// Create a view on the given GCS object generation. If rl is non-nil, it must
// contain a lease for the contents of the object and will be used when
// possible instead of re-reading the object.
//
// If the object is larger than the given chunk size, we will only read
// and cache portions of it at a time.
func NewReadProxy(
o *gcs.Object,
rl lease.ReadLease,
chunkSize uint64,
leaser lease.FileLeaser,
bucket gcs.Bucket) (rp lease.ReadProxy) {
// Sanity check: the read lease's size should match the object's size if it
// is present.
if rl != nil && uint64(rl.Size()) != o.Size {
panic(fmt.Sprintf(
"Read lease size %d doesn't match object size %d",
rl.Size(),
o.Size))
}
// Special case: don't bring in the complication of a multi-read proxy if we
// have only one refresher.
refreshers := makeRefreshers(chunkSize, o, bucket)
if len(refreshers) == 1 {
rp = lease.NewReadProxy(leaser, refreshers[0], rl)
} else {
rp = lease.NewMultiReadProxy(leaser, refreshers, rl)
}
return
}
func (t *ReadProxyTest) InitialReadLease_Valid() {
var err error
// Set up an initial lease.
rl := mock_lease.NewMockReadLease(t.mockController, "rl")
t.proxy = lease.NewReadProxy(
t.leaser,
t.makeRefresher(),
rl)
// ReadAt
ExpectCall(rl, "ReadAt")(Any(), 11).
WillOnce(Return(0, errors.New("taco"))).
WillOnce(Return(17, nil))
_, err = t.proxy.ReadAt(context.Background(), []byte{}, 11)
ExpectThat(err, Error(HasSubstr("taco")))
n, err := t.proxy.ReadAt(context.Background(), []byte{}, 11)
ExpectEq(17, n)
// Upgrade
rwl := mock_lease.NewMockReadWriteLease(t.mockController, "rwl")
ExpectCall(rl, "Revoke")()
ExpectCall(rl, "Upgrade")().
WillOnce(Return(nil, errors.New("taco"))).
WillOnce(Return(rwl, nil))
_, err = t.proxy.Upgrade(context.Background())
ExpectThat(err, Error(HasSubstr("taco")))
tmp, _ := t.proxy.Upgrade(context.Background())
ExpectEq(rwl, tmp)
}
func (t *ReadProxyTest) SetUp(ti *TestInfo) {
t.mockController = ti.MockController
// Set up the leaser.
t.leaser = mock_lease.NewMockFileLeaser(ti.MockController, "leaser")
// Set up the lease.
t.proxy = lease.NewReadProxy(
t.leaser,
t.makeRefresher(),
nil)
}
func (t *ReadProxyTest) InitialReadLease_Revoked() {
// Set up an initial lease.
rl := mock_lease.NewMockReadLease(t.mockController, "rl")
t.proxy = lease.NewReadProxy(
t.leaser,
t.makeRefresher(),
rl)
// Simulate it being revoked for all methods.
ExpectCall(rl, "ReadAt")(Any(), Any()).
WillOnce(Return(0, &lease.RevokedError{}))
ExpectCall(rl, "Upgrade")().
WillOnce(Return(nil, &lease.RevokedError{}))
ExpectCall(t.leaser, "NewFile")().
Times(2).
WillRepeatedly(Return(nil, errors.New("")))
t.proxy.ReadAt(context.Background(), []byte{}, 0)
t.proxy.Upgrade(context.Background())
}