Go language development k8s ConfigMap operation analysis

1. Structure

1.1 ConfigMapList

Package: "/api/core/v1"

type ConfigMapList struct {
     `json:",inline"`
     `json:"metadata,omitempty" protobuf:"bytes,1,opt,name=metadata"`
    Items           []ConfigMap `json:"items" protobuf:"bytes,2,rep,name=items"`
}

ItemsEach ConfigMap structure is as follows:

1.2 ConfigMap

Package: "/api/core/v1"

type ConfigMap struct {
       `json:",inline"`
     `json:"metadata,omitempty" protobuf:"bytes,1,opt,name=metadata"`
    Immutable         *bool             `json:"immutable,omitempty" protobuf:"varint,4,opt,name=immutable"`
    Data              map[string]string `json:"data,omitempty" protobuf:"bytes,2,rep,name=data"`
    BinaryData        map[string][]byte `json:"binaryData,omitempty" protobuf:"bytes,3,rep,name=binaryData"`
}

Its members are described as follows:

1.3 TypeMeta

Package: "/apimachinery/pkg/apis/meta/v1"

type TypeMeta struct {
    Kind       string `json:"kind,omitempty" protobuf:"bytes,1,opt,name=kind"`
    APIVersion string `json:"apiVersion,omitempty" protobuf:"bytes,2,opt,name=apiVersion"`
}

The following sections corresponding to the yml file that creates the service on k8s:

apiVersion: v1
kind: ConfigMap

1.4 ObjectMeta

Package: "/apimachinery/pkg/apis/meta/v1"

type ObjectMeta struct {
    Name                       string               `json:"name,omitempty" protobuf:"bytes,1,opt,name=name"`
    GenerateName               string               `json:"generateName,omitempty" protobuf:"bytes,2,opt,name=generateName"`
    Namespace                  string               `json:"namespace,omitempty" protobuf:"bytes,3,opt,name=namespace"`
    SelfLink                   string               `json:"selfLink,omitempty" protobuf:"bytes,4,opt,name=selfLink"`
    UID                                    `json:"uid,omitempty" protobuf:"bytes,5,opt,name=uid,casttype=/kubernetes/pkg/"`
    ResourceVersion            string               `json:"resourceVersion,omitempty" protobuf:"bytes,6,opt,name=resourceVersion"`
    Generation                 int64                `json:"generation,omitempty" protobuf:"varint,7,opt,name=generation"`
    CreationTimestamp          Time                 `json:"creationTimestamp,omitempty" protobuf:"bytes,8,opt,name=creationTimestamp"`
    DeletionTimestamp          *Time                `json:"deletionTimestamp,omitempty" protobuf:"bytes,9,opt,name=deletionTimestamp"`
    DeletionGracePeriodSeconds *int64               `json:"deletionGracePeriodSeconds,omitempty" protobuf:"varint,10,opt,name=deletionGracePeriodSeconds"`
    Labels                     map[string]string    `json:"labels,omitempty" protobuf:"bytes,11,rep,name=labels"`
    Annotations                map[string]string    `json:"annotations,omitempty" protobuf:"bytes,12,rep,name=annotations"`
    OwnerReferences            []OwnerReference     `json:"ownerReferences,omitempty" patchStrategy:"merge" patchMergeKey:"uid" protobuf:"bytes,13,rep,name=ownerReferences"`
    Finalizers                 []string             `json:"finalizers,omitempty" patchStrategy:"merge" protobuf:"bytes,14,rep,name=finalizers"`
    ManagedFields              []ManagedFieldsEntry `json:"managedFields,omitempty" protobuf:"bytes,17,rep,name=managedFields"`
}

The following sections corresponding to the yml file that creates the service on k8s:

metadata:
  name: nginxconf
  namespace: test

1.7 Example of comparison yml file

Attached a configMap information on the native k8s cluster, you can compare and understand the above structure

apiVersion: v1
data:
  : |2-
        worker_processes  1;
        events {
            worker_connections  1024;
        }
        http {
            include       ;
            default_type  application/octet-stream;
            client_max_body_size 50m;
            sendfile        on;
            keepalive_timeout  65;
            server {
                listen       80;
                server_name  localhost;
                root   /usr/share/nginx/html;
                location / {
                   index   ;
                }
            }
        }
kind: ConfigMap
metadata:
  creationTimestamp: "2022-10-14T06:53:14Z"
  name: nginxconf
  namespace: liubei
  resourceVersion: "23364643"
  selfLink: /api/v1/namespaces/liubei/configmaps/nginxconf
  uid: cbe236fb-b86b-47f5-bf13-696fada4e400

1.5 Immutable

Pointer to bool value

true, not changeable
Otherwise, it can be changed at any time

1.6 Data

map[string]stringType, corresponding to the yaml filedataField, each member corresponds to a key-value pair, that is, a configuration file to be mounted

1.7 BinaryData

map[string][]byteType, andDataSimilar, except that the incoming string becomes []byte

2. Create configMap

grammar

func (ConfigMapInterface) Create(ctx , configMap *, opts ) (*, error)

