comms

type ClientInfo struct {
	ID          common.ClientID
	Key         crypto.PublicKey
	Labels      []*fspb.Label
	Blacklisted bool
	Cached      bool // Whether the data was retrieved from a cache.
}

type Communicator interface {
	Setup(Context) error // Configure the communicator to work with a Server.
	Start() error        // Tells the communicator to start sending and receiving messages.
	Stop()               // Tells the communicator to stop sending and receiving messages.
}

type ConnectionInfo struct {
	Addr                     net.Addr
	Client                   ClientInfo
	ContactID                db.ContactID
	NonceSent, NonceReceived uint64
	AuthClientInfo           authorizer.ClientInfo

	// These are only set for streaming connections.
	Notices <-chan struct{} // publishes when there may be a new message for the client
	Fin     func()          // should be called to indicate that the streaming connection is closed.
	// contains filtered or unexported fields
}

type Context interface {

	// InitializeConnection attempts to validate and configure a client
	// connection, and performs an initial exchange of messages.
	//
	// On success this effectively calls both HandleMessagesFromClient and
	// GetMessagesForClient.
	//
	// The returned ContactData should be sent back to the client unconditionally,
	// in order to update the client's de-duplication nonce.
	//
	// In addition, returns an indication whether there might be additional
	// messages for the client.
	InitializeConnection(ctx context.Context, addr net.Addr, key crypto.PublicKey, wcd *fspb.WrappedContactData, streaming bool) (i *ConnectionInfo, d *fspb.ContactData, more bool, err error)

	// ValidateMessagesFromClient validates the message contained in WrappedContactData.
	// On successful validation it returns the fspb.ValidationInfo data structure.
	ValidateMessagesFromClient(ctx context.Context, info *ConnectionInfo, wcd *fspb.WrappedContactData) (*fspb.ValidationInfo, error)

	// HandleMessagesFromClient processes the messages contained in a WrappedContactData
	// received from the client.  The ConnectionInfo parameter should have been
	// created by an InitializeConnection call made for this connection.
	HandleMessagesFromClient(ctx context.Context, info *ConnectionInfo, wcd *fspb.WrappedContactData) error

	// GetMessagesForClient finds unprocessed messages for a given client and
	// reserves them for processing. The ConnectionInfo parameter should have been
	// created by an InitializeConnection call made for this connection.
	//
	// In addition to some messages, also indicates wether there may be more
	// messages to get.
	//
	// Returns nil, false, nil when there are no outstanding messages for
	// the client.
	GetMessagesForClient(ctx context.Context, info *ConnectionInfo) (data *fspb.ContactData, more bool, err error)

	// ReadFile returns the data and modification time of file. Caller is
	// responsible for closing data.
	//
	// Calls to data are permitted to fail if ctx is canceled or expired.
	ReadFile(ctx context.Context, service, name string) (data db.ReadSeekerCloser, modtime time.Time, err error)

	// IsNotFound returns whether an error returned by ReadFile indicates that the
	// file was not found.
	IsNotFound(err error) bool

	// StatsCollector returns the stats.Collector used by the Fleetspeak
	// system.
	StatsCollector() stats.Collector

	// Authorizer returns the authorizer.Authorizer used by the Fleetspeak
	// system.  The Communicator is responsible for calling Accept1.
	Authorizer() authorizer.Authorizer
}