github.com/imran-kn/cilium-fork@v1.6.9/pkg/debug/subsystem.go (about)

     1  // Copyright 2018 Authors of Cilium
     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 debug
    16  
    17  import (
    18  	"fmt"
    19  
    20  	"github.com/cilium/cilium/pkg/lock"
    21  )
    22  
    23  // StatusFunc is a function returning the debug status of a subsytem. It is
    24  // passed into RegisterStatusFunc().
    25  type StatusFunc func() string
    26  
    27  // StatusMap is the collection of debug status of all subsystems. The key is
    28  // the subsystem name. The value is the subsystem debug status.
    29  type StatusMap map[string]string
    30  
    31  // StatusObject is the interface an object must impelement to be able to be
    32  // passed into RegisterStatusObject().
    33  type StatusObject interface {
    34  	// DebugStatus() is the equivalent of StatusFunc. It must return the
    35  	// debug status as a string.
    36  	DebugStatus() string
    37  }
    38  
    39  type functionMap map[string]StatusFunc
    40  
    41  type statusFunctions struct {
    42  	functions functionMap
    43  	mutex     lock.RWMutex
    44  }
    45  
    46  func newStatusFunctions() statusFunctions {
    47  	return statusFunctions{
    48  		functions: functionMap{},
    49  	}
    50  }
    51  
    52  func (s *statusFunctions) register(name string, fn StatusFunc) error {
    53  	s.mutex.Lock()
    54  	defer s.mutex.Unlock()
    55  
    56  	if _, ok := s.functions[name]; ok {
    57  		return fmt.Errorf("subsystem already registered")
    58  	}
    59  
    60  	s.functions[name] = fn
    61  
    62  	return nil
    63  }
    64  
    65  func (s *statusFunctions) registerStatusObject(name string, obj StatusObject) error {
    66  	return s.register(name, func() string { return obj.DebugStatus() })
    67  }
    68  
    69  func (s *statusFunctions) collectStatus() StatusMap {
    70  	fnCopy := functionMap{}
    71  
    72  	// Make a copy to not hold the mutex while collecting the status
    73  	s.mutex.RLock()
    74  	for name, fn := range s.functions {
    75  		fnCopy[name] = fn
    76  	}
    77  	s.mutex.RUnlock()
    78  
    79  	status := StatusMap{}
    80  
    81  	for name, fn := range fnCopy {
    82  		status[name] = fn()
    83  	}
    84  
    85  	return status
    86  }
    87  
    88  var globalStatusFunctions = newStatusFunctions()
    89  
    90  // RegisterStatusFunc registers a subsystem and associates a status function to
    91  // call for debug status collection
    92  func RegisterStatusFunc(name string, fn StatusFunc) error {
    93  	return globalStatusFunctions.register(name, fn)
    94  }
    95  
    96  // RegisterStatusObject registers a subsystem and associated a status object on
    97  // which DebugStatus() is called to collect debug status
    98  func RegisterStatusObject(name string, obj StatusObject) error {
    99  	return globalStatusFunctions.registerStatusObject(name, obj)
   100  }
   101  
   102  // CollectSubsystemStatus collects the status of all subsystems and returns it
   103  func CollectSubsystemStatus() StatusMap {
   104  	return globalStatusFunctions.collectStatus()
   105  }