Refactor container monitor into type
Signed-off-by: Michael Crosby <michael@docker.com>
This commit is contained in:
Michael Crosby
parent
d9753ba20d
commit
2b0776c883
2 changed files with 204 additions and 127 deletions
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@ -7,7 +7,6 @@ import (
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"io"
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"io/ioutil"
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"os"
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"os/exec"
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"path"
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"path/filepath"
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"strings"
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@ -84,8 +83,8 @@ type Container struct {
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VolumesRW map[string]bool
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hostConfig *runconfig.HostConfig
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activeLinks map[string]*links.Link
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requestedStop bool
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activeLinks map[string]*links.Link
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monitor *containerMonitor
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}
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func (container *Container) FromDisk() error {
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@ -496,110 +495,6 @@ func (container *Container) releaseNetwork() {
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container.NetworkSettings = &NetworkSettings{}
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}
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func (container *Container) monitor(callback execdriver.StartCallback) error {
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var (
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err error
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exitCode int
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failCount int
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exit bool
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policy = container.hostConfig.RestartPolicy
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)
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if err := container.startLoggingToDisk(); err != nil {
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// TODO: crosbymichael cleanup IO, network, and mounts
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return err
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}
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// reset the restart count
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container.RestartCount = -1
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container.requestedStop = false
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for {
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container.RestartCount++
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pipes := execdriver.NewPipes(container.stdin, container.stdout, container.stderr, container.Config.OpenStdin)
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if exitCode, err = container.daemon.Run(container, pipes, callback); err != nil {
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failCount++
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if failCount == policy.MaximumRetryCount {
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exit = true
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}
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utils.Errorf("Error running container: %s", err)
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}
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// We still wait to set the state as stopped and ensure that the locks were released
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container.State.SetStopped(exitCode)
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if container.Config.OpenStdin {
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if err := container.stdin.Close(); err != nil {
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utils.Errorf("%s: Error close stdin: %s", container.ID, err)
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}
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}
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if err := container.stdout.Clean(); err != nil {
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utils.Errorf("%s: Error close stdout: %s", container.ID, err)
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}
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if err := container.stderr.Clean(); err != nil {
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utils.Errorf("%s: Error close stderr: %s", container.ID, err)
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}
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if container.command != nil && container.command.Terminal != nil {
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if err := container.command.Terminal.Close(); err != nil {
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utils.Errorf("%s: Error closing terminal: %s", container.ID, err)
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}
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}
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// Re-create a brand new stdin pipe once the container exited
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if container.Config.OpenStdin {
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container.stdin, container.stdinPipe = io.Pipe()
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}
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if container.daemon != nil && container.daemon.srv != nil {
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container.daemon.srv.LogEvent("die", container.ID, container.daemon.repositories.ImageName(container.Image))
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}
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if (policy.Name == "always" || (policy.Name == "on-failure" && exitCode != 0)) && !container.requestedStop || !exit {
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container.command.Cmd = copyCmd(&container.command.Cmd)
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time.Sleep(1 * time.Second)
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continue
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}
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// Cleanup networking and mounts
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container.cleanup()
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if container.daemon != nil && container.daemon.srv != nil && container.daemon.srv.IsRunning() {
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// FIXME: here is race condition between two RUN instructions in Dockerfile
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// because they share same runconfig and change image. Must be fixed
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// in builder/builder.go
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if err := container.toDisk(); err != nil {
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utils.Errorf("Error dumping container %s state to disk: %s\n", container.ID, err)
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}
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}
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return err
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}
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}
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func copyCmd(c *exec.Cmd) exec.Cmd {
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return exec.Cmd{
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Stdin: c.Stdin,
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Stdout: c.Stdout,
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Stderr: c.Stderr,
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Path: c.Path,
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Env: c.Env,
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ExtraFiles: c.ExtraFiles,
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Args: c.Args,
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Dir: c.Dir,
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SysProcAttr: c.SysProcAttr,
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}
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}
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// cleanup releases any network resources allocated to the container along with any rules
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// around how containers are linked together. It also unmounts the container's root filesystem.
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func (container *Container) cleanup() {
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@ -630,7 +525,10 @@ func (container *Container) KillSig(sig int) error {
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if !container.State.IsRunning() {
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return nil
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}
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container.requestedStop = true
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// signal to the monitor that it should not restart the container
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// after we send the kill signal
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container.monitor.ExitOnNext()
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return container.daemon.Kill(container, sig)
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}
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@ -1174,27 +1072,17 @@ func (container *Container) startLoggingToDisk() error {
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}
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func (container *Container) waitForStart() error {
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waitStart := make(chan struct{})
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callback := func(command *execdriver.Command) {
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if command.Tty {
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// The callback is called after the process Start()
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// so we are in the parent process. In TTY mode, stdin/out/err is the PtySlace
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// which we close here.
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if c, ok := command.Stdout.(io.Closer); ok {
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c.Close()
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}
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}
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container.monitor = newContainerMonitor(container, container.hostConfig.RestartPolicy)
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container.State.SetRunning(command.Pid())
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if err := container.toDisk(); err != nil {
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log.Debugf("%s", err)
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}
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var (
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cErr = utils.Go(container.monitor.Start)
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waitStart = make(chan struct{})
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)
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go func() {
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container.State.WaitRunning(-1 * time.Second)
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close(waitStart)
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}
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// We use a callback here instead of a goroutine and an chan for
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// syncronization purposes
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cErr := utils.Go(func() error { return container.monitor(callback) })
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}()
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// Start should not return until the process is actually running
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select {
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189
daemon/monitor.go
Normal file
189
daemon/monitor.go
Normal file
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@ -0,0 +1,189 @@
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package daemon
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import (
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"io"
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"os/exec"
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"sync"
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"time"
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"github.com/docker/docker/daemon/execdriver"
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"github.com/docker/docker/runconfig"
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"github.com/docker/docker/utils"
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)
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// containerMonitor monitors the execution of a container's main process.
