如何反序列化 Kubernetes YAML 文件

huangapple
go评论153阅读模式
英文:

How to deserialize Kubernetes YAML file

问题

你可以使用client-go库中的yaml包来将Kubernetes的YAML文件反序列化为Go结构体。以下是一个示例代码：

  1. package main
  3. import (
  4. 	"fmt"
  6. 	"k8s.io/apimachinery/pkg/util/yaml"
  7. )
  9. type Deployment struct {
  10. 	APIVersion string `yaml:"apiVersion"`
  11. 	Kind       string `yaml:"kind"`
  12. 	Metadata   struct {
  13. 		Name string `yaml:"name"`
  14. 	} `yaml:"metadata"`
  15. 	Spec struct {
  16. 		Replicas int `yaml:"replicas"`
  17. 		Template struct {
  18. 			Metadata struct {
  19. 				Labels struct {
  20. 					Run string `yaml:"run"`
  21. 				} `yaml:"labels"`
  22. 			} `yaml:"metadata"`
  23. 			Spec struct {
  24. 				Containers []struct {
  25. 					Name  string `yaml:"name"`
  26. 					Image string `yaml:"image"`
  27. 					Ports []struct {
  28. 						ContainerPort int `yaml:"containerPort"`
  29. 					} `yaml:"ports"`
  30. 				} `yaml:"containers"`
  31. 			} `yaml:"spec"`
  32. 		} `yaml:"template"`
  33. 	} `yaml:"spec"`
  34. }
  36. func main() {
  37. 	service := `
  38. apiVersion: apps/v1beta1
  39. kind: Deployment
  40. metadata:
  41.   name: my-nginx
  42. spec:
  43.   replicas: 2
  44.   template:
  45.     metadata:
  46.       labels:
  47.         run: my-nginx
  48.     spec:
  49.       containers:
  50.       - name: my-nginx
  51.         image: nginx
  52.         ports:
  53.         - containerPort: 80
  54. `
  56. 	var deployment Deployment
  57. 	err := yaml.Unmarshal([]byte(service), &deployment)
  58. 	if err != nil {
  59. 		panic(err)
  60. 	}
  62. 	fmt.Printf("%#v\n", deployment)
  63. }

这个示例代码定义了一个与你提供的YAML文件结构相匹配的Go结构体Deployment。你可以使用yaml.Unmarshal函数将YAML文件反序列化为该结构体。

请注意，你需要在代码中导入k8s.io/apimachinery/pkg/util/yaml包来使用yaml.Unmarshal函数。

希望这可以帮助到你！

英文:

How can I deserialize a Kubernetes YAML file into an Go struct? I took a look into the kubectl code, but somehow I get an error for every YAML file:

  1. no kind "Deployment" is registered for version "apps/v1beta1"

This is an MWE:

  1. package main
  3. import (
  4. 	"fmt"
  6. 	"k8s.io/client-go/pkg/api"
  7. )
  9. var service = `
  10. apiVersion: apps/v1beta1
  11. kind: Deployment
  12. metadata:
  13.   name: my-nginx
  14. spec:
  15.   replicas: 2
  16.   template:
  17. 	metadata:
  18. 	  labels:
  19. 		run: my-nginx
  20. 	spec:
  21. 	  containers:
  22. 	  - name: my-nginx
  23. 		image: nginx
  24. 		ports:
  25. 		- containerPort: 80
  26. `
  28. func main() {
  29. 	decode := api.Codecs.UniversalDecoder().Decode
  30. 	//decode := api.Codecs.UniversalDeserializer().Decode
  32. 	obj, _, err := decode([]byte(service), nil, nil)
  33. 	if err != nil {
  34. 		panic(err)
  35. 	}
  37. 	fmt.Printf("%#v\n", obj)
  38. }

I am using client version 2.0.0. The glide.yaml looks like this:

  1. package: test/stackoverflow
  2. import:
  3. - package: k8s.io/client-go
  4.   version: ^2.0.0

These are the references to kubectl:

Unfortunately, the docs are very confusing to me, so I have no idea how to tackle this problem.

