Add start of shim code to new interfaces
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
This commit is contained in:
Michael Crosby
253
shim/process.go
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253
shim/process.go
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@@ -0,0 +1,253 @@
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package process
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import (
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"encoding/json"
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"errors"
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"fmt"
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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/filepath"
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"strconv"
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"strings"
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"sync"
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"syscall"
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"time"
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"github.com/Sirupsen/logrus"
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"golang.org/x/sys/unix"
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)
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var errInvalidPidInt = errors.New("containerd: process pid is invalid")
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type process struct {
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name string
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root string
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cmd *exec.Cmd
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done chan struct{}
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success bool
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startTime string
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mu sync.Mutex
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containerPid int
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timeout time.Duration
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}
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// same checks if the process is the same process originally launched
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func (p *process) same() (bool, error) {
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/// for backwards compat assume true if it is not set
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if p.startTime == "" {
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return true, nil
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}
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pid, err := p.readContainerPid()
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if err != nil {
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return false, nil
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}
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started, err := readProcessStartTime(pid)
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if err != nil {
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return false, err
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}
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return p.startTime == started, nil
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}
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func (p *process) checkExited() {
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err := p.cmd.Wait()
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if err == nil {
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p.success = true
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}
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if same, _ := p.same(); same && p.hasPid() {
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// The process changed its PR_SET_PDEATHSIG, so force kill it
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logrus.Infof("containerd: %s:%s (pid %v) has become an orphan, killing it", p.container.id, p.namae, p.containerPid)
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if err := unix.Kill(p.containerPid, syscall.SIGKILL); err != nil && err != syscall.ESRCH {
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logrus.Errorf("containerd: unable to SIGKILL %s:%s (pid %v): %v", p.container.id, p.name, p.containerPid, err)
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close(p.done)
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return
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}
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// wait for the container process to exit
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for {
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if err := unix.Kill(p.pid, 0); err != nil {
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break
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}
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time.Sleep(5 * time.Millisecond)
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}
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}
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close(p.done)
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}
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func (p *process) hasPid() bool {
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p.mu.Lock()
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r := p.containerPid > 0
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p.mu.Unlock()
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return r
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}
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func (p *process) setPid(pid int) {
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p.mu.Lock()
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p.containerPid = pid
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p.mu.Unlock()
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}
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type pidResponse struct {
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pid int
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err error
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}
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func (p *process) waitForCreate() error {
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r := make(chan pidResponse, 1)
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go readContainerPid(wc)
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select {
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case resp := <-r:
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if resp.err != nil {
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return resp.err
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}
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p.setPid(resp.pid)
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started, err := readProcessStartTime(resp.pid)
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if err != nil {
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logrus.Warnf("containerd: unable to save %s:%s starttime: %v", p.container.id, p.id, err)
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}
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// TODO: save start time to disk or process state file
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p.startTime = started
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return nil
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case <-time.After(c.timeout):
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p.cmd.Process.Kill()
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p.cmd.Wait()
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return ErrContainerStartTimeout
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}
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}
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func readContainerPid(r chan pidResponse, pidFile string) {
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for {
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pid, err := readContainerPid(pidFile)
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if err != nil {
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if os.IsNotExist(err) || err == errInvalidPidInt {
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if serr := checkErrorLogs(); serr != nil {
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r <- pidResponse{
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err: err,
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}
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break
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}
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time.Sleep(15 * time.Millisecond)
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continue
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}
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r <- pidResponse{
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err: err,
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}
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break
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}
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r <- pidResponse{
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pid: pid,
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}
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break
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}
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}
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func checkErrorLogs(cmd *exec.Cmd, shimLogPath, runtimeLogPath string) error {
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alive, err := isAlive(cmd)
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if err != nil {
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return err
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}
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if !alive {
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// runc could have failed to run the container so lets get the error
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// out of the logs or the shim could have encountered an error
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messages, err := readLogMessages(shimLogPath)
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if err != nil {
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return err
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}
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for _, m := range messages {
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if m.Level == "error" {
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return fmt.Errorf("shim error: %v", m.Msg)
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}
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}
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// no errors reported back from shim, check for runc/runtime errors
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messages, err = readLogMessages(runtimeLogPath)
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if err != nil {
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if os.IsNotExist(err) {
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err = ErrContainerNotStarted
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}
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return err
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}
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for _, m := range messages {
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if m.Level == "error" {
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return fmt.Errorf("oci runtime error: %v", m.Msg)
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}
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}
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return ErrContainerNotStarted
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}
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return nil
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}
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func readProcessStartTime(pid int) (string, error) {
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return readProcStatField(pid, 22)
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}
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func readProcStatField(pid int, field int) (string, error) {
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data, err := ioutil.ReadFile(filepath.Join(string(filepath.Separator), "proc", strconv.Itoa(pid), "stat"))
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if err != nil {
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return "", err
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}
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if field > 2 {
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// First, split out the name since he could contains spaces.
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parts := strings.Split(string(data), ") ")
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// Now split out the rest, we end up with 2 fields less
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parts = strings.Split(parts[1], " ")
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return parts[field-2-1], nil // field count start at 1 in manual
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}
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parts := strings.Split(string(data), " (")
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if field == 1 {
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return parts[0], nil
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}
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return strings.Split(parts[1], ") ")[0], nil
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}
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func readContainerPid(pidFile string) (int, error) {
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data, err := ioutil.ReadFile(pidFile)
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if err != nil {
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return -1, nil
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}
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i, err := strconv.Atoi(string(data))
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if err != nil {
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return -1, errInvalidPidInt
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}
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return i, nil
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}
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// isAlive checks if the shim that launched the container is still alive
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func isAlive(cmd *exec.Cmd) (bool, error) {
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if _, err := syscall.Wait4(cmd.Process.Pid, nil, syscall.WNOHANG, nil); err == nil {
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return true, nil
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}
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if err := syscall.Kill(cmd.Process.Pid, 0); err != nil {
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if err == syscall.ESRCH {
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return false, nil
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}
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return false, err
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}
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return true, nil
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}
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type message struct {
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Level string `json:"level"`
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Msg string `json:"msg"`
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}
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func readLogMessages(path string) ([]message, error) {
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var out []message
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f, err := os.Open(path)
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if err != nil {
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return nil, err
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}
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defer f.Close()
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dec := json.NewDecoder(f)
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for {
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var m message
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if err := dec.Decode(&m); err != nil {
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if err == io.EOF {
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break
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}
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return nil, err
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}
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out = append(out, m)
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}
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return out, nil
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}
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