Adding file namespace

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

7 files changed, 324 insertions, 0 deletions

diff --git a/docs/content/functions/file.md b/docs/content/functions/file.md
new file mode 100644
index 00000000..cff6af2c
--- /dev/null
+++ b/docs/content/functions/file.md
@@ -0,0 +1,116 @@
+---
+title: file functions
+menu:
+  main:
+    parent: functions
+---
+
+## `file.Exists`
+
+Reports whether a file or directory exists at the given path.
+
+### Usage
+```go
+file.Exists path
+```
+
+### Example
+
+_`input.tmpl`:_
+```
+{{ if (file.Exists "/tmp/foo") }}yes{{else}}no{{end}}
+```
+
+```console
+$ gomplate -f input.tmpl
+no
+$ touch /tmp/foo
+$ gomplate -f input.tmpl
+yes
+```
+
+## `file.IsDir`
+
+Reports whether a given path is a directory.
+
+### Usage
+```go
+file.IsDir path
+```
+
+### Example
+
+_`input.tmpl`:_
+```
+{{ if (file.IsDir "/tmp/foo") }}yes{{else}}no{{end}}
+```
+
+```console
+$ gomplate -f input.tmpl
+no
+$ touch /tmp/foo
+$ gomplate -f input.tmpl
+no
+$ rm /tmp/foo && mkdir /tmp/foo
+$ gomplate -f input.tmpl
+yes
+```
+
+## `file.Read`
+
+Reads a given file _as text_. Note that this will succeed if the given file
+is binary, but 
+
+### Usage
+```go
+file.Read path
+```
+
+### Examples
+
+```console
+$ echo "hello world" > /tmp/hi
+$ gomplate -i '{{file.Read "/tmp/hi"}}'
+hello world
+```
+
+## `file.ReadDir`
+
+Reads a directory and lists the files and directories contained within.
+
+### Usage
+```go
+file.ReadDir path
+```
+
+### Examples
+
+```console
+$ mkdir /tmp/foo
+$ touch /tmp/foo/a; touch /tmp/foo/b; touch /tmp/foo/c
+$ mkdir /tmp/foo/d
+$ gomplate -i '{{ range (file.ReadDir "/tmp/foo") }}{{.}}{{"\n"}}{{end}}'
+a
+b
+c
+d
+```
+
+## `file.Stat`
+
+Returns a [`os.FileInfo`](https://golang.org/pkg/os/#FileInfo) describing
+the named path. 
+Essentially a wrapper for Go's [`os.Stat`](https://golang.org/pkg/os/#Stat) function.
+
+### Usage
+```go
+file.Stat path
+```
+
+### Examples
+
+```console
+$ echo "hello world" > /tmp/foo
+$ gomplate -i '{{ $s := file.Stat "/tmp/foo" }}{{ $s.Mode }} {{ $s.Size }} {{ $s.Name }}'
+-rw-r--r-- 12 foo
+```
diff --git a/file/file.go b/file/file.go
new file mode 100644
index 00000000..10f58a41
--- /dev/null
+++ b/file/file.go
@@ -0,0 +1,45 @@
+package file
+
+import (
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"os"
+
+	"github.com/spf13/afero"
+)
+
+// for overriding in tests
+var fs = afero.NewOsFs()
+
+// Read -
+func Read(filename string) (string, error) {
+	inFile, err := fs.OpenFile(filename, os.O_RDONLY, 0)
+	if err != nil {
+		return "", fmt.Errorf("failed to open %s\n%v", filename, err)
+	}
+	// nolint: errcheck
+	defer inFile.Close()
+	bytes, err := ioutil.ReadAll(inFile)
+	if err != nil {
+		err = fmt.Errorf("read failed for %s\n%v", filename, err)
+		return "", err
+	}
+	return string(bytes), nil
+}
+
+// ReadDir -
+func ReadDir(path string) ([]string, error) {
+	f, err := fs.Open(path)
+	if err != nil {
+		return nil, err
+	}
+	i, err := f.Stat()
+	if err != nil {
+		return nil, err
+	}
+	if i.IsDir() {
+		return f.Readdirnames(0)
+	}
+	return nil, errors.New("file is not a directory")
+}
diff --git a/file/file_test.go b/file/file_test.go
new file mode 100644
index 00000000..97cfa0fb
--- /dev/null
+++ b/file/file_test.go
@@ -0,0 +1,43 @@
+package file
+
+import (
+	"testing"
+
+	"github.com/spf13/afero"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestRead(t *testing.T) {
+	origfs := fs
+	defer func() { fs = origfs }()
+	fs = afero.NewMemMapFs()
+	_ = fs.Mkdir("/tmp", 0777)
+	f, _ := fs.Create("/tmp/foo")
