github.com/uber/kraken@v0.1.4/tools/lib/image/image.go (about)

     1  // Copyright (c) 2016-2019 Uber 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  package image
    15  
    16  import (
    17  	"bytes"
    18  	"fmt"
    19  	"io"
    20  	"io/ioutil"
    21  	"log"
    22  	"math/rand"
    23  	"os"
    24  	"os/exec"
    25  	"path/filepath"
    26  	"strings"
    27  	"time"
    28  )
    29  
    30  func run(name string, args ...string) error {
    31  	stderr := new(bytes.Buffer)
    32  	cmd := exec.Command(name, args...)
    33  	cmd.Stdout = os.Stdout
    34  	cmd.Stderr = stderr
    35  	if err := cmd.Run(); err != nil {
    36  		return fmt.Errorf("exec `%s`: %s, stderr:\n%s",
    37  			strings.Join(cmd.Args, " "), err, stderr.String())
    38  	}
    39  	return nil
    40  }
    41  
    42  // Generate creates a random image.
    43  func Generate(size uint64, numLayers int) (name string, err error) {
    44  	dir, err := ioutil.TempDir("", "")
    45  	if err != nil {
    46  		return "", fmt.Errorf("temp dir: %s", err)
    47  	}
    48  	defer os.RemoveAll(dir)
    49  
    50  	name = fmt.Sprintf("kraken-test-image-%s", filepath.Base(dir))
    51  
    52  	dockerfile, err := os.Create(fmt.Sprintf("%s/Dockerfile", dir))
    53  	if err != nil {
    54  		return "", fmt.Errorf("create dockerfile: %s", err)
    55  	}
    56  	log.Printf("Generating dockerfile %s", dockerfile.Name())
    57  
    58  	if _, err := fmt.Fprintln(dockerfile, "FROM scratch"); err != nil {
    59  		return "", fmt.Errorf("fprint dockerfile: %s", err)
    60  	}
    61  
    62  	layerSize := size / uint64(numLayers)
    63  	for i := 0; i < numLayers; i++ {
    64  		f, err := os.Create(fmt.Sprintf("%s/file_%d", dir, i))
    65  		if err != nil {
    66  			return "", fmt.Errorf("create file: %s", err)
    67  		}
    68  		r := io.LimitReader(rand.New(rand.NewSource(time.Now().Unix())), int64(layerSize))
    69  		if _, err := io.Copy(f, r); err != nil {
    70  			return "", fmt.Errorf("copy rand: %s", err)
    71  		}
    72  		layerName := filepath.Base(f.Name())
    73  		if _, err := fmt.Fprintf(dockerfile, "COPY %s /\n", layerName); err != nil {
    74  			return "", fmt.Errorf("fprint dockerfile: %s", err)
    75  		}
    76  	}
    77  
    78  	if err := run("sudo", "docker", "build", "-t", name, dir); err != nil {
    79  		return "", err
    80  	}
    81  	return name + ":latest", nil
    82  }
    83  
    84  // Push pushes an image to a Kraken proxy.
    85  func Push(name string, proxy string) error {
    86  	proxyName := proxy + "/" + name
    87  	log.Printf("Pushing %s to %s", name, proxyName)
    88  	if err := run("sudo", "docker", "tag", name, proxyName); err != nil {
    89  		return err
    90  	}
    91  	return run("sudo", "docker", "push", proxyName)
    92  }