tracing

Documentation

Overview

Package tracing defines an interface used by all other packages.

Tracing/logging is a cross cutting concern. Relying on a specific package for such a low-level task will create too tight a coupling—more abstract classes/packages are infected with log classes/packages.

Sub-packages of tracing will implement concrete tracers. Additionally, this package will provide helpers for more descriptive logging output, to be used with any concrete tracing/logging class.

BSD License

Copyright (c) 2017–21, Norbert Pillmayer

All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

3. Neither the name of this software nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Index

• Variables
• func With(t Trace) dumper
• type Adapter
• type Trace
• type TraceLevel
  • func TraceLevelFromString(sl string) TraceLevel
  • func (tl TraceLevel) String() string

Variables

var Tracefile *os.File

Tracefile is the gloabl file where tracing goes to. If tracing goes to a file (globally), variable Tracefile should point to it. It need not be set if tracing goes to console.

Functions

func With

func With(t Trace) dumper

With prepares to dump a data structure to a Trace. t may not be nil.

Usage:

tracing.With(mytracer).Dump(anObject)

Dumping uses https://github.com/davecgh/go-spew . Dump() is in level Debug.

Types

type Adapter

type Adapter func() Trace

Adapter is a factory function to create a virgin Trace instance.

type Trace

type Trace interface {
	P(string, interface{}) Trace // field tracing
	Debugf(string, ...interface{})
	Infof(string, ...interface{})
	Errorf(string, ...interface{})
	SetTraceLevel(TraceLevel)
	GetTraceLevel() TraceLevel
	SetOutput(io.Writer) // route tracing output to a writer
}

Trace is an interface to be implemented by a concrete tracing adapter. For examples refer to the sub-packages of package tracing.

Tracers should support parameter/field tracing given by P(...). An example would be

tracer.P("mycontext", "value").Debugf("message within context")

Tracers should be prepared to trace to console as well as to a file. By convention, no newlines at the end of tracing messages will be passed by clients.

type TraceLevel

type TraceLevel uint8

TraceLevel is a type for leveled tracing. All concrete Tracer implementations will support trace-levels.

const (
	LevelError TraceLevel = iota
	LevelInfo
	LevelDebug
)

We support three trace levels.

func TraceLevelFromString

func TraceLevelFromString(sl string) TraceLevel

TraceLevelFromString will find a trace level from a string. It will recognize "Debug", "Info" and "Error". Default is LevelDebug.

func (TraceLevel) String

func (tl TraceLevel) String() string