update with suggestions from @kr

procfile.go

@@ -1,17 +1,15 @@
 package main
 
 import (
-  "bytes"
+  "bufio"
+  "fmt"
   "github.com/kr/pretty"
   "io"
-  "io/ioutil"
   "os"
   "regexp"
 )
 
-const (
-  procfileEntryRegexp = "^([A-Za-z0-9_]+):\\s*(.+)$"
-)
+var procfileEntryRegexp = regexp.MustCompile("^([A-Za-z0-9_]+):\\s*(.+)$")
 
 type ProcfileEntry struct {
   name string
@@ -24,7 +22,7 @@ type Procfile struct {
 
 var _ = pretty.Println // lol
 
-func OpenProcfile(filename string) (*Procfile, error) {
+func ReadProcfile(filename string) (*Procfile, error) {
   fd, err := os.Open(filename)
   if err != nil {
     return nil, err
@@ -35,17 +33,13 @@ func OpenProcfile(filename string) (*Procfile, error) {
 
 func parseProcfile(r io.Reader) (*Procfile, error) {
   pf := new(Procfile)
-  b, err := ioutil.ReadAll(r)
-  if err != nil {
-    return nil, err
+  scanner := bufio.NewScanner(r)
+  for scanner.Scan() {
+    parts := procfileEntryRegexp.FindStringSubmatch(scanner.Text())
+    pf.entries = append(pf.entries, ProcfileEntry{parts[1], parts[2]})
   }
-  lines := bytes.Split(b, []byte("\n"))
-  for _, line := range lines {
-    r := regexp.MustCompile(procfileEntryRegexp)
-    parts := r.FindStringSubmatch(string(line))
-    if parts != nil {
-      pf.entries = append(pf.entries, ProcfileEntry{parts[1], parts[2]})
-    }
+  if err := scanner.Err(); err != nil {
+    return nil, fmt.Errorf("Reading Procfile: %s", err)
   }
   return pf, nil
 }

start.go

@@ -28,7 +28,7 @@ func init() {
 }
 
 func runStart(cmd *Command, args []string) {
-  pf, err := OpenProcfile(flagProcfile)
+  pf, err := ReadProcfile(flagProcfile)
   if err != nil {
     fmt.Println("ERROR:", err)
     return