github.com/stackdocker/rkt@v0.10.1-0.20151109095037-1aa827478248/rkt/image_render.go (about)

     1  // Copyright 2015 The rkt Authors
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package main
    16  
    17  import (
    18  	"encoding/json"
    19  	"io/ioutil"
    20  	"os"
    21  	"path/filepath"
    22  
    23  	"github.com/coreos/rkt/pkg/fileutil"
    24  	"github.com/coreos/rkt/pkg/uid"
    25  	"github.com/coreos/rkt/store"
    26  
    27  	"github.com/coreos/rkt/Godeps/_workspace/src/github.com/spf13/cobra"
    28  )
    29  
    30  var (
    31  	cmdImageRender = &cobra.Command{
    32  		Use:   "render IMAGE OUTPUT_DIR",
    33  		Short: "Render a stored image to a directory with all its dependencies",
    34  		Long:  `IMAGE should be a string referencing an image: either a hash or an image name.`,
    35  		Run:   runWrapper(runImageRender),
    36  	}
    37  	flagRenderRootfsOnly bool
    38  	flagRenderOverwrite  bool
    39  )
    40  
    41  func init() {
    42  	cmdImage.AddCommand(cmdImageRender)
    43  	cmdImageRender.Flags().BoolVar(&flagRenderRootfsOnly, "rootfs-only", false, "render rootfs only")
    44  	cmdImageRender.Flags().BoolVar(&flagRenderOverwrite, "overwrite", false, "overwrite output directory")
    45  }
    46  
    47  func runImageRender(cmd *cobra.Command, args []string) (exit int) {
    48  	if len(args) != 2 {
    49  		cmd.Usage()
    50  		return 1
    51  	}
    52  	outputDir := args[1]
    53  
    54  	s, err := store.NewStore(globalFlags.Dir)
    55  	if err != nil {
    56  		stderr("image render: cannot open store: %v", err)
    57  		return 1
    58  	}
    59  
    60  	key, err := getStoreKeyFromAppOrHash(s, args[0])
    61  	if err != nil {
    62  		stderr("image render: %v", err)
    63  		return 1
    64  	}
    65  
    66  	id, err := s.RenderTreeStore(key, false)
    67  	if err != nil {
    68  		stderr("image render: error rendering ACI: %v", err)
    69  		return 1
    70  	}
    71  	if err := s.CheckTreeStore(id); err != nil {
    72  		stderr("image render: warning: tree cache is in a bad state. Rebuilding...")
    73  		var err error
    74  		if id, err = s.RenderTreeStore(key, true); err != nil {
    75  			stderr("image render: error rendering ACI: %v", err)
    76  			return 1
    77  		}
    78  	}
    79  
    80  	if _, err := os.Stat(outputDir); err == nil {
    81  		if !flagRenderOverwrite {
    82  			stderr("image render: output directory exists (try --overwrite)")
    83  			return 1
    84  		}
    85  
    86  		// don't allow the user to delete the root filesystem by mistake
    87  		if outputDir == "/" {
    88  			stderr("image extract: this would delete your root filesystem. Refusing.")
    89  			return 1
    90  		}
    91  
    92  		if err := os.RemoveAll(outputDir); err != nil {
    93  			stderr("image render: error removing existing output dir: %v", err)
    94  			return 1
    95  		}
    96  	}
    97  	rootfsOutDir := outputDir
    98  	if !flagRenderRootfsOnly {
    99  		if err := os.MkdirAll(outputDir, 0755); err != nil {
   100  			stderr("image render: error creating output directory: %v", err)
   101  			return 1
   102  		}
   103  		rootfsOutDir = filepath.Join(rootfsOutDir, "rootfs")
   104  
   105  		manifest, err := s.GetImageManifest(key)
   106  		if err != nil {
   107  			stderr("image render: error getting manifest: %v", err)
   108  			return 1
   109  		}
   110  
   111  		mb, err := json.Marshal(manifest)
   112  		if err != nil {
   113  			stderr("image render: error marshalling image manifest: %v", err)
   114  			return 1
   115  		}
   116  
   117  		if err := ioutil.WriteFile(filepath.Join(outputDir, "manifest"), mb, 0700); err != nil {
   118  			stderr("image render: error writing image manifest: %v", err)
   119  			return 1
   120  		}
   121  	}
   122  
   123  	cachedTreePath := s.GetTreeStoreRootFS(id)
   124  	if err := fileutil.CopyTree(cachedTreePath, rootfsOutDir, uid.NewBlankUidRange()); err != nil {
   125  		stderr("image render: error copying ACI rootfs: %v", err)
   126  		return 1
   127  	}
   128  
   129  	return 0
   130  }