syslog

package
v0.0.0-...-3674baf Latest Latest
Warning

This package is not in the latest version of its module.

 Go to latest Published: Sep 12, 2025 License: Apache-2.0 Imports: 23 Imported by: 0

Documentation

Index

Constants

View Source 
const RFC5424TimeOffsetNum = "2006-01-02T15:04:05.999999-07:00"

Variables

This section is empty.

Functions

func ExponentialDuration 

func ExponentialDuration(attempt int) time.Duration

ExponentialDuration returns a duration that grows exponentially with each attempt. It is maxed out at 15 seconds.

func NewHTTPSBatchWriter 

func NewHTTPSBatchWriter(
	binding *URLBinding,
	netConf NetworkTimeoutConfig,
	tlsConf *tls.Config,
	egressMetric metrics.Counter,
	c *Converter,
	options ...Option,
) egress.WriteCloser

HTTPSBatchWriter is an egress.WriteCloser implementation that batches syslog messages and sends them via HTTPS in configurable batch sizes and intervals. It provides backpressure to upstream callers by using a blocking channel for incoming messages. Failed batch sends are retried according to a configurable retry policy, using a global RetryCoordinator to limit the number of concurrent retries across all drains. This prevents resource exhaustion and noisy neighbor issues, ensuring reliable and efficient delivery of batched syslog messages.

func NewHTTPSWriter 

func NewHTTPSWriter(
	binding *URLBinding,
	netConf NetworkTimeoutConfig,
	tlsConf *tls.Config,
	egressMetric metrics.Counter,
	c *Converter,
) egress.WriteCloser

func NewRetryWriter 

func NewRetryWriter(
	urlBinding *URLBinding,
	retryDuration RetryDuration,
	maxRetries int,
	writer egress.WriteCloser,
) (egress.WriteCloser, error)

func NewTCPWriter 

func NewTCPWriter(
	binding *URLBinding,
	netConf NetworkTimeoutConfig,
	egressMetric metrics.Counter,
	c *Converter,
) egress.WriteCloser

NewTCPWriter creates a new TCP syslog writer.

func NewTLSWriter 

func NewTLSWriter(
	binding *URLBinding,
	netConf NetworkTimeoutConfig,
	tlsConf *tls.Config,
	egressMetric metrics.Counter,
	syslogConverter *Converter,
) egress.WriteCloser

func NewWriterFactoryErrorf 

func NewWriterFactoryErrorf(u *url.URL, format string, a ...any) error

func WithParallelRetries 

func WithParallelRetries(n int)

testing override for maxParallelRetries

Types

type Binding 

type Binding struct {
	AppId        string    `json:"appId,omitempty"`
	Hostname     string    `json:"hostname,omitempty"`
	Drain        Drain     `json:"drain,omitempty"`
	DrainData    DrainData `json:"type,omitempty"`
	OmitMetadata bool
	InternalTls  bool
}

type ConnectorOption 

type ConnectorOption func(*SyslogConnector)

ConnectorOption allows a syslog connector to be customized.

func WithLogClient 

func WithLogClient(logClient LogClient, sourceIndex string) ConnectorOption

WithLogClient returns a ConnectorOption that will set up logging for any information about a binding.

type Converter 

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

func NewConverter 

func NewConverter(opts ...ConverterOption) *Converter

func (*Converter) BuildHostname 

func (c *Converter) BuildHostname(env *loggregator_v2.Envelope, defaultHostname string) string

func (*Converter) ToRFC5424 

func (c *Converter) ToRFC5424(env *loggregator_v2.Envelope, defaultHostname string) ([][]byte, error)

type ConverterOption 

type ConverterOption func(*Converter)

func WithoutSyslogMetadata 

func WithoutSyslogMetadata() ConverterOption

type Credentials 

type Credentials struct {
	Cert string `json:"cert"`
	Key  string `json:"key"`
	CA   string `json:"ca"`
}

type DialFunc 

type DialFunc func(addr string) (net.Conn, error)

DialFunc represents a method for creating a connection, either TCP or TLS.

type Drain 

type Drain struct {
	Url         string      `json:"url"`
	Credentials Credentials `json:"credentials"`
}

type DrainData 

type DrainData int
const (
	LOGS DrainData = iota
	METRICS
	TRACES
	ALL
	LOGS_NO_EVENTS
	LOGS_AND_METRICS
)

type EnvelopeWriter 

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

func NewEnvelopeWriter 

func NewEnvelopeWriter(drainGetter drainGetter, nextEnvelope nextEnvelope, ingress metrics.Counter, log *log.Logger) *EnvelopeWriter

func (*EnvelopeWriter) Run 

func (w *EnvelopeWriter) Run()

type FilteringDrainWriter 

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

func NewFilteringDrainWriter 

func NewFilteringDrainWriter(binding Binding, writer egress.Writer) (*FilteringDrainWriter, error)

func (*FilteringDrainWriter) Write 

func (w *FilteringDrainWriter) Write(env *loggregator_v2.Envelope) error

type HTTPSBatchWriter 

type HTTPSBatchWriter struct {
	HTTPSWriter
	// contains filtered or unexported fields
}

func (*HTTPSBatchWriter) Close 

func (w *HTTPSBatchWriter) Close() error

func (*HTTPSBatchWriter) ConfigureRetry 

func (w *HTTPSBatchWriter) ConfigureRetry(retryDuration RetryDuration, maxRetries int)

Also Marks that HTTPSBatchWriter implements the InternalRetryWriter interface

func (*HTTPSBatchWriter) Write 

func (w *HTTPSBatchWriter) Write(env *loggregator_v2.Envelope) error

type HTTPSWriter 

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

func (*HTTPSWriter) Close 

func (*HTTPSWriter) Close() error

func (*HTTPSWriter) Write 

func (w *HTTPSWriter) Write(env *loggregator_v2.Envelope) error

type InternalRetryWriter 

type InternalRetryWriter interface {
	ConfigureRetry(retryDuration RetryDuration, maxRetries int)
}

