api: add FetchSandbox

It finds out and existing sandbox and returns it.

Signed-off-by: Peng Tao <bergwolf@gmail.com>

virtcontainers/api.go

@@ -92,6 +92,24 @@ func DeleteSandbox(sandboxID string) (VCSandbox, error) {
 	return p, nil
 }
 
+// FetchSandbox is the virtcontainers sandbox fetching entry point.
+// FetchSandbox will find out and connect to an existing sandbox and
+// return the sandbox structure.
+func FetchSandbox(sandboxID string) (VCSandbox, error) {
+	if sandboxID == "" {
+		return nil, errNeedSandboxID
+	}
+
+	lockFile, err := rwLockSandbox(sandboxID)
+	if err != nil {
+		return nil, err
+	}
+	defer unlockSandbox(lockFile)
+
+	// Fetch the sandbox from storage and create it.
+	return fetchSandbox(sandboxID)
+}
+
 // StartSandbox is the virtcontainers sandbox starting entry point.
 // StartSandbox will talk to the given hypervisor to start an existing
 // sandbox and all its containers.

virtcontainers/api_test.go

@@ -2251,3 +2251,25 @@ func BenchmarkStartStop10ContainerQemuHypervisorHyperstartAgentNetworkNoop(b *te
 		createStartStopDeleteContainers(b, sandboxConfig, contConfigs)
 	}
 }
+
+func TestFetchSandbox(t *testing.T) {
+	cleanUp()
+
+	config := newTestSandboxConfigNoop()
+
+	s, err := CreateSandbox(config)
+	if s == nil || err != nil {
+		t.Fatal(err)
+	}
+
+	fetched, err := FetchSandbox(s.ID())
+	assert.Nil(t, err, "%v", err)
+	assert.True(t, fetched == s, "fetched sandboxed do not match")
+}
+
+func TestFetchNonExistingSandbox(t *testing.T) {
+	cleanUp()
+
+	_, err := FetchSandbox("some-non-existing-sandbox-name")
+	assert.NotNil(t, err, "fetch non-existing sandbox should fail")
+}

virtcontainers/implementation.go

@@ -54,6 +54,12 @@ func (impl *VCImpl) ListSandbox() ([]SandboxStatus, error) {
 	return ListSandbox()
 }
 
+// FetchSandbox will find out and connect to an existing sandbox and
+// return the sandbox structure.
+func (impl *VCImpl) FetchSandbox(sandboxID string) (VCSandbox, error) {
+	return FetchSandbox(sandboxID)
+}
+
 // StatusSandbox implements the VC function of the same name.
 func (impl *VCImpl) StatusSandbox(sandboxID string) (SandboxStatus, error) {
 	return StatusSandbox(sandboxID)

virtcontainers/interfaces.go

@@ -17,6 +17,7 @@ type VC interface {
 
 	CreateSandbox(sandboxConfig SandboxConfig) (VCSandbox, error)
 	DeleteSandbox(sandboxID string) (VCSandbox, error)
+	FetchSandbox(sandboxID string) (VCSandbox, error)
 	ListSandbox() ([]SandboxStatus, error)
 	PauseSandbox(sandboxID string) (VCSandbox, error)
 	ResumeSandbox(sandboxID string) (VCSandbox, error)

virtcontainers/pkg/vcmock/mock.go

@@ -52,6 +52,15 @@ func (m *VCMock) DeleteSandbox(sandboxID string) (vc.VCSandbox, error) {
 	return nil, fmt.Errorf("%s: %s (%+v): sandboxID: %v", mockErrorPrefix, getSelf(), m, sandboxID)
 }
 
+// FetchSandbox implements the VC function of the same name.
+func (m *VCMock) FetchSandbox(sandboxID string) (vc.VCSandbox, error) {
+	if m.FetchSandboxFunc != nil {
+		return m.FetchSandboxFunc(sandboxID)
+	}
+
+	return nil, fmt.Errorf("%s: %s (%+v): sandboxID: %v", mockErrorPrefix, getSelf(), m, sandboxID)
+}
+
 // StartSandbox implements the VC function of the same name.
 func (m *VCMock) StartSandbox(sandboxID string) (vc.VCSandbox, error) {
 	if m.StartSandboxFunc != nil {

virtcontainers/pkg/vcmock/mock_test.go

@@ -568,3 +568,31 @@ func TestVCMockProcessListContainer(t *testing.T) {
 	assert.Error(err)
 	assert.True(IsMockError(err))
 }
+
+func TestVCMockFetchSandbox(t *testing.T) {
+	assert := assert.New(t)
+
+	m := &VCMock{}
+	config := &vc.SandboxConfig{}
+	assert.Nil(m.FetchSandboxFunc)
+
+	_, err := m.FetchSandbox(config.ID)
+	assert.Error(err)
+	assert.True(IsMockError(err))
+
+	m.FetchSandboxFunc = func(id string) (vc.VCSandbox, error) {
+		return &Sandbox{}, nil
+	}
+
+	sandbox, err := m.FetchSandbox(config.ID)
+	assert.NoError(err)
+	assert.Equal(sandbox, &Sandbox{})
+
+	// reset
+	m.FetchSandboxFunc = nil
+
+	_, err = m.FetchSandbox(config.ID)
+	assert.Error(err)
+	assert.True(IsMockError(err))
+
+}

virtcontainers/pkg/vcmock/types.go

@@ -39,6 +39,7 @@ type VCMock struct {
 	CreateSandboxFunc func(sandboxConfig vc.SandboxConfig) (vc.VCSandbox, error)
 	DeleteSandboxFunc func(sandboxID string) (vc.VCSandbox, error)
 	ListSandboxFunc   func() ([]vc.SandboxStatus, error)
+	FetchSandboxFunc  func(sandboxID string) (vc.VCSandbox, error)
 	PauseSandboxFunc  func(sandboxID string) (vc.VCSandbox, error)
 	ResumeSandboxFunc func(sandboxID string) (vc.VCSandbox, error)
 	RunSandboxFunc    func(sandboxConfig vc.SandboxConfig) (vc.VCSandbox, error)