Documentation

Overview

Package client implementation a full fledged gRPC client for the xDS API used by the xds resolver and balancer implementations.

Index

Constants

This section is empty.

Variables

This section is empty.

Functions

func IsClusterResource

func IsClusterResource(url string) bool

IsClusterResource returns true if the provider URL corresponds to an xDS Cluster resource.

func IsEndpointsResource

func IsEndpointsResource(url string) bool

IsEndpointsResource returns true if the provider URL corresponds to an xDS Endpoints resource.

func IsHTTPConnManagerResource

func IsHTTPConnManagerResource(url string) bool

IsHTTPConnManagerResource returns true if the provider URL corresponds to an xDS HTTPConnManager resource.

func IsListenerResource

func IsListenerResource(url string) bool

IsListenerResource returns true if the provider URL corresponds to an xDS Listener resource.

func IsRouteConfigResource

func IsRouteConfigResource(url string) bool

IsRouteConfigResource returns true if the provider URL corresponds to an xDS RouteConfig resource.

func NewErrorf

func NewErrorf(t ErrorType, format string, args ...interface{}) error

NewErrorf creates an xds client error. The callbacks are called with this error, to pass additional information about the error.

func RegisterAPIClientBuilder

func RegisterAPIClientBuilder(b APIClientBuilder)

RegisterAPIClientBuilder registers a client builder for xDS transport protocol version specified by b.Version().

NOTE: this function must only be called during initialization time (i.e. in an init() function), and is not thread-safe. If multiple builders are registered for the same version, the one registered last will take effect.

func SetMaxRequests

func SetMaxRequests(serviceName string, maxRequests *uint32)

SetMaxRequests updates the max requests for a service's counter.

func UnmarshalCluster

func UnmarshalCluster(resources []*anypb.Any, logger *grpclog.PrefixLogger) (map[string]ClusterUpdate, error)

UnmarshalCluster processes resources received in an CDS response, validates them, and transforms them into a native struct which contains only fields we are interested in.

func UnmarshalEndpoints

func UnmarshalEndpoints(resources []*anypb.Any, logger *grpclog.PrefixLogger) (map[string]EndpointsUpdate, error)

UnmarshalEndpoints processes resources received in an EDS response, validates them, and transforms them into a native struct which contains only fields we are interested in.

func UnmarshalListener

func UnmarshalListener(resources []*anypb.Any, logger *grpclog.PrefixLogger) (map[string]ListenerUpdate, error)

UnmarshalListener processes resources received in an LDS response, validates them, and transforms them into a native struct which contains only fields we are interested in.

func UnmarshalRouteConfig

func UnmarshalRouteConfig(resources []*anypb.Any, logger *grpclog.PrefixLogger) (map[string]RouteConfigUpdate, error)

UnmarshalRouteConfig processes resources received in an RDS response, validates them, and transforms them into a native struct which contains only fields we are interested in. The provided hostname determines the route configuration resources of interest.

Types

type APIClient

type APIClient interface {
	// AddWatch adds a watch for an xDS resource given its type and name.
	AddWatch(ResourceType, string)

	// RemoveWatch cancels an already registered watch for an xDS resource
	// given its type and name.
	RemoveWatch(ResourceType, string)

	// Close cleans up resources allocated by the API client.
	Close()
	// contains filtered or unexported methods
}

APIClient represents the functionality provided by transport protocol version specific implementations of the xDS client.

TODO: unexport this interface and all the methods after the PR to make xdsClient sharable by clients. AddWatch and RemoveWatch are exported for v2/v3 to override because they need to keep track of LDS name for RDS to use. After the share xdsClient change, that's no longer necessary. After that, we will still keep this interface for testing purposes.

type APIClientBuilder

type APIClientBuilder interface {
	// Build builds a transport protocol specific implementation of the xDS
	// client based on the provided clientConn to the management server and the
	// provided options.
	Build(*grpc.ClientConn, BuildOptions) (APIClient, error)
	// Version returns the xDS transport protocol version used by clients build
	// using this builder.
	Version() version.TransportAPI
}

APIClientBuilder creates an xDS client for a specific xDS transport protocol version.

type BuildOptions

type BuildOptions struct {
	// Parent is a top-level xDS client which has the intelligence to take
	// appropriate action based on xDS responses received from the management
	// server.
	Parent UpdateHandler
	// NodeProto contains the Node proto to be used in xDS requests. The actual
	// type depends on the transport protocol version used.
	NodeProto proto.Message
	// Backoff returns the amount of time to backoff before retrying broken
	// streams.
	Backoff func(int) time.Duration
	// Logger provides enhanced logging capabilities.
	Logger *grpclog.PrefixLogger
}

BuildOptions contains options to be passed to client builders.

type Client

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

Client is a full fledged gRPC client which queries a set of discovery APIs (collectively termed as xDS) on a remote management server, to discover various dynamic resources.