Edit:

This problem also exists with other resource types:

  • no kind "Service" is registered for version "v1"

答案1

得分: 5

你需要导入_ "k8s.io/client-go/pkg/apis/extensions/install"，否则模式为空，另请参阅文档。

完整的工作示例如下：

  1. $ go get -u github.com/golang/dep/cmd/dep
  2. $ dep init
  3. $ go run main.go

使用以下main.go：

  1. package main
  3. import (
  4. 	"fmt"
  6. 	"k8s.io/client-go/pkg/api"
  7. 	_ "k8s.io/client-go/pkg/api/install"
  8. 	_ "k8s.io/client-go/pkg/apis/extensions/install"
  9. )
  11. var deployment = `
  12. apiVersion: extensions/v1beta1
  13. kind: Deployment
  14. metadata:
  15.   name: my-nginx
  16. spec:
  17.   replicas: 2
  18.   template:
  19.     metadata:
  20.       labels:
  21.         run: my-nginx
  22.     spec:
  23.       containers:
  24.       - name: my-nginx
  25.         image: nginx
  26.         ports:
  27.         - containerPort: 80
  28. `
  30. func main() {
  31. 	// decode := api.Codecs.UniversalDecoder().Decode
  32. 	decode := api.Codecs.UniversalDeserializer().Decode
  34. 	obj, _, err := decode([]byte(deployment), nil, nil)
  35. 	if err != nil {
  36. 		fmt.Printf("%#v", err)
  37. 	}
  39. 	fmt.Printf("%#v\n", obj)
  40. }

请注意，我还为您导入了_ "k8s.io/client-go/pkg/api/install"，这样您就可以使用v1中的对象，例如pods或services。

编辑：感谢我的同事Stefan Schimanski提出了最初的解决方案。

英文:

You need to import _ "k8s.io/client-go/pkg/apis/extensions/install" otherwise the schema is empty, see also docs.

The complete working example is:

  1. $ go get -u github.com/golang/dep/cmd/dep
  2. $ dep init
  3. $ go run main.go

With the following main.go:

  1. package main
  3. import (
  4. 	"fmt"
  6. 	"k8s.io/client-go/pkg/api"
  7. 	_ "k8s.io/client-go/pkg/api/install"
  8. 	_ "k8s.io/client-go/pkg/apis/extensions/install"
  9. )
  11. var deployment = `
  12. apiVersion: extensions/v1beta1
  13. kind: Deployment
  14. metadata:
  15. name: my-nginx
  16. spec:
  17. replicas: 2
  18. template:
  19.   metadata:
  20.     labels:
  21.       run: my-nginx
  22.   spec:
  23.     containers:
  24.     - name: my-nginx
  25.       image: nginx
  26.       ports:
  27.       - containerPort: 80
  28. `
  30. func main() {
  31. 	// decode := api.Codecs.UniversalDecoder().Decode
  32. 	decode := api.Codecs.UniversalDeserializer().Decode
  34. 	obj, _, err := decode([]byte(deployment), nil, nil)
  35. 	if err != nil {
  36. 		fmt.Printf("%#v", err)
  37. 	}
  39. 	fmt.Printf("%#v\n", obj)
  40. }

Note that I also imported _ "k8s.io/client-go/pkg/api/install" for you so that you can use objects in v1 such as pods or services.

EDIT: Kudos to my colleague Stefan Schimanski who proposed the initial solution.

答案2

得分: 1

我一直在使用api machinery的k8s.io/apimachinery/pkg/util/yaml来解码Kubernetes的部署和服务清单。

  1. import (
  2.    "fmt"
  3.    "bytes"
  4.    appsv1 "k8s.io/api/apps/v1"
  5.     k8Yaml "k8s.io/apimachinery/pkg/util/yaml"
  6. )
  7. ...
  9. d := &appsv1.Deployment{}
  10. dec := k8Yaml.NewYAMLOrJSONDecoder(bytes.NewReader([]byte(deploymentManifest)), 1000)
  12. if err := dec.Decode(&d); err != nil {
  13. 		return nil, err
  14. }
  16. fmt.Printf("%+v", d)
英文:

I've been using api machinery'sk8s.io/apimachinery/pkg/util/yaml to decode kubernete's deployment and service manifests.

