cache

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 Go to latest Published: May 13, 2024 License: Apache-2.0 Imports: 25 Imported by: 0

Documentation

Overview

Package cache defines a configuration cache for the server.

Index

Constants

This section is empty.

Variables

This section is empty.

Functions

func GetAllResourceReferences 

func GetAllResourceReferences(resourceGroups [types.UnknownType]Resources) map[resource.Type]map[string]bool

GetAllResourceReferences returns a map of dependent resources keyed by resources type, given all resources.

func GetResourceName 

func GetResourceName(res types.Resource) string

GetResourceName returns the resource name for a valid xDS response type.

func GetResourceNames 

func GetResourceNames(resources []types.Resource) []string

GetResourceName returns the resource names for a list of valid xDS response types.

func GetResourceReferences 

func GetResourceReferences(resources map[string]types.ResourceWithTTL) map[resource.Type]map[string]bool

GetResourceReferences returns a map of dependent resources keyed by resource type, given a map of resources. (EDS cluster names for CDS, RDS/SRDS routes names for LDS, RDS route names for SRDS).

func GetResponseType 

func GetResponseType(typeURL resource.Type) types.ResponseType

GetResponseType returns the enumeration for a valid xDS type URL.

func GetResponseTypeURL 

func GetResponseTypeURL(responseType types.ResponseType) (string, error)

GetResponseTypeURL returns the type url for a valid enum.

func HashResource 

func HashResource(resource []byte) string

HashResource will take a resource and create a SHA256 hash sum out of the marshaled bytes

func IndexRawResourcesByName 

func IndexRawResourcesByName(items []types.Resource) map[string]types.Resource

IndexRawResourcesByName creates a map from the resource name to the resource.

func IndexResourcesByName 

func IndexResourcesByName(items []types.ResourceWithTTL) map[string]types.ResourceWithTTL

IndexResourcesByName creates a map from the resource name to the resource.

func MarshalResource 

func MarshalResource(resource types.Resource) (types.MarshaledResource, error)

MarshalResource converts the Resource to MarshaledResource.

Types

type Cache 

type Cache interface {
	ConfigWatcher
	ConfigFetcher
}

Cache is a generic config cache with a watcher.

type ConfigFetcher 

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.
	// This is the entrypoint to propagate configuration changes the
	// provided Response channel. State from the gRPC server is utilized
	// to make sure consuming cache implementations can see what the server has sent to clients.
	//
	// An individual consumer normally issues a single open watch by each type URL.
	//
	// The provided channel produces requested resources as responses, once they are available.
	//
	// Cancel is an optional function to release resources in the producer. If
	// provided, the consumer may call this function multiple times.
	CreateWatch(*Request, stream.StreamState, chan Response) (cancel func())

	// CreateDeltaWatch returns a new open incremental xDS watch.
	// This is the entrypoint to propagate configuration changes the
	// provided DeltaResponse channel. State from the gRPC server is utilized
	// to make sure consuming cache implementations can see what the server has sent to clients.
	//
	// The provided channel produces requested resources as responses, or spontaneous updates in accordance
	// with the incremental xDS specification.
	//
	// Cancel is an optional function to release resources in the producer. If
	// provided, the consumer may call this function multiple times.
	CreateDeltaWatch(*DeltaRequest, stream.StreamState, chan DeltaResponse) (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 canceled by the consumer, in effect terminating the watch for the request. ConfigWatcher implementation must be thread-safe.

type DeltaPassthroughResponse 

type DeltaPassthroughResponse struct {
	// Request is the latest delta request on the stream
	DeltaRequest *discovery.DeltaDiscoveryRequest

	// NextVersionMap consists of updated version mappings after this response is applied
	NextVersionMap map[string]string

	// This discovery response that needs to be sent as is, without any marshaling transformations
	DeltaDiscoveryResponse *discovery.DeltaDiscoveryResponse
	// contains filtered or unexported fields
}

DeltaPassthroughResponse is a pre constructed xDS response that need not go through marshaling transformations.

func (*DeltaPassthroughResponse) GetContext 

func (r *DeltaPassthroughResponse) GetContext() context.Context

func (*DeltaPassthroughResponse) GetDeltaDiscoveryResponse 

func (r *DeltaPassthroughResponse) GetDeltaDiscoveryResponse() (*discovery.DeltaDiscoveryResponse, error)

GetDeltaDiscoveryResponse returns the final passthrough Delta Discovery Response.

func (*DeltaPassthroughResponse) GetDeltaRequest 

func (r *DeltaPassthroughResponse) GetDeltaRequest() *discovery.DeltaDiscoveryRequest

