github.com/coreos/rocket@v1.30.1-0.20200224141603-171c416fac02/rkt/image/finder.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 image
    16  
    17  import (
    18  	"fmt"
    19  
    20  	"github.com/hashicorp/errwrap"
    21  	"github.com/rkt/rkt/common/apps"
    22  
    23  	"github.com/appc/spec/schema/types"
    24  )
    25  
    26  // Finder will try to get images from the store. If not found, it will
    27  // try to fetch them.
    28  type Finder action
    29  
    30  // FindImages uses FindImage to attain a list of image hashes
    31  func (f *Finder) FindImages(al *apps.Apps) error {
    32  	return al.Walk(func(app *apps.App) error {
    33  		h, err := f.FindImage(app.Image, app.Asc)
    34  		if err != nil {
    35  			return err
    36  		}
    37  		app.ImageID = *h
    38  		return nil
    39  	})
    40  }
    41  
    42  // FindImage tries to get a hash of a passed image, ideally from
    43  // store. Otherwise this might involve fetching it from remote with
    44  // the Fetcher.
    45  func (f *Finder) FindImage(img string, asc string) (*types.Hash, error) {
    46  	ensureLogger(f.Debug)
    47  
    48  	// Check if it's an hash
    49  	if _, err := types.NewHash(img); err == nil {
    50  		h, err := f.getHashFromStore(img)
    51  		if err != nil {
    52  			return nil, err
    53  		}
    54  		return h, nil
    55  	}
    56  
    57  	d, err := DistFromImageString(img)
    58  	if err != nil {
    59  		return nil, err
    60  	}
    61  
    62  	// urls, names, paths have to be fetched, potentially remotely
    63  	ft := (*Fetcher)(f)
    64  	h, err := ft.FetchImage(d, img, asc)
    65  	if err != nil {
    66  		return nil, err
    67  	}
    68  	return h, nil
    69  }
    70  
    71  func (f *Finder) getHashFromStore(img string) (*types.Hash, error) {
    72  	h, err := types.NewHash(img)
    73  	if err != nil {
    74  		return nil, errwrap.Wrap(fmt.Errorf("%q is not a valid hash", img), err)
    75  	}
    76  	fullKey, err := f.S.ResolveKey(img)
    77  	if err != nil {
    78  		return nil, errwrap.Wrap(fmt.Errorf("could not resolve image %q", img), err)
    79  	}
    80  	h, err = types.NewHash(fullKey)
    81  	if err != nil {
    82  		// should never happen
    83  		log.PanicE("got an invalid hash from the store, looks like it is corrupted", err)
    84  	}
    85  	diag.Printf("using image from the store with hash %s", h.String())
    86  	return h, nil
    87  }