func createContainer()

in cmd/runhcs/container.go [256:457]
168 lines of code
53 McCabe index (conditional complexity)

func createContainer(cfg *containerConfig) (_ *container, err error) {
	// Store the container information in a volatile registry key.
	cwd, err := os.Getwd()
	if err != nil {
		return nil, err
	}

	vmisolated := cfg.Spec.Linux != nil || (cfg.Spec.Windows != nil && cfg.Spec.Windows.HyperV != nil)

	sandboxID, isSandbox := parseSandboxAnnotations(cfg.Spec.Annotations)
	hostID := cfg.HostID
	if isSandbox {
		if sandboxID != cfg.ID {
			return nil, errors.New("sandbox ID must match ID")
		}
	} else if sandboxID != "" {
		// Validate that the sandbox container exists.
		sandbox, err := getContainer(sandboxID, false)
		if err != nil {
			return nil, err
		}
		defer sandbox.Close()
		if sandbox.SandboxID != sandboxID {
			return nil, fmt.Errorf("container %s is not a sandbox", sandboxID)
		}
		if hostID == "" {
			// Use the sandbox's host.
			hostID = sandbox.HostID
		} else if sandbox.HostID == "" {
			return nil, fmt.Errorf("sandbox container %s is not running in a VM host, but host %s was specified", sandboxID, hostID)
		} else if hostID != sandbox.HostID {
			return nil, fmt.Errorf("sandbox container %s has a different host %s from the requested host %s", sandboxID, sandbox.HostID, hostID)
		}
		if vmisolated && hostID == "" {
			return nil, fmt.Errorf("container %s is not a VM isolated sandbox", sandboxID)
		}
	}

	uniqueID, err := guid.NewV4()
	if err != nil {
		return nil, err
	}

	newvm := false
	var hostUniqueID guid.GUID
	if hostID != "" {
		host, err := getContainer(hostID, false)
		if err != nil {
			return nil, err
		}
		defer host.Close()
		if !host.IsHost {
			return nil, fmt.Errorf("host container %s is not a VM host", hostID)
		}
		hostUniqueID = host.UniqueID
	} else if vmisolated && (isSandbox || cfg.Spec.Linux != nil || osversion.Build() >= osversion.RS5) {
		// This handles all LCOW, Pod Sandbox, and (Windows Xenon V2 for RS5+)
		hostID = cfg.ID
		newvm = true
		hostUniqueID = uniqueID
	}

	// Make absolute the paths in Root.Path and Windows.LayerFolders.
	rootfs := ""
	if cfg.Spec.Root != nil {
		rootfs = cfg.Spec.Root.Path
		if rootfs != "" && !filepath.IsAbs(rootfs) && !strings.HasPrefix(rootfs, `\\?\`) {
			rootfs = filepath.Join(cwd, rootfs)
			cfg.Spec.Root.Path = rootfs
		}
	}

	netNS := ""
	if cfg.Spec.Windows != nil {
		for i, f := range cfg.Spec.Windows.LayerFolders {
			if !filepath.IsAbs(f) && !strings.HasPrefix(rootfs, `\\?\`) {
				cfg.Spec.Windows.LayerFolders[i] = filepath.Join(cwd, f)
			}
		}

		// Determine the network namespace to use.
		if cfg.Spec.Windows.Network != nil {
			if cfg.Spec.Windows.Network.NetworkSharedContainerName != "" {
				// RS4 case
				err = stateKey.Get(cfg.Spec.Windows.Network.NetworkSharedContainerName, keyNetNS, &netNS)
				if err != nil {
					if _, ok := err.(*regstate.NoStateError); !ok {
						return nil, err
					}
				}
			} else if cfg.Spec.Windows.Network.NetworkNamespace != "" {
				// RS5 case
				netNS = cfg.Spec.Windows.Network.NetworkNamespace
			}
		}
	}

	// Store the initial container state in the registry so that the delete
	// command can clean everything up if something goes wrong.
	c := &container{
		persistedState: persistedState{
			ID:             cfg.ID,
			Owner:          cfg.Owner,
			Bundle:         cwd,
			Rootfs:         rootfs,
			Created:        time.Now(),
			Spec:           cfg.Spec,
			SandboxID:      sandboxID,
			HostID:         hostID,
			IsHost:         newvm,
			RequestedNetNS: netNS,
			UniqueID:       uniqueID,
			HostUniqueID:   hostUniqueID,
		},
	}
	err = stateKey.Create(cfg.ID, keyState, &c.persistedState)
	if err != nil {
		return nil, err
	}
	defer func() {
		if err != nil {
			_ = c.Remove()
		}
	}()
	if isSandbox && vmisolated {
		cnicfg := cni.NewPersistedNamespaceConfig(netNS, cfg.ID, hostUniqueID)
		err = cnicfg.Store()
		if err != nil {
			return nil, err
		}
		defer func() {
			if err != nil {
				_ = cnicfg.Remove()
			}
		}()
	}

	// Start a VM if necessary.
	if newvm {
		opts, err := oci.SpecToUVMCreateOpts(context.Background(), cfg.Spec, vmID(c.ID), cfg.Owner)
		if err != nil {
			return nil, err
		}
		switch opts := opts.(type) {
		case *uvm.OptionsLCOW:
			opts.ConsolePipe = cfg.VMConsolePipe
		case *uvm.OptionsWCOW:
			// In order for the UVM sandbox.vhdx not to collide with the actual
			// nested Argon sandbox.vhdx we append the \vm folder to the last entry
			// in the list.
			layersLen := len(cfg.Spec.Windows.LayerFolders)
			layers := make([]string, layersLen)
			copy(layers, cfg.Spec.Windows.LayerFolders)

			vmPath := filepath.Join(layers[layersLen-1], "vm")
			err := os.MkdirAll(vmPath, 0)
			if err != nil {
				return nil, err
			}
			layers[layersLen-1] = vmPath

			opts.LayerFolders = layers
		}

		shim, err := c.startVMShim(cfg.VMLogFile, opts)
		if err != nil {
			return nil, err
		}
		_ = shim.Release()
	}

	if c.HostID != "" {
		// Call to the VM shim process to create the container. This is done so
		// that the VM process can keep track of the VM's virtual hardware
		// resource use.
		err = c.issueVMRequest(runhcs.OpCreateContainer)
		if err != nil {
			return nil, err
		}
		c.hc, err = hcs.OpenComputeSystem(context.Background(), cfg.ID)
		if err != nil {
			return nil, err
		}
	} else {
		// Create the container directly from this process.
		err = createContainerInHost(c, nil)
		if err != nil {
			return nil, err
		}
	}

	// Create the shim process for the container.
	err = startContainerShim(c, cfg.PidFile, cfg.ShimLogFile)
	if err != nil {
		if e := c.Kill(); e == nil {
			_ = c.Remove()
		}
		return nil, err
	}

	return c, nil
}