github.com/inspektor-gadget/inspektor-gadget@v0.28.1/pkg/container-collection/networktracer/connect.go (about)

     1  // Copyright 2022 The Inspektor Gadget authors
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package networktracer
    16  
    17  import (
    18  	"fmt"
    19  
    20  	"github.com/google/uuid"
    21  
    22  	containercollection "github.com/inspektor-gadget/inspektor-gadget/pkg/container-collection"
    23  	eventtypes "github.com/inspektor-gadget/inspektor-gadget/pkg/types"
    24  )
    25  
    26  type Tracer interface {
    27  	Attach(pid uint32) error
    28  	Detach(pid uint32) error
    29  	EventCallback(event any)
    30  }
    31  
    32  type ConnectionToContainerCollection struct {
    33  	subKey   string
    34  	resolver containercollection.ContainerResolver
    35  }
    36  
    37  func (c *ConnectionToContainerCollection) Close() {
    38  	c.resolver.Unsubscribe(c.subKey)
    39  }
    40  
    41  type ConnectToContainerCollectionConfig[Event any] struct {
    42  	Tracer   Tracer
    43  	Resolver containercollection.ContainerResolver
    44  	Selector containercollection.ContainerSelector
    45  	Base     func(eventtypes.Event) *Event
    46  }
    47  
    48  // ConnectToContainerCollection connects a networking tracer to the
    49  // container collection package. It creates the needed logic to call the
    50  // Attach() function on the tracer each time a container is created and
    51  // to call Detach() each time the container is removed. Callers must
    52  // call Close() on the returned ConnectionToContainerCollection object.
    53  func ConnectToContainerCollection[Event any](
    54  	config *ConnectToContainerCollectionConfig[Event],
    55  ) (*ConnectionToContainerCollection, error) {
    56  	// Variables to avoid using c. in all the places below
    57  	id := uuid.New()
    58  	subscribeKey := id.String()
    59  	tracer := config.Tracer
    60  	resolver := config.Resolver
    61  	selector := config.Selector
    62  	base := config.Base
    63  
    64  	attachContainerFunc := func(container *containercollection.Container) {
    65  		err := tracer.Attach(container.Pid)
    66  		if err != nil {
    67  			msg := fmt.Sprintf("start tracing container %q: %s", container.K8s.ContainerName, err)
    68  			tracer.EventCallback(base(eventtypes.Err(msg)))
    69  			return
    70  		}
    71  		tracer.EventCallback(base(eventtypes.Debug("tracer attached")))
    72  	}
    73  
    74  	detachContainerFunc := func(container *containercollection.Container) {
    75  		err := tracer.Detach(container.Pid)
    76  		if err != nil {
    77  			msg := fmt.Sprintf("stop tracing container %q: %s", container.K8s.ContainerName, err)
    78  			tracer.EventCallback(base(eventtypes.Err(msg)))
    79  			return
    80  		}
    81  		tracer.EventCallback(base(eventtypes.Debug("tracer detached")))
    82  	}
    83  
    84  	containers := resolver.Subscribe(
    85  		subscribeKey,
    86  		selector,
    87  		func(event containercollection.PubSubEvent) {
    88  			switch event.Type {
    89  			case containercollection.EventTypeAddContainer:
    90  				attachContainerFunc(event.Container)
    91  			case containercollection.EventTypeRemoveContainer:
    92  				detachContainerFunc(event.Container)
    93  			}
    94  		},
    95  	)
    96  
    97  	for _, container := range containers {
    98  		attachContainerFunc(container)
    99  	}
   100  	return &ConnectionToContainerCollection{
   101  		subKey:   subscribeKey,
   102  		resolver: resolver,
   103  	}, nil
   104  }