do not Printf GELF messages when logging

Including: bug fixes, api changes, new packages, and more!

example/main.go

@@ -8,52 +8,51 @@ import (
 	"os/signal"
 	"time"
 
-	"git.ma-al.com/gora_filip/observer/pkg/level"
+	"git.ma-al.com/maal-libraries/observer/pkg/attr/layer_attr"
-	"git.ma-al.com/gora_filip/observer/pkg/tracer"
+	"git.ma-al.com/maal-libraries/observer/pkg/event"
+	"git.ma-al.com/maal-libraries/observer/pkg/exporters"
+	"git.ma-al.com/maal-libraries/observer/pkg/exporters/console_exporter"
+	tracing "git.ma-al.com/maal-libraries/observer/pkg/fiber_tracing"
+	"git.ma-al.com/maal-libraries/observer/pkg/level"
 	"github.com/gofiber/fiber/v2"
+	"go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp"
 	"go.opentelemetry.io/otel/trace"
 )
 
-type AttributesX struct {
-}
-
 func main() {
+	main := fiber.New()
 
-	main := fiber.New(fiber.Config{
+	exps := make([]exporters.TraceExporter, 0)
-		StreamRequestBody: true,
+	exps = append(exps, exporters.DevConsoleExporter(console_exporter.ProcessorOptions{}))
-	})
+	gelfExp, err := exporters.GelfExporter()
+	if err == nil {
+		exps = append(exps, gelfExp)
+	}
+	jaegerExp, err := exporters.OtlpHTTPExporter(otlptracehttp.WithEndpointURL("http://localhost:4318/v1/traces"))
+	if err == nil {
+		exps = append(exps, jaegerExp)
+	}
 
-	main.Use(tracer.NewTracer(tracer.Config{
+	main.Use(tracing.NewMiddleware(tracing.Config{
-		AppName:   "test",
+		AppName:         "example",
-		JaegerUrl: "http://localhost:4318/v1/traces",
+		Version:         "0.0.0",
-		GelfUrl:   "192.168.220.30:12201",
+		ServiceProvider: "maal",
-		Version:   "1",
+		Exporters:       exps,
 	}))
-	defer tracer.ShutdownTracer()
+	defer tracing.ShutdownTracer()
 
-	main.Get("/", func(c *fiber.Ctx) error {
+	main.Use(func(c *fiber.Ctx) error {
-		ctx, span := tracer.Handler(c)
+		span := tracing.SpanFromContext(c)
-		defer span.End()
+		span.AddEvent("pushed into a span an event from middleware")
 
-		span.AddEvent(
+		span = trace.SpanFromContext(c.UserContext())
-			"smthing is happening",
+		span.AddEvent("span also available from c.UserContext()")
-			trace.WithAttributes(
+		return c.Next()
-				tracer.LongMessage("smthing is happening - long"),
-				tracer.JsonAttr("smth", map[string]interface{}{
-					"xd": 1,
-				}),
-				tracer.Level(level.ALERT),
-			),
-		)
-
-		err := Serv(ctx)
-		if err != nil {
-			return tracer.RecordError(span, err)
-		}
-
-		return c.SendString("xd")
 	})
 
+	main.Get("/", Handler)
+	main.Get("/just/some/more/complex/path/:with/params", Handler)
+
 	// handle interrupts (shutdown)
 	c := make(chan os.Signal, 1)
 	signal.Notify(c, os.Interrupt)
@@ -69,8 +68,29 @@ func main() {
 
 }
 
+func Handler(c *fiber.Ctx) error {
+	ctx, span := tracing.FStart(c, layer_attr.Handler{
+		Level: level.DEBUG,
+	}.AsOpts())
+	defer span.End()
+	event.NewInSpan(event.Event{
+		Level:        level.WARN,
+		ShortMessage: "a warning event",
+	}, span)
+
+	err := Serv(ctx)
+	if err != nil {
+		return event.NewErrInSpan(event.Error{Err: err, Level: level.ERR}, span)
+	}
+
+	return c.SendStatus(fiber.StatusOK)
+}
+
 func Serv(ctx context.Context) *fiber.Error {
-	ctx, span := tracer.Service(ctx, "name of the span")
+	ctx, span := tracing.Start(ctx, "service span", layer_attr.Service{
+		Level: level.INFO,
+		Name:  "some service",
+	}.AsOpts())
 	defer span.End()
 
 	for range []int{1, 2, 3} {
@@ -86,7 +106,10 @@ func Serv(ctx context.Context) *fiber.Error {
 }
 
 func Repo(ctx context.Context) error {
-	ctx, span := tracer.Repository(ctx, "name of the span")
+	ctx, span := tracing.Start(ctx, "repo span", layer_attr.Repo{
+		Level: level.DEBUG,
+		Name:  "some repo",
+	}.AsOpts())
 	defer span.End()
 
 	for range []int{1, 2, 3} {

example/requests.hurl

@@ -0,0 +1,5 @@
+GET http://127.0.0.1:3344/
+HTTP 500
+
+GET http://127.0.0.1:3344/just/some/more/complex/path/jjj/params
+HTTP 500

go.mod

@@ -1,15 +1,12 @@
-module git.ma-al.com/gora_filip
+module git.ma-al.com/maal-libraries/observer
 
