeyRef",
  		allowedFields: sets.New(
  			"name",
  			"key",
  			"optional",
  		),
  	}, {
  		path: "containers.env.valueFrom.secretKeyRef",
  		allowedFields: sets.New(
  			"name",
  			"key",
  			"optional",
  		),
  	}, {
  		path: "containers.envFrom",
  		allowedFields: sets.New(
  			"prefix",
  			"configMapRef",
  			"secretRef",
  		),
  	}, {
  		path: "containers.envFrom.configMapRef",
  		allowedFields: sets.New(
  			"name",
  			"optional",
  		),
  	}, {
  		path: "containers.envFrom.secretRef",
  		allowedFields: sets.New(
  			"name",
  			"optional",
  		),
  	}, {
  		path: "enableServiceLinks",
  		description: "EnableServiceLinks indicates whether information about" +
  			"services should be injected into pod's environment variables, " +
  			"matching the syntax of Docker links. Optional: Knative defaults this to false.",
  	}, {
  		path: "containers.volumeMounts",
  		allowedFields: sets.New(
  			"name",
  			"readOnly",
  			"mountPath",
  			"subPath",
  		),
  		featureFlagFields: []flagField{{
  			name: "mountPropagation",
  			flag: config.FeaturePodSpecVolumesMountPropagation,
  		}},
  	}, {
  		path: "volumes",
  		allowedFields: sets.New(
  			"name",
  			"secret",
  			"configMap",
  			"projected",
  		),
  		featureFlagFields: []flagField{{
  			name: "emptyDir",
  			flag: config.FeaturePodSpecEmptyDir,
  		}, {
  			name: "persistentVolumeClaim",
  			flag: config.FeaturePodSpecPVClaim,
  		}, {
  			name: "hostPath",
  			flag: config.FeaturePodSpecHostPath,
  		}, {
  			name: "csi",
  			flag: config.FeaturePodSpecVolumesCSI,
  		}, {
  			name: "image",
  			flag: config.FeaturePodSpecVolumesImage,
  		}},
  	}, {
  		path: "volumes.secret",
  		allowedFields: sets.New(
  			"defaultMode",
  			"items",
  			"optional",
  			"secretName",
  		),
  	}, {
  		path: "volumes.secret.items",
  		allowedFields: sets.New(
  			"key",
  			"path",
  			"mode",
  		),
  	}, {
  		path: "volumes.configMap",
  		allowedFields: sets.New(
  			"defaultMode",
  			"items",
  			"optional",
  			"name",
  		),
  	}, {
  		path: "volumes.configMap.items",
  		allowedFields: sets.New(
  			"key",
  			"path",
  			"mode",
  		),
  	}, {
  		path: "volumes.projected",
  		allowedFields: sets.New(
  			"defaultMode",
  			"sources",
  		),
  	}, {
  		path: "volumes.projected.sources",
  		allowedFields: sets.New(
  			// "clusterTrustBundle",
  			"configMap",
  			"downwardAPI",
  			"secret",
  			"serviceAccountToken",
  		),
  	}, {
  		path: "volumes.projected.sources.configMap",
  		allowedFields: sets.New(
  			"items",
  			"name",
  			"optional",
  		),
  	}, {
  		path: "volumes.projected.sources.configMap.items",
  		allowedFields: sets.New(
  			"key",
  			"path",
  			"mode",
  		),
  	}, {
  		path: "volumes.projected.sources.secret",
  		allowedFields: sets.New(
  			"items",
  			"name",
  			"optional",
  		),
  	}, {
  		path: "volumes.projected.sources.secret.items",
  		allowedFields: sets.New(
  			"key",
  			"path",
  			"mode",
  		),
  	}, {
  		path: "volumes.projected.sources.serviceAccountToken",
  		allowedFields: sets.New(
  			"audience",
  			"expirationSeconds",
  			"path",
  		),
  	}, {
  		path: "volumes.projected.sources.downwardAPI",
  		allowedFields: sets.New(
  			"items",
  		),
  	}, {
  		path: "volumes.projected.sources.downwardAPI.items",
  		allowedFields: sets.New(
  			"path",
  			"fieldRef",
  			"mode",
  			"resourceFieldRef",
  		),
  	}}
  
  	probes := []string{"livenessProbe", "readinessProbe", "startupProbe"}
  
  	for _, probe := range probes {
  		entries = append(entries, entry{
  			path: "containers." + probe,
  			allowedFields: sets.New(
  				"initialDelaySeconds",
  				"timeoutSeconds",
  				"periodSeconds",
  				"successThreshold",
  				"failureThreshold",
  
  				// probe handlers
  				"httpGet",
  				"exec",
  				"tcpSocket",
  				"grpc",
  			),
  		})
  
  		entries = append(entries, entry{
  			path:        fmt.Sprintf("containers.%s.periodSeconds", probe),
  			description: "How often (in seconds) to perform the probe.",
  		}, entry{
  			path:         fmt.Sprintf("containers.%s.httpGet", probe),
  			dropRequired: sets.New("port"),
  			allowedFields: sets.New(
  				"host",
  				"httpHeaders",
  				"path",
  				"port",
  				"scheme",
  			),
  		}, entry{
  			path:          fmt.Sprintf("containers.%s.exec", probe),
  			allowedFields: sets.New("command"),
  		}, entry{
  			path:         fmt.Sprintf("containers.%s.tcpSocket", probe),
  			dropRequired: sets.New("port"),
  			allowedFields: sets.New(
  				"host",
  				"port",
  			),
  		}, entry{
  			path:         fmt.Sprintf("containers.%s.grpc", probe),
  			dropRequired: sets.New("port"),
  			allowedFields: sets.New(
  				"port",
  				"service",
  			),
  		})
  	}
  
  	for i := range entries {
  		if entries[i].path == "" {
  			entries[i].path = prefixPath
  		} else {
  			entries[i].path = prefixPath + "." + entries[i].path
  		}
  	}
  	return entries
  }
  
  func revisionSpecFields() []string {
  	var (
  		revType = reflect.TypeOf(v1.RevisionSpec{})
  		fields  = make([]string, 0, revType.NumField())
  	)
  
  	for i := range revType.NumField() {
  		if revType.Field(i).Name == "PodSpec" {
  			continue
  		}
  
  		jsonTag := revType.Field(i).Tag.Get("json")
  		fields = append(fields, strings.Split(jsonTag, ",")[0])
  	}
  
  	return fields
  }
  