Add support for the unless-stopped restart policy

We initially believed that implementing this required support for
restarting containers after reboot, but this is not the case.
The unless-stopped restart policy acts identically to the always
restart policy except in cases related to reboot (which we do not
support yet), but it does not require that support for us to
implement it.

Changes themselves are quite simple, we need a new restart policy
constant, we need to remove existing checks that block creation
of containers when unless-stopped was used, and we need to update
the manpages.

Fixes #6508

Signed-off-by: Matthew Heon <matthew.heon@pm.me>

6 files changed, 24 insertions, 10 deletions

diff --git a/docs/source/markdown/podman-create.1.md b/docs/source/markdown/podman-create.1.md
index 1da9d72e6..03ac8642f 100644
--- a/docs/source/markdown/podman-create.1.md
+++ b/docs/source/markdown/podman-create.1.md
@@ -676,6 +676,7 @@ Valid values are:
 - `no`                       : Do not restart containers on exit
 - `on-failure[:max_retries]` : Restart containers when they exit with a non-0 exit code, retrying indefinitely or until the optional max_retries count is hit
 - `always`                   : Restart containers when they exit, regardless of status, retrying indefinitely
+- `unless-stopped`           : Identical to **always**
 
 Please note that restart will not restart containers after a system reboot.
 If this functionality is required in your environment, you can invoke Podman from a systemd unit file, or create an init script for whichever init system is in use.
diff --git a/docs/source/markdown/podman-run.1.md b/docs/source/markdown/podman-run.1.md
index 3e1ade047..539e62819 100644
--- a/docs/source/markdown/podman-run.1.md
+++ b/docs/source/markdown/podman-run.1.md
@@ -682,11 +682,10 @@ Restart policy will not take effect if a container is stopped via the **podman k
 
 Valid _policy_ values are:
 
-- **no**: Do not restart containers on exit;
-- **on-failure**[:*max_retries*]: Restart containers when they exit
-with a non-zero exit code, retrying indefinitely or until the optional
-*max_retries* count is hit;
-- **always**: Restart containers when they exit, regardless of status, retrying indefinitely.
+- `no`                       : Do not restart containers on exit
+- `on-failure[:max_retries]` : Restart containers when they exit with a non-zero exit code, retrying indefinitely or until the optional *max_retries* count is hit
+- `always`                   : Restart containers when they exit, regardless of status, retrying indefinitely
+- `unless-stopped`           : Identical to **always**
 
 Please note that restart will not restart containers after a system reboot.
 If this functionality is required in your environment, you can invoke Podman from a **systemd.unit**(5) file, or create an init script for whichever init system is in use.
diff --git a/libpod/container.go b/libpod/container.go
index d4a779b13..20702903e 100644
--- a/libpod/container.go
+++ b/libpod/container.go
@@ -97,6 +97,10 @@ const (
 	// RestartPolicyOnFailure restarts the container on non-0 exit code,
 	// with an optional maximum number of retries.
 	RestartPolicyOnFailure = "on-failure"
+	// RestartPolicyUnlessStopped unconditionally restarts unless stopped
+	// by the user. It is identical to Always except with respect to
+	// handling of system restart, which Podman does not yet support.
+	RestartPolicyUnlessStopped = "unless-stopped"
 )
 
 // Container is a single OCI container.
diff --git a/libpod/options.go b/libpod/options.go
index 5a0f60093..e1c4ddf06 100644
--- a/libpod/options.go
+++ b/libpod/options.go
@@ -1285,7 +1285,7 @@ func WithRestartPolicy(policy string) CtrCreateOption {
 		}
 
 		switch policy {
-		case RestartPolicyNone, RestartPolicyNo, RestartPolicyOnFailure, RestartPolicyAlways:
+		case RestartPolicyNone, RestartPolicyNo, RestartPolicyOnFailure, RestartPolicyAlways, RestartPolicyUnlessStopped:
 			ctr.config.RestartPolicy = policy
 		default:
 			return errors.Wrapf(define.ErrInvalidArg, "%q is not a valid restart policy", policy)
diff --git a/pkg/specgen/generate/container_create.go b/pkg/specgen/generate/container_create.go
index 869601e93..2f7100e7e 100644
--- a/pkg/specgen/generate/container_create.go
+++ b/pkg/specgen/generate/container_create.go
@@ -7,7 +7,6 @@ import (
 
 	"github.com/containers/common/pkg/config"
 	"github.com/containers/libpod/libpod"
-	"github.com/containers/libpod/libpod/define"
 	"github.com/containers/libpod/libpod/image"
 	"github.com/containers/libpod/pkg/specgen"
 	"github.com/containers/libpod/pkg/util"
@@ -251,9 +250,6 @@ func createContainerOptions(ctx context.Context, rt *libpod.Runtime, s *specgen.
 	// Default used if not overridden on command line
 
 	if s.RestartPolicy != "" {
-		if s.RestartPolicy == "unless-stopped" {
-			return nil, errors.Wrapf(define.ErrInvalidArg, "the unless-stopped restart policy is not supported")
-		}
 		if s.RestartRetries != nil {
 			options = append(options, libpod.WithRestartRetries(*s.RestartRetries))
 		}
diff --git a/test/e2e/create_test.go b/test/e2e/create_test.go
index 822e470f2..52ce0b46a 100644
--- a/test/e2e/create_test.go
+++ b/test/e2e/create_test.go
@@ -401,6 +401,20 @@ var _ = Describe("Podman create", func() {
 		Expect(session.ExitCode()).To(Not(Equal(0)))
 	})
 
+	It("podman create with --restart-policy unless-stopped", func() {
+		ctrName := "testctr"
+		unlessStopped := "unless-stopped"
+		session := podmanTest.Podman([]string{"create", "-t", "--restart", unlessStopped, "--name", ctrName, ALPINE, "/bin/sh"})
+		session.WaitWithDefaultTimeout()
+		Expect(session.ExitCode()).To(Equal(0))
+
+		inspect := podmanTest.Podman([]string{"inspect", ctrName})
+		inspect.WaitWithDefaultTimeout()
+		data := inspect.InspectContainerToJSON()
+		Expect(len(data)).To(Equal(1))
+		Expect(data[0].HostConfig.RestartPolicy.Name).To(Equal(unlessStopped))
+	})
+
 	It("podman create with -m 1000000 sets swap to 2000000", func() {
 		numMem := 1000000
 		ctrName := "testCtr"