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// If a restart policy is specified for the cotnainer the monitor will ensure that the
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// process is restarted based on the rules of the policy. When the container is finally stopped
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// the monitor will reset and cleanup any of the container resources such as networking allocations
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// and the rootfs
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type containerMonitor struct {
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mux sync.Mutex
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container *Container
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restartPolicy runconfig.RestartPolicy
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failureCount int
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shouldStop bool
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}
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func newContainerMonitor(container *Container, policy runconfig.RestartPolicy) *containerMonitor {
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return &containerMonitor{
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container: container,
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restartPolicy: policy,
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}
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}
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// Stop signals to the container monitor that it should stop monitoring the container
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// for exits the next time the process dies
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func (m *containerMonitor) ExitOnNext() {
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m.mux.Lock()
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m.shouldStop = true
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m.mux.Unlock()
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}
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// Close closes the container's resources such as networking allocations and
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// unmounts the contatiner's root filesystem
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func (m *containerMonitor) Close() error {
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// Cleanup networking and mounts
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m.container.cleanup()
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if m.container.daemon != nil && m.container.daemon.srv != nil && m.container.daemon.srv.IsRunning() {
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// FIXME: here is race condition between two RUN instructions in Dockerfile
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// because they share same runconfig and change image. Must be fixed
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// in builder/builder.go
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if err := m.container.toDisk(); err != nil {
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utils.Errorf("Error dumping container %s state to disk: %s\n", m.container.ID, err)
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return err
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}
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}
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return nil
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}
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// reset resets the container's IO and ensures that the command is able to be executed again
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// by copying the data into a new struct
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func (m *containerMonitor) reset() {
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container := m.container
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if container.Config.OpenStdin {
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if err := container.stdin.Close(); err != nil {
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utils.Errorf("%s: Error close stdin: %s", container.ID, err)
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}
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}
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if err := container.stdout.Clean(); err != nil {
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utils.Errorf("%s: Error close stdout: %s", container.ID, err)
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}
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if err := container.stderr.Clean(); err != nil {
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utils.Errorf("%s: Error close stderr: %s", container.ID, err)
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}
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if container.command != nil && container.command.Terminal != nil {
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if err := container.command.Terminal.Close(); err != nil {
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utils.Errorf("%s: Error closing terminal: %s", container.ID, err)
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}
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}
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// Re-create a brand new stdin pipe once the container exited
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if container.Config.OpenStdin {
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container.stdin, container.stdinPipe = io.Pipe()
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}
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if container.daemon != nil && container.daemon.srv != nil {
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container.daemon.srv.LogEvent("die", container.ID, container.daemon.repositories.ImageName(container.Image))
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}
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c := container.command.Cmd
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container.command.Cmd = exec.Cmd{
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Stdin: c.Stdin,
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Stdout: c.Stdout,
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Stderr: c.Stderr,
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Path: c.Path,
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Env: c.Env,
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ExtraFiles: c.ExtraFiles,
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Args: c.Args,
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Dir: c.Dir,
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SysProcAttr: c.SysProcAttr,
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}
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}
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// Start starts the containers process and monitors it according to the restart policy
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func (m *containerMonitor) Start() error {
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var (
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err error
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exitCode int
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)
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defer m.Close()
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// reset the restart count
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m.container.RestartCount = -1
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for !m.shouldStop {
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m.container.RestartCount++
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if err := m.container.startLoggingToDisk(); err != nil {
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m.reset()
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return err
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}
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pipes := execdriver.NewPipes(m.container.stdin, m.container.stdout, m.container.stderr, m.container.Config.OpenStdin)
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if exitCode, err = m.container.daemon.Run(m.container, pipes, m.callback); err != nil {
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m.failureCount++
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if m.failureCount == m.restartPolicy.MaximumRetryCount {
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m.ExitOnNext()
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}
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utils.Errorf("Error running container: %s", err)
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}
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// We still wait to set the state as stopped and ensure that the locks were released
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m.container.State.SetStopped(exitCode)
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m.reset()
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if m.shouldRestart(exitCode) {
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time.Sleep(1 * time.Second)
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continue
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}
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break
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}
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return err
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}
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func (m *containerMonitor) shouldRestart(exitCode int) bool {
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m.mux.Lock()
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shouldRestart := (m.restartPolicy.Name == "always" ||
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(m.restartPolicy.Name == "on-failure" && exitCode != 0)) &&
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!m.shouldStop
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m.mux.Unlock()
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return shouldRestart
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}
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// callback ensures that the container's state is properly updated after we
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// received ack from the execution drivers
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func (m *containerMonitor) callback(command *execdriver.Command) {
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if command.Tty {
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// The callback is called after the process Start()
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// so we are in the parent process. In TTY mode, stdin/out/err is the PtySlace
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// which we close here.
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if c, ok := command.Stdout.(io.Closer); ok {
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c.Close()
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}
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}
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m.container.State.SetRunning(command.Pid())
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if err := m.container.ToDisk(); err != nil {
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utils.Debugf("%s", err)
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}
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}
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