-go 1.21.0
+go 1.21
 
 require (
-	git.ma-al.com/gora_filip/observer v0.0.0-20240430124205-be03e0ce4205
 	github.com/gofiber/fiber/v2 v2.52.4
 	github.com/psmarcin/fiber-opentelemetry v1.2.0
 	go.opentelemetry.io/otel v1.26.0
-	go.opentelemetry.io/otel/exporters/otlp/otlptrace v1.26.0
 	go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp v1.26.0
-	go.opentelemetry.io/otel/exporters/stdout/stdouttrace v1.26.0
 	go.opentelemetry.io/otel/sdk v1.26.0
 	go.opentelemetry.io/otel/trace v1.26.0
 	gopkg.in/Graylog2/go-gelf.v2 v2.0.0-20191017102106-1550ee647df0
@@ -30,6 +27,7 @@ require (
 	github.com/valyala/bytebufferpool v1.0.0 // indirect
 	github.com/valyala/fasthttp v1.52.0 // indirect
 	github.com/valyala/tcplisten v1.0.0 // indirect
+	go.opentelemetry.io/otel/exporters/otlp/otlptrace v1.26.0 // indirect
 	go.opentelemetry.io/otel/metric v1.26.0 // indirect
 	go.opentelemetry.io/proto/otlp v1.2.0 // indirect
 	golang.org/x/net v0.23.0 // indirect

go.sum

@@ -1,5 +1,3 @@
-git.ma-al.com/gora_filip/observer v0.0.0-20240430124205-be03e0ce4205 h1:tuJ7e4EAWx/IbVESEO6l3yNoGiUAoaXWssMc26Ft3Hs=
-git.ma-al.com/gora_filip/observer v0.0.0-20240430124205-be03e0ce4205/go.mod h1:NLwhsfm3SE3YwR+3z4DbH82OBjRPcE+M/GPGEc7DPUM=
 github.com/andybalholm/brotli v1.0.4/go.mod h1:fO7iG3H7G2nSZ7m0zPUDn85XEX2GTukHGRSepvi9Eig=
 github.com/andybalholm/brotli v1.1.0 h1:eLKJA0d02Lf0mVpIDgYnqXcUn0GqVmEFny3VuID1U3M=
 github.com/andybalholm/brotli v1.1.0/go.mod h1:sms7XGricyQI9K10gOSf56VKKWS4oLer58Q+mhRPtnY=
@@ -59,8 +57,6 @@ go.opentelemetry.io/otel/exporters/otlp/otlptrace v1.26.0 h1:1u/AyyOqAWzy+SkPxDp
 go.opentelemetry.io/otel/exporters/otlp/otlptrace v1.26.0/go.mod h1:z46paqbJ9l7c9fIPCXTqTGwhQZ5XoTIsfeFYWboizjs=
 go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp v1.26.0 h1:1wp/gyxsuYtuE/JFxsQRtcCDtMrO2qMvlfXALU5wkzI=
 go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp v1.26.0/go.mod h1:gbTHmghkGgqxMomVQQMur1Nba4M0MQ8AYThXDUjsJ38=
-go.opentelemetry.io/otel/exporters/stdout/stdouttrace v1.26.0 h1:0W5o9SzoR15ocYHEQfvfipzcNog1lBxOLfnex91Hk6s=
-go.opentelemetry.io/otel/exporters/stdout/stdouttrace v1.26.0/go.mod h1:zVZ8nz+VSggWmnh6tTsJqXQ7rU4xLwRtna1M4x5jq58=
 go.opentelemetry.io/otel/metric v1.26.0 h1:7S39CLuY5Jgg9CrnA9HHiEjGMF/X2VHvoXGgSllRz30=
 go.opentelemetry.io/otel/metric v1.26.0/go.mod h1:SY+rHOI4cEawI9a7N1A4nIg/nTQXe1ccCNWYOJUrpX4=
 go.opentelemetry.io/otel/sdk v1.26.0 h1:Y7bumHf5tAiDlRYFmGqetNcLaVUZmh4iYfmGxtmz7F8=

justfile

@@ -0,0 +1,4 @@
+run:
+	go run example/main.go 
+test-example:
+	hurl example/requests.hurl

