client

Documentation

Index

• Variables
• type Client
  • func New(impl ReadWriter) *Client
  • func (c *Client) Append(ctx context.Context, event EventData) (versionPrevious Version, version Version, tm time.Time, err error)
  • func (c *Client) AppendCheck(ctx context.Context, assumedVersion Version, event EventData) (version Version, tm time.Time, err error)
  • func (c *Client) AppendCheckMulti(ctx context.Context, assumedVersion Version, events ...EventData) (versionFirst Version, version Version, tm time.Time, err error)
  • func (c *Client) AppendMulti(ctx context.Context, events ...EventData) (versionPrevious Version, versionFirst Version, version Version, tm time.Time, ...)
  • func (c *Client) Listen(ctx context.Context, onUpdate func(Version)) error
  • func (c *Client) Metadata(ctx context.Context) (map[string]string, error)
  • func (c *Client) Scan(ctx context.Context, version Version, reverse bool, skipFirst bool, ...) error
  • func (c *Client) TryAppend(ctx context.Context, assumedVersion Version, ...) (versionPrevious Version, version Version, tm time.Time, err error)
  • func (c *Client) TryAppendMulti(ctx context.Context, assumedVersion Version, ...) (versionPrevious Version, versionFirst Version, version Version, tm time.Time, ...)
  • func (c *Client) Version(ctx context.Context) (Version, error)
  • func (c *Client) VersionInitial(ctx context.Context) (Version, error)
• type Event
• type EventData
• type HTTP
  • func NewHTTP(host string, logErr Log, clt *fasthttp.Client, wsDialer *websocket.Dialer) *HTTP
  • func (c *HTTP) Append(ctx context.Context, event EventData) (versionPrevious Version, version Version, tm time.Time, err error)
  • func (c *HTTP) AppendCheck(ctx context.Context, assumedVersion Version, event EventData) (version Version, tm time.Time, err error)
  • func (c *HTTP) AppendCheckMulti(ctx context.Context, assumedVersion Version, events ...EventData) (versionFirst Version, version Version, tm time.Time, err error)
  • func (c *HTTP) AppendMulti(ctx context.Context, events ...EventData) (versionPrevious Version, versionFirst Version, version Version, tm time.Time, ...)
  • func (c *HTTP) GetRetryInterval() time.Duration
  • func (c *HTTP) Listen(ctx context.Context, onUpdate func(Version)) error
  • func (c *HTTP) Metadata(ctx context.Context) (map[string]string, error)
  • func (c *HTTP) Scan(ctx context.Context, version Version, reverse bool, skipFirst bool, ...) error
  • func (c *HTTP) SetRetryInterval(d time.Duration)
  • func (c *HTTP) Version(ctx context.Context) (version Version, err error)
  • func (c *HTTP) VersionInitial(ctx context.Context) (version Version, err error)
• type Inmem
  • func NewInmem(e *eventlog.EventLog) *Inmem
  • func (c *Inmem) Append(ctx context.Context, event EventData) (versionPrevious Version, version Version, tm time.Time, err error)
  • func (c *Inmem) AppendCheck(ctx context.Context, assumedVersion Version, event EventData) (version Version, tm time.Time, err error)
  • func (c *Inmem) AppendCheckMulti(ctx context.Context, assumedVersion Version, events ...EventData) (versionFirst Version, version Version, tm time.Time, err error)
  • func (c *Inmem) AppendMulti(ctx context.Context, events ...EventData) (versionPrevious Version, versionFirst Version, version Version, tm time.Time, ...)
  • func (c *Inmem) Listen(ctx context.Context, onUpdate func(Version)) error
  • func (c *Inmem) Metadata(ctx context.Context) (m map[string]string, err error)
  • func (c *Inmem) Scan(ctx context.Context, version Version, reverse bool, skipFirst bool, ...) error
  • func (c *Inmem) Version(ctx context.Context) (Version, error)
  • func (c *Inmem) VersionInitial(ctx context.Context) (Version, error)
• type Log
• type ReadWriter
• type Reader
• type Version
• type Writer

Variables

var (
	ErrMismatchingVersions      = eventlog.ErrMismatchingVersions
	ErrInvalidPayload           = eventlog.ErrInvalidPayload
	ErrPayloadSizeLimitExceeded = eventlog.ErrPayloadSizeLimitExceeded
	ErrInvalidVersion           = errors.New("invalid version")
	ErrMalformedVersion         = errors.New("malformed version")
	ErrLabelTooLong             = fmt.Errorf(
		"label must not exceed %d bytes",
		internal.MaxLabelLen,
	)
	ErrNoEvents = errors.New("no events")
)

Error values

var ErrSocketClosed = errors.New("socket closed")

Types

type Client

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

func New

func New(impl ReadWriter) *Client

New creates a new eventlog client.

