112 lines
2.3 KiB
Go
112 lines
2.3 KiB
Go
package prometheus
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import (
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"sync"
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"golang.org/x/sys/unix"
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"github.com/Sirupsen/logrus"
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"github.com/crosbymichael/cgroups"
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metrics "github.com/docker/go-metrics"
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)
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func NewOOMCollector(ns *metrics.Namespace) (*OOMCollector, error) {
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fd, err := unix.EpollCreate1(unix.EPOLL_CLOEXEC)
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if err != nil {
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return nil, err
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}
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c := &OOMCollector{
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fd: fd,
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memoryOOM: ns.NewLabeledGauge("memory_oom", "The number of times a container received an oom event", metrics.Total, "id"),
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set: make(map[uintptr]*oom),
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}
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go c.start()
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return c, nil
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}
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type OOMCollector struct {
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mu sync.Mutex
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memoryOOM metrics.LabeledGauge
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fd int
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set map[uintptr]*oom
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}
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type oom struct {
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id string
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c cgroups.Cgroup
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}
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func (o *OOMCollector) Add(id string, cg cgroups.Cgroup) error {
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o.mu.Lock()
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defer o.mu.Unlock()
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fd, err := cg.OOMEventFD()
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if err != nil {
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return err
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}
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o.set[fd] = &oom{
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id: id,
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c: cg,
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}
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// set the gauge's default value
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o.memoryOOM.WithValues(id).Set(0)
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event := unix.EpollEvent{
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Fd: int32(fd),
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Events: unix.EPOLLHUP | unix.EPOLLIN | unix.EPOLLERR,
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}
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if err := unix.EpollCtl(o.fd, unix.EPOLL_CTL_ADD, int(fd), &event); err != nil {
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return err
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}
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return nil
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}
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// Close closes the epoll fd
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func (o *OOMCollector) Close() error {
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return unix.Close(int(o.fd))
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}
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func (o *OOMCollector) start() {
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var events [128]unix.EpollEvent
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for {
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n, err := unix.EpollWait(o.fd, events[:], -1)
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if err != nil {
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if err == unix.EINTR {
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continue
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}
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logrus.WithField("error", err).Fatal("cgroups: epoll wait")
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}
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for i := 0; i < n; i++ {
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o.process(uintptr(events[i].Fd), events[i].Events)
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}
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}
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}
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func (o *OOMCollector) process(fd uintptr, event uint32) {
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// make sure to always flush the fd
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flush(fd)
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o.mu.Lock()
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info, ok := o.set[fd]
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if !ok {
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o.mu.Unlock()
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return
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}
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o.mu.Unlock()
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// if we received an event but it was caused by the cgroup being deleted and the fd
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// being closed make sure we close our copy and remove the container from the set
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if info.c.State() == cgroups.Deleted {
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o.mu.Lock()
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delete(o.set, fd)
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o.mu.Unlock()
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unix.Close(int(fd))
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return
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}
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o.memoryOOM.WithValues(info.id).Inc(1)
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}
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func flush(fd uintptr) error {
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buf := make([]byte, 8)
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_, err := unix.Read(int(fd), buf)
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return err
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}
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