2 files changed, 141 insertions, 0 deletions
diff --git a/client/go/internal/ioutil/ioutil.go b/client/go/internal/ioutil/ioutil.go
new file mode 100644
index 00000000000..d3a33698d13
--- /dev/null
+++ b/client/go/internal/ioutil/ioutil.go
@@ -0,0 +1,84 @@
+// Copyright Vespa.ai. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+// File utilities.
+// Author: bratseth
+
+package ioutil
+
+import (
+	"bytes"
+	"encoding/json"
+	"errors"
+	"io"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+// Exists returns true if the given path exists.
+func Exists(path string) bool {
+	info, err := os.Stat(path)
+	return !errors.Is(err, os.ErrNotExist) && info != nil
+}
+
+// IsDir returns true if the given path points to an existing directory.
+func IsDir(path string) bool {
+	info, err := os.Stat(path)
+	return !errors.Is(err, os.ErrNotExist) && info != nil && info.IsDir()
+}
+
+// IsFile returns true if the given path points to an existing regular file.
+func IsFile(path string) bool {
+	info, err := os.Stat(path)
+	return !errors.Is(err, os.ErrNotExist) && info != nil && info.Mode().IsRegular()
+}
+
+// IsExecutable returns true if the given path points to an executable file.
+func IsExecutable(path string) bool {
+	info, err := os.Stat(path)
+	return !errors.Is(err, os.ErrNotExist) &&
+		info != nil &&
+		info.Mode().IsRegular() &&
+		((int(info.Mode()) & 0111) == 0111)
+}
+
+// ReaderToString Returns the content of reader as a string. Read errors are ignored.
+func ReaderToString(reader io.Reader) string {
+	var buffer strings.Builder
+	io.Copy(&buffer, reader)
+	return buffer.String()
+}
+
+// ReaderToBytes returns the content of a reader as a byte array. Read errors are ignored.
+func ReaderToBytes(reader io.Reader) []byte {
+	var buffer bytes.Buffer
+	buffer.ReadFrom(reader)
+	return buffer.Bytes()
+}
+
+// ReaderToJSON returns the contents of reader as indented JSON. Read errors are ignored.
+func ReaderToJSON(reader io.Reader) string {
+	bodyBytes, _ := io.ReadAll(reader)
+	var prettyJSON bytes.Buffer
+	parseError := json.Indent(&prettyJSON, bodyBytes, "", "    ")
+	if parseError != nil { // Not JSON: Print plainly
+		return string(bodyBytes)
+	}
+	return prettyJSON.String()
+}
+
+// AtomicWriteFile atomically writes data to filename.
+func AtomicWriteFile(filename string, data []byte) error {
+	dir := filepath.Dir(filename)
+	tmpFile, err := os.CreateTemp(dir, "vespa")
+	if err != nil {
+		return err
+	}
+	defer os.Remove(tmpFile.Name())
+	if _, err := tmpFile.Write(data); err != nil {
+		return err
+	}
+	if err := tmpFile.Close(); err != nil {
+		return err
+	}
+	return os.Rename(tmpFile.Name(), filename)
+}
diff --git a/client/go/internal/ioutil/ioutil_test.go b/client/go/internal/ioutil/ioutil_test.go
new file mode 100644
index 00000000000..907132c9eaa
--- /dev/null
+++ b/client/go/internal/ioutil/ioutil_test.go
@@ -0,0 +1,57 @@
+// Copyright Vespa.ai. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package ioutil
+
+import (
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestPathExists(t *testing.T) {
+	assert.Equal(t, true, Exists("ioutil.go"))
+	assert.Equal(t, false, Exists("nosuchthing.go"))
+
+	tmpDir := t.TempDir()
+	err := os.MkdirAll(tmpDir+"/no", 0755)
+	assert.Nil(t, err)
+	err = os.MkdirAll(tmpDir+"/no/such", 0)
+	assert.Nil(t, err)
+	assert.Equal(t, false, Exists(tmpDir+"/no/such/thing.go"))
+}
+
+func TestIsDir(t *testing.T) {
+	tmpDir := t.TempDir()
+	err := os.MkdirAll(tmpDir+"/no", 0755)
+	assert.Nil(t, err)
+	assert.Equal(t, true, IsDir(tmpDir+"/no"))
+	err = os.MkdirAll(tmpDir+"/no/such", 0)
+	assert.Nil(t, err)
+	assert.Equal(t, true, IsDir(tmpDir+"/no/such"))
+	assert.Equal(t, false, IsDir(tmpDir+"/no/such/thing.go"))
+}
+
+func TestIsRegularFile(t *testing.T) {
+	assert.Equal(t, true, IsFile("ioutil.go"))
+	assert.Equal(t, false, IsFile("."))
+	tmpDir := t.TempDir()
+	err := os.MkdirAll(tmpDir+"/no", 0755)
+	assert.Nil(t, err)
+	err = os.MkdirAll(tmpDir+"/no/such", 0)
+	assert.Nil(t, err)
+	assert.Equal(t, false, IsFile(tmpDir+"/no/such/thing.go"))
+}
+
+func TestIsExecutableFile(t *testing.T) {
+	assert.Equal(t, false, IsExecutable("io.go"))
+	assert.Equal(t, false, IsExecutable("nosuchthing.go"))
+	tmpDir := t.TempDir()
+	err := os.WriteFile(tmpDir+"/run.sh", []byte("#!/bin/sh\necho foo\n"), 0755)
+	assert.Nil(t, err)
+	assert.Equal(t, true, IsExecutable(tmpDir+"/run.sh"))
+	/* unix only:
+	out, err := BackTicksWithStderr.Run(tmpDir + "/run.sh")
+	assert.Nil(t, err)
+	assert.Equal(t, "foo\n", out)
+	*/
+}