func main() {
env := flag.Bool("env", true, "Pull variables from the environment")
inplace := flag.Bool("inplace", false, "Replace variables in the given file inplace")
flag.Parse()
remainingArgs := flag.Args()
var tmplReader io.Reader
var outWriter io.WriteCloser = os.Stdout
defer outWriter.Close()
if shouldReadStdin() {
if *inplace {
log.Fatal("Cannot do inplace replacement of stdin")
}
tmplReader = os.Stdin
} else {
if len(remainingArgs) == 0 {
log.Fatal("Must provide an argument of a file to template")
}
fileName := remainingArgs[len(remainingArgs)-1]
lastFile, err := os.Open(fileName)
if err != nil {
log.Fatalf("Could not open given file (%v) for templating: %v", fileName, err)
}
tmplReader = lastFile
if *inplace {
outWriter = &bufferedFileWriter{file: fileName, Buffer: bytes.NewBuffer([]byte{})}
}
}
resolvers := chainResolver{}
if *env {
resolvers = append(resolvers, envLookup{})
}
vars := make(map[string]interface{})
for _, arg := range remainingArgs {
avar := make(map[string]interface{})
f, err := os.Open(arg)
if err != nil {
log.Fatal("Unable to open file: " + arg)
}
data, err := ioutil.ReadAll(f)
if err != nil {
log.Fatal("Unable to read file: " + arg)
}
err = json.Unmarshal(data, &avar)
if err != nil {
log.Fatalf("Invalid json file %v: %v", arg, err)
}
for k, v := range avar {
vars[k] = v
}
}
strVars := make(gotmpl.MapLookup)
for k, v := range vars {
if v == nil {
strVars[k] = ""
} else {
strVars[k] = fmt.Sprintf("%v", v)
}
}
resolvers = append(resolvers, strVars)
if err := gotmpl.Template(tmplReader, outWriter, resolvers); err != nil {
log.Fatal(err)
}
}
func ExampleTemplate() {
r := strings.NewReader(`Hello ${name}`)
gotmpl.Template(r, os.Stdout, gotmpl.MapLookup(map[string]string{"name": "uhh, Jim"}))
// Output: Hello uhh, Jim
}