github.com/tonistiigi/docker@v0.10.1-0.20240229224939-974013b0dc6a/libnetwork/endpoint_cnt.go (about)

     1  package libnetwork
     2  
     3  import (
     4  	"encoding/json"
     5  	"fmt"
     6  	"sync"
     7  
     8  	"github.com/docker/docker/libnetwork/datastore"
     9  )
    10  
    11  type endpointCnt struct {
    12  	n        *Network
    13  	Count    uint64
    14  	dbIndex  uint64
    15  	dbExists bool
    16  	sync.Mutex
    17  }
    18  
    19  const epCntKeyPrefix = "endpoint_count"
    20  
    21  func (ec *endpointCnt) Key() []string {
    22  	ec.Lock()
    23  	defer ec.Unlock()
    24  
    25  	return []string{epCntKeyPrefix, ec.n.id}
    26  }
    27  
    28  func (ec *endpointCnt) KeyPrefix() []string {
    29  	ec.Lock()
    30  	defer ec.Unlock()
    31  
    32  	return []string{epCntKeyPrefix, ec.n.id}
    33  }
    34  
    35  func (ec *endpointCnt) Value() []byte {
    36  	ec.Lock()
    37  	defer ec.Unlock()
    38  
    39  	b, err := json.Marshal(ec)
    40  	if err != nil {
    41  		return nil
    42  	}
    43  	return b
    44  }
    45  
    46  func (ec *endpointCnt) SetValue(value []byte) error {
    47  	ec.Lock()
    48  	defer ec.Unlock()
    49  
    50  	return json.Unmarshal(value, &ec)
    51  }
    52  
    53  func (ec *endpointCnt) Index() uint64 {
    54  	ec.Lock()
    55  	defer ec.Unlock()
    56  	return ec.dbIndex
    57  }
    58  
    59  func (ec *endpointCnt) SetIndex(index uint64) {
    60  	ec.Lock()
    61  	ec.dbIndex = index
    62  	ec.dbExists = true
    63  	ec.Unlock()
    64  }
    65  
    66  func (ec *endpointCnt) Exists() bool {
    67  	ec.Lock()
    68  	defer ec.Unlock()
    69  	return ec.dbExists
    70  }
    71  
    72  func (ec *endpointCnt) Skip() bool {
    73  	ec.Lock()
    74  	defer ec.Unlock()
    75  	return !ec.n.persist
    76  }
    77  
    78  func (ec *endpointCnt) New() datastore.KVObject {
    79  	ec.Lock()
    80  	defer ec.Unlock()
    81  
    82  	return &endpointCnt{
    83  		n: ec.n,
    84  	}
    85  }
    86  
    87  func (ec *endpointCnt) CopyTo(o datastore.KVObject) error {
    88  	ec.Lock()
    89  	defer ec.Unlock()
    90  
    91  	dstEc := o.(*endpointCnt)
    92  	dstEc.n = ec.n
    93  	dstEc.Count = ec.Count
    94  	dstEc.dbExists = ec.dbExists
    95  	dstEc.dbIndex = ec.dbIndex
    96  
    97  	return nil
    98  }
    99  
   100  func (ec *endpointCnt) EndpointCnt() uint64 {
   101  	ec.Lock()
   102  	defer ec.Unlock()
   103  
   104  	return ec.Count
   105  }
   106  
   107  func (ec *endpointCnt) updateStore() error {
   108  	store := ec.n.getController().getStore()
   109  	if store == nil {
   110  		return fmt.Errorf("store not found on endpoint count update")
   111  	}
   112  	// make a copy of count and n to avoid being overwritten by store.GetObject
   113  	count := ec.EndpointCnt()
   114  	n := ec.n
   115  	for {
   116  		if err := ec.n.getController().updateToStore(ec); err == nil || err != datastore.ErrKeyModified {
   117  			return err
   118  		}
   119  		if err := store.GetObject(ec); err != nil {
   120  			return fmt.Errorf("could not update the kvobject to latest on endpoint count update: %v", err)
   121  		}
   122  		ec.Lock()
   123  		ec.Count = count
   124  		ec.n = n
   125  		ec.Unlock()
   126  	}
   127  }
   128  
   129  func (ec *endpointCnt) setCnt(cnt uint64) error {
   130  	ec.Lock()
   131  	ec.Count = cnt
   132  	ec.Unlock()
   133  	return ec.updateStore()
   134  }
   135  
   136  func (ec *endpointCnt) atomicIncDecEpCnt(inc bool) error {
   137  	store := ec.n.getController().getStore()
   138  	if store == nil {
   139  		return fmt.Errorf("store not found on endpoint count atomic inc/dec")
   140  	}
   141  
   142  	tmp := &endpointCnt{n: ec.n}
   143  	if err := store.GetObject(tmp); err != nil {
   144  		return err
   145  	}
   146  retry:
   147  	ec.Lock()
   148  	if inc {
   149  		ec.Count++
   150  	} else {
   151  		if ec.Count > 0 {
   152  			ec.Count--
   153  		}
   154  	}
   155  	ec.Unlock()
   156  
   157  	if err := ec.n.getController().updateToStore(ec); err != nil {
   158  		if err == datastore.ErrKeyModified {
   159  			if err := store.GetObject(ec); err != nil {
   160  				return fmt.Errorf("could not update the kvobject to latest when trying to atomic add endpoint count: %v", err)
   161  			}
   162  
   163  			goto retry
   164  		}
   165  
   166  		return err
   167  	}
   168  
   169  	return nil
   170  }
   171  
   172  func (ec *endpointCnt) IncEndpointCnt() error {
   173  	return ec.atomicIncDecEpCnt(true)
   174  }
   175  
   176  func (ec *endpointCnt) DecEndpointCnt() error {
   177  	return ec.atomicIncDecEpCnt(false)
   178  }