pkg/attr/attr.go

@@ -0,0 +1,268 @@
+package attr
+
+import (
+	"encoding/json"
+	"os"
+	"runtime"
+	"runtime/debug"
+	"time"
+
+	"git.ma-al.com/maal-libraries/observer/pkg/level"
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/semconv/v1.25.0"
+	"go.opentelemetry.io/otel/trace"
+)
+
+type KeyValue = attribute.KeyValue
+type Key = attribute.Key
+type Value = attribute.Value
+
+type IntoTraceAttribute interface {
+	IntoTraceAttribute() attribute.KeyValue
+}
+
+type IntoTraceAttributes interface {
+	IntoTraceAttributes() []attribute.KeyValue
+}
+
+func CollectAttributes(attrs ...interface{}) []attribute.KeyValue {
+	collected := make([]attribute.KeyValue, len(attrs))
+	for _, a := range attrs {
+		switch a.(type) {
+		case []attribute.KeyValue:
+			collected = append(collected, a.([]attribute.KeyValue)...)
+		case attribute.KeyValue:
+			collected = append(collected, a.(attribute.KeyValue))
+		case IntoTraceAttribute:
+			collected = append(collected, a.(IntoTraceAttribute).IntoTraceAttribute())
+		case IntoTraceAttributes:
+			collected = append(collected, a.(IntoTraceAttributes).IntoTraceAttributes()...)
+		}
+	}
+	return collected
+}
+
+func WithAttributes(attrs ...interface{}) trace.SpanStartEventOption {
+	return trace.WithAttributes(CollectAttributes(attrs...)...)
+}
+
+const (
+	SeverityLevelKey           = attribute.Key("level")
+	LogMessageLongKey          = attribute.Key("log_message.long")
+	LogMessageShortKey         = attribute.Key("log_message.short")
+	EnduserResponseMessageKey  = attribute.Key("enduser.response_message")
+	SessionLanguageIdKey       = attribute.Key("session.language_id")
+	SessionCountryIdKey        = attribute.Key("session.country_id")
+	SessionCurrencyIdKey       = attribute.Key("session.currency_id")
+	ProcessThreadsAvailableKey = attribute.Key("process.threads_available")
+	ServiceLayerKey            = attribute.Key("service.layer")
+	ServiceLayerNameKey        = attribute.Key("service.layer_name")
+	DBExecutionTimeMsKey       = attribute.Key("db.execution_time_ms")
+)
+
+type ServiceArchitectureLayer string
+
+const (
+	LayerFrameworkMiddleware ServiceArchitectureLayer = "framework_middleware"
+	LayerHandler                                      = "handler"
+	LayerService                                      = "service"
+	LayerRepository                                   = "repository"
+	LayerORM                                          = "orm"
+	LayerUtil                                         = "util"
+)
+
+// Build an attribute with a value formatted as json
+func JsonAttr(key string, jsonEl map[string]interface{}) attribute.KeyValue {
+	jsonStr, _ := json.Marshal(jsonEl)
+	return attribute.KeyValue{Key: attribute.Key(key), Value: attribute.StringValue(string(jsonStr))}
+
+}
+
+// An attribute informing about the severity or importance of an event using our own standard of log levels that
+// can map to syslog level.
+func SeverityLevel(lvl level.SeverityLevel) attribute.KeyValue {
+	return attribute.String(string(SeverityLevelKey), lvl.String())
+}
+
+func LogMessage(short string, expanded string) []attribute.KeyValue {
+	attrs := make([]attribute.KeyValue, 2)
+	attrs = append(attrs, LogMessageShort(short), LogMessageLong(expanded))
+	return attrs
+}
+
+// An attribute which value could be used as the full message field within the GELF format.
+func LogMessageLong(msg string) attribute.KeyValue {
+	return attribute.String(string(LogMessageLongKey), msg)
+}
+
+// An attribute which value could be used as the short message field within the GELF format.
+func LogMessageShort(msg string) attribute.KeyValue {
+	return attribute.String(string(LogMessageShortKey), msg)
+}
+
+// A message provided to the end user. For example, in case of API server errors it might be desired
+// to provide to the user a message that does not leak too many details instead of sending an original
+// (for a given package) error message.
+func EnduserResponseMessage(msg string) attribute.KeyValue {
+	return attribute.String(string(EnduserResponseMessageKey), msg)
+}
+
+// Inspect the call stack to retrieve the information about a call site location including
+// function name, file path, and line number.
+func SourceCodeLocation(skipLevelsInCallStack int) []attribute.KeyValue {
+	pc, file, line, _ := runtime.Caller(1 + skipLevelsInCallStack)
+	funcName := runtime.FuncForPC(pc).Name()
+
+	return []attribute.KeyValue{
