Add Dockerfile

Dockerfile

@@ -0,0 +1,10 @@
+FROM golang:1.10 as builder
+WORKDIR /go/src/github.com/tsg/gotpl
+RUN go get -d -v gopkg.in/yaml.v2
+RUN go get -d -v github.com/Masterminds/sprig
+COPY tpl.go .
+RUN CGO_ENABLED=0 GOOS=linux go build -a -installsuffix gotpl -o gotpl .
+
+FROM alpine
+COPY --from=builder /go/src/github.com/tsg/gotpl/gotpl /usr/local/bin/gotpl
+ENTRYPOINT ["/usr/local/bin/gotpl"]

tpl.go

@@ -4,18 +4,30 @@ import (
 	"bytes"
 	"fmt"
 	"io"
+	"io/ioutil"
 	"log"
 	"os"
 	"text/template"
 
+	"github.com/Masterminds/sprig"
 	"gopkg.in/yaml.v2"
 )
 
 // Reads a YAML document from the values_in stream, uses it as values
 // for the tpl_files templates and writes the executed templates to
 // the out stream.
-func ExecuteTemplates(values_in io.Reader, out io.Writer, tpl_files ...string) error {
-	tpl, err := template.ParseFiles(tpl_files...)
+func ExecuteTemplates(values_in io.Reader, out io.Writer, tpl_files string) error {
+	var r io.Reader
+	r, err := os.Open(tpl_files)
+	if err != nil {
+		return err
+	}
+	templateData, err := ioutil.ReadAll(r)
+	if err != nil {
+		return fmt.Errorf("Could not read input: %v", err)
+	}
+
+	tpl, err := template.New("base").Funcs(sprig.TxtFuncMap()).Parse(string(templateData))
 	if err != nil {
 		return fmt.Errorf("Error parsing template(s): %v", err)
 	}
@@ -40,7 +52,7 @@ func ExecuteTemplates(values_in io.Reader, out io.Writer, tpl_files ...string) e
 }
 
 func main() {
-	err := ExecuteTemplates(os.Stdin, os.Stdout, os.Args[1:]...)
+	err := ExecuteTemplates(os.Stdin, os.Stdout, os.Args[1])
 	if err != nil {
 		log.Println(err)
 		os.Exit(1)