func (*Client) Append

func (c *Client) Append(
	ctx context.Context,
	event EventData,
) (
	versionPrevious Version,
	version Version,
	tm time.Time,
	err error,
)

Append appends a new event onto the log.

func (*Client) AppendCheck

func (c *Client) AppendCheck(
	ctx context.Context,
	assumedVersion Version,
	event EventData,
) (
	version Version,
	tm time.Time,
	err error,
)

AppendCheck appends a new event onto the log if the assumed version matches the latest log version, otherwise the operation is rejected and ErrMismatchingVersions is returned.

func (*Client) AppendCheckMulti

func (c *Client) AppendCheckMulti(
	ctx context.Context,
	assumedVersion Version,
	events ...EventData,
) (
	versionFirst Version,
	version Version,
	tm time.Time,
	err error,
)

AppendCheckMulti appends one or multiple new events onto the log if the assumed version matches the latest log version, otherwise the operation is rejected and ErrMismatchingVersions is returned.

func (*Client) AppendMulti

func (c *Client) AppendMulti(
	ctx context.Context,
	events ...EventData,
) (
	versionPrevious Version,
	versionFirst Version,
	version Version,
	tm time.Time,
	err error,
)

AppendMulti appends one or multiple new events onto the log.

func (*Client) Listen

func (c *Client) Listen(ctx context.Context, onUpdate func(Version)) error

Listen establishes a websocket connection to the server and starts listening for version update notifications calling onUpdate when one is received.

func (*Client) Metadata

func (c *Client) Metadata(ctx context.Context) (map[string]string, error)

Metadata returns all metadata fields.

func (*Client) Scan

func (c *Client) Scan(
	ctx context.Context,
	version Version,
	reverse bool,
	skipFirst bool,
	fn func(Event) error,
) error

Scan reads events at the given version calling fn for every received event. Scans in reverse if reverse == true. Skips the first Event at version if skipFirst == true.

func (*Client) TryAppend

func (c *Client) TryAppend(
	ctx context.Context,
	assumedVersion Version,
	transaction func() (event EventData, err error),
	sync func() (Version, error),
) (
	versionPrevious Version,
	version Version,
	tm time.Time,
	err error,
)

TryAppend keeps executing transaction until either cancelled, succeeded (assumed == latest event log version) or failed due to an error.

func (*Client) TryAppendMulti

func (c *Client) TryAppendMulti(
	ctx context.Context,
	assumedVersion Version,
	transaction func() (events []EventData, err error),
	sync func() (Version, error),
) (
	versionPrevious Version,
	versionFirst Version,
	version Version,
	tm time.Time,
	err error,
)

TryAppendMulti keeps executing transaction until either cancelled, succeeded (assumed == latest event log version) or failed due to an error.

func (*Client) Version

func (c *Client) Version(ctx context.Context) (Version, error)

Version returns the latest version of the log or "0" if the log is empty.

func (*Client) VersionInitial

func (c *Client) VersionInitial(ctx context.Context) (Version, error)

VersionInitial returns either the first version of the log or "0" if the log is empty.

type Event

type Event struct {
	EventData
	Time            time.Time `json:"time"`
	Version         Version   `json:"version"`
	VersionNext     Version   `json:"version-next"`
	VersionPrevious Version   `json:"version-previous"`
}

type EventData

type EventData = eventlog.EventData

type HTTP

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

HTTP is an HTTP eventlog read-writer.

func NewHTTP

func NewHTTP(
	host string,
	logErr Log,
	clt *fasthttp.Client,
	wsDialer *websocket.Dialer,
) *HTTP

NewHTTP creates a read-writer connecting to an eventlog's HTTP API.

func (*HTTP) Append

func (c *HTTP) Append(
	ctx context.Context,
	event EventData,
) (
	versionPrevious Version,
	version Version,
	tm time.Time,
	err error,
)

Append implements Writer.Append.

func (*HTTP) AppendCheck

func (c *HTTP) AppendCheck(
	ctx context.Context,
	assumedVersion Version,
	event EventData,
) (
	version Version,
	tm time.Time,
	err error,
)

AppendCheck implements Writer.AppendCheck.

func (*HTTP) AppendCheckMulti

func (c *HTTP) AppendCheckMulti(
	ctx context.Context,
	assumedVersion Version,
	events ...EventData,
) (
	versionFirst Version,
	version Version,
	tm time.Time,
	err error,
)

AppendCheckMulti implements Writer.AppendCheckMulti.

func (*HTTP) AppendMulti

func (c *HTTP) AppendMulti(
	ctx context.Context,
	events ...EventData,
) (
	versionPrevious Version,
	versionFirst Version,
	version Version,
	tm time.Time,
	err error,
)

AppendMulti implements Writer.AppendMulti.

func (*HTTP) GetRetryInterval

func (c *HTTP) GetRetryInterval() time.Duration

GetRetryInterval returns the current retry interval. Returns 0 if automatic retry is disabled.

func (*HTTP) Listen

func (c *HTTP) Listen(ctx context.Context, onUpdate func(Version)) error

Listen establishes a websocket connection to the server and starts listening for version update notifications calling onUpdate when one is received.

func (*HTTP) Metadata

func (c *HTTP) Metadata(ctx context.Context) (map[string]string, error)

Metadata implements Reader.Metadata.

func (*HTTP) Scan

func (c *HTTP) Scan(
	ctx context.Context,
	version Version,
	reverse bool,
	skipFirst bool,
	fn func(Event) error,
) error

Scan implements Reader.Scan.