The xds client is a singleton. It will be shared by the xds resolver and balancer implementations, across multiple ClientConns and Servers.

func New

func New() (*Client, error)

New returns a new xdsClient configured by the bootstrap file specified in env variable GRPC_XDS_BOOTSTRAP.

func NewWithConfigForTesting

func NewWithConfigForTesting(config *bootstrap.Config, watchExpiryTimeout time.Duration) (*Client, error)

NewWithConfigForTesting is exported for testing only.

func (*Client) BootstrapConfig

func (c *Client) BootstrapConfig() *bootstrap.Config

BootstrapConfig returns the configuration read from the bootstrap file. Callers must treat the return value as read-only.

func (*Client) Close

func (c *Client) Close()

Close closes the client. It does ref count of the xds client implementation, and closes the gRPC connection to the management server when ref count reaches 0.

func (Client) NewClusters

func (c Client) NewClusters(updates map[string]ClusterUpdate)

NewClusters is called by the underlying xdsAPIClient when it receives an xDS response.

A response can contain multiple resources. They will be parsed and put in a map from resource name to the resource content.

func (Client) NewEndpoints

func (c Client) NewEndpoints(updates map[string]EndpointsUpdate)

NewEndpoints is called by the underlying xdsAPIClient when it receives an xDS response.

A response can contain multiple resources. They will be parsed and put in a map from resource name to the resource content.

func (Client) NewListeners

func (c Client) NewListeners(updates map[string]ListenerUpdate)

NewListeners is called by the underlying xdsAPIClient when it receives an xDS response.

A response can contain multiple resources. They will be parsed and put in a map from resource name to the resource content.

func (Client) NewRouteConfigs

func (c Client) NewRouteConfigs(updates map[string]RouteConfigUpdate)

NewRouteConfigs is called by the underlying xdsAPIClient when it receives an xDS response.

A response can contain multiple resources. They will be parsed and put in a map from resource name to the resource content.

func (Client) ReportLoad

func (c Client) ReportLoad(server string) (*load.Store, func())

ReportLoad starts an load reporting stream to the given server. If the server is not an empty string, and is different from the management server, a new ClientConn will be created.

The same options used for creating the Client will be used (including NodeProto, and dial options if necessary).

It returns a Store for the user to report loads, a function to cancel the load reporting stream.

func (Client) WatchCluster

func (c Client) WatchCluster(clusterName string, cb func(ClusterUpdate, error)) (cancel func())

WatchCluster uses CDS to discover information about the provided clusterName.

WatchCluster can be called multiple times, with same or different clusterNames. Each call will start an independent watcher for the resource.

Note that during race (e.g. an xDS response is received while the user is calling cancel()), there's a small window where the callback can be called after the watcher is canceled. The caller needs to handle this case.

func (Client) WatchEndpoints

func (c Client) WatchEndpoints(clusterName string, cb func(EndpointsUpdate, error)) (cancel func())

WatchEndpoints uses EDS to discover endpoints in the provided clusterName.

WatchEndpoints can be called multiple times, with same or different clusterNames. Each call will start an independent watcher for the resource.

Note that during race (e.g. an xDS response is received while the user is calling cancel()), there's a small window where the callback can be called after the watcher is canceled. The caller needs to handle this case.

func (Client) WatchListener

func (c Client) WatchListener(serviceName string, cb func(ListenerUpdate, error)) (cancel func())

WatchListener uses LDS to discover information about the provided listener.

Note that during race (e.g. an xDS response is received while the user is calling cancel()), there's a small window where the callback can be called after the watcher is canceled. The caller needs to handle this case.

func (Client) WatchRouteConfig

func (c Client) WatchRouteConfig(routeName string, cb func(RouteConfigUpdate, error)) (cancel func())

WatchRouteConfig starts a listener watcher for the service..

