github.com/stackdocker/rkt@v0.10.1-0.20151109095037-1aa827478248/pkg/aci/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 aci
    16  
    17  import (
    18  	"fmt"
    19  
    20  	"github.com/coreos/rkt/pkg/uid"
    21  
    22  	ptar "github.com/coreos/rkt/pkg/tar"
    23  
    24  	"github.com/coreos/rkt/Godeps/_workspace/src/github.com/appc/spec/pkg/acirenderer"
    25  	"github.com/coreos/rkt/Godeps/_workspace/src/github.com/appc/spec/schema/types"
    26  )
    27  
    28  // Given an imageID, start with the matching image available in the store,
    29  // build its dependency list and render it inside dir
    30  func RenderACIWithImageID(imageID types.Hash, dir string, ap acirenderer.ACIRegistry, uidRange *uid.UidRange) error {
    31  	renderedACI, err := acirenderer.GetRenderedACIWithImageID(imageID, ap)
    32  	if err != nil {
    33  		return err
    34  	}
    35  	return renderImage(renderedACI, dir, ap, uidRange)
    36  }
    37  
    38  // Given an image app name and optional labels, get the best matching image
    39  // available in the store, build its dependency list and render it inside dir
    40  func RenderACI(name types.ACIdentifier, labels types.Labels, dir string, ap acirenderer.ACIRegistry, uidRange *uid.UidRange) error {
    41  	renderedACI, err := acirenderer.GetRenderedACI(name, labels, ap)
    42  	if err != nil {
    43  		return err
    44  	}
    45  	return renderImage(renderedACI, dir, ap, uidRange)
    46  }
    47  
    48  // Given an already populated dependency list, it will extract, under the provided
    49  // directory, the rendered ACI
    50  func RenderACIFromList(imgs acirenderer.Images, dir string, ap acirenderer.ACIProvider, uidRange *uid.UidRange) error {
    51  	renderedACI, err := acirenderer.GetRenderedACIFromList(imgs, ap)
    52  	if err != nil {
    53  		return err
    54  	}
    55  	return renderImage(renderedACI, dir, ap, uidRange)
    56  }
    57  
    58  // Given a RenderedACI, it will extract, under the provided directory, the
    59  // needed files from the right source ACI.
    60  // The manifest will be extracted from the upper ACI.
    61  // No file overwriting is done as it should usually be called
    62  // providing an empty directory.
    63  func renderImage(renderedACI acirenderer.RenderedACI, dir string, ap acirenderer.ACIProvider, uidRange *uid.UidRange) error {
    64  	for _, ra := range renderedACI {
    65  		rs, err := ap.ReadStream(ra.Key)
    66  		if err != nil {
    67  			return err
    68  		}
    69  
    70  		// Overwrite is not needed. If a file needs to be overwritten then the renderedACI builder has a bug
    71  		if err := ptar.ExtractTar(rs, dir, false, uidRange, ra.FileMap); err != nil {
    72  			rs.Close()
    73  			return fmt.Errorf("error extracting ACI: %v", err)
    74  		}
    75  		rs.Close()
    76  	}
    77  
    78  	return nil
    79  }