Merge pull request #1333 from vrothberg/RUN-1772

containers.conf: add database backend option

pkg/config/config.go

@@ -251,6 +251,9 @@ type EngineConfig struct {
 	// in containers-registries.conf(5).
 	CompatAPIEnforceDockerHub bool `toml:"compat_api_enforce_docker_hub,omitempty"`
 
+	// DBBackend is the database backend to be used by Podman.
+	DBBackend string `toml:"database_backend,omitempty"`
+
 	// DetachKeys is the sequence of keys used to detach a container.
 	DetachKeys string `toml:"detach_keys,omitempty"`
 
@@ -898,6 +901,11 @@ func (c *EngineConfig) Validate() error {
 	if _, err := ValidatePullPolicy(pullPolicy); err != nil {
 		return fmt.Errorf("invalid pull type from containers.conf %q: %w", c.PullPolicy, err)
 	}
+
+	if _, err := ParseDBBackend(c.DBBackend); err != nil {
+		return err
+	}
+
 	return nil
 }
 

pkg/config/config_test.go

@@ -37,6 +37,11 @@ var _ = Describe("Config", func() {
 			gomega.Expect(defaultConfig.Engine.ImageVolumeMode).To(gomega.BeEquivalentTo("bind"))
 			gomega.Expect(defaultConfig.Engine.SSHConfig).To(gomega.ContainSubstring("/.ssh/config"))
 			gomega.Expect(defaultConfig.Engine.EventsContainerCreateInspectData).To(gomega.BeFalse())
+			gomega.Expect(defaultConfig.Engine.DBBackend).To(gomega.BeEquivalentTo(stringBoltDB))
+
+			dbBackend, err := defaultConfig.DBBackend()
+			gomega.Expect(dbBackend).To(gomega.BeEquivalentTo(DBBackendBoltDB))
+			gomega.Expect(err).To(gomega.BeNil())
 			path, err := defaultConfig.ImageCopyTmpDir()
 			gomega.Expect(err).To(gomega.BeNil())
 			gomega.Expect(path).To(gomega.BeEquivalentTo("/var/tmp"))
@@ -410,6 +415,11 @@ image_copy_tmp_dir="storage"`
 			gomega.Expect(config.Containers.HostContainersInternalIP).To(gomega.BeEquivalentTo("1.2.3.4"))
 			gomega.Expect(config.Engine.ImageVolumeMode).To(gomega.BeEquivalentTo("tmpfs"))
 			gomega.Expect(config.Engine.SSHConfig).To(gomega.Equal("/foo/bar/.ssh/config"))
+
+			gomega.Expect(config.Engine.DBBackend).To(gomega.Equal(stringSQLite))
+			dbBackend, err := config.DBBackend()
+			gomega.Expect(err).To(gomega.BeNil())
+			gomega.Expect(dbBackend).To(gomega.BeEquivalentTo(DBBackendSQLite))
 		})
 
 		It("contents of passed-in file should override others", func() {
@@ -553,6 +563,12 @@ image_copy_tmp_dir="storage"`
 			err := sut.Engine.Validate()
 			gomega.Expect(err).ToNot(gomega.BeNil())
 		})
+
+		It("should fail with invalid database_backend", func() {
+			sut.Engine.DBBackend = ""
+			err := sut.Engine.Validate()
+			gomega.Expect(err).ToNot(gomega.BeNil())
+		})
 	})
 
 	Describe("Service Destinations", func() {

pkg/config/db_backend.go

@@ -0,0 +1,60 @@
+package config
+
+import "fmt"
+
+// DBBackend determines which supported database backend Podman should use.
+type DBBackend int
+
+const (
+	// Unsupported database backend.  Used as a sane base value for the type.
+	DBBackendUnsupported DBBackend = iota
+	// BoltDB backend.
+	DBBackendBoltDB
+	// SQLite backend.
+	DBBackendSQLite
+
+	stringBoltDB = "boltdb"
+	stringSQLite = "sqlite"
+)
+
+// String returns the DBBackend's string representation.
+func (d DBBackend) String() string {
+	switch d {
+	case DBBackendBoltDB:
+		return stringBoltDB
+	case DBBackendSQLite:
+		return stringSQLite
+	default:
+		return fmt.Sprintf("unsupported database backend: %d", d)
+	}
+}
+
+// Validate returns whether the DBBackend is supported.
+func (d DBBackend) Validate() error {
+	switch d {
+	case DBBackendBoltDB, DBBackendSQLite:
+		return nil
+	default:
+		return fmt.Errorf("unsupported database backend: %d", d)
+	}
+}
+
+// ParseDBBackend parses the specified string into a DBBackend.
+// An error is return for unsupported backends.
+func ParseDBBackend(raw string) (DBBackend, error) {
+	// NOTE: this function should be used for parsing the user-specified
+	// values on Podman's CLI.
+	switch raw {
+	case stringBoltDB:
+		return DBBackendBoltDB, nil
+	case stringSQLite:
+		return DBBackendSQLite, nil
+	default:
+		return DBBackendUnsupported, fmt.Errorf("unsupported database backend: %q", raw)
+	}
+}
+
+// DBBackend returns the configured database backend.
+func (c *Config) DBBackend() (DBBackend, error) {
+	return ParseDBBackend(c.Engine.DBBackend)
+}

pkg/config/db_backend_test.go

@@ -0,0 +1,33 @@
+package config
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestDBBackend(t *testing.T) {
+	tests := []struct {
+		input    string
+		valid    bool
+		expected DBBackend
+	}{
+		{stringBoltDB, true, DBBackendBoltDB},
+		{stringSQLite, true, DBBackendSQLite},
+		{"", false, DBBackendUnsupported},
+		{stringSQLite + " ", false, DBBackendUnsupported},
+	}
+
+	for _, test := range tests {
+		result, err := ParseDBBackend(test.input)
+		if test.valid {
+			require.NoError(t, err, "should parse %v", test)
+			require.NoError(t, result.Validate(), "should validate %v", test)
+			require.Equal(t, test.expected, result)
+		} else {
+			require.Error(t, err, "should NOT parse %v", test)
+			require.Error(t, result.Validate(), "should NOT validate %v", test)
+			require.Equal(t, test.expected, result)
+		}
+	}
+}

pkg/config/default.go

@@ -104,6 +104,8 @@ const (
 	CgroupfsCgroupsManager = "cgroupfs"
 	// DefaultApparmorProfile  specifies the default apparmor profile for the container.
 	DefaultApparmorProfile = apparmor.Profile
+	// DefaultDBBackend specifies the default database backend to be used by Podman.
+	DefaultDBBackend = DBBackendBoltDB
 	// DefaultHostsFile is the default path to the hosts file.
 	DefaultHostsFile = "/etc/hosts"
 	// SystemdCgroupsManager represents systemd native cgroup manager.
@@ -387,6 +389,7 @@ func defaultConfigFromMemory() (*EngineConfig, error) {
 		"/run/current-system/sw/bin/conmonrs",
 	}
 	c.PullPolicy = DefaultPullPolicy
+	c.DBBackend = stringBoltDB
 	c.RuntimeSupportsJSON = []string{
 		"crun",
 		"runc",

pkg/config/testdata/containers_default.conf

@@ -117,6 +117,8 @@ dns_bind_port = 1153
 # Cgroup management implementation used for the runtime.
 cgroup_manager = "systemd"
 
+database_backend = "sqlite"
+
 # Default transport method for pulling and pushing for images
 image_default_transport = "docker://"