github.com/containerd/Containerd@v1.4.13/pkg/oom/v2/v2.go (about)

     1  // +build linux
     2  
     3  /*
     4     Copyright The containerd Authors.
     5  
     6     Licensed under the Apache License, Version 2.0 (the "License");
     7     you may not use this file except in compliance with the License.
     8     You may obtain a copy of the License at
     9  
    10         http://www.apache.org/licenses/LICENSE-2.0
    11  
    12     Unless required by applicable law or agreed to in writing, software
    13     distributed under the License is distributed on an "AS IS" BASIS,
    14     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    15     See the License for the specific language governing permissions and
    16     limitations under the License.
    17  */
    18  
    19  package v2
    20  
    21  import (
    22  	"context"
    23  
    24  	cgroupsv2 "github.com/containerd/cgroups/v2"
    25  	eventstypes "github.com/containerd/containerd/api/events"
    26  	"github.com/containerd/containerd/pkg/oom"
    27  	"github.com/containerd/containerd/runtime"
    28  	"github.com/containerd/containerd/runtime/v2/shim"
    29  	"github.com/pkg/errors"
    30  	"github.com/sirupsen/logrus"
    31  )
    32  
    33  // New returns an implementation that listens to OOM events
    34  // from a container's cgroups.
    35  func New(publisher shim.Publisher) (oom.Watcher, error) {
    36  	return &watcher{
    37  		itemCh:    make(chan item),
    38  		publisher: publisher,
    39  	}, nil
    40  }
    41  
    42  // watcher implementation for handling OOM events from a container's cgroup
    43  type watcher struct {
    44  	itemCh    chan item
    45  	publisher shim.Publisher
    46  }
    47  
    48  type item struct {
    49  	id  string
    50  	ev  cgroupsv2.Event
    51  	err error
    52  }
    53  
    54  // Close closes the watcher
    55  func (w *watcher) Close() error {
    56  	return nil
    57  }
    58  
    59  // Run the loop
    60  func (w *watcher) Run(ctx context.Context) {
    61  	lastOOMMap := make(map[string]uint64) // key: id, value: ev.OOM
    62  	for {
    63  		select {
    64  		case <-ctx.Done():
    65  			w.Close()
    66  			return
    67  		case i := <-w.itemCh:
    68  			if i.err != nil {
    69  				delete(lastOOMMap, i.id)
    70  				continue
    71  			}
    72  			lastOOM := lastOOMMap[i.id]
    73  			if i.ev.OOM > lastOOM {
    74  				if err := w.publisher.Publish(ctx, runtime.TaskOOMEventTopic, &eventstypes.TaskOOM{
    75  					ContainerID: i.id,
    76  				}); err != nil {
    77  					logrus.WithError(err).Error("publish OOM event")
    78  				}
    79  			}
    80  			if i.ev.OOM > 0 {
    81  				lastOOMMap[i.id] = i.ev.OOM
    82  			}
    83  		}
    84  	}
    85  }
    86  
    87  // Add cgroups.Cgroup to the epoll monitor
    88  func (w *watcher) Add(id string, cgx interface{}) error {
    89  	cg, ok := cgx.(*cgroupsv2.Manager)
    90  	if !ok {
    91  		return errors.Errorf("expected *cgroupsv2.Manager, got: %T", cgx)
    92  	}
    93  	// FIXME: cgroupsv2.Manager does not support closing eventCh routine currently.
    94  	// The routine shuts down when an error happens, mostly when the cgroup is deleted.
    95  	eventCh, errCh := cg.EventChan()
    96  	go func() {
    97  		for {
    98  			i := item{id: id}
    99  			select {
   100  			case ev := <-eventCh:
   101  				i.ev = ev
   102  				w.itemCh <- i
   103  			case err := <-errCh:
   104  				i.err = err
   105  				w.itemCh <- i
   106  				// we no longer get any event/err when we got an err
   107  				logrus.WithError(err).Warn("error from *cgroupsv2.Manager.EventChan")
   108  				return
   109  			}
   110  		}
   111  	}()
   112  	return nil
   113  }