portallocator

Documentation

Index

• Variables
• type ErrNotInRange
  • func (e *ErrNotInRange) Error() string
• type Interface
• type PortAllocationOperation
  • func StartOperation(pa Interface, dryRun bool) *PortAllocationOperation
  • func (op *PortAllocationOperation) Allocate(port int) error
  • func (op *PortAllocationOperation) AllocateNext() (int, error)
  • func (op *PortAllocationOperation) Commit() []error
  • func (op *PortAllocationOperation) Finish()
  • func (op *PortAllocationOperation) ReleaseDeferred(port int)
  • func (op *PortAllocationOperation) Rollback() []error
• type PortAllocator
  • func NewFromSnapshot(snap *api.RangeAllocation) (*PortAllocator, error)
  • func NewPortAllocator(pr net.PortRange) (*PortAllocator, error)
  • func NewPortAllocatorCustom(pr net.PortRange, allocatorFactory allocator.AllocatorFactory) (*PortAllocator, error)
  • func (r *PortAllocator) Allocate(port int) error
  • func (r *PortAllocator) AllocateNext() (int, error)
  • func (r *PortAllocator) ForEach(fn func(int))
  • func (r *PortAllocator) Free() int
  • func (r *PortAllocator) Has(port int) bool
  • func (r *PortAllocator) Release(port int) error
  • func (r *PortAllocator) Restore(pr net.PortRange, data []byte) error
  • func (r *PortAllocator) Snapshot(dst *api.RangeAllocation) error
  • func (r *PortAllocator) Used() int

Variables

var (
	ErrFull              = errors.New("range is full")
	ErrAllocated         = errors.New("provided port is already allocated")
	ErrMismatchedNetwork = errors.New("the provided port range does not match the current port range")
)

Types

type ErrNotInRange

type ErrNotInRange struct {
	ValidPorts string
}

func (*ErrNotInRange) Error

func (e *ErrNotInRange) Error() string

type Interface

type Interface interface {
	Allocate(int) error
	AllocateNext() (int, error)
	Release(int) error
	ForEach(func(int))

	// For testing
	Has(int) bool
}

Interface manages the allocation of ports out of a range. Interface should be threadsafe.

type PortAllocationOperation

type PortAllocationOperation struct {
	// contains filtered or unexported fields
}

Encapsulates the semantics of a port allocation 'transaction': It is better to leak ports than to double-allocate them, so we allocate immediately, but defer release. On commit we best-effort release the deferred releases. On rollback we best-effort release any allocations we did.

Pattern for use:

op := StartPortAllocationOperation(...)
defer op.Finish
...
write(updatedOwner)

/ op.Commit()

func StartOperation

func StartOperation(pa Interface, dryRun bool) *PortAllocationOperation

Creates a portAllocationOperation, tracking a set of allocations & releases If dryRun is specified, never actually allocate or release anything

func (*PortAllocationOperation) Allocate

func (op *PortAllocationOperation) Allocate(port int) error

Allocates a port, and record it for future rollback

func (*PortAllocationOperation) AllocateNext

func (op *PortAllocationOperation) AllocateNext() (int, error)

Allocates a port, and record it for future rollback

func (*PortAllocationOperation) Commit

func (op *PortAllocationOperation) Commit() []error

(Try to) perform any deferred operations. Note that even if this fails, we don't rollback; we always want to err on the side of over-allocation, and Commit should be called _after_ the owner is written

func (*PortAllocationOperation) Finish

func (op *PortAllocationOperation) Finish()

Will rollback unless marked as shouldRollback = false by a Commit(). Call from a defer block

func (*PortAllocationOperation) ReleaseDeferred

func (op *PortAllocationOperation) ReleaseDeferred(port int)

Marks a port so that it will be released if this operation Commits

func (*PortAllocationOperation) Rollback

func (op *PortAllocationOperation) Rollback() []error

(Try to) undo any operations we did

type PortAllocator

type PortAllocator struct {
	// contains filtered or unexported fields
}

func NewFromSnapshot

func NewFromSnapshot(snap *api.RangeAllocation) (*PortAllocator, error)

NewFromSnapshot allocates a PortAllocator and initializes it from a snapshot.

func NewPortAllocator

func NewPortAllocator(pr net.PortRange) (*PortAllocator, error)

Helper that wraps NewPortAllocatorCustom, for creating a range backed by an in-memory store.

func NewPortAllocatorCustom

func NewPortAllocatorCustom(pr net.PortRange, allocatorFactory allocator.AllocatorFactory) (*PortAllocator, error)

NewPortAllocatorCustom creates a PortAllocator over a net.PortRange, calling allocatorFactory to construct the backing store.

func (*PortAllocator) Allocate

func (r *PortAllocator) Allocate(port int) error

Allocate attempts to reserve the provided port. ErrNotInRange or ErrAllocated will be returned if the port is not valid for this range or has already been reserved. ErrFull will be returned if there are no ports left.

func (*PortAllocator) AllocateNext

func (r *PortAllocator) AllocateNext() (int, error)

AllocateNext reserves one of the ports from the pool. ErrFull may be returned if there are no ports left.

func (*PortAllocator) ForEach

func (r *PortAllocator) ForEach(fn func(int))

ForEach calls the provided function for each allocated port.

func (*PortAllocator) Free

func (r *PortAllocator) Free() int

Free returns the count of port left in the range.

func (*PortAllocator) Has

func (r *PortAllocator) Has(port int) bool

Has returns true if the provided port is already allocated and a call to Allocate(port) would fail with ErrAllocated.

func (*PortAllocator) Release

func (r *PortAllocator) Release(port int) error

Release releases the port back to the pool. Releasing an unallocated port or a port out of the range is a no-op and returns no error.

func (*PortAllocator) Restore

func (r *PortAllocator) Restore(pr net.PortRange, data []byte) error

Restore restores the pool to the previously captured state. ErrMismatchedNetwork is returned if the provided port range doesn't exactly match the previous range.

func (*PortAllocator) Snapshot

func (r *PortAllocator) Snapshot(dst *api.RangeAllocation) error

Snapshot saves the current state of the pool.

func (*PortAllocator) Used

func (r *PortAllocator) Used() int

Used returns the count of ports used in the range.