io.envoyproxy.controlplane.cache

Class SimpleCache<T>

java.lang.Object

io.envoyproxy.controlplane.cache.SimpleCache<T>

All Implemented Interfaces:

Cache<T>, ConfigWatcher, SnapshotCache<T>

public class SimpleCache<T>
extends Object
implements SnapshotCache<T>

SimpleCache provides a default implementation of SnapshotCache. It maintains a single versioned Snapshot per node group. For the protocol to work correctly in ADS mode, EDS/RDS requests are responded to 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.

The snapshot can be partial, e.g. only include RDS or EDS resources.

Constructor Summary

Constructors

Constructor and Description
SimpleCache(NodeGroup<T> groups) Constructs a simple cache.

Method Summary

Modifier and Type	Method and Description
boolean	clearSnapshot(T group) Clears the most recently set Snapshot and associated metadata for the given node group.
Watch	createWatch(boolean ads, Discovery.DiscoveryRequest request, Set<String> knownResourceNames, Consumer<Response> responseConsumer) Returns a new configuration resource Watch for the given discovery request.
Snapshot	getSnapshot(T group) Returns the most recently set Snapshot for the given node group.
Collection<T>	groups() Returns all known Base.Node groups.
void	setSnapshot(T group, Snapshot snapshot) Set the Snapshot for the given node group.
StatusInfo	statusInfo(T group) Returns the current StatusInfo for the given Base.Node group.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

SimpleCache

public SimpleCache(NodeGroup<T> groups)

Constructs a simple cache.

Parameters:

groups - maps an envoy host to a node group

Method Detail

clearSnapshot

public boolean clearSnapshot(T group)

Clears the most recently set Snapshot and associated metadata for the given node group.

Should only be called when the Snapshot will no longer be needed, e.g. when there are no open watches for the group.

Implementations are free to ignore this call should it possibly leave the cache in a bad state, e.g. causing watches to hang waiting for Snapshot options that will never happen.

Specified by:

clearSnapshot in interface SnapshotCache<T>

Parameters:

group - group identifier

Returns:

true if the snapshot was cleared, false otherwise

createWatch

public Watch createWatch(boolean ads,
                         Discovery.DiscoveryRequest request,
                         Set<String> knownResourceNames,
                         Consumer<Response> responseConsumer)

Returns a new configuration resource Watch for the given discovery request.

Specified by:

createWatch in interface ConfigWatcher

Parameters:

ads - is the watch for an ADS request?

request - the discovery request (node, names, etc.) to use to generate the watch

knownResourceNames - resources that are already known to the caller

responseConsumer - the response handler, used to process outgoing response messages

getSnapshot

public Snapshot getSnapshot(T group)

Returns the most recently set Snapshot for the given node group.

Specified by:

getSnapshot in interface SnapshotCache<T>

Parameters:

group - group identifier

Returns:

latest snapshot

groups

public Collection<T> groups()

Returns all known Base.Node groups.

Specified by:

groups in interface Cache<T>

setSnapshot

public void setSnapshot(T group,
                        Snapshot snapshot)

Set the Snapshot for the given node group. Snapshots should have distinct versions and be internally consistent (i.e. all referenced resources must be included in the snapshot).

Specified by:

setSnapshot in interface SnapshotCache<T>

Parameters:

group - group identifier

snapshot - a versioned collection of node config data

statusInfo

public StatusInfo statusInfo(T group)

Returns the current StatusInfo for the given Base.Node group.

Specified by:

statusInfo in interface Cache<T>

Parameters:

group - the node group whose status is being fetched