wire

type ActiveObject ¶

type ActiveObject struct {
	Kind  string
	TS    time.Time // last updated
	Props Diff
}

ActiveObject is a record in the hot start file representing an object in the active set

type ActiveSetHeader ¶

type ActiveSetHeader struct {
	Version  int
	Position Position
}

ActiveSetHeader is the header of the hot start file

type Changes ¶

type Changes map[string]KindChanges // kind -> ID -> diff

Changes is a set of diffs organized by kind and ID

func (c Changes) Clone() Changes

func (c Changes) MarshalLogObject(e zapcore.ObjectEncoder) error

func (c Changes) Optimize()

type Diff ¶

type Diff map[string]json.RawMessage

A Diff represents a patch to an entity. It is a mapping from a field name to its new value (serialized as JSON).

func Encode(metaStruct meta.Struct, before, after any, validate ValidateFn) (Diff, error)

func (d Diff) Clone() Diff

func (d Diff) MarshalLogObject(e zapcore.ObjectEncoder) error

type ErrMismatch ¶

type ErrMismatch string

ErrMismatch is an error type for fatal problems: * database version mismatch * position continuity broken

const ErrContinuityBroken ErrMismatch = "continuity broken"

func ErrVersionMismatch(expected, actual int) ErrMismatch

func (err ErrMismatch) Error() string

func (ErrMismatch) ExitCode() int

type Filter ¶

type Filter map[string][]string

Filter describes a filter for relevant kinds and property names.

The map has an entry for each kind, with the kind name as key and the list of relevant property names as value.

A nil value of a map entry means all properties of the kind are relevant.

A nil value of the map itself means all properties of all kinds are relevant.

type IncomingTransaction ¶

type IncomingTransaction struct {
	Transaction
	Position Position
}

IncomingTransaction is a transaction annotated by its position. Wire format only.

func (txn IncomingTransaction) MarshalLogObject(e zapcore.ObjectEncoder) error

type KindChanges ¶

type KindChanges map[string]Diff // ID -> diff

KindChanges is a set of diffs organized by ID, for a single kind

func (kc KindChanges) Clone() KindChanges

func (kc KindChanges) MarshalLogArray(e zapcore.ArrayEncoder) error

func (kc KindChanges) Optimize()

type Manifest ¶

type Manifest struct {
	Version int
	Topic   string

	Maintenance bool `json:",omitempty"` // If true, only maintenance tools are allowed to touch the database

	Audit json.RawMessage `json:",omitempty"` // extra metadata; exact format decoupled from Limestone
}

Manifest describes where the transaction log is stored

func (m Manifest) MarshalLogObject(e zapcore.ObjectEncoder) error

type Notification ¶

type Notification struct {
	// Reports a fatal error. The server disconnects immediately after.
	Err ErrMismatch `json:",omitempty"`

	// An incoming transaction
	Txn *IncomingTransaction `json:",omitempty"`

	// The hot end of the stream has been reached
	Hot bool `json:",omitempty"`
}

Notification is a packet sent from server to client

If more than one of the properties are present, the packet is equivalent to several packets containing one each, in the order in which they are declared below.

func (n Notification) MarshalLogObject(e zapcore.ObjectEncoder) error

type Position ¶

type Position string

A Position is an opaque token that can be used to resume reading from a known location

const Beginning Position = ""

type Request ¶

type Request struct {
	Version int
	Last    Position
	Filter  Filter
	Compact bool // OK to collapse series of transactions and strip events
}

A Request is sent from client to server as the mandatory first WS message

type Source ¶

type Source struct {
	Producer meta.Producer `json:",omitempty"` // Generic service name
	Instance string        `json:",omitempty"` // Optional string that makes the pair unique (e.g. shard ID)
}

Source describes the submitter of a database update

func (s Source) MarshalLogObject(e zapcore.ObjectEncoder) error

type Transaction ¶

type Transaction struct {
	// Timestamp override
	//
	// When submitting new transactions, leave empty.
	// When reading, assume out-of-band message timestamp if empty.
	// When converting history, set to original transaction timestamp.
	//
	// If set, must precede out-of-band message timestamp.
	// Must be monotonic.
	TS *time.Time `json:",omitempty"`

	Source  Source `json:",omitempty"`
	Session int64  `json:",omitempty"` // for echo cancellation

	Changes Changes

	Audit json.RawMessage `json:",omitempty"` // remote IP, session ID etc; exact format decoupled from Limestone
}

Transaction is a storage and wire representation of a Limestone transaction

func (txn Transaction) MarshalLogObject(e zapcore.ObjectEncoder) error

type ValidateFn ¶

type ValidateFn func(index int, before, after reflect.Value) error

A ValidateFn receives the index of a field within meta.Struct.Fields along with its old and new values, and has a chance to fail encoding or decoding by returning an error. When creating a new entity, before is a reflection of the zero value of the field type.