Dynamic resource loading

Load resources either from the dir of the executable, or from the
resolved go path, preferring the dir of the executable.

main.go

@@ -6,6 +6,7 @@ import (
 	"log"
 	"net/http"
 	"os"
+	"path/filepath"
 	"strconv"
 	"strings"
 	"time"
@@ -20,6 +21,8 @@ var (
 	lastModified    = time.Now()
 	lastModifiedStr = lastModified.UTC().Format(http.TimeFormat)
 	oneYear         = time.Duration(8700) * time.Hour
+
+	staticPath, _ = resourcePaths()
 )
 
 func shift(s []string) ([]string, string) {
@@ -105,12 +108,14 @@ func buckle(w http.ResponseWriter, r *http.Request) {
 	makePngShield(w, d)
 }
 
+const basePkg = "github.com/jbowes/buckler"
+
 func index(w http.ResponseWriter, r *http.Request) {
-	http.ServeFile(w, r, "static/index.html")
+	http.ServeFile(w, r, filepath.Join(staticPath, "index.html"))
 }
 
 func favicon(w http.ResponseWriter, r *http.Request) {
-	http.ServeFile(w, r, "static/favicon.png")
+	http.ServeFile(w, r, filepath.Join(staticPath, "favicon.png"))
 }
 
 func fatal(msg string) {

png.go

@@ -11,11 +11,11 @@ import (
 	"log"
 	"math"
 	"os"
+	"path/filepath"
 	"strconv"
 
 	"code.google.com/p/freetype-go/freetype"
 	"code.google.com/p/freetype-go/freetype/raster"
-	"code.google.com/p/freetype-go/freetype/truetype"
 )
 
 type Data struct {
@@ -55,7 +55,6 @@ var (
 
 	edge     image.Image
 	gradient image.Image
-	font     *truetype.Font
 	c        *freetype.Context
 )
 
@@ -66,7 +65,8 @@ const (
 )
 
 func init() {
-	fi, err := os.Open("data/edge.png")
+	_, dataPath := resourcePaths()
+	fi, err := os.Open(filepath.Join(dataPath, "edge.png"))
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -77,7 +77,7 @@ func init() {
 		log.Fatal(err)
 	}
 
-	fi, err = os.Open("data/gradient.png")
+	fi, err = os.Open(filepath.Join(dataPath, "gradient.png"))
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -88,12 +88,12 @@ func init() {
 		log.Fatal(err)
 	}
 
-	fontBytes, err := ioutil.ReadFile("data/opensanssemibold.ttf")
+	fontBytes, err := ioutil.ReadFile(filepath.Join(dataPath, "opensanssemibold.ttf"))
 	if err != nil {
 		log.Fatal(err)
 	}
 
-	font, err = freetype.ParseFont(fontBytes)
+	font, err := freetype.ParseFont(fontBytes)
 	if err != nil {
 		log.Fatal(err)
 	}

resources.go

@@ -0,0 +1,44 @@
+package main
+
+import (
+	"go/build"
+	"log"
+	"os"
+	"path/filepath"
+
+	"bitbucket.org/kardianos/osext"
+)
+
+// exists returns whether the given file or directory exists or not
+func exists(path string) bool {
+	_, err := os.Stat(path)
+	if err == nil {
+		return true
+	}
+	if os.IsNotExist(err) {
+		return false
+	}
+	return false
+}
+
+func resourcePaths() (staticPath string, dataPath string) {
+	base, err := osext.ExecutableFolder()
+	if err != nil {
+		log.Fatal("Could not read base dir")
+	}
+
+	staticPath = filepath.Join(base, "static")
+	dataPath = filepath.Join(base, "data")
+	if exists(dataPath) && exists(staticPath) {
+		return
+	}
+
+	p, err := build.Default.Import(basePkg, "", build.FindOnly)
+	if err != nil {
+		log.Fatal("Could not find package dir")
+	}
+
+	staticPath = filepath.Join(p.Dir, "static")
+	dataPath = filepath.Join(p.Dir, "data")
+	return
+}