Syntax example

configMapInfo,err = clientSet.CoreV1().ConfigMaps(namespaceName).Create((),configMap,{})

Complete example

The configmap of the previous nginx service on k8s is as follows

apiVersion: v1
kind: ConfigMap
metadata:
  name: nginxconf
  namespace: test
data:
  : |
    worker_processes  1;
    events {
        worker_connections  1024;
    }
    http {
        include       ;
        default_type  application/octet-stream;
        client_max_body_size 50m;
        sendfile        on;
        keepalive_timeout  65;
        server {
            listen       80;
            server_name  localhost;
            root   /usr/share/nginx/html;
            location / {
               index   ;
            }
        }
    }

Create a function

package crowK8S
import (
    "context"
    coreV1 "/api/core/v1"
    metaV1 "/apimachinery/pkg/apis/meta/v1"
    "/client-go/kubernetes"
)
func CreateConfigMap(clientSet *,namespaceName string,configMapName string,dataInfo string)(configMapInfo *,err  error)  {
    configMap := &amp;{
        ObjectMeta: {
            Name: configMapName,
        },
        Data: map[string]string{
            "" : dataInfo,
        },
    }
    configMapInfo,err = clientSet.CoreV1().ConfigMaps(namespaceName).Create((),configMap,{})
    if err != nil {
        return configMapInfo,err
    }
    return configMapInfo,nil
}

Calling functions

package main
import (
    "fmt"
    "go-k8s/crowK8S"
)
func main()  {
    clientSet,err := crowK8S.ConnectK8s()
    if err !=nil {
        (err)
    }
    var dataInfo string
    dataInfo = "    worker_processes  1;\n    events {\n        worker_connections  1024;\n    }\n    http {\n        include       ;\n        default_type  application/octet-stream;\n        client_max_body_size 50m;\n        sendfile        on;\n        keepalive_timeout  65;\n        server {\n            listen       80;\n            server_name  localhost;\n            root   /usr/share/nginx/html;\n            location / {\n               index   ;\n            }\n        }\n    }"
    configMapInfo,err := (clientSet ,"liubei","nginxconf",dataInfo)
    (configMapInfo)
}

The results are as follows on k8s

[root@crust-m01 ~]# kubectl describe -n liubei configmaps nginxconf
Name:         nginxconf
Namespace:    liubei
Labels:       &lt;none&gt;
Annotations:  &lt;none&gt;
Data
====
:
----
    worker_processes  1;
    events {
        worker_connections  1024;
    }
    http {
        include       ;
        default_type  application/octet-stream;
        client_max_body_size 50m;
        sendfile        on;
        keepalive_timeout  65;
        server {
            listen       80;
            server_name  localhost;
            root   /usr/share/nginx/html;
            location / {
               index   ;
            }
        }
    }
Events:  &lt;none&gt;

3. Get ConfigMapList

Complete example

Define functions

package crowK8S
import (
    "context"
    coreV1 "/api/core/v1"
    metaV1 "/apimachinery/pkg/apis/meta/v1"
    "/client-go/kubernetes"
)
func GetConfigMapList(clientSet *,namespaceName string)(configMapList *,err error)  {
    configMapList,err = clientSet.CoreV1().ConfigMaps(namespaceName).List((), {})
    if err != nil{
        return nil, err
    }
    return configMapList, err
}

Using functions

package main
import (
    "fmt"
    "go-k8s/crowK8S"
)
func main()  {
    clientSet,err := crowK8S.ConnectK8s()
    if err !=nil {
        (err)
    }
    configMapList,err := (clientSet ,"liubei")
    if err != nil {
        (err)
    }
    (configMapList)
}

Results Print

&ConfigMapList{ListMeta:{/api/v1/namespaces/liubei/configmaps 22893420 <nil>},Items:[]ConfigMap{ConfigMap{ObjectMeta:{ liubei /api/v1/namespaces/liubei/configmaps/ ecb54dbb-3082-4caa-9055-8061e5d9d7b6 19106476 0 2022-09-28 13:23:29 +0800 CST <nil> <nil> map[] map[] [] [] [{kube-controller-manager Update v1 2022-09-28 13:23:29 +0800 CST FieldsV1 {"f:data":{".":{},"f:":{}}} }]},Data:map[string]string{: -----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----
,},BinaryData:map[string][]byte{},Immutable:nil,},ConfigMap{ObjectMeta:{nginxconf liubei /api/v1/namespaces/liubei/configmaps/nginxconf 395535db-1df7-408a-9976-18e6ded1207e 22854355 0 2022-10-12 17:21:03 +0800 CST <nil> <nil> map[] map[] [] [] [{___go_build_main_go.exe Update v1 2022-10-12 17:21:03 +0800 CST FieldsV1 {"f:data":{".":{},"f:":{}}} }]},Data:map[string]string{: worker_processes 1;
events {
worker_connections 1024;
}
http {
include ;
default_type application/octet-stream;
client_max_body_size 50m;
sendfile on;
keepalive_timeout 65;
server {
listen 80;
server_name localhost;
root /usr/share/nginx/html;
location / {
index ;
}
}
},},BinaryData:map[string][]byte{},Immutable:nil,},},}

