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@ricardobranco777
Last active April 3, 2024 06:42
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Copy file from Docker image to standard output
package main
import (
"archive/tar"
"fmt"
"io"
"io/ioutil"
"os"
"github.com/docker/docker/api/types"
"github.com/docker/docker/api/types/container"
"github.com/docker/docker/client"
"golang.org/x/net/context"
)
func main() {
if len(os.Args) != 3 {
fmt.Fprintf(os.Stderr, "Usage: %s IMAGE FILE\n", os.Args[0])
os.Exit(1)
}
imageName := os.Args[1]
filePath := os.Args[2]
ctx := context.Background()
cli, err := client.NewEnvClient()
if err != nil {
panic(err)
}
out, err := cli.ImagePull(ctx, imageName, types.ImagePullOptions{})
if err != nil {
panic(err)
}
defer out.Close()
if _, err := ioutil.ReadAll(out); err != nil {
panic(err)
}
info, err := cli.ContainerCreate(ctx, &container.Config{
Image: imageName,
}, nil, nil, "")
if err != nil {
panic(err)
}
tarStream, _, err := cli.CopyFromContainer(ctx, info.ID, filePath)
if err != nil {
panic(err)
}
tr := tar.NewReader(tarStream)
if _, err := tr.Next(); err != nil {
panic(err)
}
io.Copy(os.Stdout, tr)
if err := cli.ContainerRemove(ctx, info.ID, types.ContainerRemoveOptions{}); err != nil {
panic(err)
}
}
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