InternalRetryWriter is an interface that defines methods for configuring retry behavior for syslog writers. It allows setting a retry duration function and the maximum number of retries.

type LogClient 

type LogClient interface {
	EmitLog(message string, opts ...loggregator.EmitLogOption)
}

LogClient is used to emit logs.

type NetworkTimeoutConfig 

type NetworkTimeoutConfig struct {
	Keepalive    time.Duration
	DialTimeout  time.Duration
	WriteTimeout time.Duration
}

NetworkTimeoutConfig stores various timeout values.

type Option 

type Option func(*HTTPSBatchWriter)

func WithBatchSize 

func WithBatchSize(size int) Option

testing override for batch size and send interval

func WithSendInterval 

func WithSendInterval(interval time.Duration) Option

type RetryCoordinator 

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

RetryCoordinator provides global concurrency control for retry operations across all drain writers. It uses a semaphore pattern to enforce a configurable limit on the number of concurrent retries, preventing resource exhaustion and noisy-neighbor problems during periods of high retry load. When all retry slots are in use, additional retries will wait until a slot becomes available, ensuring the system remains stable while still attempting delivery of all messages. This coordinator will be used as a singleton.

func GetGlobalRetryCoordinator 

func GetGlobalRetryCoordinator() *RetryCoordinator

GetGlobalRetryCoordinator returns a singleton instance of RetryCoordinator. It initializes the coordinator with a semaphore that limits the number of concurrent retries.

func (*RetryCoordinator) Acquire 

func (c *RetryCoordinator) Acquire(redactedURLString string, appId string)

func (*RetryCoordinator) Release 

func (c *RetryCoordinator) Release()

type RetryDuration 

type RetryDuration func(attempt int) time.Duration

RetryDuration calculates a duration based on the number of write attempts.

type RetryWriter 

type RetryWriter struct {
	Writer egress.WriteCloser //public to allow testing
	// contains filtered or unexported fields
}

RetryWriter wraps a WriteCloser and will retry writes if the first fails.

func (*RetryWriter) Close 

func (r *RetryWriter) Close() error

Close delegates to the syslog writer.

func (*RetryWriter) Write 

func (r *RetryWriter) Write(e *loggregator_v2.Envelope) error

Write will retry writes unitl maxRetries has been reached.

type Retryer 

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

func NewRetryer 

func NewRetryer(
	binding *URLBinding,
	retryDuration RetryDuration,
	maxRetries int,
) *Retryer

Retryer handles retry logic for failed operations with configurable policies. It coordinates with the global RetryCoordinator to limit concurrent retries, implements exponential backoff with configurable intervals, and respects context cancellation for graceful shutdown. The first attempt is always performed without acquiring a retry slot (fast path), while subsequent retries are subject to global concurrency limits.

func (*Retryer) Retry 

func (r *Retryer) Retry(batch []byte, msgCount float64, funcToRetry func([]byte, float64) error) (failed bool)

Retry will retry the provided function up to maxRetries times. It returns true if the function failed after all retries, false otherwise.

type SyslogConnector 

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

SyslogConnector creates the various egress syslog writers.

func NewSyslogConnector 

func NewSyslogConnector(
	skipCertVerify bool,
	wg egress.WaitGroup,
	f writerFactory,
	m metricClient,
	opts ...ConnectorOption,
) *SyslogConnector

NewSyslogConnector configures and returns a new SyslogConnector.

func (*SyslogConnector) Connect 

func (w *SyslogConnector) Connect(ctx context.Context, b Binding) (egress.Writer, error)

Connect returns an egress writer based on the scheme of the binding drain URL.

type TCPWriter 

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

TCPWriter represents a syslog writer that connects over unencrypted TCP. This writer is not meant to be used from multiple goroutines. The same goroutine that calls `.Write()` should be the one that calls `.Close()`.

func (*TCPWriter) Close 

func (w *TCPWriter) Close() error

Close tears down any active connections to the drain and prevents reconnect.

func (*TCPWriter) Write 

func (w *TCPWriter) Write(env *loggregator_v2.Envelope) error

Write writes an envelope to the syslog drain connection.

type TLSWriter 

type TLSWriter struct {
	TCPWriter
}

TLSWriter represents a syslog writer that connects over unencrypted TCP.

type URLBinding 

type URLBinding struct {
	Context      context.Context
	AppID        string
	Hostname     string
	OmitMetadata bool
	InternalTls  bool
	URL          *url.URL
	PrivateKey   []byte
	Certificate  []byte
	CA           []byte
}

application is identified by AppID and Hostname. The syslog URL is identified by URL.

func (*URLBinding) Scheme 

func (u *URLBinding) Scheme() string

Scheme is a convenience wrapper around the *url.URL Scheme field

type WriterFactory 

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

func NewWriterFactory 

func NewWriterFactory(internalTlsConfig *tls.Config, externalTlsConfig *tls.Config, netConf NetworkTimeoutConfig, m metricClient) WriterFactory

func (WriterFactory) NewWriter 

func (f WriterFactory) NewWriter(ub *URLBinding) (egress.WriteCloser, error)

type WriterFactoryError 

type WriterFactoryError struct {
	Message string
	URL     *url.URL
}

func (WriterFactoryError) Error 

func (e WriterFactoryError) Error() string

Source Files

View all Source files

Jump to

Keyboard shortcuts

? : This menu
/ : Search site
f or F : Jump to
y or Y : Canonical URL
go.dev uses cookies from Google to deliver and enhance the quality of its services and to analyze traffic. Learn more.