resolver

type Address struct {
	// Addr is the server address on which a connection will be established.
	Addr string

	// ServerName is the name of this address.
	// If non-empty, the ServerName is used as the transport certification authority for
	// the address, instead of the hostname from the Dial target string. In most cases,
	// this should not be set.
	//
	// WARNING: ServerName must only be populated with trusted values. It
	// is insecure to populate it with data from untrusted inputs since untrusted
	// values could be used to bypass the authority checks performed by TLS.
	ServerName string

	// Attributes contains arbitrary data about this address intended for
	// consumption by the SubConn.
	Attributes *attributes.Attributes

	// BalancerAttributes contains arbitrary data about this address intended
	// for consumption by the LB policy.  These attributes do not affect SubConn
	// creation, connection establishment, handshaking, etc.
	//
	// Deprecated: when an Address is inside an Endpoint, this field should not
	// be used, and it will eventually be removed entirely.
	BalancerAttributes *attributes.Attributes

	// Metadata is the information associated with Addr, which may be used
	// to make load balancing decision.
	//
	// Deprecated: use Attributes instead.
	Metadata any
}

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

type AuthorityOverrider interface {
	// OverrideAuthority returns the authority to use for a ClientConn with the
	// given target. The implementation must generate it without blocking,
	// typically in line, and must keep it unchanged.
	OverrideAuthority(Target) string
}

type BuildOptions struct {
	// DisableServiceConfig indicates whether a resolver implementation should
	// fetch service config data.
	DisableServiceConfig bool
	// DialCreds is the transport credentials used by the ClientConn for
	// communicating with the target gRPC service (set via
	// WithTransportCredentials). In cases where a name resolution service
	// requires the same credentials, the resolver may use this field. In most
	// cases though, it is not appropriate, and this field may be ignored.
	DialCreds credentials.TransportCredentials
	// CredsBundle is the credentials bundle used by the ClientConn for
	// communicating with the target gRPC service (set via
	// WithCredentialsBundle). In cases where a name resolution service
	// requires the same credentials, the resolver may use this field. In most
	// cases though, it is not appropriate, and this field may be ignored.
	CredsBundle credentials.Bundle
	// Dialer is the custom dialer used by the ClientConn for dialling the
	// target gRPC service (set via WithDialer). In cases where a name
	// resolution service requires the same dialer, the resolver may use this
	// field. In most cases though, it is not appropriate, and this field may
	// be ignored.
	Dialer func(context.Context, string) (net.Conn, error)
	// Authority is the effective authority of the clientconn for which the
	// resolver is built.
	Authority string
}

type Builder interface {
	// Build creates a new resolver for the given target.
	//
	// gRPC dial calls Build synchronously, and fails if the returned error is
	// not nil.
	Build(target Target, cc ClientConn, opts BuildOptions) (Resolver, error)
	// Scheme returns the scheme supported by this resolver.  Scheme is defined
	// at https://github.com/grpc/grpc/blob/master/doc/naming.md.  The returned
	// string should not contain uppercase characters, as they will not match
	// the parsed target's scheme as defined in RFC 3986.
	Scheme() string
}

type ClientConn interface {
	// UpdateState updates the state of the ClientConn appropriately.
	//
	// If an error is returned, the resolver should try to resolve the
	// target again. The resolver should use a backoff timer to prevent
	// overloading the server with requests. If a resolver is certain that
	// reresolving will not change the result, e.g. because it is
	// a watch-based resolver, returned errors can be ignored.
	//
	// If the resolved State is the same as the last reported one, calling
	// UpdateState can be omitted.
	UpdateState(State) error
	// ReportError notifies the ClientConn that the Resolver encountered an
	// error.  The ClientConn will notify the load balancer and begin calling
	// ResolveNow on the Resolver with exponential backoff.
	ReportError(error)
	// NewAddress is called by resolver to notify ClientConn a new list
	// of resolved addresses.
	// The address list should be the complete list of resolved addresses.
	//
	// Deprecated: Use UpdateState instead.
	NewAddress(addresses []Address)
	// ParseServiceConfig parses the provided service config and returns an
	// object that provides the parsed config.
	ParseServiceConfig(serviceConfigJSON string) *serviceconfig.ParseResult
}

type Endpoint struct {
	// Addresses contains a list of addresses used to access this endpoint.
	Addresses []Address

	// Attributes contains arbitrary data about this endpoint intended for
	// consumption by the LB policy.
	Attributes *attributes.Attributes
}

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

type ResolveNowOptions struct{}

type Resolver interface {
	// ResolveNow will be called by gRPC to try to resolve the target name
	// again. It's just a hint, resolver can ignore this if it's not necessary.
	//
	// It could be called multiple times concurrently.
	ResolveNow(ResolveNowOptions)
	// Close closes the resolver.
	Close()
}

type State struct {
	// Addresses is the latest set of resolved addresses for the target.
	//
	// If a resolver sets Addresses but does not set Endpoints, one Endpoint
	// will be created for each Address before the State is passed to the LB
	// policy.  The BalancerAttributes of each entry in Addresses will be set
	// in Endpoints.Attributes, and be cleared in the Endpoint's Address's
	// BalancerAttributes.
	//
	// Soon, Addresses will be deprecated and replaced fully by Endpoints.
	Addresses []Address

	// Endpoints is the latest set of resolved endpoints for the target.
	//
	// If a resolver produces a State containing Endpoints but not Addresses,
	// it must take care to ensure the LB policies it selects will support
	// Endpoints.
	Endpoints []Endpoint

	// ServiceConfig contains the result from parsing the latest service
	// config.  If it is nil, it indicates no service config is present or the
	// resolver does not provide service configs.
	ServiceConfig *serviceconfig.ParseResult

	// Attributes contains arbitrary data about the resolver intended for
	// consumption by the load balancing policy.
	Attributes *attributes.Attributes
}

type Target struct {
	// URL contains the parsed dial target with an optional default scheme added
	// to it if the original dial target contained no scheme or contained an
	// unregistered scheme. Any query params specified in the original dial
	// target can be accessed from here.
	URL url.URL
}