4. Get ConfigMap

func (ConfigMapInterface) Get(ctx , name string, opts ) (*, error)

Syntax example

configmapInfo,err = clientSet.CoreV1().ConfigMaps(namespaceName).Get((),configMapName,{})

Complete example

Create a function

package crowK8S
import (
    "context"
    coreV1 "/api/core/v1"
    metaV1 "/apimachinery/pkg/apis/meta/v1"
    "/client-go/kubernetes"
)
func GetConfigMap(clientSet *,namespaceName string,configMapName string)(configmapInfo *,err error)  {
    configmapInfo,err = clientSet.CoreV1().ConfigMaps(namespaceName).Get((), configMapName,{})
    if err != nil{
        return nil, err
    }
    return configmapInfo, err
}

Call

package main
import (
    "fmt"
    "go-k8s/crowK8S"
)
func main()  {
    clientSet,err := crowK8S.ConnectK8s()
    if err !=nil {
        (err)
    }
    configmapInfo,err := (clientSet ,"liubei","nginxconf")
    if err != nil {
        (err)
    }
    (configmapInfo)
}

result

&ConfigMap{ObjectMeta:{nginxconf liubei /api/v1/namespaces/liubei/configmaps/nginxconf 395535db-1df7-408a-9976-18e6ded1207e 22854355 0 2022-10-12 17:21:03 +0800 CST <nil> <nil> map[] map[] [] [] [{___go_build_main_go.exe Update v1 2022-10-12 17:21:03 +0800 CST FieldsV1 {"f:data":{".":{},"f:":{}}} }]},Data:map[string]string{: worker_processes 1;
events {
worker_connections 1024;
}
http {
include ;
default_type application/octet-stream;
client_max_body_size 50m;
sendfile on;
keepalive_timeout 65;
server {
listen 80;
server_name localhost;
root /usr/share/nginx/html;
location / {
index ;
}
}
},},BinaryData:map[string][]byte{},Immutable:nil,}

5. Update ConfigMap

func (ConfigMapInterface) Update(ctx , configMap *, opts ) (*, error)

Syntax example

configmapInfo,err = clientSet.CoreV1().ConfigMaps(namespaceName).Update((),configmapInfo,{})

Complete example

Create a function

package crowK8S
import (
    "context"
    coreV1 "/api/core/v1"
    metaV1 "/apimachinery/pkg/apis/meta/v1"
    "/client-go/kubernetes"
)
func ApplyConfigMap(clientSet *,namespaceName string,configMapName string,fileName string,configMapData string)(configmapInfo *,err error)  {
    configmapInfo,err = clientSet.CoreV1().ConfigMaps(namespaceName).Get((), configMapName,{})
    if err != nil{
        return nil, err
    }
    [fileName] = configMapData
    configmapInfo,err = clientSet.CoreV1().ConfigMaps(namespaceName).Update((),configmapInfo,{})
    if err !=nil {
        return configmapInfo,err
    }
    return configmapInfo,nil
}

Call

func main()  {
    clientSet,err := crowK8S.ConnectK8s()
    if err !=nil {
        (err)
    }
    configMapInfo,err := (clientSet ,"liubei","nginxconf","","hello world")
    (configMapInfo)
}

Results Print

&ConfigMap{ObjectMeta:{nginxconf liubei /api/v1/namespaces/liubei/configmaps/nginxconf 395535db-1df7-408a-9976-18e6ded1207e 22901163 0 2022-10-12 17:21:03 +0800 CST <nil> <nil> map[] map[] [] [] [{___go_build_main_go.exe Update v1 2022-10-12 17:21:03 +0800 CST FieldsV1 {"f:data":{".":{},"f:":{}}} }]},Data:map[string]string{: hello world,},BinaryData:map[string][]byte{},Immutable:nil,}

View results on k8s

[root@crust-m01 ~]# kubectl describe -n liubei configmaps nginxconf
Name:         nginxconf
Namespace:    liubei
Labels:       <none>
Annotations:  <none>
Data
====
:
----
hello world
Events:  <none>

6. Delete ConfigMap

func (ConfigMapInterface) Delete(ctx , name string, opts ) error

Syntax example

err = clientSet.CoreV1().ConfigMaps(namespaceName).Delete((),configMapName,{})

Complete example

Create a function

package crowK8S
import (
    "context"
    coreV1 "/api/core/v1"
    metaV1 "/apimachinery/pkg/apis/meta/v1"
    "/client-go/kubernetes"
)
func DeleteConfigMap(clientSet *,namespaceName string,configMapName string)(err error)  {
    err = clientSet.CoreV1().ConfigMaps(namespaceName).Delete((),configMapName,{})
    if err != nil {
        return err
    }
    return nil
}

Call

package main
import (
    "fmt"
    "go-k8s/crowK8S"
)
func main()  {
    clientSet,err := crowK8S.ConnectK8s()
    if err !=nil {
        (err)
    }
    err = (clientSet,"liubei","nginxconf")
    if err != nil {
        (err)
    }else {
        ("Delete successfully")
    }
}

Results Print

Delete successfully

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