+	_, _ = f.Write([]byte("foo"))
+
+	actual, err := Read("/tmp/foo")
+	assert.NoError(t, err)
+	assert.Equal(t, "foo", actual)
+
+	actual, err = Read("/tmp/bar")
+	assert.Error(t, err)
+}
+
+func TestReadDir(t *testing.T) {
+	origfs := fs
+	defer func() { fs = origfs }()
+	fs = afero.NewMemMapFs()
+	fs.Mkdir("/tmp", 0777)
+	fs.Create("/tmp/foo")
+	fs.Create("/tmp/bar")
+	fs.Create("/tmp/baz")
+	fs.Mkdir("/tmp/qux", 0777)
+	fs.Create("/tmp/qux/quux")
+
+	actual, err := ReadDir("/tmp")
+	assert.NoError(t, err)
+	assert.Equal(t, []string{"bar", "baz", "foo", "qux"}, actual)
+
+	_, err = ReadDir("/tmp/foo")
+	assert.Error(t, err)
+}
diff --git a/funcs.go b/funcs.go
index 9e20ee8c..99445bc3 100644
--- a/funcs.go
+++ b/funcs.go
@@ -21,5 +21,6 @@ func initFuncs(d *data.Data) template.FuncMap {
 	funcs.AddTimeFuncs(f)
 	funcs.AddMathFuncs(f)
 	funcs.AddCryptoFuncs(f)
+	funcs.AddFileFuncs(f)
 	return f
 }
diff --git a/funcs/file.go b/funcs/file.go
new file mode 100644
index 00000000..1f1a30bd
--- /dev/null
+++ b/funcs/file.go
@@ -0,0 +1,57 @@
+package funcs
+
+import (
+	"os"
+	"sync"
+
+	"github.com/hairyhenderson/gomplate/file"
+	"github.com/spf13/afero"
+)
+
+var (
+	ff     *FileFuncs
+	ffInit sync.Once
+)
+
+// FileNS - the File namespace
+func FileNS() *FileFuncs {
+	ffInit.Do(func() { ff = &FileFuncs{afero.NewOsFs()} })
+	return ff
+}
+
+// AddFileFuncs -
+func AddFileFuncs(f map[string]interface{}) {
+	f["file"] = FileNS
+}
+
+// FileFuncs -
+type FileFuncs struct {
+	fs afero.Fs
+}
+
+// Read -
+func (f *FileFuncs) Read(path string) (string, error) {
+	return file.Read(path)
+}
+
+// Stat -
+func (f *FileFuncs) Stat(path string) (os.FileInfo, error) {
+	return f.fs.Stat(path)
+}
+
+// Exists -
+func (f *FileFuncs) Exists(path string) bool {
+	_, err := f.Stat(path)
+	return err == nil
+}
+
+// IsDir -
+func (f *FileFuncs) IsDir(path string) bool {
+	i, err := f.Stat(path)
+	return err == nil && i.IsDir()
+}
+
+// ReadDir -
+func (f *FileFuncs) ReadDir(path string) ([]string, error) {
+	return file.ReadDir(path)
+}
diff --git a/funcs/file_test.go b/funcs/file_test.go
new file mode 100644
index 00000000..2a3ce9a9
--- /dev/null
+++ b/funcs/file_test.go
@@ -0,0 +1,32 @@
+package funcs
+
+import (
+	"testing"
+
+	"github.com/spf13/afero"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestFileExists(t *testing.T) {
+	fs := afero.NewMemMapFs()
+	ff := &FileFuncs{fs}
+
+	_ = fs.Mkdir("/tmp", 0777)
+	f, _ := fs.Create("/tmp/foo")
+	_, _ = f.Write([]byte("foo"))
+
+	assert.True(t, ff.Exists("/tmp/foo"))
+	assert.False(t, ff.Exists("/tmp/bar"))
+}
+
+func TestFileIsDir(t *testing.T) {
+	fs := afero.NewMemMapFs()
+	ff := &FileFuncs{fs}
+
+	_ = fs.Mkdir("/tmp", 0777)
+	f, _ := fs.Create("/tmp/foo")
+	_, _ = f.Write([]byte("foo"))
+
+	assert.True(t, ff.IsDir("/tmp"))
+	assert.False(t, ff.IsDir("/tmp/foo"))
+}
diff --git a/test/integration/file_test.go b/test/integration/file_test.go
new file mode 100644
index 00000000..4d3fed22
--- /dev/null
+++ b/test/integration/file_test.go
@@ -0,0 +1,30 @@
+//+build !xxintegration
+//+build !windows
+
+package integration
+
+import (
+	. "gopkg.in/check.v1"
+
+	"github.com/gotestyourself/gotestyourself/fs"
+)
+
+type FileSuite struct {
+	tmpDir *fs.Dir
+}
+
+var _ = Suite(&FileSuite{})
+
+func (s *FileSuite) SetUpSuite(c *C) {
+	s.tmpDir = fs.NewDir(c, "gomplate-inttests",
+		fs.WithFile("one", "hi\n"),
+		fs.WithFile("two", "hello\n"))
+}
+
+func (s *FileSuite) TearDownSuite(c *C) {
+	s.tmpDir.Remove()
+}
+
+func (s *FileSuite) TestReadsFile(c *C) {
+	inOutTest(c, `{{ file.Read "`+s.tmpDir.Join("one")+`"}}`, "hi")
+}