Documentation
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Overview ¶
Package filepubsub provides an AsyncQueue adapter that wraps the gocloud pubsub file driver, enabling sync endpoints to use filesystem-backed pubsub queues.
URLs ¶
The queue registers the "fpub" scheme. The URL format is:
fpub:///path/to/spool?name=streamname&ackdeadline=1m
Query parameters:
- name: Required stream name (used for directory naming)
- ackdeadline: Optional ack deadline (defaults to 1m)
- sendbatchsize: Optional send batch size for publisher (defaults to 10)
- recvbatchsize: Optional receive batch size for subscriber (defaults to 1)
Example:
fpub:///shared/broker?name=syncro
Package filepubsub provides a filesystem-backed pubsub implementation using gocloud.dev/pubsub. It writes messages as .pb files to a directory and uses filesystem notifications (notify) for efficient subscription instead of polling.
Use NewTopic to construct a *pubsub.Topic, and NewSubscription to construct a *pubsub.Subscription.
filepubsub provides at-least-once delivery semantics. Messages that are not acknowledged within the ack deadline will be redelivered.
URLs ¶
For pubsub.OpenTopic and pubsub.OpenSubscription, filepubsub registers for the scheme "file". The host+path is used as the directory path for message storage. Query parameters:
- ackdeadline: The ack deadline for OpenSubscription, in time.ParseDuration formats. Defaults to 1m.
Examples:
- file:///shared/broker/mytopic
- file:///var/spool/pubsub/events?ackdeadline=30s
As ¶
filepubsub does not support any types for As.
Index ¶
- Constants
- Variables
- func NewSubscription(pstopic *pubsub.Topic, ackDeadline time.Duration) (*pubsub.Subscription, error)
- func NewSubscriptionWithOptions(pstopic *pubsub.Topic, ackDeadline time.Duration, opts *SubscriptionOptions) (*pubsub.Subscription, error)
- func NewTopic(basePath string) (*pubsub.Topic, error)
- func NewTopicWithOptions(basePath string, opts *TopicOptions) (*pubsub.Topic, error)
- type SubscriptionOptions
- type TopicOptions
- type URLOpener
Constants ¶
const Scheme = "file"
Scheme is the URL scheme filepubsub registers its URLOpeners under on pubsub.DefaultMux.
Variables ¶
var ( ErrTopicNotExist = errors.New("filepubsub: topic does not exist") ErrTopicClosed = errors.New("filepubsub: topic is closed") ErrSubscriptionClosed = errors.New("filepubsub: subscription is closed") ErrInvalidPath = errors.New("filepubsub: path is required") ErrInvalidParam = errors.New("filepubsub: invalid query parameter") ErrInvalidAckDeadline = errors.New("filepubsub: invalid ackdeadline") ErrCreateDir = errors.New("filepubsub: failed to create directory") ErrWriteFile = errors.New("filepubsub: failed to write file") ErrMoveFile = errors.New("filepubsub: failed to move file") )
Sentinel errors for filepubsub package
Functions ¶
func NewSubscription ¶
func NewSubscription(pstopic *pubsub.Topic, ackDeadline time.Duration) (*pubsub.Subscription, error)
NewSubscription creates a new subscription for the given topic. It panics if the given topic did not come from filepubsub.
func NewSubscriptionWithOptions ¶
func NewSubscriptionWithOptions(pstopic *pubsub.Topic, ackDeadline time.Duration, opts *SubscriptionOptions) (*pubsub.Subscription, error)
NewSubscriptionWithOptions is similar to NewSubscription, but supports SubscriptionOptions.
func NewTopicWithOptions ¶
func NewTopicWithOptions(basePath string, opts *TopicOptions) (*pubsub.Topic, error)
NewTopicWithOptions is similar to NewTopic, but supports TopicOptions.
Types ¶
type SubscriptionOptions ¶
type SubscriptionOptions struct {
// ReceiveBatcherOptions adds constraints to the default batching done for receives.
ReceiveBatcherOptions batcher.Options
// AckBatcherOptions adds constraints to the default batching done for acks.
AckBatcherOptions batcher.Options
}
SubscriptionOptions sets options for constructing a *pubsub.Subscription backed by filepubsub.
type TopicOptions ¶
type TopicOptions struct {
// BatcherOptions adds constraints to the default batching done for sends.
BatcherOptions batcher.Options
}
TopicOptions contains configuration options for topics.
type URLOpener ¶
type URLOpener struct {
// contains filtered or unexported fields
}
URLOpener opens filepubsub URLs like "file:///path/to/topic".
The URL's host+path is used as the directory for message storage.
Query parameters:
- ackdeadline: The ack deadline for OpenSubscription, in time.ParseDuration formats. Defaults to 1m.
func (*URLOpener) OpenSubscriptionURL ¶
func (o *URLOpener) OpenSubscriptionURL(ctx context.Context, u *url.URL) (*pubsub.Subscription, error)
OpenSubscriptionURL opens a pubsub.Subscription based on u.
Source Files