log · pkg.go.dev

README

go-log

The logging library used by go-ipfs

It currently uses a modified version of go-logging to implement the standard printf-style log output.

Install

go get github.com/ipfs/go-log

Usage

Once the package is imported under the name logging, an instance of EventLogger can be created like so:

var log = logging.Logger("subsystem name")

It can then be used to emit log messages, either plain printf-style messages at six standard levels or structured messages using Start, StartFromParentState, Finish and FinishWithErr methods.

Example

func (s *Session) GetBlock(ctx context.Context, c *cid.Cid) (blk blocks.Block, err error) {

    // Starts Span called "Session.GetBlock", associates with `ctx`
    ctx = log.Start(ctx, "Session.GetBlock")

    // defer so `blk` and `err` can be evaluated after call
    defer func() {
        // tag span associated with `ctx`
        log.SetTags(ctx, map[string]interface{}{
            "cid": c,
            "block", blk,
        })
        // if err is non-nil tag the span with an error
        log.FinishWithErr(ctx, err)
    }()

    if shouldStartSomething() {
        // log message on span associated with `ctx`
        log.LogKV(ctx, "startSomething", true)
    }
  ...
}

Tracing

go-log wraps the opentracing-go methods - StartSpan, Finish, LogKV, and SetTag.

go-log implements its own tracer - loggabletracer - based on the basictracer-go implementation. If there is an active WriterGroup the loggabletracer will record span data to the WriterGroup. An example of this can be seen in the log tail command of go-ipfs.

Third party tracers may be used by calling opentracing.SetGlobalTracer() with your desired tracing implementation. An example of this can be seen using the go-jaeger-plugin and the go-ipfs tracer plugin

Contribute

Feel free to join in. All welcome. Open an issue!

This repository falls under the IPFS Code of Conduct.

Want to hack on IPFS?

License

MIT

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Documentation

Constants ¶

This section is empty.

Variables ¶

View Source

var (
	LevelDebug  = log2.LevelDebug
	LevelInfo   = log2.LevelInfo
	LevelWarn   = log2.LevelWarn
	LevelError  = log2.LevelError
	LevelDPanic = log2.LevelDPanic
	LevelPanic  = log2.LevelPanic
	LevelFatal  = log2.LevelFatal
)

Functions ¶

func ContextWithLoggable ¶

func ContextWithLoggable(ctx context.Context, l Loggable) context.Context

ContextWithLoggable returns a derived context which contains the provided Loggable. Any Events logged with the derived context will include the provided Loggable.

func FormatRFC3339 ¶

func FormatRFC3339(t time.Time) string

FormatRFC3339 returns the given time in UTC with RFC3999Nano format.

func GetSubsystems ¶

func GetSubsystems() []string

GetSubsystems returns a slice containing the names of the current loggers

func SetAllLoggers ¶

func SetAllLoggers(lvl LogLevel)

SetAllLoggers changes the logging level of all loggers to lvl

func SetDebugLogging ¶

func SetDebugLogging()

SetDebugLogging calls SetAllLoggers with logging.DEBUG

func SetLogLevel ¶

func SetLogLevel(name, level string) error

SetLogLevel changes the log level of a specific subsystem name=="*" changes all subsystems

func SetLogLevelRegex ¶

func SetLogLevelRegex(e, l string) error

SetLogLevelRegex sets all loggers to level `l` that match expression `e`. An error is returned if `e` fails to compile.

func SetupLogging ¶

func SetupLogging()

Types ¶

type EventInProgress ¶

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

DEPRECATED EventInProgress represent and event which is happening Deprecated: Stop using go-log for event logging

func (*EventInProgress) Append ¶

func (eip *EventInProgress) Append(l Loggable)

DEPRECATED use `LogKV` or `SetTag` Append adds loggables to be included in the call to Done

func (*EventInProgress) Close ¶

func (eip *EventInProgress) Close() error

Close is an alias for done Deprecated: Stop using go-log for event logging

func (*EventInProgress) Done ¶

func (eip *EventInProgress) Done()

