mirror of https://github.com/status-im/consul.git
110 lines
2.8 KiB
Go
110 lines
2.8 KiB
Go
package submatview
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import (
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"context"
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"errors"
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"github.com/hashicorp/consul/acl"
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"github.com/hashicorp/consul/agent/consul/state"
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"github.com/hashicorp/consul/agent/consul/stream"
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"github.com/hashicorp/consul/lib/retry"
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"github.com/hashicorp/consul/proto/pbsubscribe"
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)
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// LocalMaterializer is a materializer for a stream of events
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// and manages the local subscription to the event publisher
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// until the cache result is discarded when its TTL expires.
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type LocalMaterializer struct {
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deps Deps
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backend LocalBackend
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retryWaiter *retry.Waiter
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handler eventHandler
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mat *materializer
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}
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var _ Materializer = (*LocalMaterializer)(nil)
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type LocalBackend interface {
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Subscribe(req *stream.SubscribeRequest) (*stream.Subscription, error)
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}
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func NewLocalMaterializer(backend LocalBackend, deps Deps) *LocalMaterializer {
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m := LocalMaterializer{
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backend: backend,
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deps: deps,
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mat: newMaterializer(deps.Logger, deps.View, deps.Waiter),
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}
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return &m
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}
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// Query implements Materializer
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func (m *LocalMaterializer) Query(ctx context.Context, minIndex uint64) (Result, error) {
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return m.mat.query(ctx, minIndex)
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}
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// Run receives events from a local subscription backend and sends them to the View.
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// It runs until ctx is cancelled, so it is expected to be run in a goroutine.
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// Mirrors implementation of RPCMaterializer.
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//
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// Run implements Materializer
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func (m *LocalMaterializer) Run(ctx context.Context) {
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for {
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req := m.deps.Request(m.mat.currentIndex())
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err := m.subscribeOnce(ctx, req)
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if ctx.Err() != nil {
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return
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}
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m.mat.handleError(req, err)
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if err := m.mat.retryWaiter.Wait(ctx); err != nil {
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return
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}
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}
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}
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// subscribeOnce opens a new subscription to a local backend and runs
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// for its lifetime or until the view is closed.
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func (m *LocalMaterializer) subscribeOnce(ctx context.Context, req *pbsubscribe.SubscribeRequest) error {
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ctx, cancel := context.WithCancel(ctx)
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defer cancel()
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m.handler = initialHandler(req.Index)
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entMeta := acl.NewEnterpriseMetaWithPartition(req.Partition, req.Namespace)
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sub, err := m.backend.Subscribe(state.PBToStreamSubscribeRequest(req, entMeta))
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if err != nil {
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return err
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}
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defer sub.Unsubscribe()
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for {
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event, err := sub.Next(ctx)
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switch {
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case errors.Is(err, stream.ErrSubForceClosed):
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m.deps.Logger.Trace("subscription reset by server")
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return err
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case err != nil:
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return err
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}
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e := event.Payload.ToSubscriptionEvent(event.Index)
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m.handler, err = m.handler(m, e)
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if err != nil {
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m.mat.reset()
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return err
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}
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}
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}
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// updateView implements viewState
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func (m *LocalMaterializer) updateView(events []*pbsubscribe.Event, index uint64) error {
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return m.mat.updateView(events, index)
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}
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// reset implements viewState
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func (m *LocalMaterializer) reset() {
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m.mat.reset()
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}
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