container-{create,run}: add `--pod-id-file`

Allow containers to join an existing pod via the `--pod-id-file` which
is already supported by a number of `podman-pod` subcommands.  Also add
tests to make sure it's working and to prevent future regressions.

Signed-off-by: Valentin Rothberg <rothberg@redhat.com>

cmd/podman/common/create.go

@@ -338,6 +338,11 @@ func GetCreateFlags(cf *ContainerCLIOpts) *pflag.FlagSet {
 		"pod", "",
 		"Run container in an existing pod",
 	)
+	createFlags.StringVar(
+		&cf.PodIDFile,
+		"pod-id-file", "",
+		"Read the pod ID from the file",
+	)
 	createFlags.BoolVar(
 		&cf.Privileged,
 		"privileged", false,

cmd/podman/common/create_opts.go

@@ -68,6 +68,7 @@ type ContainerCLIOpts struct {
 	PID               string
 	PIDsLimit         int64
 	Pod               string
+	PodIDFile         string
 	Privileged        bool
 	PublishAll        bool
 	Pull              string

cmd/podman/common/specgen.go

@@ -254,6 +254,17 @@ func FillOutSpecGen(s *specgen.SpecGenerator, c *ContainerCLIOpts, args []string
 	s.PublishExposedPorts = c.PublishAll
 	s.Pod = c.Pod
 
+	if len(c.PodIDFile) > 0 {
+		if len(s.Pod) > 0 {
+			return errors.New("Cannot specify both --pod and --pod-id-file")
+		}
+		podID, err := ReadPodIDFile(c.PodIDFile)
+		if err != nil {
+			return err
+		}
+		s.Pod = podID
+	}
+
 	expose, err := createExpose(c.Expose)
 	if err != nil {
 		return err

cmd/podman/common/util.go

@@ -1,6 +1,7 @@
 package common
 
 import (
+	"io/ioutil"
 	"net"
 	"strconv"
 	"strings"
@@ -10,6 +11,30 @@ import (
 	"github.com/sirupsen/logrus"
 )
 
+// ReadPodIDFile reads the specified file and returns its content (i.e., first
+// line).
+func ReadPodIDFile(path string) (string, error) {
+	content, err := ioutil.ReadFile(path)
+	if err != nil {
+		return "", errors.Wrap(err, "error reading pod ID file")
+	}
+	return strings.Split(string(content), "\n")[0], nil
+}
+
+// ReadPodIDFiles reads the specified files and returns their content (i.e.,
+// first line).
+func ReadPodIDFiles(files []string) ([]string, error) {
+	ids := []string{}
+	for _, file := range files {
+		id, err := ReadPodIDFile(file)
+		if err != nil {
+			return nil, err
+		}
+		ids = append(ids, id)
+	}
+	return ids, nil
+}
+
 // createExpose parses user-provided exposed port definitions and converts them
 // into SpecGen format.
 // TODO: The SpecGen format should really handle ranges more sanely - we could

cmd/podman/pods/common.go

@@ -1,23 +0,0 @@
-package pods
-
-import (
-	"io/ioutil"
-	"strings"
-
-	"github.com/pkg/errors"
-)
-
-// readPodIDFiles reads the specified files and returns their content (i.e.,
-// first line).
-func readPodIDFiles(files []string) ([]string, error) {
-	ids := []string{}
-	for _, podFile := range files {
-		content, err := ioutil.ReadFile(podFile)
-		if err != nil {
-			return nil, errors.Wrap(err, "error reading pod ID file")
-		}
-		id := strings.Split(string(content), "\n")[0]
-		ids = append(ids, id)
-	}
-	return ids, nil
-}

cmd/podman/pods/rm.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"fmt"
 
+	"github.com/containers/libpod/cmd/podman/common"
 	"github.com/containers/libpod/cmd/podman/parse"
 	"github.com/containers/libpod/cmd/podman/registry"
 	"github.com/containers/libpod/cmd/podman/utils"
@@ -61,7 +62,7 @@ func rm(cmd *cobra.Command, args []string) error {
 		errs utils.OutputErrors
 	)
 
-	ids, err := readPodIDFiles(rmOptions.PodIDFiles)
+	ids, err := common.ReadPodIDFiles(rmOptions.PodIDFiles)
 	if err != nil {
 		return err
 	}

cmd/podman/pods/start.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"fmt"
 
+	"github.com/containers/libpod/cmd/podman/common"
 	"github.com/containers/libpod/cmd/podman/parse"
 	"github.com/containers/libpod/cmd/podman/registry"
 	"github.com/containers/libpod/cmd/podman/utils"
@@ -61,7 +62,7 @@ func start(cmd *cobra.Command, args []string) error {
 		errs utils.OutputErrors
 	)
 
