podman/pkg/api/handlers/compat/containers_export.go

package compat

import (
	"io/ioutil"
	"net/http"
	"os"

	"github.com/containers/podman/v2/libpod"
	"github.com/containers/podman/v2/pkg/api/handlers/utils"
	"github.com/pkg/errors"
)

func ExportContainer(w http.ResponseWriter, r *http.Request) {
	runtime := r.Context().Value("runtime").(*libpod.Runtime)
	name := utils.GetName(r)
	con, err := runtime.LookupContainer(name)
	if err != nil {
		utils.ContainerNotFound(w, name, err)
		return
	}
	tmpfile, err := ioutil.TempFile("", "api.tar")
	if err != nil {
		utils.Error(w, "unable to create tarball tempfile", http.StatusInternalServerError, errors.Wrap(err, "unable to create tempfile"))
		return
	}
	defer os.Remove(tmpfile.Name())
	if err := tmpfile.Close(); err != nil {
		utils.Error(w, "unable to close tempfile", http.StatusInternalServerError, errors.Wrap(err, "unable to close tempfile"))
		return
	}
	if err := con.Export(tmpfile.Name()); err != nil {
		utils.Error(w, "failed to save the image", http.StatusInternalServerError, errors.Wrap(err, "failed to save image"))
		return
	}
	rdr, err := os.Open(tmpfile.Name())
	if err != nil {
		utils.Error(w, "failed to read temp tarball", http.StatusInternalServerError, errors.Wrap(err, "failed to read the exported tarfile"))
		return
	}
	defer rdr.Close()
	utils.WriteResponse(w, http.StatusOK, rdr)
}