+		{
+			Key:   semconv.CodeFunctionKey,
+			Value: attribute.StringValue(funcName),
+		},
+		{
+			Key:   semconv.CodeFilepathKey,
+			Value: attribute.StringValue(file),
+		},
+		{
+			Key:   semconv.CodeLineNumberKey,
+			Value: attribute.IntValue(line),
+		},
+	}
+}
+
+// Use within some panic handler to generate an attribute that will contain a stack trace.
+func PanicStackTrace() attribute.KeyValue {
+	stackTrace := string(debug.Stack())
+	return semconv.ExceptionStacktrace(stackTrace)
+}
+
+// Builds attributes describing a server.
+func Server(address string, port int) []attribute.KeyValue {
+	return []attribute.KeyValue{
+		{
+			Key:   semconv.ServerAddressKey,
+			Value: attribute.StringValue(address),
+		},
+		{
+			Key:   semconv.ServerPortKey,
+			Value: attribute.IntValue(port),
+		},
+	}
+}
+
+// Investigates the running process to derive attributes that describe it. This will only
+// try to retrive these details which provide any valuable information at the start of a
+// process.
+func ProcessStart() []attribute.KeyValue {
+	attrs := make([]attribute.KeyValue, 5)
+	executablePath, err := os.Executable()
+	if err == nil {
+		attrs = append(attrs, semconv.ProcessExecutablePath(executablePath))
+	}
+	hostname, err := os.Hostname()
+	if err == nil {
+		attrs = append(attrs, semconv.HostName(hostname))
+	}
+
+	runtimeVersion := runtime.Version()
+	cpuThreads := runtime.NumCPU()
+	pid := os.Getpid()
+	attrs = append(attrs, semconv.ProcessParentPID(pid), semconv.ProcessRuntimeVersion(runtimeVersion), attribute.KeyValue{
+		Key:   ProcessThreadsAvailableKey,
+		Value: attribute.IntValue(cpuThreads),
+	})
+
+	return attrs
+}
+
+// Id of an end user's session.
+func SessionId(id string) attribute.KeyValue {
+	return attribute.KeyValue{
+		Key:   semconv.SessionIDKey,
+		Value: attribute.StringValue(id),
+	}
+}
+
+// Id of a language associated with a user's session.
+func SessionLanguageId(id uint) attribute.KeyValue {
+	return attribute.KeyValue{
+		Key:   SessionLanguageIdKey,
+		Value: attribute.IntValue(int(id)),
+	}
+}
+
+// Id of a country associated with a user's session.
+func SessionCountryId(id uint) attribute.KeyValue {
+	return attribute.KeyValue{
+		Key:   SessionCountryIdKey,
+		Value: attribute.IntValue(int(id)),
+	}
+}
+
+// Id of a currency associated with a user's session.
+func SessionCurrencyId(id uint) attribute.KeyValue {
+	return attribute.KeyValue{
+		Key:   SessionCurrencyIdKey,
+		Value: attribute.IntValue(int(id)),
+	}
+}
+
+// Render details about session as attributes.
+func Session(deets SessionDetails) []attribute.KeyValue {
+	return deets.IntoTraceAttributes()
+}
+
+// A collection of attributes that we at maal frequently attach to user sessions that can
+// be converted into a collection of trace attributes. All fields are optional.
+type SessionDetails struct {
+	ID         *string
+	PreviousID *string
+	LanguageID *uint
+	CountryID  *uint
+	CurrencyID *uint
+}
+
+func (deets SessionDetails) IntoTraceAttributes() []attribute.KeyValue {
+	attrs := make([]attribute.KeyValue, 4) // most frequently we won't have previous session ID
+	if deets.ID != nil {
+		attrs = append(attrs, SessionId(*deets.ID))
+	}
+	if deets.PreviousID != nil {
+		attrs = append(attrs, attribute.KeyValue{
+			Key:   semconv.SessionPreviousIDKey,
+			Value: attribute.StringValue(*deets.PreviousID),
+		})
+	}
+	if deets.LanguageID != nil {
+		attrs = append(attrs, SessionLanguageId(*deets.LanguageID))
+	}
+	if deets.CountryID != nil {
+		attrs = append(attrs, SessionCountryId(*deets.CountryID))
+	}
+	if deets.CurrencyID != nil {
+		attrs = append(attrs, SessionCurrencyId(*deets.CurrencyID))
+	}
+	return attrs
+}
+
+// Describes a layer of a web server architecture with some of terms frequently used at maal.
+func ServiceLayer(layer ServiceArchitectureLayer) attribute.KeyValue {
+	return attribute.KeyValue{
+		Key:   ServiceLayerKey,
+		Value: attribute.StringValue(string(layer)),
+	}
+}
+
+func ServiceLayerName(name string) attribute.KeyValue {
+	return attribute.KeyValue{
+		Key:   ServiceLayerNameKey,
+		Value: attribute.StringValue(name),
+	}
+}
+
+// Take duration as an execution time of a query measured in milisecongs.
+func DBExecutionTimeMs(duration time.Duration) attribute.KeyValue {
+	return attribute.KeyValue{
+		Key:   DBExecutionTimeMsKey,
+		Value: attribute.Int64Value(duration.Milliseconds()),
+	}
+}

