cache

type Cache ¶

type Cache interface {
	ConfigWatcher
	ConfigFetcher
}

Cache is a generic config cache with a watcher.

type ConfigFetcher ¶ added in v0.9.7

type ConfigFetcher interface {
	// Fetch implements the polling method of the config cache using a non-empty request.
	Fetch(context.Context, *Request) (Response, error)
}

ConfigFetcher fetches configuration resources from cache

type ConfigWatcher ¶

type ConfigWatcher interface {
	// CreateWatch returns a new open watch from a non-empty request.
	// An individual consumer normally issues a single open watch by each type URL.
	//
	// Value channel produces requested resources, once they are available.  If
	// the channel is closed prior to cancellation of the watch, an unrecoverable
	// error has occurred in the producer, and the consumer should close the
	// corresponding stream.
	//
	// Cancel is an optional function to release resources in the producer. If
	// provided, the consumer may call this function multiple times.
	CreateWatch(*Request) (value chan Response, cancel func())
}

ConfigWatcher requests watches for configuration resources by a node, last applied version identifier, and resource names hint. The watch should send the responses when they are ready. The watch can be cancelled by the consumer, in effect terminating the watch for the request. ConfigWatcher implementation must be thread-safe.

type IDHash ¶

type IDHash struct{}

IDHash uses ID field as the node hash.

func (IDHash) ID(node *core.Node) string

type LinearCache ¶ added in v0.9.7

type LinearCache struct {
	// contains filtered or unexported fields
}

LinearCache supports collectons of opaque resources. This cache has a single collection indexed by resource names and manages resource versions internally. It implements the cache interface for a single type URL and should be combined with other caches via type URL muxing. It can be used to supply EDS entries, for example, uniformly across a fleet of proxies.

func NewLinearCache(typeURL string, opts ...LinearCacheOption) *LinearCache

func (cache *LinearCache) CreateWatch(request *Request) (chan Response, func())

func (cache *LinearCache) DeleteResource(name string) error

func (cache *LinearCache) Fetch(ctx context.Context, request *Request) (Response, error)

func (cache *LinearCache) NumWatches(name string) int

func (cache *LinearCache) UpdateResource(name string, res types.Resource) error

type LinearCacheOption ¶ added in v0.9.7

type LinearCacheOption func(*LinearCache)

Options for modifying the behavior of the linear cache.

func WithInitialResources(resources map[string]types.Resource) LinearCacheOption

func WithVersionPrefix(prefix string) LinearCacheOption

type MuxCache ¶ added in v0.9.7

type MuxCache struct {
	// Classification functions.
	Classify func(Request) string
	// Muxed caches.
	Caches map[string]Cache
}

MuxCache multiplexes across several caches using a classification function. If there is no matching cache for a classification result, the cache responds with an empty closed channel, which effectively terminates the stream on the server. It might be preferred to respond with a "nil" channel instead which will leave the stream open in case the stream is aggregated by making sure there is always a matching cache.

func (mux *MuxCache) CreateWatch(request *Request) (chan Response, func())

func (mux *MuxCache) Fetch(ctx context.Context, request *Request) (Response, error)

type NodeHash ¶

type NodeHash interface {
	// ID function defines a unique string identifier for the remote Envoy node.
	ID(node *core.Node) string
}

NodeHash computes string identifiers for Envoy nodes.

type PassthroughResponse ¶ added in v0.9.6

type PassthroughResponse struct {
	// Request is the original request.
	Request *discovery.DiscoveryRequest

	// The discovery response that needs to be sent as is, without any marshalling transformations.
	DiscoveryResponse *discovery.DiscoveryResponse
}

PassthroughResponse is a pre constructed xDS response that need not go through marshalling transformations.

func (r *PassthroughResponse) GetDiscoveryResponse() (*discovery.DiscoveryResponse, error)

func (r *PassthroughResponse) GetRequest() *discovery.DiscoveryRequest

func (r *PassthroughResponse) GetVersion() (string, error)

type RawResponse ¶ added in v0.9.6

type RawResponse struct {
	// Request is the original request.
	Request *discovery.DiscoveryRequest

