cli cmd for merging one or more kubeconfig files in to ~/.kube/config

Makefile

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+.PHONY: build install
+
+build:
+	@go build -o ckc ./...
+	@echo "✅ ckc built"
+
+install:
+	@sudo mv ./ckc /usr/local/bin/ckc
+	@echo "✅ ckc installed"

README.md

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+# combine-kube-config - ckc
+
+## Build and Install
+`make && make install`
+
+## Usage
+`ckc <file1>...<fileN>`
+
+`ckc ~/Downloads/staging ~/Downloads/loadtest`
+will add both staging and loadtest to the ~/.kube/config file

go.mod

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+module ckc
+
+go 1.19
+
+require gopkg.in/yaml.v2 v2.4.0

go.sum

@@ -0,0 +1,4 @@
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v2 v2.4.0 h1:D8xgwECY7CYvx+Y2n4sBz93Jn9JRvxdiyyo8CTfuKaY=
+gopkg.in/yaml.v2 v2.4.0/go.mod h1:RDklbk79AGWmwhnvt/jBztapEOGDOx6ZbXqjP6csGnQ=

main.go

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+package main
+
+import (
+	"fmt"
+	"os"
+	"path"
+
+	"gopkg.in/yaml.v2"
+)
+
+type kubeConfig struct {
+	APIVersion     string      `yaml:"apiVersion"`
+	Kind           string      `yaml:"kind"`
+	CurrentContext string      `yaml:"current-context"`
+	Clusters       []cluster   `yaml:"clusters"`
+	Users          []user      `yaml:"users"`
+	Contexts       []context   `yaml:"contexts"`
+	Preferences    preferences `yaml:"Preferences,omitempty"`
+}
+
+type cluster struct {
+	Name    string     `yaml:"name"`
+	Cluster clusterDef `yaml:"cluster"`
+}
+
+type clusterDef struct {
+	Server                   string `yaml:"server"`
+	ProxyURL                 string `yaml:"proxy-url,omitempty"`
+	CertificateAuthorityData string `yaml:"certificate-authority-data"`
+	InsecureSkipTLSVerify    bool   `yaml:"insecure-skip-tls-verify"`
+}
+
+type user struct {
+	Name string  `yaml:"name"`
+	User userDef `yaml:"user"`
+}
+
+type userDef struct {
+	ClientCertificateData string `yaml:"client-certificate-data"`
+	ClientKeyData         string `yaml:"client-key-data"`
+}
+
+type context struct {
+	Name    string     `yaml:"name"`
+	Context contextDef `yaml:"context"`
+}
+
+type contextDef struct {
+	Cluster string `yaml:"cluster"`
+	User    string `yaml:"user"`
+	Name    string `yaml:"name,omitempty"`
+}
+
+type preferences struct {
+	Colors bool `yaml:"colors,omitempty"`
+}
+
+var args []string
+
+func init() {
+	if len(os.Args) == 1 {
+		fmt.Println("No source files")
+		os.Exit(1)
+	}
+	args = os.Args[1:]
+}
+
+func main() {
+	var err error
+	home := os.Getenv("HOME")
+	if home == "" {
+		home = os.Getenv("USERPROFILE")
+	}
+	if home == "" {
+		home, err = os.Getwd()
+		if err != nil {
+			panic(err)
+		}
+	}
+	kubeDir := ".kube"
+	kubeConfigFile := path.Join(home, kubeDir, "config")
+
+	contents, err := os.ReadFile(kubeConfigFile)
+	if err != nil {
+		panic(err)
+	}
+	var config kubeConfig
+	err = yaml.Unmarshal(contents, &config)
+	if err != nil {
+		panic(err)
+	}
+
+	var newConf kubeConfig
+	for i := range args {
+		contents, err = os.ReadFile(args[i])
+		if err != nil {
+			fmt.Printf("⛔ %s\n", err)
+			continue
+		}
+
+		err = yaml.Unmarshal(contents, &newConf)
+		if err != nil {
+			fmt.Printf("⛔ %s\n", err)
+			continue
+		}
+
+		for i := range newConf.Clusters {
+			found := false
+			for j := range config.Clusters {
+				if newConf.Clusters[i].Name == config.Clusters[j].Name {
+					fmt.Printf("⚠️  cluster %s from %s already exists\n", config.Clusters[j].Name, args[i])
+					found = true
+					break
+				}
+			}
+			if !found {
+				config.Clusters = append(config.Clusters, newConf.Clusters[i])
+			}
+		}
+
+		for i := range newConf.Users {
+			found := false
+			for j := range config.Users {
+				if newConf.Users[i].Name == config.Users[j].Name {
+					found = true
+					fmt.Printf("⚠️  user %s from %s already exists\n", config.Users[j].Name, args[i])
+					break
+				}
+			}
+			if !found {
+				config.Users = append(config.Users, newConf.Users[i])
+			}
+		}
+
+		for i := range newConf.Contexts {
+			found := false
+			for j := range config.Contexts {
+				if newConf.Contexts[i].Name == config.Contexts[j].Name {
+					found = true
+					fmt.Printf("⚠️  context %s from %s already exists\n", config.Contexts[j].Name, args[i])
+					break
+				}
+			}
+			if !found {
+				config.Contexts = append(config.Contexts, newConf.Contexts[i])
+			}
+		}
+
+		if newConf.CurrentContext != "" && config.CurrentContext != newConf.CurrentContext {
+			config.CurrentContext = newConf.CurrentContext
+		}
+		if config.Preferences.Colors != newConf.Preferences.Colors {
+			config.Preferences.Colors = newConf.Preferences.Colors
+		}
+		config.APIVersion = newConf.APIVersion
+		config.Kind = newConf.Kind
+	}
+
+	result, err := yaml.Marshal(config)
+	if err != nil {
+		fmt.Printf("⛔ %s\n", err)
+		os.Exit(1)
+	}
+
+	err = os.WriteFile(kubeConfigFile, result, 0644)
+	if err != nil {
+		fmt.Printf("⛔ %s\n", err)
+		os.Exit(1)
+	}
+	fmt.Printf("✅ %s updated\n", kubeConfigFile)
+}