helper.go

package dockerhelper

import (
	"bytes"
	"errors"
	"fmt"
	"io"
	"net"
	"net/url"
	"regexp"
	"strconv"

	"github.com/docker/distribution/reference"
	"github.com/docker/docker/api/types"
	"github.com/docker/docker/client"
	"github.com/golang/glog"

	"github.com/openshift/imagebuilder/imageprogress"
	starterrors "github.com/openshift/origin/pkg/oc/bootstrap/docker/errors"
)

// Helper provides utility functions to help with Docker
type Helper struct {
	client Interface
	info   *types.Info
}

// NewHelper creates a new Helper
func NewHelper(client Interface) *Helper {
	return &Helper{
		client: client,
	}
}

func (h *Helper) Client() Interface {
	return h.client
}

func (h *Helper) dockerInfo() (*types.Info, error) {
	if h.info != nil {
		return h.info, nil
	}
	if h.client == nil {
		return nil, fmt.Errorf("the Docker engine API client is not initialized")
	}
	glog.V(5).Infof("Retrieving Docker daemon info")
	info, err := h.client.Info()
	if err != nil {
		glog.V(2).Infof("Could not retrieve Docker info: %v", err)
		return nil, err
	}
	glog.V(5).Infof("Docker daemon info: %#v", info)
	h.info = info
	return h.info, nil
}

func (h *Helper) CgroupDriver() (string, error) {
	info, err := h.dockerInfo()
	if err != nil {
		return "", err
	}
	return info.CgroupDriver, nil
}

// InsecureRegistryIsConfigured checks to see if the Docker daemon has an appropriate insecure registry argument set so that our services can access the registry
//hasEntries specifies if Docker daemon has entries at all
func (h *Helper) InsecureRegistryIsConfigured(insecureRegistryCIDR string) (configured bool, hasEntries bool, error error) {
	info, err := h.dockerInfo()
	if err != nil {
		return false, false, err
	}
	registryConfig := NewRegistryConfig(info)
	if !registryConfig.HasCustomInsecureRegistryCIDRs() {
		return false, false, nil
	}
	containsRegistryCIDR, err := registryConfig.ContainsInsecureRegistryCIDR(insecureRegistryCIDR)
	if err != nil {
		return false, true, err
	}
	return containsRegistryCIDR, true, nil
}

var (
	fedoraPackage = regexp.MustCompile("\\.fc[0-9_]*\\.")
	rhelPackage   = regexp.MustCompile("\\.el[0-9_]*\\.")
)

// DockerRoot returns the root directory for Docker
func (h *Helper) DockerRoot() (string, error) {
	info, err := h.dockerInfo()
	if err != nil {
		return "", err
	}
	return info.DockerRootDir, nil
}

// Version returns the Docker API version and whether it is a Red Hat distro version
func (h *Helper) APIVersion() (*types.Version, error) {
	glog.V(5).Infof("Retrieving Docker version")
	version, err := h.client.ServerVersion()
	if err != nil {
		glog.V(2).Infof("Error retrieving version: %v", err)
		return nil, err
	}
	glog.V(5).Infof("Docker version results: %#v", version)
	if len(version.APIVersion) == 0 {
		return nil, errors.New("did not get an API version")
	}
	return version, nil
}

func (h *Helper) IsRedHat() (bool, error) {
	version, err := h.APIVersion()
	if err != nil {
		return false, err
	}
	if len(version.APIVersion) == 0 {
		return false, errors.New("did not get an API version")
	}
	kernelVersion := version.KernelVersion
	if len(kernelVersion) == 0 {
		return false, nil
	}
	return fedoraPackage.MatchString(kernelVersion) || rhelPackage.MatchString(kernelVersion), nil
}

func (h *Helper) GetDockerProxySettings() (httpProxy, httpsProxy, noProxy string, err error) {
	info, err := h.dockerInfo()
	if err != nil {
		return "", "", "", err
	}
	return info.HTTPProxy, info.HTTPSProxy, info.NoProxy, nil
}

