qemu, ciao-launcher: Move ConfigDrive ISO creation code to qemu

Launcher's ConfigDrive ISO creation function, createCloudInitISO has
been moved to the qemu package so that it can be re-used by ciao-down.

Signed-off-by: Mark Ryan <mark.d.ryan@intel.com>

image.go

@@ -0,0 +1,72 @@
+/*
+// Copyright (c) 2017 Intel Corporation
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+*/
+
+package qemu
+
+import (
+	"context"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"os/exec"
+	"path"
+)
+
+// CreateCloudInitISO creates a cloud-init ConfigDrive ISO image.  This is
+// useful for configuring newly booted VMs. Before it can create the ISO
+// image it needs to create a file tree with the various files that will
+// make up the image.  This directory is created under scratchDir and is
+// deleted when when the function returns, successfully or otherwise.  ctx is
+// a context that can be used to timeout or cancel the image creation.
+// isoPath contains the desired path of the ISO image to be created.  The
+// userdata and metadata parameters are byte slices that contain the
+// ConfigDrive userdata and metadata that will be stored with the ISO image.
+func CreateCloudInitISO(ctx context.Context, scratchDir, isoPath string,
+	userData, metaData []byte) error {
+	configDrivePath := path.Join(scratchDir, "clr-cloud-init")
+	dataDirPath := path.Join(configDrivePath, "openstack", "latest")
+	metaDataPath := path.Join(dataDirPath, "meta_data.json")
+	userDataPath := path.Join(dataDirPath, "user_data")
+
+	defer func() {
+		_ = os.RemoveAll(configDrivePath)
+	}()
+
+	err := os.MkdirAll(dataDirPath, 0755)
+	if err != nil {
+		return fmt.Errorf("Unable to create config drive directory %s : %v",
+			dataDirPath, err)
+	}
+
+	err = ioutil.WriteFile(metaDataPath, metaData, 0644)
+	if err != nil {
+		return fmt.Errorf("Unable to create %s : %v", metaDataPath, err)
+	}
+
+	err = ioutil.WriteFile(userDataPath, userData, 0644)
+	if err != nil {
+		return fmt.Errorf("Unable to create %s : %v", userDataPath, err)
+	}
+
+	cmd := exec.CommandContext(ctx, "xorriso", "-as", "mkisofs", "-R", "-V", "config-2",
+		"-o", isoPath, configDrivePath)
+	err = cmd.Run()
+	if err != nil {
+		return fmt.Errorf("Unable to create cloudinit iso image %v", err)
+	}
+
+	return nil
+}