open-vault/physical/physical.go

155 lines
4.4 KiB
Go

package physical
import (
"strings"
"sync"
log "github.com/mgutz/logxi/v1"
)
const DefaultParallelOperations = 128
// The operation type
type Operation string
const (
DeleteOperation Operation = "delete"
GetOperation = "get"
ListOperation = "list"
PutOperation = "put"
)
// ShutdownSignal
type ShutdownChannel chan struct{}
// Backend is the interface required for a physical
// backend. A physical backend is used to durably store
// data outside of Vault. As such, it is completely untrusted,
// and is only accessed via a security barrier. The backends
// must represent keys in a hierarchical manner. All methods
// are expected to be thread safe.
type Backend interface {
// Put is used to insert or update an entry
Put(entry *Entry) error
// Get is used to fetch an entry
Get(key string) (*Entry, error)
// Delete is used to permanently delete an entry
Delete(key string) error
// List is used ot list all the keys under a given
// prefix, up to the next prefix.
List(prefix string) ([]string, error)
}
// HABackend is an extensions to the standard physical
// backend to support high-availability. Vault only expects to
// use mutual exclusion to allow multiple instances to act as a
// hot standby for a leader that services all requests.
type HABackend interface {
// LockWith is used for mutual exclusion based on the given key.
LockWith(key, value string) (Lock, error)
// Whether or not HA functionality is enabled
HAEnabled() bool
}
// Purgable is an optional interface for backends that support
// purging of their caches.
type Purgable interface {
Purge()
}
// RedirectDetect is an optional interface that an HABackend
// can implement. If they do, a redirect address can be automatically
// detected.
type RedirectDetect interface {
// DetectHostAddr is used to detect the host address
DetectHostAddr() (string, error)
}
// Callback signatures for RunServiceDiscovery
type ActiveFunction func() bool
type SealedFunction func() bool
// ServiceDiscovery is an optional interface that an HABackend can implement.
// If they do, the state of a backend is advertised to the service discovery
// network.
type ServiceDiscovery interface {
// NotifyActiveStateChange is used by Core to notify a backend
// capable of ServiceDiscovery that this Vault instance has changed
// its status to active or standby.
NotifyActiveStateChange() error
// NotifySealedStateChange is used by Core to notify a backend
// capable of ServiceDiscovery that Vault has changed its Sealed
// status to sealed or unsealed.
NotifySealedStateChange() error
// Run executes any background service discovery tasks until the
// shutdown channel is closed.
RunServiceDiscovery(waitGroup *sync.WaitGroup, shutdownCh ShutdownChannel, redirectAddr string, activeFunc ActiveFunction, sealedFunc SealedFunction) error
}
type Lock interface {
// Lock is used to acquire the given lock
// The stopCh is optional and if closed should interrupt the lock
// acquisition attempt. The return struct should be closed when
// leadership is lost.
Lock(stopCh <-chan struct{}) (<-chan struct{}, error)
// Unlock is used to release the lock
Unlock() error
// Returns the value of the lock and if it is held
Value() (bool, string, error)
}
// Entry is used to represent data stored by the physical backend
type Entry struct {
Key string
Value []byte
}
// Factory is the factory function to create a physical backend.
type Factory func(config map[string]string, logger log.Logger) (Backend, error)
// PermitPool is used to limit maximum outstanding requests
type PermitPool struct {
sem chan int
}
// NewPermitPool returns a new permit pool with the provided
// number of permits
func NewPermitPool(permits int) *PermitPool {
if permits < 1 {
permits = DefaultParallelOperations
}
return &PermitPool{
sem: make(chan int, permits),
}
}
// Acquire returns when a permit has been acquired
func (c *PermitPool) Acquire() {
c.sem <- 1
}
// Release returns a permit to the pool
func (c *PermitPool) Release() {
<-c.sem
}
// Prefixes is a shared helper function returns all parent 'folders' for a
// given vault key.
// e.g. for 'foo/bar/baz', it returns ['foo', 'foo/bar']
func Prefixes(s string) []string {
components := strings.Split(s, "/")
result := []string{}
for i := 1; i < len(components); i++ {
result = append(result, strings.Join(components[:i], "/"))
}
return result
}