legacy.go

Documentation: k8s.io/kubernetes/pkg/kubelet/kuberuntime

     1  /*
     2  Copyright 2016 The Kubernetes Authors.
     3  
     4  Licensed under the Apache License, Version 2.0 (the "License");
     5  you may not use this file except in compliance with the License.
     6  You may obtain a copy of the License at
     7  
     8      http://www.apache.org/licenses/LICENSE-2.0
     9  
    10  Unless required by applicable law or agreed to in writing, software
    11  distributed under the License is distributed on an "AS IS" BASIS,
    12  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13  See the License for the specific language governing permissions and
    14  limitations under the License.
    15  */
    16  
    17  package kuberuntime
    18  
    19  import (
    20  	"fmt"
    21  	"path/filepath"
    22  	"strings"
    23  
    24  	kubecontainer "k8s.io/kubernetes/pkg/kubelet/container"
    25  )
    26  
    27  // This file implements the functions that are needed for backward
    28  // compatibility. Therefore, it imports various kubernetes packages
    29  // directly.
    30  
    31  const (
    32  	// legacyContainerLogsDir is the legacy location of container logs. It is the same with
    33  	// kubelet.containerLogsDir.
    34  	legacyContainerLogsDir = "/var/log/containers"
    35  	// legacyLogSuffix is the legacy log suffix.
    36  	legacyLogSuffix = "log"
    37  
    38  	ext4MaxFileNameLen = 255
    39  )
    40  
    41  // legacyLogSymlink composes the legacy container log path. It is only used for legacy cluster
    42  // logging support.
    43  func legacyLogSymlink(containerID string, containerName, podName, podNamespace string) string {
    44  	return logSymlink(legacyContainerLogsDir, kubecontainer.BuildPodFullName(podName, podNamespace),
    45  		containerName, containerID)
    46  }
    47  
    48  // getContainerIDFromLegacyLogSymlink returns error if container Id cannot be parsed
    49  func getContainerIDFromLegacyLogSymlink(logSymlink string) (string, error) {
    50  	parts := strings.Split(logSymlink, "-")
    51  	if len(parts) == 0 {
    52  		return "", fmt.Errorf("unable to find separator in %q", logSymlink)
    53  	}
    54  	containerIDWithSuffix := parts[len(parts)-1]
    55  	suffix := fmt.Sprintf(".%s", legacyLogSuffix)
    56  	if !strings.HasSuffix(containerIDWithSuffix, suffix) {
    57  		return "", fmt.Errorf("%q doesn't end with %q", logSymlink, suffix)
    58  	}
    59  	containerIDWithoutSuffix := strings.TrimSuffix(containerIDWithSuffix, suffix)
    60  	// container can be retrieved with container Id as short as 6 characters
    61  	if len(containerIDWithoutSuffix) < 6 {
    62  		return "", fmt.Errorf("container Id %q is too short", containerIDWithoutSuffix)
    63  	}
    64  	return containerIDWithoutSuffix, nil
    65  }
    66  
    67  func logSymlink(containerLogsDir, podFullName, containerName, containerID string) string {
    68  	suffix := fmt.Sprintf(".%s", legacyLogSuffix)
    69  	logPath := fmt.Sprintf("%s_%s-%s", podFullName, containerName, containerID)
    70  	// Length of a filename cannot exceed 255 characters in ext4 on Linux.
    71  	if len(logPath) > ext4MaxFileNameLen-len(suffix) {
    72  		logPath = logPath[:ext4MaxFileNameLen-len(suffix)]
    73  	}
    74  	return filepath.Join(containerLogsDir, logPath+suffix)
    75  }
    76
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