GetDeltaRequest returns the original Delta Discovery Request

func (*DeltaPassthroughResponse) GetNextVersionMap 

func (r *DeltaPassthroughResponse) GetNextVersionMap() map[string]string

NextVersionMap returns the version map from a DeltaPassthroughResponse

func (*DeltaPassthroughResponse) GetSystemVersion 

func (r *DeltaPassthroughResponse) GetSystemVersion() (string, error)

GetSystemVersion returns the response version.

type DeltaRequest 

type DeltaRequest = discovery.DeltaDiscoveryRequest

DeltaRequest is an alias for the delta discovery request type.

type DeltaResponse 

type DeltaResponse interface {
	// Get the constructed DeltaDiscoveryResponse
	GetDeltaDiscoveryResponse() (*discovery.DeltaDiscoveryResponse, error)

	// Get the request that created the watch that we're now responding to. This is provided to allow the caller to correlate the
	// response with a request. Generally this will be the latest request seen on the stream for the specific type.
	GetDeltaRequest() *discovery.DeltaDiscoveryRequest

	// Get the version in the DeltaResponse. This field is generally used for debugging purposes as noted by the Envoy documentation.
	GetSystemVersion() (string, error)

	// Get the version map of the internal cache.
	// The version map consists of updated version mappings after this response is applied
	GetNextVersionMap() map[string]string

	// Get the context provided during response creation
	GetContext() context.Context
}

DeltaResponse is a wrapper around Envoy's DeltaDiscoveryResponse

type DeltaResponseWatch 

type DeltaResponseWatch struct {
	// Request is the most recent delta request for the watch
	Request *DeltaRequest

	// Response is the channel to push the delta responses to
	Response chan DeltaResponse

	// VersionMap for the stream
	StreamState stream.StreamState
}

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

type IDHash 

type IDHash struct{}

IDHash uses ID field as the node hash.

func (IDHash) ID 

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

ID uses the node ID field

type LinearCache 

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

LinearCache supports collections 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 

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

NewLinearCache creates a new cache. See the comments on the struct definition.

func (*LinearCache) CreateDeltaWatch 

func (cache *LinearCache) CreateDeltaWatch(request *DeltaRequest, state stream.StreamState, value chan DeltaResponse) func()

func (*LinearCache) CreateWatch 

func (cache *LinearCache) CreateWatch(request *Request, _ stream.StreamState, value chan Response) func()

func (*LinearCache) DeleteResource 

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

DeleteResource removes a resource in the collection.

func (*LinearCache) Fetch 

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

func (*LinearCache) GetResources 

func (cache *LinearCache) GetResources() map[string]types.Resource

GetResources returns current resources stored in the cache

func (*LinearCache) NumDeltaWatches 

func (cache *LinearCache) NumDeltaWatches() int

Number of active delta watches.

func (*LinearCache) NumResources 

func (cache *LinearCache) NumResources() int

Number of resources currently on the cache. As GetResources is building a clone it is expensive to get metrics otherwise.

func (*LinearCache) NumWatches 

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

Number of active watches for a resource name.

func (*LinearCache) SetResources 

func (cache *LinearCache) SetResources(resources map[string]types.Resource)

SetResources replaces current resources with a new set of resources. This function is useful for wildcard xDS subscriptions. This way watches that are subscribed to all resources are triggered only once regardless of how many resources are changed.

func (*LinearCache) UpdateResource 

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

UpdateResource updates a resource in the collection.

func (*LinearCache) UpdateResources 

func (cache *LinearCache) UpdateResources(toUpdate map[string]types.Resource, toDelete []string) error

UpdateResources updates/deletes a list of resources in the cache. Calling UpdateResources instead of iterating on UpdateResource and DeleteResource is significantly more efficient when using delta or wildcard watches.

type LinearCacheOption 

type LinearCacheOption func(*LinearCache)

Options for modifying the behavior of the linear cache.

func WithInitialResources 

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

WithInitialResources initializes the initial set of resources.

func WithLogger 

func WithLogger(log log.Logger) LinearCacheOption

func WithVersionPrefix 

func WithVersionPrefix(prefix string) LinearCacheOption

WithVersionPrefix sets a version prefix of the form "prefixN" in the version info. Version prefix can be used to distinguish replicated instances of the cache, in case a client re-connects to another instance.

type MuxCache 

type MuxCache struct {
	// Classification functions.
	Classify      func(*Request) string
	ClassifyDelta func(*DeltaRequest) 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 (*MuxCache) CreateDeltaWatch 

func (mux *MuxCache) CreateDeltaWatch(request *DeltaRequest, state stream.StreamState, value chan DeltaResponse) func()

func (*MuxCache) CreateWatch 

func (mux *MuxCache) CreateWatch(request *Request, state stream.StreamState, value chan Response) func()

func (*MuxCache) Fetch 

func (mux *MuxCache) Fetch(context.Context, *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 

