api: add sandbox CreateContainer API

And make CreateContainer in api.go a wrapper of it.

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

virtcontainers/api.go

@@ -299,36 +299,17 @@ func CreateContainer(sandboxID string, containerConfig ContainerConfig) (VCSandb
 	}
 	defer unlockSandbox(lockFile)
 
-	p, err := fetchSandbox(sandboxID)
+	s, err := fetchSandbox(sandboxID)
 	if err != nil {
 		return nil, nil, err
 	}
 
-	// Create the container.
-	c, err := createContainer(p, containerConfig)
+	c, err := s.CreateContainer(containerConfig)
 	if err != nil {
 		return nil, nil, err
 	}
 
-	// Add the container to the containers list in the sandbox.
-	if err := p.addContainer(c); err != nil {
-		return nil, nil, err
-	}
-
-	// Store it.
-	err = c.storeContainer()
-	if err != nil {
-		return nil, nil, err
-	}
-
-	// Update sandbox config.
-	p.config.Containers = append(p.config.Containers, containerConfig)
-	err = p.storage.storeSandboxResource(sandboxID, configFileType, *(p.config))
-	if err != nil {
-		return nil, nil, err
-	}
-
-	return p, c, nil
+	return s, c, nil
 }
 
 // DeleteContainer is the virtcontainers container deletion entry point.

virtcontainers/interfaces.go

@@ -50,6 +50,7 @@ type VCSandbox interface {
 	Resume() error
 	Release() error
 	Delete() error
+	CreateContainer(contConfig ContainerConfig) (VCContainer, error)
 }
 
 // VCContainer is the Container interface

virtcontainers/pkg/vcmock/sandbox.go

@@ -69,3 +69,8 @@ func (p *Sandbox) Resume() error {
 func (p *Sandbox) Delete() error {
 	return nil
 }
+
+// CreateContainer implements the VCSandbox function of the same name.
+func (p *Sandbox) CreateContainer(conf vc.ContainerConfig) (vc.VCContainer, error) {
+	return &Container{}, nil
+}

virtcontainers/sandbox.go

@@ -865,6 +865,35 @@ func (s *Sandbox) newContainers() error {
 	return nil
 }
 
+// CreateContainer creates a new container in the sandbox
+func (s *Sandbox) CreateContainer(contConfig ContainerConfig) (VCContainer, error) {
+	// Create the container.
+	c, err := createContainer(s, contConfig)
+	if err != nil {
+		return nil, err
+	}
+
+	// Add the container to the containers list in the sandbox.
+	if err := s.addContainer(c); err != nil {
+		return nil, err
+	}
+
+	// Store it.
+	err = c.storeContainer()
+	if err != nil {
+		return nil, err
+	}
+
+	// Update sandbox config.
+	s.config.Containers = append(s.config.Containers, contConfig)
+	err = s.storage.storeSandboxResource(s.id, configFileType, *(s.config))
+	if err != nil {
+		return nil, err
+	}
+
+	return c, nil
+}
+
 // createContainers registers all containers to the proxy, create the
 // containers in the guest and starts one shim per container.
 func (s *Sandbox) createContainers() error {

virtcontainers/sandbox_test.go

@@ -1288,3 +1288,14 @@ func TestRemoveContainerSuccess(t *testing.T) {
 
 	assert.Equal(t, len(sandbox.containers), 0, "Containers list from sandbox structure should be empty")
 }
+
+func TestCreateContainer(t *testing.T) {
+	s, err := testCreateSandbox(t, testSandboxID, MockHypervisor, newHypervisorConfig(nil, nil), NoopAgentType, NoopNetworkModel, NetworkConfig{}, nil, nil)
+	assert.Nil(t, err, "VirtContainers should not allow empty sandboxes")
+	defer cleanUp()
+
+	contID := "999"
+	contConfig := newTestContainerConfigNoop(contID)
+	_, err = s.CreateContainer(contConfig)
+	assert.Nil(t, err, "Failed to create container %+v in sandbox %+v: %v", contConfig, s, err)
+}