Done creates a new Event entry that includes the duration and appended loggables. Deprecated: Stop using go-log for event logging

func (*EventInProgress) DoneWithErr ¶

func (eip *EventInProgress) DoneWithErr(err error)

DEPRECATED use `FinishWithErr` DoneWithErr creates a new Event entry that includes the duration and appended loggables. DoneWithErr accepts an error, if err is non-nil, it is set on the EventInProgress. Otherwise the logic is the same as the `Done()` method

func (*EventInProgress) SetError ¶

func (eip *EventInProgress) SetError(err error)

DEPRECATED use `SetError(ctx, error)` SetError includes the provided error

type EventLogger ¶

type EventLogger interface {
	StandardLogger

	// Event merges structured data from the provided inputs into a single
	// machine-readable log event.
	//
	// If the context contains metadata, a copy of this is used as the base
	// metadata accumulator.
	//
	// If one or more loggable objects are provided, these are deep-merged into base blob.
	//
	// Next, the event name is added to the blob under the key "event". If
	// the key "event" already exists, it will be over-written.
	//
	// Finally the timestamp and package name are added to the accumulator and
	// the metadata is logged.
	// DEPRECATED
	// Deprecated: Stop using go-log for event logging
	Event(ctx context.Context, event string, m ...Loggable)

	// DEPRECATED
	// Deprecated: Stop using go-log for event logging
	EventBegin(ctx context.Context, event string, m ...Loggable) *EventInProgress

	// Start starts an opentracing span with `name`, using
	// any Span found within `ctx` as a ChildOfRef. If no such parent could be
	// found, Start creates a root (parentless) Span.
	//
	// The return value is a context.Context object built around the
	// returned Span.
	//
	// Example usage:
	//
	//    SomeFunction(ctx context.Context, ...) {
	//        ctx := log.Start(ctx, "SomeFunction")
	//        defer log.Finish(ctx)
	//        ...
	//    }
	// Deprecated: Stop using go-log for event logging
	Start(ctx context.Context, name string) context.Context

	// StartFromParentState starts an opentracing span with `name`, using
	// any Span found within `ctx` as a ChildOfRef. If no such parent could be
	// found, StartSpanFromParentState creates a root (parentless) Span.
	//
	// StartFromParentState will attempt to deserialize a SpanContext from `parent`,
	// using any Span found within to continue the trace
	//
	// The return value is a context.Context object built around the
	// returned Span.
	//
	// An error is returned when `parent` cannot be deserialized to a SpanContext
	//
	// Example usage:
	//
	//    SomeFunction(ctx context.Context, bParent []byte) {
	//        ctx := log.StartFromParentState(ctx, "SomeFunction", bParent)
	//        defer log.Finish(ctx)
	//        ...
	//    }
	// Deprecated: Stop using go-log for event logging
	StartFromParentState(ctx context.Context, name string, parent []byte) (context.Context, error)

	// Finish completes the span associated with `ctx`.
	//
	// Finish() must be the last call made to any span instance, and to do
	// otherwise leads to undefined behavior.
	// Finish will do its best to notify (log) when used in correctly
	//		.e.g called twice, or called on a spanless `ctx`
	// Deprecated: Stop using go-log for event logging
	Finish(ctx context.Context)

	// FinishWithErr completes the span associated with `ctx` and also calls
	// SetErr if `err` is non-nil
	//
	// FinishWithErr() must be the last call made to any span instance, and to do
	// otherwise leads to undefined behavior.
	// FinishWithErr will do its best to notify (log) when used in correctly
	//		.e.g called twice, or called on a spanless `ctx`
	// Deprecated: Stop using go-log for event logging
	FinishWithErr(ctx context.Context, err error)

	// SetErr tags the span associated with `ctx` to reflect an error occured, and
	// logs the value `err` under key `error`.
	// Deprecated: Stop using go-log for event logging
	SetErr(ctx context.Context, err error)

	// LogKV records key:value logging data about an event stored in `ctx`
	// Eexample:
	//    log.LogKV(
	//        "error", "resolve failure",
	//        "type", "cache timeout",
	//        "waited.millis", 1500)
	// Deprecated: Stop using go-log for event logging
	LogKV(ctx context.Context, alternatingKeyValues ...interface{})