// CheckAndPull checks whether a Docker image exists. If not, it pulls it.
func (h *Helper) CheckAndPull(image string, out io.Writer) error {
	glog.V(5).Infof("Inspecting Docker image %q", image)
	imageMeta, _, err := h.client.ImageInspectWithRaw(image, false)
	if err == nil {
		glog.V(5).Infof("Image %q found: %#v", image, imageMeta)
		return nil
	}
	if !client.IsErrImageNotFound(err) {
		return starterrors.NewError("unexpected error inspecting image %s", image).WithCause(err)
	}
	glog.V(5).Infof("Image %q not found. Pulling", image)
	fmt.Fprintf(out, "Pulling image %s\n", image)
	logProgress := func(s string) {
		fmt.Fprintf(out, "%s\n", s)
	}
	pw := imageprogress.NewPullWriter(logProgress)
	defer pw.Close()
	outputStream := pw.(io.Writer)
	if glog.V(5) {
		outputStream = out
	}

	normalized, err := reference.ParseNormalizedNamed(image)
	if err != nil {
		return err
	}

	err = h.client.ImagePull(normalized.String(), types.ImagePullOptions{}, outputStream)
	if err != nil {
		return starterrors.NewError("error pulling Docker image %s", image).WithCause(err)
	}

	// This is to work around issue https://github.com/docker/docker/api/issues/138
	// where engine-api/client/ImagePull does not return an error when it should.
	// which also still seems to exist in https://github.com/moby/moby/blob/master/client/image_pull.go
	_, _, err = h.client.ImageInspectWithRaw(image, false)
	if err != nil {
		glog.V(5).Infof("Image %q not found: %v", image, err)
		return starterrors.NewError("error pulling Docker image %s", image).WithCause(err)
	}

	fmt.Fprintln(out, "Image pull complete")
	return nil
}

// GetContainerState returns whether a container exists and if it does whether it's running
func (h *Helper) GetContainerState(id string) (*types.ContainerJSON, bool, error) {
	glog.V(5).Infof("Inspecting docker container %q", id)
	container, err := h.client.ContainerInspect(id)
	if err != nil {
		if client.IsErrContainerNotFound(err) {
			glog.V(5).Infof("Container %q was not found", id)
			return nil, false, nil
		}
		glog.V(5).Infof("An error occurred inspecting container %q: %v", id, err)
		return nil, false, err
	}
	glog.V(5).Infof("Container inspect result: %#v", container)

	running := container.State != nil && container.State.Running
	glog.V(5).Infof("Container running = %v", running)
	return container, running, nil
}

// RemoveContainer removes the container with the given id
func (h *Helper) RemoveContainer(id string) error {
	glog.V(5).Infof("Removing container %q", id)
	err := h.client.ContainerRemove(id, types.ContainerRemoveOptions{})
	if err != nil {
		return starterrors.NewError("cannot delete container %s", id).WithCause(err)
	}
	glog.V(5).Infof("Removed container %q", id)
	return nil
}

// HostIP returns the IP of the Docker host if connecting via TCP
func (h *Helper) HostIP() string {
	// By default, if the Docker client uses tcp, then use the Docker daemon's address
	endpoint := h.client.Endpoint()
	u, err := url.Parse(endpoint)
	if err == nil && (u.Scheme == "tcp" || u.Scheme == "http" || u.Scheme == "https") {
		glog.V(2).Infof("Using the Docker host %s for the server IP", endpoint)
		if host, _, serr := net.SplitHostPort(u.Host); serr == nil {
			return host
		}
		return u.Host
	}
	glog.V(5).Infof("Cannot use Docker endpoint (%s) because it is not using one of the following protocols: tcp, http, https", endpoint)
	return ""
}

func (h *Helper) ContainerLog(container string, numLines int) string {
	outBuf := &bytes.Buffer{}
	if err := h.client.ContainerLogs(container, types.ContainerLogsOptions{ShowStdout: true, ShowStderr: true, Tail: strconv.Itoa(numLines)}, outBuf, outBuf); err != nil {
		glog.V(2).Infof("Error getting container %q log: %v", container, err)
	}
	return outBuf.String()
}

func (h *Helper) StopAndRemoveContainer(container string) error {
	err := h.client.ContainerStop(container, 10)
	if err != nil {
		glog.V(2).Infof("Cannot stop container %s: %v", container, err)
	}
	return h.RemoveContainer(container)
}

func (h *Helper) ListContainerNames() ([]string, error) {
	containers, err := h.client.ContainerList(types.ContainerListOptions{
		All: true,
	})
	if err != nil {
		return nil, err
	}
	names := []string{}
	for _, c := range containers {
		names = append(names, c.Names...)
	}
	return names, nil
}

// UserNamespaceEnabled checks whether docker daemon is running in user
// namespace mode.
func (h *Helper) UserNamespaceEnabled() (bool, error) {
	info, err := h.dockerInfo()
	if err != nil {
		return false, err
	}
	for _, val := range info.SecurityOptions {
		if val == "name=userns" {
			return true, nil
		}
	}
	return false, nil
}