1 files changed, 302 insertions, 0 deletions
diff --git a/vendor/github.com/hashicorp/vault/api/renewer.go b/vendor/github.com/hashicorp/vault/api/renewer.go
new file mode 100644
index 0000000..a2a4b66
--- /dev/null
+++ b/vendor/github.com/hashicorp/vault/api/renewer.go
@@ -0,0 +1,302 @@
+package api
+
+import (
+	"errors"
+	"math/rand"
+	"sync"
+	"time"
+)
+
+var (
+	ErrRenewerMissingInput  = errors.New("missing input to renewer")
+	ErrRenewerMissingSecret = errors.New("missing secret to renew")
+	ErrRenewerNotRenewable  = errors.New("secret is not renewable")
+	ErrRenewerNoSecretData  = errors.New("returned empty secret data")
+
+	// DefaultRenewerGrace is the default grace period
+	DefaultRenewerGrace = 15 * time.Second
+
+	// DefaultRenewerRenewBuffer is the default size of the buffer for renew
+	// messages on the channel.
+	DefaultRenewerRenewBuffer = 5
+)
+
+// Renewer is a process for renewing a secret.
+//
+// 	renewer, err := client.NewRenewer(&RenewerInput{
+// 		Secret: mySecret,
+// 	})
+// 	go renewer.Renew()
+// 	defer renewer.Stop()
+//
+// 	for {
+// 		select {
+// 		case err := <-renewer.DoneCh():
+// 			if err != nil {
+// 				log.Fatal(err)
+// 			}
+//
+// 			// Renewal is now over
+// 		case renewal := <-renewer.RenewCh():
+// 			log.Printf("Successfully renewed: %#v", renewal)
+// 		}
+// 	}
+//
+//
+// The `DoneCh` will return if renewal fails or if the remaining lease duration
+// after a renewal is less than or equal to the grace (in number of seconds). In
+// both cases, the caller should attempt a re-read of the secret. Clients should
+// check the return value of the channel to see if renewal was successful.
+type Renewer struct {
+	l sync.Mutex
+
+	client  *Client
+	secret  *Secret
+	grace   time.Duration
+	random  *rand.Rand
+	doneCh  chan error
+	renewCh chan *RenewOutput
+
+	stopped bool
+	stopCh  chan struct{}
+}
+
+// RenewerInput is used as input to the renew function.
+type RenewerInput struct {
+	// Secret is the secret to renew
+	Secret *Secret
+
+	// Grace is a minimum renewal before returning so the upstream client
+	// can do a re-read. This can be used to prevent clients from waiting
+	// too long to read a new credential and incur downtime.
+	Grace time.Duration
+
+	// Rand is the randomizer to use for underlying randomization. If not
+	// provided, one will be generated and seeded automatically. If provided, it
+	// is assumed to have already been seeded.
+	Rand *rand.Rand
+
+	// RenewBuffer is the size of the buffered channel where renew messages are
+	// dispatched.
+	RenewBuffer int
+}
+
+// RenewOutput is the metadata returned to the client (if it's listening) to
+// renew messages.
+type RenewOutput struct {
+	// RenewedAt is the timestamp when the renewal took place (UTC).
+	RenewedAt time.Time
+
+	// Secret is the underlying renewal data. It's the same struct as all data
+	// that is returned from Vault, but since this is renewal data, it will not
+	// usually include the secret itself.
+	Secret *Secret
+}
+
+// NewRenewer creates a new renewer from the given input.
+func (c *Client) NewRenewer(i *RenewerInput) (*Renewer, error) {
+	if i == nil {
+		return nil, ErrRenewerMissingInput
+	}
+
+	secret := i.Secret
+	if secret == nil {
+		return nil, ErrRenewerMissingSecret
+	}
+
+	grace := i.Grace
+	if grace == 0 {
+		grace = DefaultRenewerGrace
+	}
+
+	random := i.Rand
+	if random == nil {
+		random = rand.New(rand.NewSource(int64(time.Now().Nanosecond())))
+	}
+
+	renewBuffer := i.RenewBuffer
+	if renewBuffer == 0 {
+		renewBuffer = DefaultRenewerRenewBuffer
+	}
+
+	return &Renewer{
+		client:  c,
+		secret:  secret,
+		grace:   grace,
+		random:  random,
+		doneCh:  make(chan error, 1),
+		renewCh: make(chan *RenewOutput, renewBuffer),
+
+		stopped: false,
+		stopCh:  make(chan struct{}),
+	}, nil
+}
+
+// DoneCh returns the channel where the renewer will publish when renewal stops.
+// If there is an error, this will be an error.
+func (r *Renewer) DoneCh() <-chan error {
+	return r.doneCh
+}
+
+// RenewCh is a channel that receives a message when a successful renewal takes
+// place and includes metadata about the renewal.
