Use regular expressions instead of os.Expand.

README.md

@@ -4,9 +4,10 @@
 
 Trivial templating for configuration files using environment keys:
 
-1. Keys are defined as `${key}` or `$key` in various configuration files (glob patterns work)
-* Definitions without a value result in an error
-* envplate can optionally
+1. Keys are defined as `${key}` in arbitrary configuration files (glob patterns work)
+* Key definitions without a value in the environment results in an error
+* The failure to resolve the supplied glob pattern(s) to at least one file results in an error
+* `ep` can optionally
 	* create backups using the `-b` flag, appending a `.bak` extension to backup copies
 	* output to stdout instead of replacing values in files using the `-d` flag
 	* be verbose about it's operations by using the `-v` flag
@@ -40,8 +41,4 @@ RUN curl -sLo /usr/local/bin/ep https://github.com/yawn/envplate/releases/downlo
 ...
 
 CMD [ "/usr/local/bin/ep", "-v", "/etc/nginx/nginx.conf", "--", "/usr/sbin/nginx", "-c", "/etc/nginx/conf" ]
-```
-
-## TODO
-
-* (Maybe) drop the `$key` variable syntax (in favor of `${key}`-only)
+```

envplate.go

@@ -6,12 +6,15 @@ import (
 	"io/ioutil"
 	"os"
 	"path/filepath"
+	"regexp"
 )
 
 const (
 	NoKeyDefined = ""
 )
 
+var exp = regexp.MustCompile(`(\$\{\w+\})`)
+
 func Apply(globs []string) {
 
 	matches := false
@@ -82,8 +85,9 @@ func parse(file string) error {
 
 	Log(DEBUG, "Parsing environment references in '%s'", file)
 
-	parsed := os.Expand(string(content), func(key string) string {
+	parsed := exp.ReplaceAllStringFunc(string(content), func(match string) string {
 
+		key := match[2 : len(match)-1]
 		value := os.Getenv(key)
 
 		Log(DEBUG, "Expanding reference to '%s' to value '%s'", key, value)

envplate_test.go

@@ -38,11 +38,10 @@ func _read(t *testing.T, name string) string {
 
 func _template(t *testing.T) (string, string) {
 
-	tpl := `
-  Database1=${DATABASE}
+	tpl := `Database1=${DATABASE}
   Mode=${MODE}
   Database2=${DATABASE}
-  `
+  Database3=$FOOBAR`
 
 	return _write(t, "parse.txt", tpl, 0644), tpl
 
@@ -124,20 +123,19 @@ func TestFullParse(t *testing.T) {
 
 	assert := assert.New(t)
 
-	file, tpl := _template(t)
+	file, _ := _template(t)
 	defer _delete(t, file)
 
 	backup := fmt.Sprintf("%s.bak", file)
-	fmt.Println(backup)
-
-	//	time.Sleep(5 * time.Second)
 
 	err := parse(file)
 
 	assert.NoError(err)
-
 	assert.True(_exists(backup))
-	assert.NotEqual(tpl, _read(t, file), "content unchanged")
+	assert.Equal(`Database1=db.example.com
+  Mode=debug
+  Database2=db.example.com
+  Database3=$FOOBAR`, _read(t, file))
 
 }