Documentation
¶
Overview ¶
Package event implements an event bus. for a great introduction to the event bus pattern in go, see: https://levelup.gitconnected.com/lets-write-a-simple-event-bus-in-go-79b9480d8997
Example ¶
const (
ETMainSaidHello = Type("main:SaidHello")
ETMainOpSucceeded = Type("main:OperationSucceeded")
ETMainOpFailed = Type("main:OperationFailed")
)
ctx, done := context.WithCancel(context.Background())
defer done()
bus := NewBus(ctx)
makeDoneHandler := func(label string) Handler {
return func(ctx context.Context, t Type, payload interface{}) error {
fmt.Printf("%s handler called\n", label)
return nil
}
}
bus.Subscribe(makeDoneHandler("first"), ETMainSaidHello, ETMainOpSucceeded)
bus.Subscribe(makeDoneHandler("second"), ETMainSaidHello)
bus.Subscribe(makeDoneHandler("third"), ETMainSaidHello)
bus.Publish(ctx, ETMainSaidHello, "hello")
bus.Publish(ctx, ETMainOpSucceeded, "operation worked!")
Output: first handler called second handler called third handler called first handler called
Index ¶
Examples ¶
Constants ¶
View Source
const ( // ETDatasetNameInit is when a dataset is initialized // payload is a DsChange ETDatasetNameInit = Type("dataset:Init") // ETDatasetCommitChange is when a dataset changes its newest commit // payload is a DsChange ETDatasetCommitChange = Type("dataset:CommitChange") // ETDatasetDeleteAll is when a dataset is entirely deleted // payload is a DsChange ETDatasetDeleteAll = Type("dataset:DeleteAll") // ETDatasetRename is when a dataset is renamed // payload is a DsChange ETDatasetRename = Type("dataset:Rename") // ETDatasetCreateLink is when a dataset is linked to a working directory // payload is a DsChange ETDatasetCreateLink = Type("dataset:CreateLink") )
View Source
const ( // ETCreatedNewFile is the event for creating a new file ETCreatedNewFile = Type("watchfs:CreatedNewFile") // ETModifiedFile is the event for modifying a file ETModifiedFile = Type("watchfs:ModifiedFile") // ETDeletedFile is the event for deleting a file ETDeletedFile = Type("watchfs:DeletedFile") // ETRenamedFolder is the event for renaming a folder ETRenamedFolder = Type("watchfs:RenamedFolder") // ETRemovedFolder is the event for removing a folder ETRemovedFolder = Type("watchfs:RemovedFolder") )
View Source
const ( // ETRemoteClientPushVersionProgress indicates a change in progress of a // dataset version push. Progress can fire as much as once-per-block. // subscriptions do not block the publisher // payload will be a RemoteEvent ETRemoteClientPushVersionProgress = Type("remoteClient:PushVersionProgress") // ETRemoteClientPushVersionCompleted indicates a version successfully pushed // to a remote. // payload will be a RemoteEvent ETRemoteClientPushVersionCompleted = Type("remoteClient:PushVersionCompleted") // ETRemoteClientPushDatasetCompleted indicates pushing a dataset // (logbook + versions) completed // payload will be a RemoteEvent ETRemoteClientPushDatasetCompleted = Type("remoteClient:PushDatasetCompleted") // ETRemoteClientPullVersionProgress indicates a change in progress of a // dataset version pull. Progress can fire as much as once-per-block. // subscriptions do not block the publisher // payload will be a RemoteEvent ETRemoteClientPullVersionProgress = Type("remoteClient:PullVersionProgress") // ETRemoteClientPullVersionCompleted indicates a version successfully pulled // from a remote. // payload will be a RemoteEvent ETRemoteClientPullVersionCompleted = Type("remoteClient:PullVersionCompleted") // ETRemoteClientPullDatasetCompleted indicates pulling a dataset // (logbook + versions) completed // payload will be a RemoteEvent ETRemoteClientPullDatasetCompleted = Type("remoteClient:PullDatasetCompleted") // ETRemoteClientRemoveDatasetCompleted indicates removing a dataset // (logbook + versions) remove completed // payload will be a RemoteEvent ETRemoteClientRemoveDatasetCompleted = Type("remoteClient:RemoveDatasetCompleted") )
View Source
const ( // ETFSICreateLinkEvent type for when FSI creates a link between a dataset // and working directory ETFSICreateLinkEvent = Type("fsi:CreateLinkEvent") )
