// Copyright (C) 2016-2019 Vincent Ambo <mail@tazj.in>
//
// Kontemplate is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
package main
import (
"fmt"
"os"
"os/exec"
"strings"
"github.com/tazjin/kontemplate/context"
"github.com/tazjin/kontemplate/templater"
"gopkg.in/alecthomas/kingpin.v2"
)
const version string = "1.8.0"
// This variable will be initialised by the Go linker during the builder
var gitHash string
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()
variables = app.Flag("var", "Provide variables to templates explicitly").Strings()
kubectlBin = app.Flag("kubectl", "Path to the kubectl binary (default 'kubectl')").Default("kubectl").String()
// Commands
template = app.Command("template", "Template resource sets and print them")
templateFile = template.Arg("file", "Cluster configuration file to use").Required().String()
templateOutputDir = template.Flag("output", "Output directory in which to save templated files instead of printing them").Short('o').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()
versionCmd = app.Command("version", "Show kontemplate version")
)
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()
case versionCmd.FullCommand():
versionCommand()
}
}
func versionCommand() {
if gitHash == "" {
fmt.Printf("Kontemplate version %s (git commit unknown)\n", version)
} else {
fmt.Printf("Kontemplate version %s (git commit: %s)\n", version, gitHash)
}
}
func templateCommand() {
_, resourceSets := loadContextAndResources(templateFile)
for _, rs := range *resourceSets {
if len(rs.Resources) == 0 {
fmt.Fprintf(os.Stderr, "Warning: Resource set '%s' does not exist or contains no valid templates\n", rs.Name)
continue
}
if *templateOutputDir != "" {
templateIntoDirectory(templateOutputDir, rs)
} else {
for _, r := range rs.Resources {
fmt.Fprintf(os.Stderr, "Rendered file %s/%s:\n", rs.Name, r.Filename)
fmt.Println(r.Rendered)
}
}
}
}
func templateIntoDirectory(outputDir *string, rs templater.RenderedResourceSet) {
// Attempt to create the output directory if it does not
// already exist:
if err := os.MkdirAll(*templateOutputDir, 0775); err != nil {
app.Fatalf("Could not create output directory: %v\n", err)
}
// Nested resource sets may contain slashes in their names.
// These are replaced with dashes for the purpose of writing a
// flat list of output files:
setName := strings.Replace(rs.Name, "/", "-", -1)
for _, r := range rs.Resources {
filename := fmt.Sprintf("%s/%s-%s", *templateOutputDir, setName, r.Filename)
fmt.Fprintf(os.Stderr, "Writing file %s\n", filename)
file, err := os.Create(filename)
if err != nil {
app.Fatalf("Could not create file %s: %v\n", filename, err)
}
_, err = fmt.Fprintf(file, r.Rendered)
if err != nil {
app.Fatalf("Error writing file %s: %v\n", filename, err)
}
}
}
func applyCommand() {
ctx, resources := loadContextAndResources(applyFile)
var kubectlArgs []string
if *applyDryRun {
kubectlArgs = []string{"apply", "-f", "-", "--dry-run"}
} else {
kubectlArgs = []string{"apply", "-f", "-"}
}
if err := runKubectlWithResources(ctx, &kubectlArgs, resources); err != nil {
failWithKubectlError(err)
}
}
func replaceCommand() {
ctx, resources := loadContextAndResources(replaceFile)
args := []string{"replace", "--save-config=true", "-f", "-"}
if err := runKubectlWithResources(ctx, &args, resources); err != nil {
failWithKubectlError(err)
}
}
func deleteCommand() {
ctx, resources := loadContextAndResources(deleteFile)
args := []string{"delete", "-f", "-"}
if err := runKubectlWithResources(ctx, &args, resources); err != nil {
failWithKubectlError(err)
}
}
func createCommand() {
ctx, resources := loadContextAndResources(createFile)
args := []string{"create", "--save-config=true", "-f", "-"}
if err := runKubectlWithResources(ctx, &args, resources); err != nil {
failWithKubectlError(err)
}
}
func loadContextAndResources(file *string) (*context.Context, *[]templater.RenderedResourceSet) {
ctx, err := context.LoadContext(*file, variables)
if err != nil {
app.Fatalf("Error loading context: %v\n", err)
}
resources, err := templater.LoadAndApplyTemplates(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, resourceSets *[]templater.RenderedResourceSet) error {
argsWithContext := append(*kubectlArgs, fmt.Sprintf("--context=%s", c.Name))
for _, rs := range *resourceSets {
if len(rs.Resources) == 0 {
fmt.Fprintf(os.Stderr, "Warning: Resource set '%s' contains no valid templates\n", rs.Name)
continue
}
argsWithResourceSetArgs := append(argsWithContext, rs.Args...)
kubectl := exec.Command(*kubectlBin, argsWithResourceSetArgs...)
stdin, err := kubectl.StdinPipe()
if err != nil {
return fmt.Errorf("kubectl error: %v", err)
}
kubectl.Stdout = os.Stdout
kubectl.Stderr = os.Stderr
if err = kubectl.Start(); err != nil {
return fmt.Errorf("kubectl error: %v", err)
}
for _, r := range rs.Resources {
fmt.Printf("Passing file %s/%s to kubectl\n", rs.Name, r.Filename)
fmt.Fprintln(stdin, r.Rendered)
}
stdin.Close()
if err = kubectl.Wait(); err != nil {
return err
}
}
return nil
}
func failWithKubectlError(err error) {
app.Fatalf("Kubectl error: %v\n", err)
}
