open-vault/vault/eventbus/bus.go

164 lines
4.1 KiB
Go
Raw Normal View History

package eventbus
import (
"context"
"errors"
"net/url"
"strings"
"sync/atomic"
"github.com/hashicorp/eventlogger"
"github.com/hashicorp/eventlogger/formatter_filters/cloudevents"
"github.com/hashicorp/go-hclog"
"github.com/hashicorp/go-uuid"
"github.com/hashicorp/vault/sdk/logical"
)
var ErrNotStarted = errors.New("event broker has not been started")
var cloudEventsFormatterFilter *cloudevents.FormatterFilter
// EventBus contains the main logic of running an event broker for Vault.
// Start() must be called before the EventBus will accept events for sending.
type EventBus struct {
logger hclog.Logger
broker *eventlogger.Broker
started atomic.Bool
formatterNodeID eventlogger.NodeID
}
type asyncChanNode struct {
// TODO: add bounded deque buffer of *any
ch chan any
}
var _ eventlogger.Node = &asyncChanNode{}
func init() {
// TODO: maybe this should relate to the Vault core somehow?
sourceUrl, err := url.Parse("https://vaultproject.io/")
if err != nil {
panic(err)
}
cloudEventsFormatterFilter = &cloudevents.FormatterFilter{
Source: sourceUrl,
Predicate: func(_ context.Context, e interface{}) (bool, error) {
return true, nil
},
}
}
func NewEventBus() (*EventBus, error) {
broker := eventlogger.NewBroker()
formatterID, err := uuid.GenerateUUID()
if err != nil {
return nil, err
}
formatterNodeID := eventlogger.NodeID(formatterID)
err = broker.RegisterNode(formatterNodeID, cloudEventsFormatterFilter)
if err != nil {
return nil, err
}
return &EventBus{
logger: hclog.Default().Named("eventbus"),
broker: broker,
formatterNodeID: formatterNodeID,
}, nil
}
// Start starts the event bus, allowing events to be written.
// It is not possible to stop or restart the event bus.
// It is safe to call Start() multiple times.
func (bus *EventBus) Start() {
bus.started.Store(true)
}
var _ logical.EventSender = (*EventBus)(nil)
// Send sends an event to the event bus and routes it to all relevant subscribers.
// This function does *not* wait for all subscribers to acknowledge before returning.
// TODO: use schema once it is defined
func (bus *EventBus) Send(ctx context.Context, eventType logical.EventType, s any) error {
if !bus.started.Load() {
return ErrNotStarted
}
bus.logger.Info("Sending event", "event", s)
_, err := bus.broker.Send(ctx, eventlogger.EventType(eventType), s)
if err != nil {
// if no listeners for this event type are registered, that's okay, the event
// will just not be sent anywhere
if strings.Contains(strings.ToLower(err.Error()), "no graph for eventtype") {
return nil
}
}
return err
}
func (bus *EventBus) Subscribe(_ context.Context, eventType logical.EventType) (chan any, error) {
// subscriptions are still stored even if the bus has not been started
pipelineID, err := uuid.GenerateUUID()
if err != nil {
return nil, err
}
nodeID, err := uuid.GenerateUUID()
if err != nil {
return nil, err
}
// TODO: should we have just one node, and handle all the routing ourselves?
asyncNode := newAsyncNode()
err = bus.broker.RegisterNode(eventlogger.NodeID(nodeID), asyncNode)
if err != nil {
defer asyncNode.Close()
return nil, err
}
nodes := []eventlogger.NodeID{bus.formatterNodeID, eventlogger.NodeID(nodeID)}
pipeline := eventlogger.Pipeline{
PipelineID: eventlogger.PipelineID(pipelineID),
EventType: eventlogger.EventType(eventType),
NodeIDs: nodes,
}
err = bus.broker.RegisterPipeline(pipeline)
if err != nil {
defer asyncNode.Close()
return nil, err
}
return asyncNode.ch, nil
}
func newAsyncNode() *asyncChanNode {
return &asyncChanNode{
ch: make(chan any),
}
}
func (node *asyncChanNode) Close() error {
close(node.ch)
return nil
}
func (node *asyncChanNode) Process(ctx context.Context, e *eventlogger.Event) (*eventlogger.Event, error) {
// TODO: add timeout on sending to node.ch
// sends to the channel async in another goroutine
go func() {
select {
case node.ch <- e.Payload:
case <-ctx.Done():
}
}()
return e, nil
}
func (node *asyncChanNode) Reopen() error {
return nil
}
func (node *asyncChanNode) Type() eventlogger.NodeType {
return eventlogger.NodeTypeSink
}