Note that during race (e.g. an xDS response is received while the user is calling cancel()), there's a small window where the callback can be called after the watcher is canceled. The caller needs to handle this case.

type ClusterUpdate

type ClusterUpdate struct {
	// ServiceName is the service name corresponding to the clusterName which
	// is being watched for through CDS.
	ServiceName string
	// EnableLRS indicates whether or not load should be reported through LRS.
	EnableLRS bool
	// SecurityCfg contains security configuration sent by the control plane.
	SecurityCfg *SecurityConfig
	// MaxRequests for circuit breaking, if any (otherwise nil).
	MaxRequests *uint32
}

ClusterUpdate contains information from a received CDS response, which is of interest to the registered CDS watcher.

type Endpoint

type Endpoint struct {
	Address      string
	HealthStatus EndpointHealthStatus
	Weight       uint32
}

Endpoint contains information of an endpoint.

type EndpointHealthStatus

type EndpointHealthStatus int32

EndpointHealthStatus represents the health status of an endpoint.

const (
	// EndpointHealthStatusUnknown represents HealthStatus UNKNOWN.
	EndpointHealthStatusUnknown EndpointHealthStatus = iota
	// EndpointHealthStatusHealthy represents HealthStatus HEALTHY.
	EndpointHealthStatusHealthy
	// EndpointHealthStatusUnhealthy represents HealthStatus UNHEALTHY.
	EndpointHealthStatusUnhealthy
	// EndpointHealthStatusDraining represents HealthStatus DRAINING.
	EndpointHealthStatusDraining
	// EndpointHealthStatusTimeout represents HealthStatus TIMEOUT.
	EndpointHealthStatusTimeout
	// EndpointHealthStatusDegraded represents HealthStatus DEGRADED.
	EndpointHealthStatusDegraded
)

type EndpointsUpdate

type EndpointsUpdate struct {
	Drops      []OverloadDropConfig
	Localities []Locality
}

EndpointsUpdate contains an EDS update.

type ErrResourceTypeUnsupported

type ErrResourceTypeUnsupported struct {
	ErrStr string
}

ErrResourceTypeUnsupported is an error used to indicate an unsupported xDS resource type. The wrapped ErrStr contains the details.

func (ErrResourceTypeUnsupported) Error

Error helps implements the error interface.

type ErrorType

type ErrorType int

ErrorType is the type of the error that the watcher will receive from the xds client.

const (
	// ErrorTypeUnknown indicates the error doesn't have a specific type. It is
	// the default value, and is returned if the error is not an xds error.
	ErrorTypeUnknown ErrorType = iota
	// ErrorTypeConnection indicates a connection error from the gRPC client.
	ErrorTypeConnection
	// ErrorTypeResourceNotFound indicates a resource is not found from the xds
	// response. It's typically returned if the resource is removed in the xds
	// server.
	ErrorTypeResourceNotFound
)

func ErrType

func ErrType(e error) ErrorType

ErrType returns the error's type.

type HeaderMatcher

type HeaderMatcher struct {
	Name         string      `json:"name"`
	InvertMatch  *bool       `json:"invertMatch,omitempty"`
	ExactMatch   *string     `json:"exactMatch,omitempty"`
	RegexMatch   *string     `json:"regexMatch,omitempty"`
	PrefixMatch  *string     `json:"prefixMatch,omitempty"`
	SuffixMatch  *string     `json:"suffixMatch,omitempty"`
	RangeMatch   *Int64Range `json:"rangeMatch,omitempty"`
	PresentMatch *bool       `json:"presentMatch,omitempty"`
}

HeaderMatcher represents header matchers.

type Int64Range

type Int64Range struct {
	Start int64 `json:"start"`
	End   int64 `json:"end"`
}

Int64Range is a range for header range match.

type ListenerUpdate

type ListenerUpdate struct {
	// RouteConfigName is the route configuration name corresponding to the
	// target which is being watched through LDS.
	RouteConfigName string
	// SecurityCfg contains security configuration sent by the control plane.
	SecurityCfg *SecurityConfig
	// MaxStreamDuration contains the HTTP connection manager's
	// common_http_protocol_options.max_stream_duration field, or zero if
	// unset.
	MaxStreamDuration time.Duration
}

ListenerUpdate contains information received in an LDS response, which is of interest to the registered LDS watcher.

