ft

README

ft – function trace

A very simple utility library written in Go to log and trace a function lifecycle.

Why?

Because I'm tired of adding the same boilerplate code to every function I write, that usually requires three or more lines of code to log and trace a function and some metrics.

Usage

Just add these two lines to the beginning of the function:

ctx, span := ft.Start(ctx, "package.Function", ft.WithErr(&err))
defer span.End()

func Do(ctx context.Context) (err error) {
	ctx, span := ft.Start(ctx, "main.Do", ft.WithErr(&err))
	defer span.End()
	
	err := callAnotherFn()
	if err != nil {
		return err
    }   

	return nil
}

If you run the code above, you will see the following output:

time=2025-01-20T00:32:20.025+01:00 level=INFO msg="action started" action=main.Do
time=2025-01-20T00:32:20.330+01:00 level=ERROR msg="action ended" action=main.Do duration_ms=137.546 error="error from callAnotherFn"

Configuration

ft package provides many functions to configure its behaviour. See the table below:

Here's a markdown table with all the Set functions and their descriptions:

Function	Description
SetDurationMetricUnit(unit string)	Sets the global duration metric unit. Accepts either millisecond (ms) or second (s) as valid units. Defaults to millisecond if invalid unit is provided.
SetDefaultLogger(l *slog.Logger)	Sets the global logger instance. Does nothing if nil logger is provided.
SetLogLevelOnFailure(level slog.Level)	Sets the global log level for failure scenarios.
SetLogLevelOnSuccess(level slog.Level)	Sets the global log level for success scenarios.
SetTracingEnabled(v bool)	Enables or disables global tracing functionality.
SetMetricsEnabled(v bool)	Enables or disables global metrics collection.
SetClock(c clockwork.Clock)	Sets the global clock instance used for time-related operations.
SetAppendOtelAttrs(v bool)	Enables or disables the appending of OpenTelemetry attributes globally.

License

BSD Zero Clause License

Copyright (c) 2024 Amanbolat Balabekov

Permission to use, copy, modify, and/or distribute this software for any purpose with or without fee is hereby granted.

THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

Documentation

Index

• Constants
• func SetAppendOtelAttrs(v bool)
• func SetClock(c clockwork.Clock)
• func SetDefaultLogger(l *slog.Logger)
• func SetDurationMetricUnit(unit string)
• func SetLogLevelOnFailure(level slog.Level)
• func SetLogLevelOnSuccess(level slog.Level)
• func SetMetricsEnabled(v bool)
• func SetTracingEnabled(v bool)
• type Option
  • func WithAttrs(attrs ...slog.Attr) Option
  • func WithErr(err *error) Option
• type Span
  • func Start(ctx context.Context, action string, opts ...Option) (context.Context, Span)
• type SpanConfig

Constants

const (
	DurationMetricUnitSecond      = "ms"
	DurationMetricUnitMillisecond = "s"
)

Functions

func SetAppendOtelAttrs

func SetAppendOtelAttrs(v bool)

func SetClock

func SetClock(c clockwork.Clock)

func SetDefaultLogger

func SetDefaultLogger(l *slog.Logger)

func SetDurationMetricUnit

func SetDurationMetricUnit(unit string)

func SetLogLevelOnFailure

func SetLogLevelOnFailure(level slog.Level)

func SetLogLevelOnSuccess

func SetLogLevelOnSuccess(level slog.Level)

func SetMetricsEnabled

func SetMetricsEnabled(v bool)

func SetTracingEnabled

func SetTracingEnabled(v bool)

Types

type Option

type Option func(cfg *SpanConfig)

func WithAttrs

func WithAttrs(attrs ...slog.Attr) Option

func WithErr

func WithErr(err *error) Option

type Span

type Span interface {
	End()
}

func Start

func Start(ctx context.Context, action string, opts ...Option) (context.Context, Span)

type SpanConfig

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