-	ids, err := readPodIDFiles(startOptions.PodIDFiles)
+	ids, err := common.ReadPodIDFiles(startOptions.PodIDFiles)
 	if err != nil {
 		return err
 	}

cmd/podman/pods/stop.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"fmt"
 
+	"github.com/containers/libpod/cmd/podman/common"
 	"github.com/containers/libpod/cmd/podman/parse"
 	"github.com/containers/libpod/cmd/podman/registry"
 	"github.com/containers/libpod/cmd/podman/utils"
@@ -68,7 +69,7 @@ func stop(cmd *cobra.Command, args []string) error {
 		stopOptions.Timeout = int(stopOptions.TimeoutCLI)
 	}
 
-	ids, err := readPodIDFiles(stopOptions.PodIDFiles)
+	ids, err := common.ReadPodIDFiles(stopOptions.PodIDFiles)
 	if err != nil {
 		return err
 	}

completions/bash/podman

@@ -2102,6 +2102,7 @@ _podman_container_run() {
 		--pid
 		--pids-limit
 		--pod
+		--pod-id-file
 		--publish -p
 		--pull
 		--runtime
@@ -2206,7 +2207,7 @@ _podman_container_run() {
 			__podman_complete_capabilities
 			return
 			;;
-		--cidfile|--env-file|--init-path|--label-file)
+		--cidfile|--env-file|--init-path|--label-file|--pod-id-file)
 			_filedir
 			return
 			;;

docs/source/markdown/podman-create.1.md

@@ -593,6 +593,10 @@ Tune the container's pids limit. Set `0` to have unlimited pids for the containe
 Run container in an existing pod. If you want Podman to make the pod for you, preference the pod name with `new:`.
 To make a pod with more granular options, use the `podman pod create` command before creating a container.
 
+**--pod-id-file**=*path*
+
+Run container in an existing pod and read the pod's ID from the specified file.  If a container is run with a pod, and the pod has an infra-container, the infra-container will be started before the container is.
+
 **--privileged**=*true|false*
 
 Give extended privileges to this container. The default is *false*.

docs/source/markdown/podman-run.1.md

@@ -605,6 +605,10 @@ Run container in an existing pod. If you want Podman to make the pod for you, pr
 To make a pod with more granular options, use the **podman pod create** command before creating a container.
 If a container is run with a pod, and the pod has an infra-container, the infra-container will be started before the container is.
 
+**--pod-id-file**=*path*
+
+Run container in an existing pod and read the pod's ID from the specified file.  If a container is run with a pod, and the pod has an infra-container, the infra-container will be started before the container is.
+
 **--privileged**=**true**|**false**
 
 Give extended privileges to this container. The default is **false**.

test/e2e/create_test.go

@@ -2,6 +2,7 @@ package integration
 
 import (
 	"fmt"
+	"io/ioutil"
 	"os"
 	"path/filepath"
 
@@ -221,6 +222,42 @@ var _ = Describe("Podman create", func() {
 		Expect(match).To(BeTrue())
 	})
 
+	It("podman create --pod-id-file", func() {
+		// First, make sure that --pod and --pod-id-file yield an error
+		// if used together.
+		session := podmanTest.Podman([]string{"create", "--pod", "foo", "--pod-id-file", "bar", ALPINE, "ls"})
+		session.WaitWithDefaultTimeout()
+		Expect(session.ExitCode()).To(Equal(125))
+
+		tmpDir, err := ioutil.TempDir("", "")
+		Expect(err).To(BeNil())
+		defer os.RemoveAll(tmpDir)
+
+		podName := "rudoplh"
+		ctrName := "prancer"
+		podIDFile := tmpDir + "pod-id-file"
+
+		// Now, let's create a pod with --pod-id-file.
+		session = podmanTest.Podman([]string{"pod", "create", "--pod-id-file", podIDFile, "--name", podName})
+		session.WaitWithDefaultTimeout()
+		Expect(session.ExitCode()).To(Equal(0))
+
+		session = podmanTest.Podman([]string{"pod", "inspect", podName})
+		session.WaitWithDefaultTimeout()
+		Expect(session.ExitCode()).To(Equal(0))
+		Expect(session.IsJSONOutputValid()).To(BeTrue())
+		podData := session.InspectPodToJSON()
+
+		// Finally we can create a container with --pod-id-file and do
+		// some checks to make sure it's working as expected.
+		session = podmanTest.Podman([]string{"create", "--pod-id-file", podIDFile, "--name", ctrName, ALPINE, "top"})
+		session.WaitWithDefaultTimeout()
+		Expect(session.ExitCode()).To(Equal(0))
+
+		ctrJSON := podmanTest.InspectContainer(ctrName)
+		Expect(podData.ID).To(Equal(ctrJSON[0].Pod)) // Make sure the container's pod matches the pod's ID
+	})
+
 	It("podman run entrypoint and cmd test", func() {
 		name := "test101"
 		create := podmanTest.Podman([]string{"create", "--name", name, redis})