add podman volume reload to sync volume plugins

Libpod requires that all volumes are stored in the libpod db. Because
volume plugins can be created outside of podman, it will not show all
available plugins. This podman volume reload command allows users to
sync the libpod db with their external volume plugins. All new volumes
from the plugin are also created in the libpod db and when a volume from
the db no longer exists it will be removed if possible.

There are some problems:
- naming conflicts, in this case we only use the first volume we found.
  This is not deterministic.
- race conditions, we have no control over the volume plugins. It is
  possible that the volumes changed while we run this command.

Fixes #14207

Signed-off-by: Paul Holzinger <pholzing@redhat.com>

2 files changed, 69 insertions, 1 deletions

diff --git a/test/e2e/config.go b/test/e2e/config.go
index 2ca8e2a15..fbcc9dfff 100644
--- a/test/e2e/config.go
+++ b/test/e2e/config.go
@@ -15,7 +15,7 @@ var (
 	healthcheck       = "quay.io/libpod/alpine_healthcheck:latest"
 	ImageCacheDir     = "/tmp/podman/imagecachedir"
 	fedoraToolbox     = "registry.fedoraproject.org/fedora-toolbox:36"
-	volumeTest        = "quay.io/libpod/volume-plugin-test-img:latest"
+	volumeTest        = "quay.io/libpod/volume-plugin-test-img:20220623"
 
 	// This image has seccomp profiles that blocks all syscalls.
 	// The intention behind blocking all syscalls is to prevent
diff --git a/test/e2e/volume_plugin_test.go b/test/e2e/volume_plugin_test.go
index 4700afdb5..b585f8dd8 100644
--- a/test/e2e/volume_plugin_test.go
+++ b/test/e2e/volume_plugin_test.go
@@ -6,6 +6,7 @@ import (
 	"path/filepath"
 
 	. "github.com/containers/podman/v4/test/utils"
+	"github.com/containers/storage/pkg/stringid"
 	. "github.com/onsi/ginkgo"
 	. "github.com/onsi/gomega"
 	. "github.com/onsi/gomega/gexec"
@@ -188,4 +189,71 @@ var _ = Describe("Podman volume plugins", func() {
 		rmAll.WaitWithDefaultTimeout()
 		Expect(rmAll).Should(Exit(0))
 	})
+
+	It("podman volume reload", func() {
+		podmanTest.AddImageToRWStore(volumeTest)
+
+		confFile := filepath.Join(podmanTest.TempDir, "containers.conf")
+		err := os.WriteFile(confFile, []byte(`[engine]
+[engine.volume_plugins]
+testvol5 = "/run/docker/plugins/testvol5.sock"`), 0o644)
+		Expect(err).ToNot(HaveOccurred())
+		os.Setenv("CONTAINERS_CONF", confFile)
+
+		pluginStatePath := filepath.Join(podmanTest.TempDir, "volumes")
+		err = os.Mkdir(pluginStatePath, 0755)
+		Expect(err).ToNot(HaveOccurred())
+
+		// Keep this distinct within tests to avoid multiple tests using the same plugin.
+		pluginName := "testvol5"
+		ctrName := "pluginCtr"
+		plugin := podmanTest.Podman([]string{"run", "--name", ctrName, "--security-opt", "label=disable", "-v", "/run/docker/plugins:/run/docker/plugins",
+			"-v", fmt.Sprintf("%v:%v", pluginStatePath, pluginStatePath), "-d", volumeTest, "--sock-name", pluginName, "--path", pluginStatePath})
+		plugin.WaitWithDefaultTimeout()
+		Expect(plugin).Should(Exit(0))
+
+		localvol := "local-" + stringid.GenerateNonCryptoID()
+		// create local volume
+		session := podmanTest.Podman([]string{"volume", "create", localvol})
+		session.WaitWithDefaultTimeout()
+		Expect(session).To(Exit(0))
+
+		vol1 := "vol1-" + stringid.GenerateNonCryptoID()
+		session = podmanTest.Podman([]string{"volume", "create", "--driver", pluginName, vol1})
+		session.WaitWithDefaultTimeout()
+		Expect(session).To(Exit(0))
+
+		// now create volume in plugin without podman
+		vol2 := "vol2-" + stringid.GenerateNonCryptoID()
+		plugin = podmanTest.Podman([]string{"exec", ctrName, "/usr/local/bin/testvol", "--sock-name", pluginName, "create", vol2})
+		plugin.WaitWithDefaultTimeout()
+		Expect(plugin).Should(Exit(0))
+
+		session = podmanTest.Podman([]string{"volume", "ls", "-q"})
+		session.WaitWithDefaultTimeout()
+		Expect(session).To(Exit(0))
+		Expect(session.OutputToStringArray()).To(ContainElements(localvol, vol1))
+		Expect(session.ErrorToString()).To(Equal("")) // make sure no errors are shown
+
+		plugin = podmanTest.Podman([]string{"exec", ctrName, "/usr/local/bin/testvol", "--sock-name", pluginName, "remove", vol1})
+		plugin.WaitWithDefaultTimeout()
+		Expect(plugin).Should(Exit(0))
+
+		// now reload volumes from plugins
+		session = podmanTest.Podman([]string{"volume", "reload"})
+		session.WaitWithDefaultTimeout()
+		Expect(session).To(Exit(0))
+		Expect(string(session.Out.Contents())).To(Equal(fmt.Sprintf(`Added:
+%s
+Removed:
+%s
+`, vol2, vol1)))
+		Expect(session.ErrorToString()).To(Equal("")) // make sure no errors are shown
+
+		session = podmanTest.Podman([]string{"volume", "ls", "-q"})
+		session.WaitWithDefaultTimeout()
+		Expect(session).To(Exit(0))
+		Expect(session.OutputToStringArray()).To(ContainElements(localvol, vol2))
+		Expect(session.ErrorToString()).To(Equal("")) // make no errors are shown
+	})
 })