types

Documentation

Index

• Constants
• func IsError(err error, otherError error) bool
• func LoggerWithReaderID(logger log.Logger, readerID ReaderID) log.Logger
• type Action
• type Fields
• type Formatter
• type FormatterFunc
  • func (f FormatterFunc) Format(buf *bytes.Buffer, message Message) error
• type Matcher
• type Message
  • func NewMessage(timestamp time.Time, readerID ReaderID, text string, extra Fields) Message
  • func (m *Message) Text() string
• type Persister
• type Processor
• type ReadLogsParams
  • func (w ReadLogsParams) Send(ctx context.Context, message Message) error
• type Reader
• type ReaderID
• type ReaderParams
• type Source
• type State
  • func (s State) String() string
  • func (s State) WithCursor(cursor string) State
  • func (s State) WithTimestamp(timestamp time.Time) State

Constants

const MessageKey = "MESSAGE"

Functions

func IsError

func IsError(err error, otherError error) bool

isError checks if err was caused by otherError.

func LoggerWithReaderID

func LoggerWithReaderID(logger log.Logger, readerID ReaderID) log.Logger

LoggerWithReaderID adds the reader_id meta to the logger.

Types

type Action

type Action interface {
	// PerformAction does something with matched messages.
	PerformAction(ctx context.Context, messages []Message) error
}

Action defines an action to perform when a match is found.

type Fields

type Fields map[string]string

Fields contains the message key-value pairs.

type Formatter

type Formatter interface {
	// Format formats the message.
	Format(*bytes.Buffer, Message) error
}

Formatter formats the message.

type FormatterFunc

type FormatterFunc func(*bytes.Buffer, Message) error

FormatterFunc allows functions to implement Formatter.

func (FormatterFunc) Format

func (f FormatterFunc) Format(buf *bytes.Buffer, message Message) error

Format implements Formatter.

type Matcher

type Matcher interface {
	MatchMessage(message Message) bool
}

type Message

type Message struct {
	Timestamp time.Time `json:"ts"`                  // Timestamp of the event.
	Cursor    string    `json:"cursor,omitempty"`    // Cursor position of the message.
	Fields    Fields    `json:"fields,omitempty"`    // Fields contains message fields.
	Source    Source    `json:"source,omitempty"`    // Source the message was read from.
	ReaderID  ReaderID  `json:"reader_id,omitempty"` // ReaderID that read the message.
}

Message is the main log message.

func NewMessage

func NewMessage(
	timestamp time.Time,
	readerID ReaderID,
	text string,
	extra Fields,
) Message

NewMessage is a helper function for creating a Message. The text will be added as the MESSAGE field.

func (*Message) Text

func (m *Message) Text() string

type Persister

type Persister interface {
	// LoadState loads the reader state. When the state doees not exist, it must
	// return no error.
	LoadState(context.Context, ReaderID) (State, error)
	// SaveSave saves the reader state.
	SaveState(context.Context, ReaderID, State) error
}

Persister is a component for loading and reading reader state.

type Processor

type Processor interface {
	// ProcessMessage processes the message read.
	ProcessMessage(context.Context, Message) error
	Tick(context.Context, time.Time) error
}

Processor is a message processor.

type ReadLogsParams

type ReadLogsParams struct {
	State State          // State for resuming reading.
	Ch    chan<- Message // Ch is a channel to write the messages to.
}

ReadLogsParams contains parameters for Reader.ReadLogs.

func (ReadLogsParams) Send

func (w ReadLogsParams) Send(ctx context.Context, message Message) error

ReadLogsParams is a convenience wrapper that tries to send to Ch until the ctx is done.

type Reader

type Reader interface {
	// ReaderID returns the reader's ID.
	ReaderID() ReaderID
	// ReadLogs reads logs until context is done, or an error is encountered.
	// Implementations must not close the ReadLogsParams.Ch as that is done
	// conditionally in Watcher.
	ReadLogs(context.Context, ReadLogsParams) error
}

Reader describes a component that can read logs.

type ReaderID

type ReaderID string

ReaderID is a unique ID of a reader.

type ReaderParams

type ReaderParams struct {
	ReaderID ReaderID
	Logger   log.Logger
}

ReaderParams contains common parameters for all Reader implementations.

type Source

type Source int

Source describes the message source.

const (
	SourceUndefined Source = iota // SourceUndefined is the default.
	SourceStdout                  // SourceStdout means the message was read from stdout.
	SourceStderr                  // SourceStderr means the message was read from stderr.
)

type State

type State struct {
	// Timestamp is the last timestamp read.
	Timestamp time.Time `json:"time"`
	// NumMessages is the number of messages read with the same Timestamp.
	NumMessages int `json:"num_messages"`
	// Cursor is the current cursor, if any.
	Cursor string `json:"cursor,omitempty"`
}

State describes the reader state.

func (State) String

func (s State) String() string

String implements fmt.Stringer.

func (State) WithCursor

func (s State) WithCursor(cursor string) State

WithCursor returns a new State with cursor.

func (State) WithTimestamp

func (s State) WithTimestamp(timestamp time.Time) State

WithTimestamp returns a new State with timestamp set. If the timestamp has advanced, the NumMessages is reset.