func (*ListenerUpdate) String

func (lu *ListenerUpdate) String() string

type Locality

type Locality struct {
	Endpoints []Endpoint
	ID        internal.LocalityID
	Priority  uint32
	Weight    uint32
}

Locality contains information of a locality.

type OverloadDropConfig

type OverloadDropConfig struct {
	Category    string
	Numerator   uint32
	Denominator uint32
}

OverloadDropConfig contains the config to drop overloads.

type ResourceType

type ResourceType int

ResourceType identifies resources in a transport protocol agnostic way. These will be used in transport version agnostic code, while the versioned API clients will map these to appropriate version URLs.

const (
	UnknownResource ResourceType = iota
	ListenerResource
	HTTPConnManagerResource
	RouteConfigResource
	ClusterResource
	EndpointsResource
)

Version agnostic resource type constants.

func (ResourceType) String

func (r ResourceType) String() string

type Route

type Route struct {
	Path, Prefix, Regex *string
	// Indicates if prefix/path matching should be case insensitive. The default
	// is false (case sensitive).
	CaseInsensitive bool
	Headers         []*HeaderMatcher
	Fraction        *uint32

	// If the matchers above indicate a match, the below configuration is used.
	Action map[string]uint32 // action is weighted clusters.
	// If MaxStreamDuration is nil, it indicates neither of the route action's
	// max_stream_duration fields (grpc_timeout_header_max nor
	// max_stream_duration) were set.  In this case, the ListenerUpdate's
	// MaxStreamDuration field should be used.  If MaxStreamDuration is set to
	// an explicit zero duration, the application's deadline should be used.
	MaxStreamDuration *time.Duration
}

Route is both a specification of how to match a request as well as an indication of the action to take upon match.

type RouteConfigUpdate

type RouteConfigUpdate struct {
	VirtualHosts []*VirtualHost
}

RouteConfigUpdate contains information received in an RDS response, which is of interest to the registered RDS watcher.

type SecurityConfig

type SecurityConfig struct {
	// RootInstanceName identifies the certProvider plugin to be used to fetch
	// root certificates. This instance name will be resolved to the plugin name
	// and its associated configuration from the certificate_providers field of
	// the bootstrap file.
	RootInstanceName string
	// RootCertName is the certificate name to be passed to the plugin (looked
	// up from the bootstrap file) while fetching root certificates.
	RootCertName string
	// IdentityInstanceName identifies the certProvider plugin to be used to
	// fetch identity certificates. This instance name will be resolved to the
	// plugin name and its associated configuration from the
	// certificate_providers field of the bootstrap file.
	IdentityInstanceName string
	// IdentityCertName is the certificate name to be passed to the plugin
	// (looked up from the bootstrap file) while fetching identity certificates.
	IdentityCertName string
	// AcceptedSANs is a list of Subject Alternative Names. During the TLS
	// handshake, the SAN present in the peer certificate is compared against
	// this list, and the handshake succeeds only if a match is found. Used only
	// on the client-side.
	AcceptedSANs []string
	// RequireClientCert indicates if the server handshake process expects the
	// client to present a certificate. Set to true when performing mTLS. Used
	// only on the server-side.
	RequireClientCert bool
}

SecurityConfig contains the security configuration received as part of the Cluster resource on the client-side, and as part of the Listener resource on the server-side.

type ServiceRequestsCounter

type ServiceRequestsCounter struct {
	ServiceName string
	// contains filtered or unexported fields
}

ServiceRequestsCounter is used to track the total inflight requests for a service with the provided name.

func GetServiceRequestsCounter

func GetServiceRequestsCounter(serviceName string) *ServiceRequestsCounter

GetServiceRequestsCounter returns the ServiceRequestsCounter with the provided serviceName. If one does not exist, it creates it.

func (*ServiceRequestsCounter) EndRequest

func (c *ServiceRequestsCounter) EndRequest()

EndRequest ends a request for a service, decrementing its number of requests by 1.

func (*ServiceRequestsCounter) StartRequest

func (c *ServiceRequestsCounter) StartRequest() error

StartRequest starts a request for a service, incrementing its number of requests by 1. Returns an error if the max number of requests is exceeded.

type TransportHelper

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

TransportHelper contains all xDS transport protocol related functionality which is common across different versioned client implementations.

TransportHelper takes care of sending and receiving xDS requests and responses on an ADS stream. It also takes care of ACK/NACK handling. It delegates to the actual versioned client implementations wherever appropriate.

