resource(template): implement and test template

resource/template/template.go

@@ -14,16 +14,54 @@
 
 package template
 
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+)
+
 // Template renders a template to disk
 type Template struct {
 	Content     string
 	Destination string
 }
 
+// Check if the template needs to be rendered
 func (t *Template) Check() (status string, willChange bool, err error) {
-	return
+	stat, err := os.Stat(t.Destination)
+	if os.IsNotExist(err) {
+		return "", true, nil
+	} else if err != nil {
+		return "", false, err
+	} else if stat.IsDir() {
+		return "", true, fmt.Errorf("cannot template %q, is a directory", t.Destination)
+	}
+
+	actual, err := ioutil.ReadFile(t.Destination)
+	if err != nil {
+		return "", false, err
+	}
+
+	return string(actual), t.Content != string(actual), nil
 }
 
+// Apply writes the content to disk
 func (t *Template) Apply() error {
+	var perm os.FileMode
+
+	stat, err := os.Stat(t.Destination)
+	if os.IsNotExist(err) {
+		perm = 0600
+	} else if err != nil {
+		return err
+	} else {
+		perm = stat.Mode()
+	}
+
+	err = ioutil.WriteFile(t.Destination, []byte(t.Content), perm)
+	if err != nil {
+		return err
+	}
+
 	return nil
 }

resource/template/template_test.go

@@ -15,15 +15,137 @@
 package template_test
 
 import (
+	"fmt"
+	"io/ioutil"
+	"os"
 	"testing"
 
 	"github.com/asteris-llc/converge/resource"
 	"github.com/asteris-llc/converge/resource/template"
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 func TestTemplateInterface(t *testing.T) {
 	t.Parallel()
 
 	assert.Implements(t, (*resource.Task)(nil), new(template.Template))
 }
+
+func TestTemplateCheckEmptyFile(t *testing.T) {
+	tmpfile, err := ioutil.TempFile("", "test-check-empty-file")
+	require.NoError(t, err)
+	defer func() { require.NoError(t, os.Remove(tmpfile.Name())) }()
+
+	tmpl := template.Template{
+		Destination: tmpfile.Name(),
+		Content:     "this is a test",
+	}
+
+	current, change, err := tmpl.Check()
+	assert.Equal(t, "", current)
+	assert.True(t, change)
+	assert.NoError(t, err)
+}
+
+func TestTemplateCheckEmptyDir(t *testing.T) {
+	tmpdir, err := ioutil.TempDir("", "test-check-empty-dir")
+	require.NoError(t, err)
+	defer func() { require.NoError(t, os.RemoveAll(tmpdir)) }()
+
+	tmpl := template.Template{
+		Destination: tmpdir,
+		Content:     "this is a test",
+	}
+
+	current, change, err := tmpl.Check()
+	assert.Equal(t, "", current)
+	assert.True(t, change)
+	if assert.Error(t, err) {
+		assert.EqualError(
+			t,
+			err,
+			fmt.Sprintf("cannot template %q, is a directory", tmpdir),
+		)
+	}
+}
+
+func TestTemplateCheckContentGood(t *testing.T) {
+	tmpfile, err := ioutil.TempFile("", "test-check-content-good")
+	require.NoError(t, err)
+	defer func() { require.NoError(t, os.RemoveAll(tmpfile.Name())) }()
+
+	_, err = tmpfile.Write([]byte("this is a test"))
+	require.NoError(t, err)
+	require.NoError(t, tmpfile.Sync())
+
+	tmpl := template.Template{
+		Destination: tmpfile.Name(),
+		Content:     "this is a test",
+	}
+
+	current, change, err := tmpl.Check()
+	assert.Equal(t, "this is a test", current)
+	assert.False(t, change)
+	assert.NoError(t, err)
+}
+
+func TestTemplateApply(t *testing.T) {
+	tmpfile, err := ioutil.TempFile("", "test-check-empty-file")
+	require.NoError(t, err)
+	defer func() { require.NoError(t, os.Remove(tmpfile.Name())) }()
+
+	tmpl := template.Template{
+		Destination: tmpfile.Name(),
+		Content:     "1",
+	}
+
+	assert.NoError(t, tmpl.Apply())
+
+	// read the new file
+	content, err := ioutil.ReadFile(tmpfile.Name())
+	assert.Equal(t, "1", string(content))
+	assert.NoError(t, err)
+}
+
+func TestTemplateApplyPermissionDefault(t *testing.T) {
+	tmpfile, err := ioutil.TempFile("", "test-template-apply-permission")
+	require.NoError(t, err)
+	defer func() { require.NoError(t, os.Remove(tmpfile.Name())) }()
+
+	tmpl := template.Template{
+		Destination: tmpfile.Name(),
+		Content:     "1",
+	}
+
+	assert.NoError(t, tmpl.Apply())
+
+	// stat the new file
+	stat, err := os.Stat(tmpfile.Name())
+	assert.NoError(t, err)
+
+	perm := stat.Mode().Perm()
+	assert.Equal(t, os.FileMode(0600), perm)
+}
+
+func TestTemplateApplyKeepPermission(t *testing.T) {
+	tmpfile, err := ioutil.TempFile("", "test-template-keep-permission")
+	require.NoError(t, err)
+	defer func() { require.NoError(t, os.Remove(tmpfile.Name())) }()
+
+	var perm os.FileMode = 0777
+	require.NoError(t, os.Chmod(tmpfile.Name(), perm))
+
+	tmpl := template.Template{
+		Destination: tmpfile.Name(),
+		Content:     "1",
+	}
+
+	assert.NoError(t, tmpl.Apply())
+
+	// check permissions matched
+	stat, err := os.Stat(tmpfile.Name())
+	assert.NoError(t, err)
+
+	assert.Equal(t, perm, stat.Mode().Perm())
+}