results_manager.go

Documentation: k8s.io/kubernetes/pkg/kubelet/prober/results

     1  /*
     2  Copyright 2015 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 results
    18  
    19  import (
    20  	"sync"
    21  
    22  	v1 "k8s.io/api/core/v1"
    23  	"k8s.io/apimachinery/pkg/types"
    24  	kubecontainer "k8s.io/kubernetes/pkg/kubelet/container"
    25  )
    26  
    27  // Manager provides a probe results cache and channel of updates.
    28  type Manager interface {
    29  	// Get returns the cached result for the container with the given ID.
    30  	Get(kubecontainer.ContainerID) (Result, bool)
    31  	// Set sets the cached result for the container with the given ID.
    32  	// The pod is only included to be sent with the update.
    33  	Set(kubecontainer.ContainerID, Result, *v1.Pod)
    34  	// Remove clears the cached result for the container with the given ID.
    35  	Remove(kubecontainer.ContainerID)
    36  	// Updates creates a channel that receives an Update whenever its result changes (but not
    37  	// removed).
    38  	// NOTE: The current implementation only supports a single updates channel.
    39  	Updates() <-chan Update
    40  }
    41  
    42  // Result is the type for probe results.
    43  type Result int
    44  
    45  const (
    46  	// Unknown is encoded as -1 (type Result)
    47  	Unknown Result = iota - 1
    48  
    49  	// Success is encoded as 0 (type Result)
    50  	Success
    51  
    52  	// Failure is encoded as 1 (type Result)
    53  	Failure
    54  )
    55  
    56  func (r Result) String() string {
    57  	switch r {
    58  	case Success:
    59  		return "Success"
    60  	case Failure:
    61  		return "Failure"
    62  	default:
    63  		return "UNKNOWN"
    64  	}
    65  }
    66  
    67  // ToPrometheusType translates a Result to a form which is better understood by prometheus.
    68  func (r Result) ToPrometheusType() float64 {
    69  	switch r {
    70  	case Success:
    71  		return 0
    72  	case Failure:
    73  		return 1
    74  	default:
    75  		return -1
    76  	}
    77  }
    78  
    79  // Update is an enum of the types of updates sent over the Updates channel.
    80  type Update struct {
    81  	ContainerID kubecontainer.ContainerID
    82  	Result      Result
    83  	PodUID      types.UID
    84  }
    85  
    86  // Manager implementation.
    87  type manager struct {
    88  	// guards the cache
    89  	sync.RWMutex
    90  	// map of container ID -> probe Result
    91  	cache map[kubecontainer.ContainerID]Result
    92  	// channel of updates
    93  	updates chan Update
    94  }
    95  
    96  var _ Manager = &manager{}
    97  
    98  // NewManager creates and returns an empty results manager.
    99  func NewManager() Manager {
   100  	return &manager{
   101  		cache:   make(map[kubecontainer.ContainerID]Result),
   102  		updates: make(chan Update, 20),
   103  	}
   104  }
   105  
   106  func (m *manager) Get(id kubecontainer.ContainerID) (Result, bool) {
   107  	m.RLock()
   108  	defer m.RUnlock()
   109  	result, found := m.cache[id]
   110  	return result, found
   111  }
   112  
   113  func (m *manager) Set(id kubecontainer.ContainerID, result Result, pod *v1.Pod) {
   114  	if m.setInternal(id, result) {
   115  		m.updates <- Update{id, result, pod.UID}
   116  	}
   117  }
   118  
   119  // Internal helper for locked portion of set. Returns whether an update should be sent.
   120  func (m *manager) setInternal(id kubecontainer.ContainerID, result Result) bool {
   121  	m.Lock()
   122  	defer m.Unlock()
   123  	prev, exists := m.cache[id]
   124  	if !exists || prev != result {
   125  		m.cache[id] = result
   126  		return true
   127  	}
   128  	return false
   129  }
   130  
   131  func (m *manager) Remove(id kubecontainer.ContainerID) {
   132  	m.Lock()
   133  	defer m.Unlock()
   134  	delete(m.cache, id)
   135  }
   136  
   137  func (m *manager) Updates() <-chan Update {
   138  	return m.updates
   139  }
   140
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