	// SetTag tags key `k` and value `v` on the span associated with `ctx`
	// Deprecated: Stop using go-log for event logging
	SetTag(ctx context.Context, key string, value interface{})

	// SetTags tags keys from the `tags` maps on the span associated with `ctx`
	// Example:
	//    log.SetTags(ctx, map[string]{
	//		"type": bizStruct,
	//      "request": req,
	//		})
	// Deprecated: Stop using go-log for event logging
	SetTags(ctx context.Context, tags map[string]interface{})

	// SerializeContext takes the SpanContext instance stored in `ctx` and Seralizes
	// it to bytes. An error is returned if the `ctx` cannot be serialized to
	// a bytes array
	// Deprecated: Stop using go-log for event logging
	SerializeContext(ctx context.Context) ([]byte, error)
}

EventLogger extends the StandardLogger interface to allow for log items containing structured metadata

Example ¶

{
	log := EventLogger(nil)
	e := log.EventBegin(context.Background(), "dial")
	e.Done()
}
{
	log := EventLogger(nil)
	e := log.EventBegin(context.Background(), "dial")
	_ = e.Close() // implements io.Closer for convenience
}

Output:

type LogLevel ¶

type LogLevel = log2.LogLevel

LogLevel represents a log severity level. Use the package variables as an enum.

func LevelFromString ¶

func LevelFromString(level string) (LogLevel, error)

LevelFromString parses a string-based level and returns the corresponding LogLevel.

Supported strings are: DEBUG, INFO, WARN, ERROR, DPANIC, PANIC, FATAL, and their lower-case forms.

The returned LogLevel must be discarded if error is not nil.

type Loggable ¶

type Loggable interface {
	Loggable() map[string]interface{}
}

Loggable describes objects that can be marshalled into Metadata for logging

func Deferred ¶

func Deferred(key string, f func() string) Loggable

Deferred returns a LoggableF where the execution of the provided function is deferred.

func Pair ¶

func Pair(key string, l Loggable) Loggable

Pair returns a Loggable where key is paired to Loggable.

type LoggableF ¶

type LoggableF func() map[string]interface{}

LoggableF converts a func into a Loggable

func (LoggableF) Loggable ¶

func (l LoggableF) Loggable() map[string]interface{}

Loggable implements the Loggable interface by running the LoggableF function.

type LoggableMap ¶

type LoggableMap map[string]interface{}

LoggableMap is just a generic map keyed by string. It implements the Loggable interface.

func (LoggableMap) Loggable ¶

func (l LoggableMap) Loggable() map[string]interface{}

Loggable implements the Loggable interface for LoggableMap

type Metadata ¶

type Metadata map[string]interface{}

Metadata is a convenience type for generic maps

func DeepMerge ¶

func DeepMerge(b, a Metadata) Metadata

DeepMerge merges the second Metadata parameter into the first. Nested Metadata are merged recursively. Primitives are over-written.

func MetadataFromContext ¶

func MetadataFromContext(ctx context.Context) (Metadata, error)

MetadataFromContext extracts Matadata from a given context's value.

func Metadatify ¶

func Metadatify(i interface{}) (Metadata, error)

Metadatify converts maps into Metadata.

func (Metadata) JsonString ¶

func (m Metadata) JsonString() (string, error)

JsonString returns the marshaled JSON string for the metadata.

func (Metadata) Loggable ¶

func (m Metadata) Loggable() map[string]interface{}

Loggable implements the Loggable interface.

type StandardLogger ¶

type StandardLogger interface {
	log2.StandardLogger
	// Deprecated use Warn
	Warning(args ...interface{})
	// Deprecated use Warnf
	Warningf(format string, args ...interface{})
}

StandardLogger provides API compatibility with standard printf loggers eg. go-logging

type ZapEventLogger ¶

type ZapEventLogger struct {
	zap.SugaredLogger
	// contains filtered or unexported fields
}

ZapEventLogger implements the EventLogger and wraps a go-logging Logger

func Logger ¶

func Logger(system string) *ZapEventLogger

Logger retrieves an event logger by name