  1. import (
  2.    "fmt"
  3.    "bytes"
  4.    appsv1 "k8s.io/api/apps/v1"
  5.     k8Yaml "k8s.io/apimachinery/pkg/util/yaml"
  6. )
  7. ...
  9. d := &appsv1.Deployment{}
  10. dec := k8Yaml.NewYAMLOrJSONDecoder(bytes.NewReader([]byte(deploymentManifest)), 1000)
  12. if err := dec.Decode(&d); err != nil {
  13. 		return nil, err
  14. }
  16. fmt.Printf("%+v", d)

答案3

得分: 0

  1. import (
  2. 	"fmt"
  3. 	"gopkg.in/yaml.v2"
  4. 	"log"
  5. 	//corev1 "k8s.io/api/core/v1"
  6. 	"k8s.io/apimachinery/pkg/runtime/serializer/json"
  7.     "k8s.io/client-go/kubernetes/scheme"
  8.     v1alpha1 "github.com/argoproj/argo-cd/pkg/apis/application/v1alpha1"
  9. )
  11. ....
  13. func ParseYaml2(yaml []byte) (v1alpha1.Application, error) {
  14. 	// 创建一个YAML序列化器。JSON是YAML的子集，所以也支持。
  15. 	s := json.NewYAMLSerializer(json.DefaultMetaFactory, scheme.Scheme,
  16. 		scheme.Scheme)
  18. 	// 将YAML解码为对象。
  19. 	var app v1alpha1.Application
  20. 	_, _, err := s.Decode(yaml, nil, &app)
  21. 	if err != nil {
  22. 		panic(err)
  23.     }
  24.     //fmt.Printf("%#v\n", app)
  25.     return app, err
  26. }
  27. ---
  28. go.mod
  29. // https://github.com/argoproj/argo-cd/issues/4055
  30. replace github.com/argoproj/argo-cd => github.com/argoproj/argo-cd v1.5.5
  32. var yaml2 = []byte(`
  33. apiVersion: argoproj.io/v1alpha1
  34. kind: Application
  35. metadata:
  36. ...
  38. var app v1alpha1.Application
  39. app,err := ParseYaml2(yaml2)
  40. // Types from https://github.com/argoproj/argo-cd/blob/master/pkg/apis/application/v1alpha1/types.go
  41.     fmt.Printf("--- t:\n%s\n\n", app.Spec.Source.Path)
  42.     fmt.Printf("--- t:\n%s\n\n", app.Spec.Source.Helm.ValueFiles)
  43. ----
  45. <details>
  46. <summary>英文:</summary>

import (
"fmt"
"gopkg.in/yaml.v2"
"log"
//corev1 "k8s.io/api/core/v1"
"k8s.io/apimachinery/pkg/runtime/serializer/json"
"k8s.io/client-go/kubernetes/scheme"
v1alpha1 "github.com/argoproj/argo-cd/pkg/apis/application/v1alpha1"
)

....

func ParseYaml2(yaml []byte) (v1alpha1.Application, error) {
// Create a YAML serializer. JSON is a subset of YAML, so is supported too.
s := json.NewYAMLSerializer(json.DefaultMetaFactory, scheme.Scheme,
scheme.Scheme)

  1. // Decode the YAML to an object.
  2. var app v1alpha1.Application
  3. _, _, err := s.Decode(yaml, nil, &amp;app)
  4. if err != nil {
  5. 	panic(err)
  6. }
  7. //fmt.Printf(&quot;%#v\n&quot;, app)
  8. return app, err

}

go.mod
// https://github.com/argoproj/argo-cd/issues/4055
replace github.com/argoproj/argo-cd => github.com/argoproj/argo-cd v1.5.5

var yaml2 = []byte(`
apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
...

var app v1alpha1.Application
app,err := ParseYaml2(yaml2)
// Types from https://github.com/argoproj/argo-cd/blob/master/pkg/apis/application/v1alpha1/types.go
fmt.Printf("--- t:\n%s\n\n", app.Spec.Source.Path)
fmt.Printf("--- t:\n%s\n\n", app.Spec.Source.Helm.ValueFiles)

  4. </details>

huangapple
  • 本文由 发表于 2017年6月1日 19:41:26
  • 转载请务必保留本文链接：https://go.coder-hub.com/44306554.html
  • go
  • kubernetes
  • kubernetes-go-client
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