Implements the APIClient interface which makes it possible for versioned client implementations to embed this type, and thereby satisfy the interface requirements.

func NewTransportHelper

func NewTransportHelper(vc VersionedClient, logger *grpclog.PrefixLogger, backoff func(int) time.Duration) *TransportHelper

NewTransportHelper creates a new transport helper to be used by versioned client implementations.

func (*TransportHelper) AddWatch

func (t *TransportHelper) AddWatch(rType ResourceType, resourceName string)

AddWatch adds a watch for an xDS resource given its type and name.

func (*TransportHelper) Close

func (t *TransportHelper) Close()

Close closes the transport helper.

func (*TransportHelper) RemoveWatch

func (t *TransportHelper) RemoveWatch(rType ResourceType, resourceName string)

RemoveWatch cancels an already registered watch for an xDS resource given its type and name.

type UpdateHandler

type UpdateHandler interface {
	// NewListeners handles updates to xDS listener resources.
	NewListeners(map[string]ListenerUpdate)
	// NewRouteConfigs handles updates to xDS RouteConfiguration resources.
	NewRouteConfigs(map[string]RouteConfigUpdate)
	// NewClusters handles updates to xDS Cluster resources.
	NewClusters(map[string]ClusterUpdate)
	// NewEndpoints handles updates to xDS ClusterLoadAssignment (or tersely
	// referred to as Endpoints) resources.
	NewEndpoints(map[string]EndpointsUpdate)
}

UpdateHandler receives and processes (by taking appropriate actions) xDS resource updates from an APIClient for a specific version.

type VersionedClient

type VersionedClient interface {
	// NewStream returns a new xDS client stream specific to the underlying
	// transport protocol version.
	NewStream(ctx context.Context) (grpc.ClientStream, error)

	// SendRequest constructs and sends out a DiscoveryRequest message specific
	// to the underlying transport protocol version.
	SendRequest(s grpc.ClientStream, resourceNames []string, rType ResourceType, version, nonce, errMsg string) error

	// RecvResponse uses the provided stream to receive a response specific to
	// the underlying transport protocol version.
	RecvResponse(s grpc.ClientStream) (proto.Message, error)

	// HandleResponse parses and validates the received response and notifies
	// the top-level client which in turn notifies the registered watchers.
	//
	// Return values are: resourceType, version, nonce, error.
	// If the provided protobuf message contains a resource type which is not
	// supported, implementations must return an error of type
	// ErrResourceTypeUnsupported.
	HandleResponse(proto.Message) (ResourceType, string, string, error)

	// NewLoadStatsStream returns a new LRS client stream specific to the underlying
	// transport protocol version.
	NewLoadStatsStream(ctx context.Context, cc *grpc.ClientConn) (grpc.ClientStream, error)

	// SendFirstLoadStatsRequest constructs and sends the first request on the
	// LRS stream.
	SendFirstLoadStatsRequest(s grpc.ClientStream) error

	// HandleLoadStatsResponse receives the first response from the server which
	// contains the load reporting interval and the clusters for which the
	// server asks the client to report load for.
	//
	// If the response sets SendAllClusters to true, the returned clusters is
	// nil.
	HandleLoadStatsResponse(s grpc.ClientStream) (clusters []string, _ time.Duration, _ error)

	// SendLoadStatsRequest will be invoked at regular intervals to send load
	// report with load data reported since the last time this method was
	// invoked.
	SendLoadStatsRequest(s grpc.ClientStream, loads []*load.Data) error
}

VersionedClient is the interface to be provided by the transport protocol specific client implementations. This mainly deals with the actual sending and receiving of messages.

type VirtualHost

type VirtualHost struct {
	Domains []string
	// Routes contains a list of routes, each containing matchers and
	// corresponding action.
	Routes []*Route
}

VirtualHost contains the routes for a list of Domains.

Note that the domains in this slice can be a wildcard, not an exact string. The consumer of this struct needs to find the best match for its hostname.

Directories

Path Synopsis
bootstrap Package bootstrap provides the functionality to initialize certain aspects of an xDS client by reading a bootstrap file.
load Package load provides functionality to record and maintain load data.
v2 Package v2 provides xDS v2 transport protocol specific functionality.
v3 Package v3 provides xDS v3 transport protocol specific functionality.