108 lines
3.1 KiB
Go
108 lines
3.1 KiB
Go
package cachetype
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import (
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"context"
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"fmt"
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"strconv"
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"time"
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external "github.com/hashicorp/consul/agent/grpc-external"
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"github.com/hashicorp/consul/proto/pbpeering"
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"github.com/mitchellh/hashstructure"
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"google.golang.org/grpc"
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"google.golang.org/grpc/codes"
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"google.golang.org/grpc/status"
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"github.com/hashicorp/consul/agent/cache"
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"github.com/hashicorp/consul/agent/structs"
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)
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// PeeringListName is the recommended name for registration.
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const PeeringListName = "peers"
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type PeeringListRequest struct {
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Request *pbpeering.PeeringListRequest
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structs.QueryOptions
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}
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func (r *PeeringListRequest) CacheInfo() cache.RequestInfo {
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info := cache.RequestInfo{
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Token: r.Token,
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Datacenter: "",
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MinIndex: 0,
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Timeout: 0,
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MustRevalidate: false,
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// OPTIMIZE(peering): Cache.notifyPollingQuery polls at this interval. We need to revisit how that polling works.
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// Using an exponential backoff when the result hasn't changed may be preferable.
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MaxAge: 1 * time.Second,
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}
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v, err := hashstructure.Hash([]interface{}{
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r.Request.Partition,
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}, nil)
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if err == nil {
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// If there is an error, we don't set the key. A blank key forces
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// no cache for this request so the request is forwarded directly
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// to the server.
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info.Key = strconv.FormatUint(v, 10)
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}
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return info
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}
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// Peerings supports fetching the list of peers for a given partition or wildcard-specifier.
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type Peerings struct {
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RegisterOptionsNoRefresh
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Client PeeringLister
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}
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//go:generate mockery --name PeeringLister --inpackage --filename mock_PeeringLister_test.go
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type PeeringLister interface {
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PeeringList(
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ctx context.Context, in *pbpeering.PeeringListRequest, opts ...grpc.CallOption,
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) (*pbpeering.PeeringListResponse, error)
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}
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func (t *Peerings) Fetch(_ cache.FetchOptions, req cache.Request) (cache.FetchResult, error) {
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var result cache.FetchResult
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// The request should be a PeeringListRequest.
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// We do not need to make a copy of this request type like in other cache types
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// because the RequestInfo is synthetic.
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reqReal, ok := req.(*PeeringListRequest)
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if !ok {
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return result, fmt.Errorf(
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"Internal cache failure: request wrong type: %T", req)
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}
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// Always allow stale - there's no point in hitting leader if the request is
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// going to be served from cache and end up arbitrarily stale anyway. This
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// allows cached service-discover to automatically read scale across all
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// servers too.
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reqReal.QueryOptions.SetAllowStale(true)
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ctx, err := external.ContextWithQueryOptions(context.Background(), reqReal.QueryOptions)
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if err != nil {
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return result, err
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}
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// Fetch
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reply, err := t.Client.PeeringList(ctx, reqReal.Request)
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if err != nil {
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// Return an empty result if the error is due to peering being disabled.
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// This allows mesh gateways to receive an update and confirm that the watch is set.
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if e, ok := status.FromError(err); ok && e.Code() == codes.FailedPrecondition {
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result.Index = 1
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result.Value = &pbpeering.PeeringListResponse{}
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return result, nil
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}
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return result, err
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}
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result.Value = reply
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result.Index = reply.Index
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return result, nil
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}
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