1. Capabilities 对象
Capabilities： 这提供了关于 Kubernetes 集群支持的功能的信息。
Capabilities.APIVersions 是一组版本信息。
Capabilities.APIVersions.Has $version 指示是否在群集上启用版本（batch/v1）。
Capabilities.KubeVersion 提供了查找 Kubernetes 版本的方法。它具有以下值：Major，Minor，GitVersion，GitCommit，GitTreeState，BuildDate，GoVersion，Compiler，和 Platform。
Capabilities.TillerVersion 提供了查找 Tiller 版本的方法。它具有以下值：SemVer，GitCommit，和 GitTreeState。2. 通用模板
通用模板配置
cat _capabilities.tpl
{{/* vim: set filetype=mustache: */}}
{{/*
Return the target Kubernetes version
*/}}
{{- define "common.capabilities.kubeVersion" -}}
{{- if .Values.global }}
{{- if .Values.global.kubeVersion }}
{{- .Values.global.kubeVersion -}}
{{- else }}
{{- default .Capabilities.KubeVersion.Version .Values.kubeVersion -}}
{{- end -}}
{{- else }}
{{- default .Capabilities.KubeVersion.Version .Values.kubeVersion -}}
{{- end -}}
{{- end -}}
{{/*
Return the appropriate apiVersion for poddisruptionbudget.
*/}}
{{- define "common.capabilities.policy.apiVersion" -}}
{{- if semverCompare "<1.21-0" (include "common.capabilities.kubeVersion" .) -}}
{{- print "policy/v1beta1" -}}
{{- else -}}
{{- print "policy/v1" -}}
{{- end -}}
{{- end -}}
{{/*
Return the appropriate apiVersion for networkpolicy.
*/}}
{{- define "common.capabilities.networkPolicy.apiVersion" -}}
{{- if semverCompare "<1.7-0" (include "common.capabilities.kubeVersion" .) -}}
{{- print "extensions/v1beta1" -}}
{{- else -}}
{{- print "networking.k8s.io/v1" -}}
{{- end -}}
{{- end -}}
{{/*
Return the appropriate apiVersion for cronjob.
*/}}
{{- define "common.capabilities.cronjob.apiVersion" -}}
{{- if semverCompare "<1.21-0" (include "common.capabilities.kubeVersion" .) -}}
{{- print "batch/v1beta1" -}}
{{- else -}}
{{- print "batch/v1" -}}
{{- end -}}
{{- end -}}
{{/*
Return the appropriate apiVersion for deployment.
*/}}
{{- define "common.capabilities.deployment.apiVersion" -}}
{{- if semverCompare "<1.14-0" (include "common.capabilities.kubeVersion" .) -}}
{{- print "extensions/v1beta1" -}}
{{- else -}}
{{- print "apps/v1" -}}
{{- end -}}
{{- end -}}
{{/*
Return the appropriate apiVersion for statefulset.
*/}}
{{- define "common.capabilities.statefulset.apiVersion" -}}
{{- if semverCompare "<1.14-0" (include "common.capabilities.kubeVersion" .) -}}
{{- print "apps/v1beta1" -}}
{{- else -}}
{{- print "apps/v1" -}}
{{- end -}}
{{- end -}}
{{/*
Return the appropriate apiVersion for ingress.
*/}}
{{- define "common.capabilities.ingress.apiVersion" -}}
{{- if .Values.ingress -}}
{{- if .Values.ingress.apiVersion -}}
{{- .Values.ingress.apiVersion -}}
{{- else if semverCompare "<1.14-0" (include "common.capabilities.kubeVersion" .) -}}
{{- print "extensions/v1beta1" -}}
{{- else if semverCompare "<1.19-0" (include "common.capabilities.kubeVersion" .) -}}
{{- print "networking.k8s.io/v1beta1" -}}
{{- else -}}
{{- print "networking.k8s.io/v1" -}}
{{- end }}
{{- else if semverCompare "<1.14-0" (include "common.capabilities.kubeVersion" .) -}}
{{- print "extensions/v1beta1" -}}
{{- else if semverCompare "<1.19-0" (include "common.capabilities.kubeVersion" .) -}}
{{- print "networking.k8s.io/v1beta1" -}}
{{- else -}}
{{- print "networking.k8s.io/v1" -}}
{{- end -}}
{{- end -}}
{{/*
Return the appropriate apiVersion for RBAC resources.
*/}}
{{- define "common.capabilities.rbac.apiVersion" -}}
{{- if semverCompare "<1.17-0" (include "common.capabilities.kubeVersion" .) -}}
{{- print "rbac.authorization.k8s.io/v1beta1" -}}
{{- else -}}
{{- print "rbac.authorization.k8s.io/v1" -}}
{{- end -}}
{{- end -}}
{{/*
Return the appropriate apiVersion for CRDs.