pkg/attr/layer_attr/layer_attr.go

@@ -0,0 +1,124 @@
+package layer_attr
+
+import (
+	"git.ma-al.com/maal-libraries/observer/pkg/attr"
+	"git.ma-al.com/maal-libraries/observer/pkg/level"
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/trace"
+)
+
+type Handler struct {
+	// Extra attributes to be attached. Can be also added with [Handler.CustomAttrs] method.
+	Attributes       []attribute.KeyValue
+	Level            level.SeverityLevel
+	Name             string
+	extraSkipInStack int
+}
+
+func (h Handler) IntoTraceAttributes() []attribute.KeyValue {
+	attrs := make([]attribute.KeyValue, 5+len(h.Attributes))
+	attrs = append(attrs, attr.SourceCodeLocation(1+h.extraSkipInStack)...) // 3 attrs added here
+	attrs = append(attrs, attr.ServiceLayer(attr.LayerHandler), attr.SeverityLevel(h.Level))
+	if len(h.Name) > 0 {
+		attrs = append(attrs, attr.ServiceLayerName(h.Name))
+	}
+	attrs = append(attrs, h.Attributes...)
+	return attrs
+}
+
+func (h Handler) CustomAttrs(attrs ...interface{}) Handler {
+	h.Attributes = append(h.Attributes, attr.CollectAttributes(attrs...)...)
+	return h
+}
+
+func (h *Handler) SkipMoreInCallStack(skip int) {
+	h.extraSkipInStack += skip
+}
+
+// Works the same as [Handler.IntoTraceAttributes]
+func (h Handler) AsAttrs() []attribute.KeyValue {
+	h.extraSkipInStack += 1
+	return h.IntoTraceAttributes()
+}
+
+func (h Handler) AsOpts() trace.SpanStartEventOption {
+	h.extraSkipInStack += 1
+	return trace.WithAttributes(h.IntoTraceAttributes()...)
+}
+
+type Service struct {
+	// Extra attributes to be attached. Can be also added with [Service.CustomAttrs] method.
+	Attributes       []attribute.KeyValue
+	Level            level.SeverityLevel
+	Name             string
+	extraSkipInStack int
+}
+
+func (s Service) IntoTraceAttributes() []attribute.KeyValue {
+	attrs := make([]attribute.KeyValue, 6+len(s.Attributes))
+	attrs = append(attrs, attr.SourceCodeLocation(1+s.extraSkipInStack)...)
+	attrs = append(attrs, attr.ServiceLayer(attr.LayerService), attr.SeverityLevel(s.Level))
+	if len(s.Name) > 0 {
+		attrs = append(attrs, attr.ServiceLayerName(s.Name))
+	}
+	attrs = append(attrs, s.Attributes...)
+	return attrs
+}
+
+// Works the same as [Service.IntoTraceAttributes]
+func (s Service) AsAttrs() []attribute.KeyValue {
+	s.extraSkipInStack += 1
+	return s.IntoTraceAttributes()
+}
+
+func (s Service) CustomAttrs(attrs ...interface{}) Service {
+	s.Attributes = append(s.Attributes, attr.CollectAttributes(attrs...)...)
+	return s
+}
+
+func (s *Service) SkipMoreInCallStack(skip int) {
+	s.extraSkipInStack += skip
+}
+
+func (s Service) AsOpts() trace.SpanStartEventOption {
+	s.extraSkipInStack += 1
+	return trace.WithAttributes(s.IntoTraceAttributes()...)
+}
+
+type Repo struct {
+	// Extra attributes to be attached. Can be also added with [Repo.CustomAttrs] method
+	Attributes       []attribute.KeyValue
+	Level            level.SeverityLevel
+	Name             string
+	extraSkipInStack int
+}
+
+func (r Repo) IntoTraceAttributes() []attribute.KeyValue {
+	attrs := make([]attribute.KeyValue, 6+len(r.Attributes))
+	attrs = append(attrs, attr.SourceCodeLocation(1+r.extraSkipInStack)...)
+	attrs = append(attrs, attr.ServiceLayer(attr.LayerRepository), attr.SeverityLevel(r.Level))
+	if len(r.Name) > 0 {
+		attrs = append(attrs, attr.ServiceLayerName(r.Name))
+	}
+	attrs = append(attrs, r.Attributes...)
+	return attrs
+}
+
+// Works the same as [Repo.IntoTraceAttributes]
+func (r Repo) AsAttrs() []attribute.KeyValue {
+	r.extraSkipInStack += 1
+	return r.IntoTraceAttributes()
+}
+
+func (r Repo) CustomAttrs(attrs ...interface{}) Repo {
+	r.Attributes = append(r.Attributes, attr.CollectAttributes(attrs...)...)
+	return r
+}
+func (r *Repo) SkipMoreInCallStack(skip int) {
+	r.extraSkipInStack += skip
+}
+
+func (r Repo) AsOpts() trace.SpanStartEventOption {
+	r.extraSkipInStack += 1
+	return trace.WithAttributes(r.IntoTraceAttributes()...)
+}

pkg/code_location/code_location.go

@@ -0,0 +1,28 @@
+package code_location
+
+import (
+	"runtime"
+)
+
+type CodeLocation struct {
+	FilePath     string
+	FuncName     string
+	LineNumber   int
+	ColumnNumber int
+}
+
+func FromStackTrace(atDepth ...int) CodeLocation {
+	skipLevelsInCallStack := 0
+
+	if len(atDepth) > 1 {
+		skipLevelsInCallStack = atDepth[0]
+	}
+	pc, file, line, _ := runtime.Caller(1 + skipLevelsInCallStack)
+	funcName := runtime.FuncForPC(pc).Name()
+
+	return CodeLocation{
+		FilePath:   file,
+		LineNumber: line,
+		FuncName:   funcName,
+	}
+}

pkg/console_fmt/fmt.go

@@ -0,0 +1,85 @@
+package console_fmt
+
+import (
+	"git.ma-al.com/maal-libraries/observer/pkg/level"
+)
+
+const (
+	ColorReset              = "\033[0m"
+	ColorRed                = "\033[31m"
+	ColorGreen              = "\033[32m"
+	ColorYellow             = "\033[33m"
+	ColorBlue               = "\033[34m"
+	ColorPurple             = "\033[35m"
+	ColorCyan               = "\033[36m"
+	ColorWhite              = "\033[37m"
+	ColorBlackOnYellow      = "\033[43m\033[30m"
+	ColorWhiteOnRed         = "\033[37m\033[41m"
+	ColorWhiteOnRedBlinking = "\033[37m\033[41m\033[5m"
+	ColorBold               = "\033[1m"
+)
+
+func Bold(txt string) string {
+	return ColorBold + txt + ColorReset
+}
+
+func Red(txt string) string {
+	return ColorRed + txt + ColorReset
+}
+
+func Green(txt string) string {
+	return ColorGreen + txt + ColorReset
+}
+
+func Yellow(txt string) string {
+	return ColorYellow + txt + ColorReset
+}
+
+func Blue(txt string) string {
+	return ColorBlue + txt + ColorReset
+}
+
+func Purple(txt string) string {
+	return ColorPurple + txt + ColorReset
+}
+
+func Cyan(txt string) string {
+	return ColorCyan + txt + ColorReset
+}
+
+func White(txt string) string {
+	return ColorWhite + txt + ColorReset
+}
+
+func BlackOnYellow(txt string) string {
+	return ColorBlackOnYellow + txt + ColorReset
+}
+
+func WhiteOnRed(txt string) string {
+	return ColorWhiteOnRed + txt + ColorReset
+}
+
+func WhiteOnRedBlinking(txt string) string {
+	return ColorWhiteOnRedBlinking + txt + ColorReset
+}
+
+func SeverityLevelToColor(lvl level.SeverityLevel) string {
+	switch lvl {
+	case level.TRACE:
+		return ColorWhite
+	case level.DEBUG:
+		return ColorPurple
+	case level.INFO:
+		return ColorBlue
+	case level.WARN:
+		return ColorYellow
+	case level.ERR:
+		return ColorRed
+	case level.CRIT:
+		return ColorBlackOnYellow
+	case level.ALERT:
+		return ColorWhiteOnRed
+	default:
+		return ColorWhite
+	}
+}