Variables ¶
View Source
var ( // ETP2PGoneOnline occurs when a p2p node opens up for peer-2-peer connections // payload will be []multiaddr.Addr, the listening addresses of this peer ETP2PGoneOnline = Type("p2p:GoneOnline") // ETP2PGoneOffline occurs when a p2p node has finished disconnecting from // a peer-2-peer network // payload will be nil ETP2PGoneOffline = Type("p2p:GoneOffline") // ETP2PQriPeerConnected fires whenever a peer-2-peer connection that // supports the qri protocol is established // payload is a *profile.Profile // subscribers cannot block the publisher ETP2PQriPeerConnected = Type("p2p:QriPeerConnected") // ETP2PQriPeerDisconnected fires whenever a qri peer-2-peer connection // is closed // payload is a *profile.Profile // a nil payload means we never successfully obtained the peer's profile // information // subscribers cannot block the publisher ETP2PQriPeerDisconnected = Type("p2p:QriPeerDisconnected") // ETP2PPeerConnected occurs after any peer has connected to this node // payload will be a libp2p.peerInfo ETP2PPeerConnected = Type("p2p:PeerConnected") // ETP2PPeerDisconnected occurs after any peer has connected to this node // payload will be a libp2p.peerInfo ETP2PPeerDisconnected = Type("p2p:PeerDisconnected") // ETP2PMessageReceived fires whenever the p2p protocol receives a message // from a Qri peer // payload will be a p2p.Message ETP2PMessageReceived = Type("p2p:MessageReceived") )
View Source
var ETInstanceConstructed = Type("lib:InstanceConstructed")
ETInstanceConstructed is fired once a node is created payload is nil
View Source
var ( // ErrBusClosed indicates the event bus is no longer coordinating events // because it's parent context has closed ErrBusClosed = fmt.Errorf("event bus is closed") )
View Source
var NilBus = nilBus{}
NilBus replaces a nil value. it implements the bus interface, but does nothing
Functions ¶
This section is empty.
Types ¶
type Bus ¶
type Bus interface {
// Publish an event to the bus
Publish(ctx context.Context, t Type, data interface{}) error
// Subscribe to one or more topics with a handler function that will be called
// whenever the event topic is published
Subscribe(handler Handler, topics ...Type)
// NumSubscriptions returns the number of subscribers to the bus's events
NumSubscribers() int
}
Bus is a central coordination point for event publication and subscription zero or more subscribers register topics to be notified of, a publisher writes a topic event to the bus, which broadcasts to all subscribers of that topic
type DsChange ¶ added in v0.9.10
type DsChange struct {
InitID string `json:"initID"`
TopIndex int `json:"topIndex"`
ProfileID string `json:"profileID"`
Username string `json:"username"`
PrettyName string `json:"prettyName"`
HeadRef string `json:"headRef"`
Info *dsref.VersionInfo `json:"info"`
Dir string `json:"dir"`
}
DsChange represents the result of a change to a dataset
type FSICreateLinkEvent ¶
type FSICreateLinkEvent struct {
FSIPath string `json:"fsiPath"`
Username string `json:"username"`
Dsname string `json:"dsName"`
}
FSICreateLinkEvent describes an FSI created link
type Handler ¶ added in v0.9.10
Handler is a function that will be called by the event bus whenever a subscribed topic is published. Handler calls are blocking, called in order of subscription. Any error returned by a handler is passed back to the event publisher. The handler context originates from the publisher, and in practice will often be scoped to a "request context" like an HTTP request or CLI command invocation. Generally, even handlers should aim to return quickly, and only delegate to goroutines when the publishing event is firing on a long-running process
type RemoteEvent ¶ added in v0.9.10
type RemoteEvent struct {
Ref dsref.Ref `json:"ref"`
RemoteAddr string `json:"remoteAddr"`
Progress dag.Completion `json:"progress"`
}
RemoteEvent encapsulates the push / pull progress of a dataset version
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