*/}}
{{- define "common.capabilities.crd.apiVersion" -}}
{{- if semverCompare "<1.19-0" (include "common.capabilities.kubeVersion" .) -}}
{{- print "apiextensions.k8s.io/v1beta1" -}}
{{- else -}}
{{- print "apiextensions.k8s.io/v1" -}}
{{- end -}}
{{- end -}}
{{/*
Returns true if the used Helm version is 3.3+.
A way to check the used Helm version was not introduced until version 3.3.0 with .Capabilities.HelmVersion, which contains an additional "{}}" structure.
This check is introduced as a regexMatch instead of {{ if .Capabilities.HelmVersion }} because checking for the key HelmVersion in <3.3 results in a "interface not found" error.
**To be removed when the catalog's minimun Helm version is 3.3**
*/}}
{{- define "common.capabilities.supportsHelmVersion" -}}
{{- if regexMatch "{(v[0-9])*[^}]*}}$" (.Capabilities | toString ) }}
{{- true -}}
{{- end -}}
{{- end -}}3. 源码
/*
Copyright The Helm 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 chartutil
import (
"fmt"
"strconv"
"github.com/Masterminds/semver/v3"
"k8s.io/client-go/kubernetes/scheme"
apiextensionsv1 "k8s.io/apiextensions-apiserver/pkg/apis/apiextensions/v1"
apiextensionsv1beta1 "k8s.io/apiextensions-apiserver/pkg/apis/apiextensions/v1beta1"
helmversion "helm.sh/helm/v3/internal/version"
)
var (
// The Kubernetes version can be set by LDFLAGS. In order to do that the value
// must be a string.
k8sVersionMajor = "1"
k8sVersionMinor = "20"
// DefaultVersionSet is the default version set, which includes only Core V1 ("v1").
DefaultVersionSet = allKnownVersions()
// DefaultCapabilities is the default set of capabilities.
DefaultCapabilities = &Capabilities{
KubeVersion: KubeVersion{
Version: fmt.Sprintf("v%s.%s.0", k8sVersionMajor, k8sVersionMinor),
Major: k8sVersionMajor,
Minor: k8sVersionMinor,
},
APIVersions: DefaultVersionSet,
HelmVersion: helmversion.Get(),
}
)
// Capabilities describes the capabilities of the Kubernetes cluster.
type Capabilities struct {
// KubeVersion is the Kubernetes version.
KubeVersion KubeVersion
// APIversions are supported Kubernetes API versions.
APIVersions VersionSet
// HelmVersion is the build information for this helm version
HelmVersion helmversion.BuildInfo
}
func (capabilities *Capabilities) Copy() *Capabilities {
return &Capabilities{
KubeVersion: capabilities.KubeVersion,
APIVersions: capabilities.APIVersions,
HelmVersion: capabilities.HelmVersion,
}
}
// KubeVersion is the Kubernetes version.
type KubeVersion struct {
Version string // Kubernetes version
Major string // Kubernetes major version
Minor string // Kubernetes minor version
}
// String implements fmt.Stringer
func (kv *KubeVersion) String() string { return kv.Version }
// GitVersion returns the Kubernetes version string.
//
// Deprecated: use KubeVersion.Version.
func (kv *KubeVersion) GitVersion() string { return kv.Version }
// ParseKubeVersion parses kubernetes version from string
func ParseKubeVersion(version string) (*KubeVersion, error) {
sv, err := semver.NewVersion(version)
if err != nil {
return nil, err
}
return &KubeVersion{
Version: "v" + sv.String(),
Major: strconv.FormatUint(sv.Major(), 10),
Minor: strconv.FormatUint(sv.Minor(), 10),
}, nil
}
// VersionSet is a set of Kubernetes API versions.
type VersionSet []string
// Has returns true if the version string is in the set.
//
// vs.Has("apps/v1")
func (v VersionSet) Has(apiVersion string) bool {
for _, x := range v {
if x == apiVersion {
return true
}
}
return false
}
func allKnownVersions() VersionSet {
// We should register the built in extension APIs as well so CRDs are
// supported in the default version set. This has caused problems with `helm
// template` in the past, so let's be safe
apiextensionsv1beta1.AddToScheme(scheme.Scheme)
apiextensionsv1.AddToScheme(scheme.Scheme)
groups := scheme.Scheme.PrioritizedVersionsAllGroups()
vs := make(VersionSet, 0, len(groups))
for _, gv := range groups {
vs = append(vs, gv.String())
}
return vs
}