pkg/event/event.go

@@ -0,0 +1,115 @@
+package event
+
+import (
+	"git.ma-al.com/maal-libraries/observer/pkg/attr"
+	"git.ma-al.com/maal-libraries/observer/pkg/level"
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/codes"
+	"go.opentelemetry.io/otel/trace"
+)
+
+// An event that maps well to a log message
+type Event struct {
+	FullMessage  string
+	ShortMessage string
+	Attributes   []attribute.KeyValue
+	// Defaults to INFO when converted into attributes and unset
+	Level            level.SeverityLevel
+	extraSkipInStack int
+}
+
+type IntoEvent interface {
+	IntoEvent() Event
+}
+
+func (e Event) IntoEvent() Event {
+	return e
+}
+
+func (e Event) IntoTraceAttributes() []attribute.KeyValue {
+	attrs := make([]attribute.KeyValue, 0)
+	attrs = append(attrs, attr.SourceCodeLocation(1+e.extraSkipInStack)...)
+	attrs = append(attrs, e.Attributes...)
+	if len(e.FullMessage) > 0 {
+		attrs = append(attrs, attr.LogMessageLong(e.FullMessage))
+	}
+	if len(e.ShortMessage) > 0 {
+		attrs = append(attrs, attr.LogMessageShort(e.ShortMessage))
+	}
+	if e.Level == 0 {
+		e.Level = level.INFO
+	}
+	attrs = append(attrs, attr.SeverityLevel(e.Level))
+	return attrs
+}
+
+func (e Event) AsOpts() trace.EventOption {
+	e.extraSkipInStack += 1
+	return trace.WithAttributes(e.IntoTraceAttributes()...)
+}
+
+func (e Event) SkipMoreInCallStack(skip int) Event {
+	e.extraSkipInStack += skip
+	return e
+}
+
+func NewInSpan[E IntoEvent](ev E, span trace.Span) {
+	event := ev.IntoEvent()
+	event.extraSkipInStack += 1
+	span.AddEvent(event.ShortMessage, trace.WithAttributes(event.IntoTraceAttributes()...))
+}
+
+type Error struct {
+	Err             error
+	ExtendedMessage string
+	// Defaults to ALERT when converted into attributes and unset
+	Level            level.SeverityLevel
+	Attributes       []attribute.KeyValue
+	extraSkipInStack int
+}
+
+type IntoErrorEvent interface {
+	IntoErrorEvent() Error
+}
+
+func (e Error) Error() string {
+	return e.Err.Error()
+}
+
+func (e Error) IntoErrorEvent() Error {
+	return e
+}
+
+func (e Error) IntoTraceAttributes() []attribute.KeyValue {
+	attrs := make([]attribute.KeyValue, 0)
+	attrs = append(attrs, e.Attributes...)
+	if len(e.ExtendedMessage) > 0 {
+		attrs = append(attrs, attr.LogMessageLong(e.ExtendedMessage))
+	}
+	if e.Level == 0 {
+		e.Level = level.ALERT
+	}
+	attrs = append(attrs, attr.SeverityLevel(e.Level), attr.LogMessageShort(e.Err.Error()))
+	attrs = append(attrs, attr.SourceCodeLocation(1+e.extraSkipInStack)...)
+	return attrs
+}
+
+func (e Error) AsOpts() trace.EventOption {
+	e.extraSkipInStack += 1
+	return trace.WithAttributes(e.IntoTraceAttributes()...)
+}
+
+func (e Error) SkipMoreInCallStack(skip int) Error {
+	e.extraSkipInStack += skip
+	return e
+}
+
+func NewErrInSpan[E IntoErrorEvent](err E, span trace.Span) E {
+	er := err.IntoErrorEvent()
+	er.extraSkipInStack += 1
+	span.RecordError(er.Err, er.AsOpts())
+	if er.Level <= level.ERR {
+		span.SetStatus(codes.Error, er.Error())
+	}
+	return err
+}

