/
epp.go
92 lines (72 loc) · 1.53 KB
/
epp.go
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package main
import (
"flag"
"fmt"
"io/ioutil"
"os"
"strings"
"github.com/flosch/pongo2"
)
var (
Version string
GitCommit string
output = flag.String("o", "", "output file")
version = flag.Bool("version", false, "print epp version")
)
func main() {
flag.Parse()
if *version {
fmt.Fprintf(os.Stderr, "epp %s (%s)\n", Version, GitCommit)
os.Exit(0)
}
if len(flag.Args()) == 0 {
fmt.Fprintln(os.Stderr, "error: an input file is required")
os.Exit(1)
}
fileContents, err := readInput(flag.Arg(0))
if err != nil {
fmt.Fprintf(os.Stderr, "IO error: %s\n", err)
os.Exit(1)
}
out, err := parse(fileContents)
if err != nil {
fmt.Fprintf(os.Stderr, "templating error: %s\n", err)
os.Exit(1)
}
if *output == "" {
fmt.Printf(string(out))
return
}
err = ioutil.WriteFile(*output, out, 0644)
if err != nil {
fmt.Fprintf(os.Stderr, "IO error: %s\n", err)
os.Exit(1)
}
}
func parse(input []byte) ([]byte, error) {
tpl, err := pongo2.FromString(string(input))
if err != nil {
return nil, err
}
context := environToContext()
out, err := tpl.ExecuteBytes(context)
if err != nil {
return nil, err
}
return out, nil
}
func readInput(input string) ([]byte, error) {
if inputFile := flag.Arg(0); inputFile == "-" {
return ioutil.ReadAll(os.Stdin)
}
return ioutil.ReadFile(input)
}
func environToContext() pongo2.Context {
ctx := pongo2.Context{}
for _, env := range os.Environ() {
variable := strings.SplitN(env, "=", 2)
key, value := variable[0], variable[1]
ctx[key] = value
}
return ctx
}