WARNING: manually cancelable (non-timeout and non-deadline) contexts are not supported.

func (*HTTP) SetRetryInterval

func (c *HTTP) SetRetryInterval(d time.Duration)

SetRetryInterval enables automatic retries if d > 0, otherwise automatic retry is disabled.

func (*HTTP) Version

func (c *HTTP) Version(ctx context.Context) (version Version, err error)

Version implements Reader.Version.

func (*HTTP) VersionInitial

func (c *HTTP) VersionInitial(
	ctx context.Context,
) (version Version, err error)

VersionInitial implements Reader.VersionInitial.

type Inmem

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

Inmem is an in-memory eventlog connecter.

func NewInmem

func NewInmem(e *eventlog.EventLog) *Inmem

NewInmem create a new in-memory eventlog connecter.

func (*Inmem) Append

func (c *Inmem) Append(ctx context.Context, event EventData) (
	versionPrevious Version,
	version Version,
	tm time.Time,
	err error,
)

Append implements Connecter.Append.

func (*Inmem) AppendCheck

func (c *Inmem) AppendCheck(
	ctx context.Context,
	assumedVersion Version,
	event EventData,
) (
	version Version,
	tm time.Time,
	err error,
)

AppendCheck implements Connecter.AppendCheck.

func (*Inmem) AppendCheckMulti

func (c *Inmem) AppendCheckMulti(
	ctx context.Context,
	assumedVersion Version,
	events ...EventData,
) (
	versionFirst Version,
	version Version,
	tm time.Time,
	err error,
)

AppendCheckMulti implements Connecter.AppendCheckMulti.

func (*Inmem) AppendMulti

func (c *Inmem) AppendMulti(ctx context.Context, events ...EventData) (
	versionPrevious Version,
	versionFirst Version,
	version Version,
	tm time.Time,
	err error,
)

AppendMulti implements Connecter.AppendMulti.

func (*Inmem) Listen

func (c *Inmem) Listen(ctx context.Context, onUpdate func(Version)) error

Listen implements Connecter.Listen.

func (*Inmem) Metadata

func (c *Inmem) Metadata(ctx context.Context) (
	m map[string]string,
	err error,
)

func (*Inmem) Scan

func (c *Inmem) Scan(
	ctx context.Context,
	version Version,
	reverse bool,
	skipFirst bool,
	fn func(Event) error,
) error

Scan implements Connecter.Scan.

func (*Inmem) Version

func (c *Inmem) Version(ctx context.Context) (Version, error)

Version implements Connecter.Version.

func (*Inmem) VersionInitial

func (c *Inmem) VersionInitial(ctx context.Context) (Version, error)

VersionInitial implements Connecter.VersionInitial.

type Log

type Log interface {
	Printf(format string, v ...interface{})
}

type ReadWriter

type ReadWriter interface {
	Reader
	Writer
}

ReadWriter is both an eventlog reader and a writer.

type Reader

type Reader interface {
	Metadata(ctx context.Context) (map[string]string, error)

	Scan(
		ctx context.Context,
		version Version,
		reverse bool,
		skipFirst bool,
		fn func(Event) error,
	) error

	VersionInitial(context.Context) (Version, error)

	Version(context.Context) (Version, error)

	Listen(ctx context.Context, onUpdate func(Version)) error
}

Reader is an eventlog reader. All reader methods are idempotent.

type Version

type Version = string

type Writer

type Writer interface {
	Append(
		ctx context.Context,
		event EventData,
	) (
		versionPrevious Version,
		version Version,
		tm time.Time,
		err error,
	)

	AppendMulti(
		ctx context.Context,
		events ...EventData,
	) (
		versionPrevious Version,
		versionFirst Version,
		version Version,
		tm time.Time,
		err error,
	)

	AppendCheck(
		ctx context.Context,
		assumedVersion Version,
		event EventData,
	) (
		version Version,
		tm time.Time,
		err error,
	)

	AppendCheckMulti(
		ctx context.Context,
		assumedVersion Version,
		eventsEncoded ...EventData,
	) (
		versionFirst Version,
		version Version,
		tm time.Time,
		err error,
	)
}

Writer is an eventlog writer.