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package main
import (
"fmt"
"os"
"os/exec"
"github.com/polydawn/meep"
"github.com/tazjin/kontemplate/context"
"github.com/tazjin/kontemplate/templater"
"gopkg.in/alecthomas/kingpin.v2"
)
type KubeCtlError struct {
meep.AllTraits
}
var (
app = kingpin.New("kontemplate", "simple Kubernetes resource templating")
// Global flags
includes = app.Flag("include", "Resource sets to include explicitly").Short('i').Strings()
excludes = app.Flag("exclude", "Resource sets to exclude explicitly").Short('e').Strings()
// Commands
template = app.Command("template", "Template resource sets and print them")
templateFile = template.Arg("file", "Cluster configuration file to use").Required().String()
apply = app.Command("apply", "Template resources and pass to 'kubectl apply'")
applyFile = apply.Arg("file", "Cluster configuration file to use").Required().String()
applyDryRun = apply.Flag("dry-run", "Print remote operations without executing them").Default("false").Bool()
replace = app.Command("replace", "Template resources and pass to 'kubectl replace'")
replaceFile = replace.Arg("file", "Cluster configuration file to use").Required().String()
delete = app.Command("delete", "Template resources and pass to 'kubectl delete'")
deleteFile = delete.Arg("file", "Cluster configuration file to use").Required().String()
create = app.Command("create", "Template resources and pass to 'kubectl create'")
createFile = create.Arg("file", "Cluster configuration file to use").Required().String()
)
func main() {
app.HelpFlag.Short('h')
switch kingpin.MustParse(app.Parse(os.Args[1:])) {
case template.FullCommand():
templateCommand()
case apply.FullCommand():
applyCommand()
case replace.FullCommand():
replaceCommand()
case delete.FullCommand():
deleteCommand()
case create.FullCommand():
createCommand()
}
}
func templateCommand() {
_, resources := loadContextAndResources(templateFile)
for _, r := range *resources {
fmt.Println(r)
}
}
func applyCommand() {
ctx, resources := loadContextAndResources(applyFile)
var kubectlArgs []string
if *applyDryRun {
kubectlArgs = []string{"apply", "-f", "-", "--dry-run"}
} else {
kubectlArgs = []string{"apply", "-f", "-"}
}
runKubectlWithResources(ctx, &kubectlArgs, resources)
}
func replaceCommand() {
ctx, resources := loadContextAndResources(replaceFile)
args := []string{"replace", "--save-config=true", "-f", "-"}
runKubectlWithResources(ctx, &args, resources)
}
func deleteCommand() {
ctx, resources := loadContextAndResources(deleteFile)
args := []string{"delete", "-f", "-"}
runKubectlWithResources(ctx, &args, resources)
}
func createCommand() {
ctx, resources := loadContextAndResources(createFile)
args := []string{"create", "--save-config=true", "-f", "-"}
runKubectlWithResources(ctx, &args, resources)
}
func loadContextAndResources(file *string) (*context.Context, *[]string) {
ctx, err := context.LoadContextFromFile(*file)
if err != nil {
app.Fatalf("Error loading context: %v\n", err)
}
resources, err := templater.LoadAndPrepareTemplates(includes, excludes, ctx)
if err != nil {
app.Fatalf("Error templating resource sets: %v\n", err)
}
return ctx, &resources
}
func runKubectlWithResources(c *context.Context, kubectlArgs *[]string, resources *[]string) error {
args := append(*kubectlArgs, fmt.Sprintf("--context=%s", c.Name))
kubectl := exec.Command("kubectl", args...)
stdin, err := kubectl.StdinPipe()
if err != nil {
return meep.New(&KubeCtlError{}, meep.Cause(err))
}
kubectl.Stdout = os.Stdout
kubectl.Stderr = os.Stderr
if err = kubectl.Start(); err != nil {
return meep.New(&KubeCtlError{}, meep.Cause(err))
}
for _, r := range *resources {
fmt.Fprintln(stdin, r)
}
stdin.Close()
kubectl.Wait()
return nil
}
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