Documentation ¶
Overview ¶
Package longrunning supports Long Running Operations for the Google Cloud Libraries. See google.golang.org/genproto/googleapis/longrunning for its service definition.
Users of the Google Cloud Libraries will typically not use this package directly. Instead they will call functions returning Operations and call their methods.
This package is still experimental and subject to change.
Index ¶
- Constants
- Variables
- type Operation
- func (op *Operation) Cancel(ctx context.Context, opts ...gax.CallOption) error
- func (op *Operation) Delete(ctx context.Context, opts ...gax.CallOption) error
- func (op *Operation) Done() bool
- func (op *Operation) Metadata(meta proto.Message) error
- func (op *Operation) Name() string
- func (op *Operation) Poll(ctx context.Context, resp proto.Message, opts ...gax.CallOption) error
- func (op *Operation) Wait(ctx context.Context, resp proto.Message, opts ...gax.CallOption) error
- func (op *Operation) WaitWithInterval(ctx context.Context, resp proto.Message, interval time.Duration, ...) error
Examples ¶
Constants ¶
const DefaultWaitInterval = 60 * time.Second
DefaultWaitInterval is the polling interval used by Operation.Wait.
Variables ¶
var ErrNoMetadata = errors.New("operation contains no metadata")
ErrNoMetadata is the error returned by Metadata if the operation contains no metadata.
Functions ¶
This section is empty.
Types ¶
type Operation ¶
type Operation struct {
// contains filtered or unexported fields
}
Operation represents the result of an API call that may not be ready yet.
func InternalNewOperation ¶
func InternalNewOperation(inner *autogen.OperationsClient, proto *pb.Operation) *Operation
InternalNewOperation is for use by the google Cloud Libraries only.
InternalNewOperation returns an long-running operation, abstracting the raw pb.Operation. The conn parameter refers to a server that proto was received from.
func (*Operation) Cancel ¶
Cancel starts asynchronous cancellation on a long-running operation. The server makes a best effort to cancel the operation, but success is not guaranteed. If the server doesn't support this method, it returns status.Code(err) == codes.Unimplemented. Clients can use Poll or other methods to check whether the cancellation succeeded or whether the operation completed despite cancellation. On successful cancellation, the operation is not deleted; instead, op.Poll returns an error with code Canceled.
Example ¶
op, err := bestMomentInHistory() if err != nil { // TODO: Handle err. } if err := op.Cancel(context.Background()); err != nil { // TODO: Handle err. }
Output:
func (*Operation) Delete ¶
Delete deletes a long-running operation. This method indicates that the client is no longer interested in the operation result. It does not cancel the operation. If the server doesn't support this method, status.Code(err) == codes.Unimplemented.
Example ¶
op, err := bestMomentInHistory() if err != nil { // TODO: Handle err. } if err := op.Delete(context.Background()); err != nil { // TODO: Handle err. }
Output:
func (*Operation) Metadata ¶
Metadata unmarshals op's metadata into meta. If op does not contain any metadata, Metadata returns ErrNoMetadata and meta is unmodified.
Example ¶
op, err := bestMomentInHistory() if err != nil { // TODO: Handle err. } // The operation might contain metadata. // In this example, the metadata contains the estimated length of time // the operation might take to complete. var meta duration.Duration if err := op.Metadata(&meta); err != nil { // TODO: Handle err. } d, err := ptypes.Duration(&meta) if err == ErrNoMetadata { fmt.Println("no metadata") } else if err != nil { // TODO: Handle err. } else { fmt.Println(d) }
Output: 1h0m0s
func (*Operation) Name ¶
Name returns the name of the long-running operation. The name is assigned by the server and is unique within the service from which the operation is created.
func (*Operation) Poll ¶
Poll fetches the latest state of a long-running operation.
If Poll fails, the error is returned and op is unmodified. If Poll succeeds and the operation has completed with failure, the error is returned and op.Done will return true. If Poll succeeds and the operation has completed successfully, op.Done will return true; if resp != nil, the response of the operation is stored in resp.
func (*Operation) Wait ¶
Wait is equivalent to WaitWithInterval using DefaultWaitInterval.
Example ¶
// Complex computation, might take a long time. op, err := bestMomentInHistory() if err != nil { // TODO: Handle err. } var ts timestamp.Timestamp err = op.Wait(context.TODO(), &ts) if err != nil && !op.Done() { fmt.Println("failed to fetch operation status", err) } else if err != nil && op.Done() { fmt.Println("operation completed with error", err) } else { fmt.Println(ptypes.TimestampString(&ts)) }
Output: 2009-11-10T23:00:00Z
func (*Operation) WaitWithInterval ¶ added in v0.11.0
func (op *Operation) WaitWithInterval(ctx context.Context, resp proto.Message, interval time.Duration, opts ...gax.CallOption) error
WaitWithInterval blocks until the operation is completed. If resp != nil, Wait stores the response in resp. WaitWithInterval polls every interval, except initially when it polls using exponential backoff.
See documentation of Poll for error-handling information.