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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"
"github.com/urfave/cli"
)
type KubeCtlError struct {
meep.AllTraits
}
func main() {
app := cli.NewApp()
app.Name = "kontemplate"
app.Usage = "simple Kubernetes resource templating"
app.Version = "0.0.1"
app.Commands = []cli.Command{
templateCommand(),
applyCommand(),
replaceCommand(),
}
app.Run(os.Args)
}
func templateCommand() cli.Command {
return cli.Command{
Name: "template",
Usage: "Interpolate and print templates",
Flags: commonFlags(),
Action: func(c *cli.Context) error {
include := c.StringSlice("include")
exclude := c.StringSlice("exclude")
ctx, err := loadContext(c)
resources, err := templater.LoadAndPrepareTemplates(&include, &exclude, ctx)
if err != nil {
return err
}
for _, r := range resources {
fmt.Println(r)
}
return nil
},
}
}
func applyCommand() cli.Command {
dryRun := false
return cli.Command{
Name: "apply",
Usage: "Interpolate templates and run 'kubectl apply'",
Flags: append(commonFlags(), cli.BoolFlag{
Name: "dry-run",
Usage: "Only print objects that would be sent, without sending them",
Destination: &dryRun,
}),
Action: func(c *cli.Context) error {
include := c.StringSlice("include")
exclude := c.StringSlice("exclude")
ctx, err := loadContext(c)
resources, err := templater.LoadAndPrepareTemplates(&include, &exclude, ctx)
if err != nil {
return err
}
var args []string
if dryRun {
args = []string{"apply", "-f", "-", "--dry-run"}
} else {
args = []string{"apply", "-f", "-"}
}
return runKubectlWithResources(ctx, &args, &resources)
},
}
}
func replaceCommand() cli.Command {
return cli.Command{
Name: "replace",
Usage: "Interpolate templates and run 'kubectl replace'",
Flags: commonFlags(),
Action: func(c *cli.Context) error {
include := c.StringSlice("include")
exclude := c.StringSlice("exclude")
ctx, err := loadContext(c)
resources, err := templater.LoadAndPrepareTemplates(&include, &exclude, ctx)
if err != nil {
return err
}
args := []string{"replace", "--save-config=true", "-f", "-"}
return runKubectlWithResources(ctx, &args, &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
}
func commonFlags() []cli.Flag {
return []cli.Flag{
cli.StringFlag{
Name: "file, f",
Usage: "Cluster configuration file to use",
},
cli.StringSliceFlag{
Name: "include, i",
Usage: "Limit templating to explicitly included resource sets",
},
cli.StringSliceFlag{
Name: "exclude, e",
Usage: "Exclude certain resource sets from templating",
},
}
}
func loadContext(c *cli.Context) (*context.Context, error) {
f := c.String("file")
if f == "" {
return nil, meep.New(
&meep.ErrInvalidParam{
Param: "file",
Reason: "Cluster config file must be specified",
},
)
}
ctx, err := context.LoadContextFromFile(f)
if err != nil {
return nil, err
}
return ctx, nil
}
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