internal/frontend : serve static assets (#392)

Signed-off-by: Bobby DeSimone <bobbydesimone@gmail.com>

internal/frontend/templates.go

@@ -0,0 +1,55 @@
+//go:generate statik -src=./assets -include=*.svg,*.html,*.css,*.js
+
+package frontend // import "github.com/pomerium/pomerium/internal/frontend"
+
+import (
+	"fmt"
+	"html/template"
+	"io/ioutil"
+	"net/http"
+	"os"
+
+	"github.com/rakyll/statik/fs"
+
+	_ "github.com/pomerium/pomerium/internal/frontend/statik" // load static assets
+)
+
+// NewTemplates loads pomerium's templates. Panics on failure.
+func NewTemplates() (*template.Template, error) {
+	t := template.New("pomerium-templates")
+	statikFS, err := fs.New()
+	if err != nil {
+		return nil, fmt.Errorf("internal/frontend: error creating new file system: %w", err)
+	}
+
+	err = fs.Walk(statikFS, "/html", func(filePath string, fileInfo os.FileInfo, err error) error {
+		if !fileInfo.IsDir() {
+			file, err := statikFS.Open(filePath)
+			if err != nil {
+				return fmt.Errorf("internal/frontend: error opening %s: %w", filePath, err)
+			}
+
+			buf, err := ioutil.ReadAll(file)
+			if err != nil {
+				return fmt.Errorf("internal/frontend: error reading %s: %w", filePath, err)
+			}
+			t.Parse(string(buf))
+		}
+		return nil
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	return t, nil
+}
+
+// MustAssetHandler wraps a call to the embedded static file system and panics
+// if the error is non-nil. It is intended for use in variable initializations
+func MustAssetHandler() http.Handler {
+	statikFS, err := fs.New()
+	if err != nil {
+		panic(err)
+	}
+	return http.FileServer(statikFS)
+}