+func (r *Renewer) RenewCh() <-chan *RenewOutput {
+	return r.renewCh
+}
+
+// Stop stops the renewer.
+func (r *Renewer) Stop() {
+	r.l.Lock()
+	if !r.stopped {
+		close(r.stopCh)
+		r.stopped = true
+	}
+	r.l.Unlock()
+}
+
+// Renew starts a background process for renewing this secret. When the secret
+// is has auth data, this attempts to renew the auth (token). When the secret
+// has a lease, this attempts to renew the lease.
+func (r *Renewer) Renew() {
+	var result error
+	if r.secret.Auth != nil {
+		result = r.renewAuth()
+	} else {
+		result = r.renewLease()
+	}
+
+	select {
+	case r.doneCh <- result:
+	case <-r.stopCh:
+	}
+}
+
+// renewAuth is a helper for renewing authentication.
+func (r *Renewer) renewAuth() error {
+	if !r.secret.Auth.Renewable || r.secret.Auth.ClientToken == "" {
+		return ErrRenewerNotRenewable
+	}
+
+	client, token := r.client, r.secret.Auth.ClientToken
+
+	for {
+		// Check if we are stopped.
+		select {
+		case <-r.stopCh:
+			return nil
+		default:
+		}
+
+		// Renew the auth.
+		renewal, err := client.Auth().Token().RenewTokenAsSelf(token, 0)
+		if err != nil {
+			return err
+		}
+
+		// Push a message that a renewal took place.
+		select {
+		case r.renewCh <- &RenewOutput{time.Now().UTC(), renewal}:
+		default:
+		}
+
+		// Somehow, sometimes, this happens.
+		if renewal == nil || renewal.Auth == nil {
+			return ErrRenewerNoSecretData
+		}
+
+		// Do nothing if we are not renewable
+		if !renewal.Auth.Renewable {
+			return ErrRenewerNotRenewable
+		}
+
+		// Grab the lease duration and sleep duration - note that we grab the auth
+		// lease duration, not the secret lease duration.
+		leaseDuration := time.Duration(renewal.Auth.LeaseDuration) * time.Second
+		sleepDuration := r.sleepDuration(leaseDuration)
+
+		// If we are within grace, return now.
+		if leaseDuration <= r.grace || sleepDuration <= r.grace {
+			return nil
+		}
+
+		select {
+		case <-r.stopCh:
+			return nil
+		case <-time.After(sleepDuration):
+			continue
+		}
+	}
+}
+
+// renewLease is a helper for renewing a lease.
+func (r *Renewer) renewLease() error {
+	if !r.secret.Renewable || r.secret.LeaseID == "" {
+		return ErrRenewerNotRenewable
+	}
+
+	client, leaseID := r.client, r.secret.LeaseID
+
+	for {
+		// Check if we are stopped.
+		select {
+		case <-r.stopCh:
+			return nil
+		default:
+		}
+
+		// Renew the lease.
+		renewal, err := client.Sys().Renew(leaseID, 0)
+		if err != nil {
+			return err
+		}
+
+		// Push a message that a renewal took place.
+		select {
+		case r.renewCh <- &RenewOutput{time.Now().UTC(), renewal}:
+		default:
+		}
+
+		// Somehow, sometimes, this happens.
+		if renewal == nil {
+			return ErrRenewerNoSecretData
+		}
+
+		// Do nothing if we are not renewable
+		if !renewal.Renewable {
+			return ErrRenewerNotRenewable
+		}
+
+		// Grab the lease duration and sleep duration
+		leaseDuration := time.Duration(renewal.LeaseDuration) * time.Second
+		sleepDuration := r.sleepDuration(leaseDuration)
+
+		// If we are within grace, return now.
+		if leaseDuration <= r.grace || sleepDuration <= r.grace {
+			return nil
+		}
+
+		select {
+		case <-r.stopCh:
+			return nil
+		case <-time.After(sleepDuration):
+			continue
+		}
+	}
+}
+
+// sleepDuration calculates the time to sleep given the base lease duration. The
+// base is the resulting lease duration. It will be reduced to 1/3 and
+// multiplied by a random float between 0.0 and 1.0. This extra randomness
+// prevents multiple clients from all trying to renew simultaneously.
+func (r *Renewer) sleepDuration(base time.Duration) time.Duration {
+	sleep := float64(base)
+
+	// Renew at 1/3 the remaining lease. This will give us an opportunity to retry
+	// at least one more time should the first renewal fail.
+	sleep = sleep / 3.0
+
+	// Use a randomness so many clients do not hit Vault simultaneously.
+	sleep = sleep * (r.random.Float64() + 1) / 2.0
+
+	return time.Duration(sleep)
+}