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watchtower/container/client.go

245 lines
6.6 KiB
Go

package container
import (
"fmt"
"io/ioutil"
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"time"
log "github.com/Sirupsen/logrus"
"github.com/docker/docker/api/types"
"github.com/docker/docker/api/types/network"
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dockerclient "github.com/docker/docker/client"
"golang.org/x/net/context"
)
const (
defaultStopSignal = "SIGTERM"
)
// A Filter is a prototype for a function that can be used to filter the
// results from a call to the ListContainers() method on the Client.
type Filter func(Container) bool
// A Client is the interface through which watchtower interacts with the
// Docker API.
type Client interface {
ListContainers(Filter) ([]Container, error)
StopContainer(Container, time.Duration) error
StartContainer(Container) error
RenameContainer(Container, string) error
IsContainerStale(Container) (bool, error)
RemoveImage(Container) error
}
// NewClient returns a new Client instance which can be used to interact with
// the Docker API.
// The client reads its configuration from the following environment variables:
// * DOCKER_HOST the docker-engine host to send api requests to
// * DOCKER_TLS_VERIFY whether to verify tls certificates
// * DOCKER_API_VERSION the minimum docker api version to work with
func NewClient(pullImages bool) Client {
cli, err := dockerclient.NewEnvClient()
if err != nil {
log.Fatalf("Error instantiating Docker client: %s", err)
}
return dockerClient{api: cli, pullImages: pullImages}
}
type dockerClient struct {
api *dockerclient.Client
pullImages bool
}
func (client dockerClient) ListContainers(fn Filter) ([]Container, error) {
cs := []Container{}
bg := context.Background()
log.Debug("Retrieving running containers")
runningContainers, err := client.api.ContainerList(
bg,
types.ContainerListOptions{})
if err != nil {
return nil, err
}
for _, runningContainer := range runningContainers {
containerInfo, err := client.api.ContainerInspect(bg, runningContainer.ID)
if err != nil {
return nil, err
}
imageInfo, _, err := client.api.ImageInspectWithRaw(bg, containerInfo.Image)
if err != nil {
return nil, err
}
c := Container{containerInfo: &containerInfo, imageInfo: &imageInfo}
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if fn(c) {
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cs = append(cs, c)
}
}
return cs, nil
}
func (client dockerClient) StopContainer(c Container, timeout time.Duration) error {
bg := context.Background()
signal := c.StopSignal()
if signal == "" {
signal = defaultStopSignal
}
log.Infof("Stopping %s (%s) with %s", c.Name(), c.ID(), signal)
if err := client.api.ContainerKill(bg, c.ID(), signal); err != nil {
return err
}
// Wait for container to exit, but proceed anyway after the timeout elapses
client.waitForStop(c, timeout)
log.Debugf("Removing container %s", c.ID())
if err := client.api.ContainerRemove(bg, c.ID(), types.ContainerRemoveOptions{Force: true, RemoveVolumes: false}); err != nil {
return err
}
// Wait for container to be removed. In this case an error is a good thing
if err := client.waitForStop(c, timeout); err == nil {
return fmt.Errorf("Container %s (%s) could not be removed", c.Name(), c.ID())
}
return nil
}
func (client dockerClient) StartContainer(c Container) error {
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bg := context.Background()
config := c.runtimeConfig()
hostConfig := c.hostConfig()
networkConfig := &network.NetworkingConfig{EndpointsConfig: c.containerInfo.NetworkSettings.Networks}
// simpleNetworkConfig is a networkConfig with only 1 network.
// see: https://github.com/docker/docker/issues/29265
simpleNetworkConfig := func() *network.NetworkingConfig {
oneEndpoint := make(map[string]*network.EndpointSettings)
for k, v := range networkConfig.EndpointsConfig {
oneEndpoint[k] = v
// we only need 1
break
}
return &network.NetworkingConfig{EndpointsConfig: oneEndpoint}
}()
name := c.Name()
log.Infof("Starting %s", name)
creation, err := client.api.ContainerCreate(bg, config, hostConfig, simpleNetworkConfig, name)
if err != nil {
return err
}
log.Debugf("Starting container %s (%s)", name, creation.ID)
err = client.api.ContainerStart(bg, creation.ID, types.ContainerStartOptions{})
if err != nil {
return err
}
for k := range simpleNetworkConfig.EndpointsConfig {
err = client.api.NetworkDisconnect(bg, k, creation.ID, true)
if err != nil {
return err
}
}
for k, v := range networkConfig.EndpointsConfig {
err = client.api.NetworkConnect(bg, k, creation.ID, v)
if err != nil {
return err
}
}
return nil
}
func (client dockerClient) RenameContainer(c Container, newName string) error {
bg := context.Background()
log.Debugf("Renaming container %s (%s) to %s", c.Name(), c.ID(), newName)
return client.api.ContainerRename(bg, c.ID(), newName)
}
func (client dockerClient) IsContainerStale(c Container) (bool, error) {
bg := context.Background()
oldImageInfo := c.imageInfo
imageName := c.ImageName()
if client.pullImages {
log.Debugf("Pulling %s for %s", imageName, c.Name())
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var opts types.ImagePullOptions // ImagePullOptions can take a RegistryAuth arg to authenticate against a private registry
auth, err := EncodedAuth(imageName)
if err != nil {
log.Debugf("Error loading authentication credentials %s", err)
return false, err
} else if auth == "" {
log.Debugf("No authentication credentials found for %s", imageName)
opts = types.ImagePullOptions{} // empty/no auth credentials
} else {
opts = types.ImagePullOptions{RegistryAuth: auth, PrivilegeFunc: DefaultAuthHandler}
}
response, err := client.api.ImagePull(bg, imageName, opts)
if err != nil {
log.Debugf("Error pulling image %s, %s", imageName, err)
return false, err
}
defer response.Close()
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// the pull request will be aborted prematurely unless the response is read
_, err = ioutil.ReadAll(response)
}
newImageInfo, _, err := client.api.ImageInspectWithRaw(bg, imageName)
if err != nil {
return false, err
}
if newImageInfo.ID != oldImageInfo.ID {
log.Infof("Found new %s image (%s)", imageName, newImageInfo.ID)
return true, nil
} else {
log.Debugf("No new images found for %s", c.Name())
}
return false, nil
}
func (client dockerClient) RemoveImage(c Container) error {
imageID := c.ImageID()
log.Infof("Removing image %s", imageID)
_, err := client.api.ImageRemove(context.Background(), imageID, types.ImageRemoveOptions{Force: true})
return err
}
func (client dockerClient) waitForStop(c Container, waitTime time.Duration) error {
bg := context.Background()
timeout := time.After(waitTime)
for {
select {
case <-timeout:
return nil
default:
if ci, err := client.api.ContainerInspect(bg, c.ID()); err != nil {
return err
} else if !ci.State.Running {
return nil
}
}
time.Sleep(1 * time.Second)
}
}