github.com/jdhenke/godel@v0.0.0-20161213181855-abeb3861bf0d/cmd/godel/tgz.go (about)

     1  // Copyright 2016 Palantir Technologies, Inc.
     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 godel
    16  
    17  import (
    18  	"archive/tar"
    19  	"compress/gzip"
    20  	"io"
    21  	"os"
    22  	"path"
    23  	"sort"
    24  	"strings"
    25  
    26  	"github.com/pkg/errors"
    27  
    28  	"github.com/palantir/godel/layout"
    29  )
    30  
    31  func verifyPackageTgz(tgzFile string) (string, error) {
    32  	entries, err := getPathsInTgz(tgzFile)
    33  	if err != nil {
    34  		return "", errors.Wrapf(err, "failed to get directories in tgz file %s", tgzFile)
    35  	}
    36  	actualPaths := sortedKeys(entries)
    37  	version, err := versionFromEntries(actualPaths)
    38  	if err != nil {
    39  		return "", errors.Wrapf(err, "could not determine version from tgz file entries")
    40  	}
    41  
    42  	expectedPaths := layout.AppSpec().Paths(layout.AppSpecTemplate(version), false)
    43  	for _, currExpectedPath := range expectedPaths {
    44  		if _, ok := entries[currExpectedPath]; !ok {
    45  			return "", errors.Errorf("tgz %s does not contain a valid package: failed to find %s.\nRequired: %v\nActual:   %v", tgzFile, currExpectedPath, expectedPaths, actualPaths)
    46  		}
    47  	}
    48  
    49  	return version, nil
    50  }
    51  
    52  func versionFromEntries(sortedEntries []string) (string, error) {
    53  	dirEntry := sortedEntries[0]
    54  	expectedPrefix := layout.AppName + "-"
    55  	if !strings.HasPrefix(dirEntry, expectedPrefix) {
    56  		return "", errors.Errorf("entry %s in %v did not have expected prefix %s", dirEntry, sortedEntries, expectedPrefix)
    57  	}
    58  	return dirEntry[len(expectedPrefix):], nil
    59  }
    60  
    61  // getPathsInTgz returns a map that contains the paths to the entries present in the specified tgz file. The returned
    62  // map will also contain subdirectories as independent entries -- that is, if the archive contains
    63  // "root/intermediate/leaf.txt", the returned map will have "root", "root/intermediate" and "root/intermediate/leaf.txt"
    64  // as entries.
    65  func getPathsInTgz(tgzFile string) (rPaths map[string]bool, rErr error) {
    66  	file, err := os.Open(tgzFile)
    67  	if err != nil {
    68  		return nil, errors.Wrapf(err, "failed to open file %s", tgzFile)
    69  	}
    70  	defer func() {
    71  		if err := file.Close(); err != nil && rErr == nil {
    72  			rErr = errors.Wrapf(err, "failed to close file %s in defer", tgzFile)
    73  		}
    74  	}()
    75  
    76  	gzf, err := gzip.NewReader(file)
    77  	if err != nil {
    78  		return nil, errors.Wrapf(err, "failed to create gzip reader for file %s", tgzFile)
    79  	}
    80  
    81  	tarReader := tar.NewReader(gzf)
    82  	dirs := make(map[string]bool)
    83  	for {
    84  		header, err := tarReader.Next()
    85  		if err == io.EOF {
    86  			break
    87  		} else if err != nil {
    88  			return nil, errors.Wrapf(err, "failed to read entry in file %s", tgzFile)
    89  		}
    90  
    91  		switch header.Typeflag {
    92  		case tar.TypeDir:
    93  			dirs[path.Dir(header.Name)] = true
    94  		case tar.TypeReg:
    95  			dirs[header.Name] = true
    96  		default:
    97  		}
    98  	}
    99  	return dirs, nil
   100  }
   101  
   102  func sortedKeys(input map[string]bool) []string {
   103  	output := make([]string, 0, len(input))
   104  	for key := range input {
   105  		output = append(output, key)
   106  	}
   107  	sort.Strings(output)
   108  	return output
   109  }