containerd

Documentation

Overview

Package containerd implements the containerd EngineClient.

Notes

containerd's task states of pausing and paused are both mapped to a paused container from the perspective of the whalewatcher module.

Index

• Constants
• type ContainerdWatcher
  • func NewContainerdWatcher(client *containerd.Client, opts ...NewOption) *ContainerdWatcher
  • func (cw *ContainerdWatcher) API() string
  • func (cw *ContainerdWatcher) Client() interface{}
  • func (cw *ContainerdWatcher) Close()
  • func (cw *ContainerdWatcher) ID(ctx context.Context) string
  • func (cw *ContainerdWatcher) Inspect(ctx context.Context, nameorid string) (*whalewatcher.Container, error)
  • func (cw *ContainerdWatcher) LifecycleEvents(ctx context.Context) (<-chan engineclient.ContainerEvent, <-chan error)
  • func (cw *ContainerdWatcher) List(ctx context.Context) ([]*whalewatcher.Container, error)
  • func (cw *ContainerdWatcher) PID() int
  • func (cw *ContainerdWatcher) Type() string
  • func (cw *ContainerdWatcher) Version(ctx context.Context) string
• type InspectionDetails
• type NewOption
  • func WithPID(pid int) NewOption
  • func WithRucksackPacker(packer engineclient.RucksackPacker) NewOption

Constants

const ComposerProjectLabel = "com.docker.compose.project"

ComposerProjectLabel is the name of an optional container label identifying the composer project a container is part of. We don't import the definition from the moby package in order to not having to rely on that dependency.

const DockerNamespace = "moby"

DockerNamespace is the name of the containerd namespace used by Docker for its own containers (and tasks). As the whalewatcher module has a dedicated Docker engine client, we need to skip this namespace -- the rationale is that especially the container name is missing at the containerd engine level, but only available via the docker/moby API.

const NerdctlLabelPrefix = "nerdctl/"

NerdctlLabelPrefix is the label key prefix used to namespace (oh no, not another "namespace") nertctl-related labels. On purpose, we don't import nerdctl's definitions in order to avoid even more dependencies.

const NerdctlNameLabel = NerdctlLabelPrefix + "name"

NerdctlNameLabel stores a container's name, as opposed to the ID.

const Type = "containerd.io"

Type specifies this container engine's type identifier.

Types

type ContainerdWatcher

type ContainerdWatcher struct {
	// contains filtered or unexported fields
}

ContainerdWatcher is a containerd EngineClient for interfacing the generic whale watching with containerd daemons.

func NewContainerdWatcher

func NewContainerdWatcher(client *containerd.Client, opts ...NewOption) *ContainerdWatcher

NewContainerdWatcher returns a new ontainerdWatcher using the specified containerd engine client; normally, you would want to use this lower-level constructor only in unit tests.

func (*ContainerdWatcher) API

func (cw *ContainerdWatcher) API() string

API returns the container engine API path.

func (*ContainerdWatcher) Client

func (cw *ContainerdWatcher) Client() interface{}

Client returns the underlying engine client (engine-specific).

func (*ContainerdWatcher) Close

func (cw *ContainerdWatcher) Close()

Close cleans up and release any engine client resources, if necessary.

func (*ContainerdWatcher) ID

func (cw *ContainerdWatcher) ID(ctx context.Context) string

ID returns the (more or less) unique engine identifier; the exact format is engine-specific.

func (*ContainerdWatcher) Inspect

func (cw *ContainerdWatcher) Inspect(ctx context.Context, nameorid string) (*whalewatcher.Container, error)

Inspect (only) those container details of interest to us, given the name or ID of a container.

func (*ContainerdWatcher) LifecycleEvents

func (cw *ContainerdWatcher) LifecycleEvents(ctx context.Context) (
	<-chan engineclient.ContainerEvent, <-chan error,
)

LifecycleEvents streams container engine events, limited just to those events in the lifecycle of containers getting born (=alive, as opposed to, say, "conceived") and die.

func (*ContainerdWatcher) List

func (cw *ContainerdWatcher) List(ctx context.Context) ([]*whalewatcher.Container, error)

List all the currently alive and kicking containers, but do not list any containers without any processes.

func (*ContainerdWatcher) PID

func (cw *ContainerdWatcher) PID() int

PID returns the container engine PID, when known.

func (*ContainerdWatcher) Type

func (cw *ContainerdWatcher) Type() string

Type returns the type identifier for this container engine.

func (*ContainerdWatcher) Version

func (cw *ContainerdWatcher) Version(ctx context.Context) string

Version information about the engine.

type InspectionDetails

type InspectionDetails struct {
	*containers.Container
	*task.Process
}

InspectionDetails combines the container inspection details with its task process details. InspectionDetails gets passed to Rucksack packers where registered in order to pick additional inspection information beyond the generic staple data maintained by the whalewatcher module.

type NewOption

type NewOption func(*ContainerdWatcher)

NewOption represents options to NewContainerdWatcher when creating new watchers keeping eyes on containerd engines.

func WithPID

func WithPID(pid int) NewOption

WithPID sets the engine's PID when known.

func WithRucksackPacker

func WithRucksackPacker(packer engineclient.RucksackPacker) NewOption

WithRucksackPacker sets the Rucksack packer that adds application-specific container information based on the inspected container data. The specified Rucksack packer gets passed the inspection data in form of a InspectionDetails.