custom-kube-scheduler/kubernetes-v1.15.4/pkg/kubelet/dockershim/docker_legacy_service.go

/*
Copyright 2016 The Kubernetes Authors.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package dockershim

import (
	"context"
	"fmt"
	"io"
	"strconv"
	"time"

	"github.com/armon/circbuf"
	dockertypes "github.com/docker/docker/api/types"

	"k8s.io/api/core/v1"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	kubetypes "k8s.io/apimachinery/pkg/types"
	kubecontainer "k8s.io/kubernetes/pkg/kubelet/container"
	"k8s.io/kubernetes/pkg/kubelet/kuberuntime"

	"k8s.io/kubernetes/pkg/kubelet/dockershim/libdocker"
)

// DockerLegacyService interface embeds some legacy methods for backward compatibility.
// This file/interface will be removed in the near future. Do not modify or add
// more functions.
type DockerLegacyService interface {
	// GetContainerLogs gets logs for a specific container.
	GetContainerLogs(context.Context, *v1.Pod, kubecontainer.ContainerID, *v1.PodLogOptions, io.Writer, io.Writer) error

	// IsCRISupportedLogDriver checks whether the logging driver used by docker is
	// supported by native CRI integration.
	// TODO(resouer): remove this when deprecating unsupported log driver
	IsCRISupportedLogDriver() (bool, error)

	kuberuntime.LegacyLogProvider
}

// GetContainerLogs get container logs directly from docker daemon.
func (d *dockerService) GetContainerLogs(_ context.Context, pod *v1.Pod, containerID kubecontainer.ContainerID, logOptions *v1.PodLogOptions, stdout, stderr io.Writer) error {
	container, err := d.client.InspectContainer(containerID.ID)
	if err != nil {
		return err
	}

	var since int64
	if logOptions.SinceSeconds != nil {
		t := metav1.Now().Add(-time.Duration(*logOptions.SinceSeconds) * time.Second)
		since = t.Unix()
	}
	if logOptions.SinceTime != nil {
		since = logOptions.SinceTime.Unix()
	}
	opts := dockertypes.ContainerLogsOptions{
		ShowStdout: true,
		ShowStderr: true,
		Since:      strconv.FormatInt(since, 10),
		Timestamps: logOptions.Timestamps,
		Follow:     logOptions.Follow,
	}
	if logOptions.TailLines != nil {
		opts.Tail = strconv.FormatInt(*logOptions.TailLines, 10)
	}

	sopts := libdocker.StreamOptions{
		OutputStream: stdout,
		ErrorStream:  stderr,
		RawTerminal:  container.Config.Tty,
	}
	return d.client.Logs(containerID.ID, opts, sopts)
}

// GetContainerLogTail attempts to read up to MaxContainerTerminationMessageLogLength
// from the end of the log when docker is configured with a log driver other than json-log.
// It reads up to MaxContainerTerminationMessageLogLines lines.
func (d *dockerService) GetContainerLogTail(uid kubetypes.UID, name, namespace string, containerId kubecontainer.ContainerID) (string, error) {
	value := int64(kubecontainer.MaxContainerTerminationMessageLogLines)
	buf, _ := circbuf.NewBuffer(kubecontainer.MaxContainerTerminationMessageLogLength)
	// Although this is not a full spec pod, dockerLegacyService.GetContainerLogs() currently completely ignores its pod param
	pod := &v1.Pod{
		ObjectMeta: metav1.ObjectMeta{
			UID:       uid,
			Name:      name,
			Namespace: namespace,
		},
	}
	err := d.GetContainerLogs(context.Background(), pod, containerId, &v1.PodLogOptions{TailLines: &value}, buf, buf)
	if err != nil {
		return "", err
	}
	return buf.String(), nil
}

// criSupportedLogDrivers are log drivers supported by native CRI integration.
var criSupportedLogDrivers = []string{"json-file"}

// IsCRISupportedLogDriver checks whether the logging driver used by docker is
// supported by native CRI integration.
func (d *dockerService) IsCRISupportedLogDriver() (bool, error) {
	info, err := d.client.Info()
	if err != nil {
		return false, fmt.Errorf("failed to get docker info: %v", err)
	}
	for _, driver := range criSupportedLogDrivers {
		if info.LoggingDriver == driver {
			return true, nil
		}
	}
	return false, nil
}