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

	// The discovery response that needs to be sent as is, without any marshaling transformations.
	DiscoveryResponse *discovery.DiscoveryResponse
	// contains filtered or unexported fields
}

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

func (*PassthroughResponse) GetContext 

func (r *PassthroughResponse) GetContext() context.Context

func (*PassthroughResponse) GetDiscoveryResponse 

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

GetDiscoveryResponse returns the final passthrough Discovery Response.

func (*PassthroughResponse) GetRequest 

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

GetRequest returns the original Discovery Request

func (*PassthroughResponse) GetVersion 

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

GetVersion returns the response version.

type RawDeltaResponse 

type RawDeltaResponse struct {
	// Request is the latest delta request on the stream.
	DeltaRequest *discovery.DeltaDiscoveryRequest

	// SystemVersionInfo holds the currently applied response system version and should be used for debugging purposes only.
	SystemVersionInfo string

	// Resources to be included in the response.
	Resources []types.Resource

	// RemovedResources is a list of resource aliases which should be dropped by the consuming client.
	RemovedResources []string

	// NextVersionMap consists of updated version mappings after this response is applied
	NextVersionMap map[string]string

	// Context provided at the time of response creation. This allows associating additional
	// information with a generated response.
	Ctx context.Context
	// contains filtered or unexported fields
}

RawDeltaResponse is a pre-serialized xDS response that utilizes the delta discovery request/response objects.

func (*RawDeltaResponse) GetContext 

func (r *RawDeltaResponse) GetContext() context.Context

func (*RawDeltaResponse) GetDeltaDiscoveryResponse 

func (r *RawDeltaResponse) GetDeltaDiscoveryResponse() (*discovery.DeltaDiscoveryResponse, error)

GetDeltaDiscoveryResponse performs the marshaling the first time its called and uses the cached response subsequently. We can do this because the marshaled response does not change across the calls. This caching behavior is important in high throughput scenarios because grpc marshaling has a cost and it drives the cpu utilization under load.

func (*RawDeltaResponse) GetDeltaRequest 

func (r *RawDeltaResponse) GetDeltaRequest() *discovery.DeltaDiscoveryRequest

GetDeltaRequest returns the original DeltaRequest

func (*RawDeltaResponse) GetNextVersionMap 

func (r *RawDeltaResponse) GetNextVersionMap() map[string]string

NextVersionMap returns the version map which consists of updated version mappings after this response is applied

func (*RawDeltaResponse) GetSystemVersion 

func (r *RawDeltaResponse) GetSystemVersion() (string, error)

GetSystemVersion returns the raw SystemVersion

type RawResponse 

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.ResourceWithTTL

	// Whether this is a heartbeat response. For xDS versions that support TTL, this
	// will be converted into a response that doesn't contain the actual resource protobuf.
	// This allows for more lightweight updates that server only to update the TTL timer.
	Heartbeat bool

	// Context provided at the time of response creation. This allows associating additional
	// information with a generated response.
	Ctx context.Context
	// 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 (*RawResponse) GetContext 

func (r *RawResponse) GetContext() context.Context

func (*RawResponse) GetDiscoveryResponse 

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

GetDiscoveryResponse performs the marshaling the first time its called and uses the cached response subsequently. This is necessary because the marshaled response does not change across the calls. This caching behavior is important in high throughput scenarios because grpc marshaling has a cost and it drives the cpu utilization under load.

func (*RawResponse) GetRequest 

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

GetRequest returns the original Discovery Request.

func (*RawResponse) GetVersion 

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

GetVersion returns the response version.

type Request 

type Request = discovery.DiscoveryRequest

Request is an alias for the discovery request type.

type ResourceSnapshot 

type ResourceSnapshot interface {
	// GetVersion should return the current version of the resource indicated
	// by typeURL. The version string that is returned is opaque and should
	// only be compared for equality.
	GetVersion(typeURL string) string

	// GetResourcesAndTTL returns all resources of the type indicted by
	// typeURL, together with their TTL.
	GetResourcesAndTTL(typeURL string) map[string]types.ResourceWithTTL

	// GetResources returns all resources of the type indicted by
	// typeURL. This is identical to GetResourcesAndTTL, except that
	// the TTL is omitted.
	GetResources(typeURL string) map[string]types.Resource