pkg/exporters/console_exporter/console_exporter.go

@@ -0,0 +1,218 @@
+package console_exporter
+
+import (
+	"context"
+	"fmt"
+	"slices"
+
+	"git.ma-al.com/maal-libraries/observer/pkg/attr"
+	"git.ma-al.com/maal-libraries/observer/pkg/level"
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/sdk/trace"
+)
+
+type TraceFormatter interface {
+	FormatSpanStart(span trace.ReadOnlySpan, selectedAttrs []attribute.KeyValue, lvl level.SeverityLevel) (string, error)
+	FormatSpanEnd(span trace.ReadOnlySpan, selectedAttrs []attribute.KeyValue, lvl level.SeverityLevel) (string, error)
+	FormatEvent(event trace.Event, span trace.ReadOnlySpan, selectedAttr []attribute.KeyValue, lvl level.SeverityLevel) (string, error)
+}
+
+// Configuration for the exporter.
+//
+// Most of options are passed to the formatter.
+type ProcessorOptions struct {
+	// Try to parse filters from an environment variable with a name provided by this field.
+	// Result will only by applied to unset options. NOT IMPLEMENTED!
+	FilterFromEnvVar *string
+	// Filter the output based on the [level.SeverityLevel].
+	FilterOnLevel level.SeverityLevel
+	// Fields that should be removed from the output.
+	FilterOutFields []attribute.Key
+	// Print only trace events instead of whole traces.
+	EmitEventsOnly bool
+	// Add trace id as an attribute.
+	AddTraceId bool
+	// Print output only when an error is found
+	SkipNonErrors bool
+	// Used only when `EmitEventsOnly` is set to true.
+	TraceFormatter             *TraceFormatter
+	SkipEmittingOnSpanStart    bool
+	SkipEmittingOnSpanEnd      bool
+	SkipAttributesOnSpanEnd    bool
+	SkippAttributesOnSpanStart bool
+}
+
+type Processor struct {
+	lvl                  level.SeverityLevel
+	removedFields        []attribute.Key
+	addTraceId           bool
+	onlyErrs             bool
+	onlyEvents           bool
+	traceFormatter       TraceFormatter
+	skipSpanStart        bool
+	skipSpanEnd          bool
+	skipAttrsOnSpanEnd   bool
+	skipAttrsOnSpanStart bool
+}
+
+// NOTE: The configuration might change in future releases
+func DefaultConsoleExportProcessor() trace.SpanProcessor {
+	fmt := NewPrettyMultilineFormatter()
+	return NewProcessor(ProcessorOptions{
+		FilterFromEnvVar:           nil,
+		FilterOutFields:            []attribute.Key{},
+		EmitEventsOnly:             false,
+		SkipEmittingOnSpanStart:    false,
+		SkippAttributesOnSpanStart: true,
+		AddTraceId:                 false,
+		TraceFormatter:             &fmt,
+	})
+}
+
+func NewProcessor(opts ProcessorOptions) trace.SpanProcessor {
+	var formatter TraceFormatter
+	var lvl level.SeverityLevel
+
+	if opts.TraceFormatter != nil {
+		formatter = *opts.TraceFormatter
+	} else {
+		fmt := NewPrettyMultilineFormatter()
+		formatter = fmt
+	}
+	if opts.FilterOnLevel != level.SeverityLevel(0) {
+		lvl = opts.FilterOnLevel
+	} else {
+		lvl = level.TRACE + 1
+	}
+
+	return &Processor{
+		traceFormatter:       formatter,
+		removedFields:        opts.FilterOutFields,
+		addTraceId:           opts.AddTraceId,
+		onlyEvents:           opts.EmitEventsOnly,
+		onlyErrs:             opts.SkipNonErrors,
+		skipSpanStart:        opts.SkipEmittingOnSpanStart,
+		skipSpanEnd:          opts.SkipEmittingOnSpanEnd,
+		skipAttrsOnSpanEnd:   opts.SkipAttributesOnSpanEnd,
+		skipAttrsOnSpanStart: opts.SkippAttributesOnSpanStart,
+		lvl:                  lvl,
+	}
+}
+
+// Implements [trace.SpanProcessor]
+func (e *Processor) OnStart(ctx context.Context, span trace.ReadWriteSpan) {
+	if !e.skipSpanStart && !e.onlyEvents {
+		attrs := span.Attributes()
+		filteredAttrs := make([]attribute.KeyValue, 0)
+		severityLvl := level.TRACE
+
+		if !e.skipAttrsOnSpanStart {
+			for i := range attrs {
+				if !slices.Contains(e.removedFields, attrs[i].Key) {
+					filteredAttrs = append(filteredAttrs, attrs[i])
+				}
+				if attrs[i].Key == attr.SeverityLevelKey {
+					severityLvl = level.FromString(attrs[i].Value.AsString())
+				}
+
+			}
+		}
+		if e.addTraceId {
+			filteredAttrs = append(filteredAttrs, attribute.String("trace_id", span.SpanContext().TraceID().String()))
+		}
+		if severityLvl <= e.lvl {
+			line, err := e.traceFormatter.FormatSpanStart(span, filteredAttrs, severityLvl)
+			if err != nil {
+				fmt.Println("FAILED TO FORMAT SPAN START")
+			} else {
+				fmt.Printf("%s", line)
+			}
+		}
+	}
+	return
+}
+
+// Implements [trace.SpanProcessor]
+func (e *Processor) OnEnd(span trace.ReadOnlySpan) {
+	eventsString := ""
+	spanEndString := ""
+
+	for _, event := range span.Events() {
+		attrs := event.Attributes
+		filteredAttrs := make([]attribute.KeyValue, 0)
+		severityLvl := level.TRACE
+		for i := range attrs {
+			if !slices.Contains(e.removedFields, attrs[i].Key) {
+				filteredAttrs = append(filteredAttrs, attrs[i])
+			}
+			if attrs[i].Key == attr.SeverityLevelKey {
+				severityLvl = level.FromString(attrs[i].Value.AsString())
+			}
+		}
+		if e.addTraceId {
+			filteredAttrs = append(filteredAttrs, attribute.String("trace_id", span.SpanContext().TraceID().String()))
+		}
+		if severityLvl <= e.lvl {
+			eventString, err := e.traceFormatter.FormatEvent(event, span, filteredAttrs, severityLvl)
+			if err != nil {
+				fmt.Println("FAILED TO FORMAT TRACE EVENT")
+			} else {
+				eventsString += eventString
+			}
+		}
+	}
+
+	if !e.skipSpanEnd && !e.onlyEvents {
+		attrs := span.Attributes()
+		filteredAttrs := make([]attribute.KeyValue, len(attrs))
+		severityLvl := level.TRACE
+
+		if !e.skipAttrsOnSpanEnd {
+			for i := range attrs {
+				if !slices.Contains(e.removedFields, attrs[i].Key) {
+					filteredAttrs = append(filteredAttrs, attrs[i])
+				}
+				if attrs[i].Key == attr.SeverityLevelKey {
+					severityLvl = level.FromString(attrs[i].Value.AsString())
+
+				}
+
+			}
+		}
+		if e.addTraceId {
+			filteredAttrs = append(filteredAttrs, attribute.String("trace_id", span.SpanContext().TraceID().String()))
+		}
+		if severityLvl <= e.lvl {
+			spanString, err := e.traceFormatter.FormatSpanEnd(span, filteredAttrs, severityLvl)
+			if err != nil {
+				fmt.Println("FAILED TO FORMAT SPAN END")
+			} else {
+				spanEndString += spanString
+			}
+		}
+
+	}
+
+	if e.skipSpanStart {
+		fmt.Printf("%s", spanEndString+eventsString)
+	} else {
+		fmt.Printf("%s", eventsString+spanEndString)
+	}
+
+	return
+}
+
+// Implements [trace.SpanProcessor]
+func (e *Processor) ForceFlush(ctx context.Context) error {
+	return nil
+}
+
+// Implements [trace.SpanExporter]
+func (e *Processor) Shutdown(ctx context.Context) error {
+	select {
+	case <-ctx.Done():
+		return ctx.Err()
+	default:
+	}
+	return nil
+}

