Use go-fsimpl to read from datasources (#1336)

* Use go-fsimpl to read from datasources

Signed-off-by: Dave Henderson <dhenderson@gmail.com>

* trying to fix windows bug

Signed-off-by: Dave Henderson <dhenderson@gmail.com>

* attempts to fix some of the path madness

Signed-off-by: Dave Henderson <dhenderson@gmail.com>

* remove 'HOME' from expected env vars

Signed-off-by: Dave Henderson <dhenderson@gmail.com>

* more tweaks

Signed-off-by: Dave Henderson <dhenderson@gmail.com>

* lint fix

Signed-off-by: Dave Henderson <dhenderson@gmail.com>

---------

Signed-off-by: Dave Henderson <dhenderson@gmail.com>

2 files changed, 2 insertions, 141 deletions

diff --git a/env/env.go b/env/env.go
index e9ab3632..598361bf 100644
--- a/env/env.go
+++ b/env/env.go
@@ -2,10 +2,6 @@
 package env
 
 import (
-	"io/fs"
-	"os"
-	"strings"
-
 	osfs "github.com/hack-pad/hackpadfs/os"
 	"github.com/hairyhenderson/gomplate/v4/internal/datafs"
 )
@@ -16,55 +12,11 @@ import (
 // Otherwise the provided default (or an emptry string) is returned.
 func Getenv(key string, def ...string) string {
 	fsys := datafs.WrapWdFS(osfs.NewFS())
-	return getenvVFS(fsys, key, def...)
+	return datafs.GetenvFsys(fsys, key, def...)
 }
 
 // ExpandEnv - like os.ExpandEnv, except supports `_FILE` vars as well
 func ExpandEnv(s string) string {
 	fsys := datafs.WrapWdFS(osfs.NewFS())
-	return expandEnvVFS(fsys, s)
-}
-
-// expandEnvVFS -
-func expandEnvVFS(fsys fs.FS, s string) string {
-	return os.Expand(s, func(s string) string {
-		return getenvVFS(fsys, s)
-	})
-}
-
-// getenvVFS - a convenience function intended for internal use only!
-func getenvVFS(fsys fs.FS, key string, def ...string) string {
-	val := getenvFile(fsys, key)
-	if val == "" && len(def) > 0 {
-		return def[0]
-	}
-
-	return val
-}
-
-func getenvFile(fsys fs.FS, key string) string {
-	val := os.Getenv(key)
-	if val != "" {
-		return val
-	}
-
-	p := os.Getenv(key + "_FILE")
-	if p != "" {
-		val, err := readFile(fsys, p)
-		if err != nil {
-			return ""
-		}
-		return strings.TrimSpace(val)
-	}
-
-	return ""
-}
-
-func readFile(fsys fs.FS, p string) (string, error) {
-	b, err := fs.ReadFile(fsys, p)
-	if err != nil {
-		return "", err
-	}
-
-	return string(b), nil
+	return datafs.ExpandEnvFsys(fsys, s)
 }
diff --git a/env/env_test.go b/env/env_test.go
index faaaa603..9f637944 100644
--- a/env/env_test.go
+++ b/env/env_test.go
@@ -1,14 +1,8 @@
 package env
 
 import (
-	"errors"
-	"io/fs"
 	"os"
 	"testing"
-	"testing/fstest"
-
-	"github.com/hack-pad/hackpadfs"
-	"github.com/hairyhenderson/gomplate/v4/internal/datafs"
 
 	"github.com/stretchr/testify/assert"
 )
@@ -19,25 +13,6 @@ func TestGetenv(t *testing.T) {
 	assert.Equal(t, "default value", Getenv("BLAHBLAHBLAH", "default value"))
 }
 
-func TestGetenvFile(t *testing.T) {
-	fsys := fs.FS(fstest.MapFS{
-		"tmp":            &fstest.MapFile{Mode: fs.ModeDir | 0o777},
-		"tmp/foo":        &fstest.MapFile{Data: []byte("foo")},
-		"tmp/unreadable": &fstest.MapFile{Data: []byte("foo"), Mode: 0o000},
-	})
-	fsys = datafs.WrapWdFS(fsys)
-
-	t.Setenv("FOO_FILE", "/tmp/foo")
-	assert.Equal(t, "foo", getenvVFS(fsys, "FOO", "bar"))
-
-	t.Setenv("FOO_FILE", "/tmp/missing")
-	assert.Equal(t, "bar", getenvVFS(fsys, "FOO", "bar"))
-
-	fsys = writeOnly(fsys)
-	t.Setenv("FOO_FILE", "/tmp/unreadable")
-	assert.Equal(t, "bar", getenvVFS(fsys, "FOO", "bar"))
-}
-
 func TestExpandEnv(t *testing.T) {
 	assert.Empty(t, ExpandEnv("${FOOBARBAZ}"))
 	assert.Equal(t, os.Getenv("USER"), ExpandEnv("$USER"))
@@ -45,69 +20,3 @@ func TestExpandEnv(t *testing.T) {
 	assert.Equal(t, os.Getenv("USER")+": "+os.Getenv("HOME"),
 		ExpandEnv("$USER: ${HOME}"))
 }
-
-func TestExpandEnvFile(t *testing.T) {
-	fsys := fs.FS(fstest.MapFS{
-		"tmp":            &fstest.MapFile{Mode: fs.ModeDir | 0o777},
-		"tmp/foo":        &fstest.MapFile{Data: []byte("foo")},
-		"tmp/unreadable": &fstest.MapFile{Data: []byte("foo"), Mode: 0o000},
-	})
-	fsys = datafs.WrapWdFS(fsys)
-
-	t.Setenv("FOO_FILE", "/tmp/foo")
-	assert.Equal(t, "foo is foo", expandEnvVFS(fsys, "foo is $FOO"))
-
-	t.Setenv("FOO_FILE", "/tmp/missing")
-	assert.Equal(t, "empty", expandEnvVFS(fsys, "${FOO}empty"))
-
-	fsys = writeOnly(fsys)
-	t.Setenv("FOO_FILE", "/tmp/unreadable")
-	assert.Equal(t, "", expandEnvVFS(fsys, "${FOO}"))
-}
-
-// Maybe extract this into a separate package sometime...
-// writeOnly - represents a filesystem that's writeable, but read operations fail
-func writeOnly(fsys fs.FS) fs.FS {
-	return &woFS{fsys}
-}
-
-type woFS struct {
-	fsys fs.FS
-}
-
-func (fsys woFS) Open(name string) (fs.File, error) {
-	f, err := fsys.fsys.Open(name)
-	return writeOnlyFile(f), err
-}
-
-func (fsys woFS) ReadDir(_ string) ([]fs.DirEntry, error) {
-	return nil, ErrWriteOnly
-}
-
-func (fsys woFS) Stat(_ string) (fs.FileInfo, error) {
-	return nil, ErrWriteOnly
-}
-
-func writeOnlyFile(f fs.File) fs.File {
-	if f == nil {
-		return nil
-	}
-
-	return &woFile{f}
-}
-
-type woFile struct {
-	fs.File
-}
-
-// Write -
-func (f woFile) Write(p []byte) (n int, err error) {
-	return hackpadfs.WriteFile(f.File, p)
-}
-
-// Read is disabled and returns ErrWriteOnly
-func (f woFile) Read([]byte) (n int, err error) {
-	return 0, ErrWriteOnly
-}
-
-var ErrWriteOnly = errors.New("filesystem is write-only")