	// ConstructVersionMap is a hint that a delta watch will soon make a
	// call to GetVersionMap. The snapshot should construct an internal
	// opaque version string for each collection of resource types.
	ConstructVersionMap() error

	// GetVersionMap returns a map of resource name to resource version for
	// all the resources of type indicated by typeURL.
	GetVersionMap(typeURL string) map[string]string
}

ResourceSnapshot is an abstract snapshot of a collection of resources that can be stored in a SnapshotCache. This enables applications to use the SnapshotCache watch machinery with their own resource types. Most applications will use Snapshot.

type Resources 

type Resources struct {
	// Version information.
	Version string

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

Resources is a versioned group of resources.

func NewResources 

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

NewResources creates a new resource group.

func NewResourcesWithTTL 

func NewResourcesWithTTL(version string, items []types.ResourceWithTTL) Resources

NewResourcesWithTTL creates a new resource group.

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)

	// Get the context provided during response creation.
	GetContext() context.Context
}

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

	// VersionMap holds the current hash map of all resources in the snapshot.
	// This field should remain nil until it is used, at which point should be
	// instantiated by calling ConstructVersionMap().
	// VersionMap is only to be used with delta xDS.
	VersionMap map[string]map[string]string
}

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 

func NewSnapshot(version string, resources map[resource.Type][]types.Resource) (*Snapshot, error)

NewSnapshot creates a snapshot from response types and a version. The resources map is keyed off the type URL of a resource, followed by the slice of resource objects.

func NewSnapshotWithTTLs 

func NewSnapshotWithTTLs(version string, resources map[resource.Type][]types.ResourceWithTTL) (*Snapshot, error)

NewSnapshotWithTTLs creates a snapshot of ResourceWithTTLs. The resources map is keyed off the type URL of a resource, followed by the slice of resource objects.

func (*Snapshot) Consistent 

func (s *Snapshot) Consistent() error

Consistent check verifies that the dependent resources are exactly listed in the snapshot: - all EDS resources are listed by name in CDS resources - all SRDS/RDS resources are listed by name in LDS resources - all RDS resources are listed by name in SRDS resources

Note that clusters and listeners are requested without name references, so Envoy will accept the snapshot list of clusters as-is even if it does not match all references found in xDS.

func (*Snapshot) ConstructVersionMap 

func (s *Snapshot) ConstructVersionMap() error

ConstructVersionMap will construct a version map based on the current state of a snapshot

func (*Snapshot) GetResources 

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

GetResources selects snapshot resources by type, returning the map of resources.

func (*Snapshot) GetResourcesAndTTL 

func (s *Snapshot) GetResourcesAndTTL(typeURL resource.Type) map[string]types.ResourceWithTTL

GetResourcesAndTTL selects snapshot resources by type, returning the map of resources and the associated TTL.

func (*Snapshot) GetVersion 

func (s *Snapshot) GetVersion(typeURL resource.Type) string

GetVersion returns the version for a resource type.

func (*Snapshot) GetVersionMap 

func (s *Snapshot) GetVersionMap(typeURL string) map[string]string

GetVersionMap will return the internal version map of the currently applied snapshot.

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(ctx context.Context, node string, snapshot ResourceSnapshot) error

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

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

NewSnapshotCache initializes a simple cache.

ADS flag forces a delay in responding to streaming requests until all resources are explicitly named in the request. This avoids the problem of a partial request over a single stream for a subset of resources which would require generating a fresh version for acknowledgement. ADS flag requires snapshot consistency. For non-ADS case (and fetch), multiple partial requests are sent across multiple streams and re-using the snapshot version is OK.

Logger is optional.

func NewSnapshotCacheWithHeartbeating 

func NewSnapshotCacheWithHeartbeating(ctx context.Context, ads bool, hash NodeHash, logger log.Logger, heartbeatInterval time.Duration) SnapshotCache

NewSnapshotCacheWithHeartbeating initializes a simple cache that sends periodic heartbeat responses for resources with a TTL.

ADS flag forces a delay in responding to streaming requests until all resources are explicitly named in the request. This avoids the problem of a partial request over a single stream for a subset of resources which would require generating a fresh version for acknowledgement. ADS flag requires snapshot consistency. For non-ADS case (and fetch), multiple partial requests are sent across multiple streams and re-using the snapshot version is OK.

Logger is optional.

The context provides a way to cancel the heartbeating routine, while the heartbeatInterval parameter controls how often heartbeating occurs.

type StatusInfo 

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

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

	// GetNumDeltaWatches returns the number of open delta watches.
	GetNumDeltaWatches() int

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

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

StatusInfo publishes information about nodes that are watching the xDS cache.

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