Simplify Docker test infrastructure.

This change adds a layer of abstraction around the internal Docker APIs,
and eliminates all direct dependencies on Dockerfiles in the infrastructure.

A subsequent change will automated the generation of local images (with
efficient caching). Note that this change drops the use of bazel container
rules, as that experiment does not seem to be viable.

PiperOrigin-RevId: 308095430

1 files changed, 185 insertions, 0 deletions

diff --git a/test/cmd/test_app/fds.go b/test/cmd/test_app/fds.go
new file mode 100644
index 000000000..a7658eefd
--- /dev/null
+++ b/test/cmd/test_app/fds.go
@@ -0,0 +1,185 @@
+// Copyright 2019 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package main
+
+import (
+	"context"
+	"io/ioutil"
+	"log"
+	"os"
+	"time"
+
+	"github.com/google/subcommands"
+	"gvisor.dev/gvisor/pkg/test/testutil"
+	"gvisor.dev/gvisor/pkg/unet"
+	"gvisor.dev/gvisor/runsc/flag"
+)
+
+const fileContents = "foobarbaz"
+
+// fdSender will open a file and send the FD over a unix domain socket.
+type fdSender struct {
+	socketPath string
+}
+
+// Name implements subcommands.Command.Name.
+func (*fdSender) Name() string {
+	return "fd_sender"
+}
+
+// Synopsis implements subcommands.Command.Synopsys.
+func (*fdSender) Synopsis() string {
+	return "creates a file and sends the FD over the socket"
+}
+
+// Usage implements subcommands.Command.Usage.
+func (*fdSender) Usage() string {
+	return "fd_sender <flags>"
+}
+
+// SetFlags implements subcommands.Command.SetFlags.
+func (fds *fdSender) SetFlags(f *flag.FlagSet) {
+	f.StringVar(&fds.socketPath, "socket", "", "path to socket")
+}
+
+// Execute implements subcommands.Command.Execute.
+func (fds *fdSender) Execute(ctx context.Context, f *flag.FlagSet, args ...interface{}) subcommands.ExitStatus {
+	if fds.socketPath == "" {
+		log.Fatalf("socket flag must be set")
+	}
+
+	dir, err := ioutil.TempDir("", "")
+	if err != nil {
+		log.Fatalf("TempDir failed: %v", err)
+	}
+
+	fileToSend, err := ioutil.TempFile(dir, "")
+	if err != nil {
+		log.Fatalf("TempFile failed: %v", err)
+	}
+	defer fileToSend.Close()
+
+	if _, err := fileToSend.WriteString(fileContents); err != nil {
+		log.Fatalf("Write(%q) failed: %v", fileContents, err)
+	}
+
+	// Receiver may not be started yet, so try connecting in a poll loop.
+	var s *unet.Socket
+	if err := testutil.Poll(func() error {
+		var err error
+		s, err = unet.Connect(fds.socketPath, true /* SEQPACKET, so we can send empty message with FD */)
+		return err
+	}, 10*time.Second); err != nil {
+		log.Fatalf("Error connecting to socket %q: %v", fds.socketPath, err)
+	}
+	defer s.Close()
+
+	w := s.Writer(true)
+	w.ControlMessage.PackFDs(int(fileToSend.Fd()))
+	if _, err := w.WriteVec([][]byte{[]byte{'a'}}); err != nil {
+		log.Fatalf("Error sending FD %q over socket %q: %v", fileToSend.Fd(), fds.socketPath, err)
+	}
+
+	log.Print("FD SENDER exiting successfully")
+	return subcommands.ExitSuccess
+}
+
+// fdReceiver receives an FD from a unix domain socket and does things to it.
+type fdReceiver struct {
+	socketPath string
+}
+
+// Name implements subcommands.Command.Name.
+func (*fdReceiver) Name() string {
+	return "fd_receiver"
+}
+
+// Synopsis implements subcommands.Command.Synopsys.
+func (*fdReceiver) Synopsis() string {
+	return "reads an FD from a unix socket, and then does things to it"
+}
+
+// Usage implements subcommands.Command.Usage.
+func (*fdReceiver) Usage() string {
+	return "fd_receiver <flags>"
+}
+
+// SetFlags implements subcommands.Command.SetFlags.
+func (fdr *fdReceiver) SetFlags(f *flag.FlagSet) {
+	f.StringVar(&fdr.socketPath, "socket", "", "path to socket")
+}
+
+// Execute implements subcommands.Command.Execute.
+func (fdr *fdReceiver) Execute(ctx context.Context, f *flag.FlagSet, args ...interface{}) subcommands.ExitStatus {
+	if fdr.socketPath == "" {
+		log.Fatalf("Flags cannot be empty, given: socket: %q", fdr.socketPath)
+	}
+
+	ss, err := unet.BindAndListen(fdr.socketPath, true /* packet */)
+	if err != nil {
+		log.Fatalf("BindAndListen(%q) failed: %v", fdr.socketPath, err)
+	}
+	defer ss.Close()
+
+	var s *unet.Socket
+	c := make(chan error, 1)
+	go func() {
+		var err error
+		s, err = ss.Accept()
+		c <- err
+	}()
+
+	select {
+	case err := <-c:
+		if err != nil {
+			log.Fatalf("Accept() failed: %v", err)
+		}
+	case <-time.After(10 * time.Second):
+		log.Fatalf("Timeout waiting for accept")
+	}
+
+	r := s.Reader(true)
+	r.EnableFDs(1)
+	b := [][]byte{{'a'}}
+	if n, err := r.ReadVec(b); n != 1 || err != nil {
+		log.Fatalf("ReadVec got n=%d err %v (wanted 0, nil)", n, err)
+	}
+
+	fds, err := r.ExtractFDs()
+	if err != nil {
+		log.Fatalf("ExtractFD() got err %v", err)
+	}
+	if len(fds) != 1 {
+		log.Fatalf("ExtractFD() got %d FDs, wanted 1", len(fds))
+	}
+	fd := fds[0]
+
+	file := os.NewFile(uintptr(fd), "received file")
+	defer file.Close()
+	if _, err := file.Seek(0, os.SEEK_SET); err != nil {
+		log.Fatalf("Seek(0, 0) failed: %v", err)
+	}
+
+	got, err := ioutil.ReadAll(file)
+	if err != nil {
+		log.Fatalf("ReadAll failed: %v", err)
+	}
+	if string(got) != fileContents {
+		log.Fatalf("ReadAll got %q want %q", string(got), fileContents)
+	}
+
+	log.Print("FD RECEIVER exiting successfully")
+	return subcommands.ExitSuccess
+}