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korvike/app.go
Knut Ahlers 5a833fa112
Add support for executing sub-templates
Signed-off-by: Knut Ahlers <knut@ahlers.me>
2021-03-22 16:22:23 +01:00

89 lines
1.9 KiB
Go

package main
import (
"errors"
"fmt"
"io"
"io/ioutil"
"log"
"os"
"text/template"
"github.com/Luzifer/go_helpers/v2/env"
korvike "github.com/Luzifer/korvike/functions"
"github.com/Luzifer/rconfig/v2"
)
var (
cfg = struct {
Input string `flag:"in,i" default:"-" description:"Source to read the template from ('-' = stdin)"`
KeyPairs []string `flag:"key-value,v" default:"" description:"Key-value pairs to use in templating (-v key=value)"`
Output string `flag:"out,o" default:"-" description:"Destination to write the output to ('-' = stdout)"`
VersionAndExit bool `flag:"version" default:"false" description:"Prints current version and exits"`
}{}
version = "dev"
)
func init() {
if err := rconfig.Parse(&cfg); err != nil {
log.Fatalf("Unable to parse commandline options: %s", err)
}
if cfg.VersionAndExit {
fmt.Printf("korvike %s\n", version)
os.Exit(0)
}
}
func openInput(f string) (io.Reader, error) {
if f == "-" {
return os.Stdin, nil
}
if _, err := os.Stat(f); err != nil {
return nil, errors.New("Could not find file " + f)
}
return os.Open(f)
}
func openOutput(f string) (io.Writer, error) {
if f == "-" {
return os.Stdout, nil
}
return os.Create(f)
}
func main() {
in, err := openInput(cfg.Input)
if err != nil {
log.Fatalf("Unable to open input: %s", err)
}
out, err := openOutput(cfg.Output)
if err != nil {
log.Fatalf("Unable to open output: %s", err)
}
rawTpl, err := ioutil.ReadAll(in)
if err != nil {
log.Fatalf("Unable to read from input: %s", err)
}
tpl, err := template.New("in").Funcs(korvike.GetFunctionMap()).Parse(string(rawTpl))
if err != nil {
log.Fatalf("Unable to parse template: %s", err)
}
vars := map[string]interface{}{}
for k, v := range env.ListToMap(cfg.KeyPairs) {
vars[k] = v
}
korvike.SetSubTemplateVariables(vars)
if err := tpl.Execute(out, vars); err != nil {
log.Fatalf("Unable to execute template: %s", err)
}
}