	// Version of the resources as tracked by the cache for the given type.
	// Proxy responds with this version as an acknowledgement.
	Version string

	// Resources to be included in the response.
	Resources []types.Resource
	// contains filtered or unexported fields
}

RawResponse is a pre-serialized xDS response containing the raw resources to be included in the final Discovery Response.

func (r *RawResponse) GetDiscoveryResponse() (*discovery.DiscoveryResponse, error)

func (r *RawResponse) GetRequest() *discovery.DiscoveryRequest

func (r *RawResponse) GetVersion() (string, error)

type Request ¶

type Request = discovery.DiscoveryRequest

Request is an alias for the discovery request type.

type Resources ¶

type Resources struct {
	// Version information.
	Version string

	// Items in the group indexed by name.
	Items map[string]types.Resource
}

Resources is a versioned group of resources.

func NewResources(version string, items []types.Resource) Resources

type Response ¶

type Response interface {
	// Get the Constructed DiscoveryResponse
	GetDiscoveryResponse() (*discovery.DiscoveryResponse, error)

	// Get the original Request for the Response.
	GetRequest() *discovery.DiscoveryRequest

	// Get the version in the Response.
	GetVersion() (string, error)
}

Response is a wrapper around Envoy's DiscoveryResponse.

type ResponseWatch ¶

type ResponseWatch struct {
	// Request is the original request for the watch.
	Request *Request

	// Response is the channel to push responses to.
	Response chan Response
}

ResponseWatch is a watch record keeping both the request and an open channel for the response.

type Snapshot ¶

type Snapshot struct {
	Resources [types.UnknownType]Resources
}

Snapshot is an internally consistent snapshot of xDS resources. Consistency is important for the convergence as different resource types from the snapshot may be delivered to the proxy in arbitrary order.

func NewSnapshot(version string,
	endpoints []types.Resource,
	clusters []types.Resource,
	routes []types.Resource,
	listeners []types.Resource,
	runtimes []types.Resource,
	secrets []types.Resource) Snapshot

func (s *Snapshot) Consistent() error

func (s *Snapshot) GetResources(typeURL string) map[string]types.Resource

func (s *Snapshot) GetVersion(typeURL string) string

type SnapshotCache ¶

type SnapshotCache interface {
	Cache

	// SetSnapshot sets a response snapshot for a node. For ADS, the snapshots
	// should have distinct versions and be internally consistent (e.g. all
	// referenced resources must be included in the snapshot).
	//
	// This method will cause the server to respond to all open watches, for which
	// the version differs from the snapshot version.
	SetSnapshot(node string, snapshot Snapshot) error

	// GetSnapshots gets the snapshot for a node.
	GetSnapshot(node string) (Snapshot, error)

	// ClearSnapshot removes all status and snapshot information associated with a node.
	ClearSnapshot(node string)

	// GetStatusInfo retrieves status information for a node ID.
	GetStatusInfo(string) StatusInfo

	// GetStatusKeys retrieves node IDs for all statuses.
	GetStatusKeys() []string
}

SnapshotCache is a snapshot-based cache that maintains a single versioned snapshot of responses per node. SnapshotCache consistently replies with the latest snapshot. For the protocol to work correctly in ADS mode, EDS/RDS requests are responded only when all resources in the snapshot xDS response are named as part of the request. It is expected that the CDS response names all EDS clusters, and the LDS response names all RDS routes in a snapshot, to ensure that Envoy makes the request for all EDS clusters or RDS routes eventually.

SnapshotCache can operate as a REST or regular xDS backend. The snapshot can be partial, e.g. only include RDS or EDS resources.

func NewSnapshotCache(ads bool, hash NodeHash, logger log.Logger) SnapshotCache

type StatusInfo ¶

type StatusInfo interface {
	// GetNode returns the node metadata.
	GetNode() *core.Node

	// GetNumWatches returns the number of open watches.
	GetNumWatches() int

	// GetLastWatchRequestTime returns the timestamp of the last discovery watch request.
	GetLastWatchRequestTime() time.Time
}

StatusInfo tracks the server state for the remote Envoy node. Not all fields are used by all cache implementations.