pkg/exporters/console_exporter/multiline_formatter.go

@@ -0,0 +1,93 @@
+package console_exporter
+
+import (
+	"fmt"
+	"slices"
+
+	"git.ma-al.com/maal-libraries/observer/pkg/console_fmt"
+	"git.ma-al.com/maal-libraries/observer/pkg/level"
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/sdk/trace"
+)
+
+func NewPrettyMultilineFormatter() TraceFormatter {
+	return &PrettyMultilineFormatter{}
+}
+
+// A formatter that will print only events using a multiline format with colors.
+// It uses attributes from the [attr] and [semconv] packages.
+type PrettyMultilineFormatter struct{}
+
+func (f *PrettyMultilineFormatter) FormatSpanStart(span trace.ReadOnlySpan, selectedAttrs []attribute.KeyValue, lvl level.SeverityLevel) (string, error) {
+	attrs := ""
+	slices.SortFunc(selectedAttrs, func(a, b attribute.KeyValue) int {
+		if a.Key > b.Key {
+			return 1
+		} else {
+			return -1
+		}
+	})
+
+	for _, kv := range selectedAttrs {
+		if len(kv.Key) > 0 {
+			attrs += fmt.Sprintf("\t%s = %s\n", string(kv.Key), kv.Value.AsString())
+		}
+	}
+
+	formattedSpanString := fmt.Sprintf(
+		"%s\n%s",
+		console_fmt.Bold(console_fmt.SeverityLevelToColor(lvl)+fmt.Sprintf("[%s][SpanStart] ", lvl.String())+span.Name()),
+		attrs,
+	)
+
+	return formattedSpanString, nil
+}
+func (f *PrettyMultilineFormatter) FormatSpanEnd(span trace.ReadOnlySpan, selectedAttrs []attribute.KeyValue, lvl level.SeverityLevel) (string, error) {
+	attrs := ""
+	slices.SortFunc(selectedAttrs, func(a, b attribute.KeyValue) int {
+		if a.Key > b.Key {
+			return 1
+		} else {
+			return -1
+		}
+	})
+
+	for _, kv := range selectedAttrs {
+		if len(kv.Key) > 0 {
+			attrs += fmt.Sprintf("\t%s = %s\n", string(kv.Key), kv.Value.AsString())
+		}
+	}
+
+	formattedSpanString := fmt.Sprintf(
+		"%s\n%s",
+		console_fmt.Bold(console_fmt.SeverityLevelToColor(lvl)+fmt.Sprintf("[%s][SpanEnd] ", lvl.String())+span.Name()),
+		attrs,
+	)
+
+	return formattedSpanString, nil
+
+}
+func (f *PrettyMultilineFormatter) FormatEvent(event trace.Event, span trace.ReadOnlySpan, selectedAttrs []attribute.KeyValue, lvl level.SeverityLevel) (string, error) {
+	attrs := ""
+	slices.SortFunc(selectedAttrs, func(a, b attribute.KeyValue) int {
+		if a.Key > b.Key {
+			return 1
+		} else {
+			return -1
+		}
+	})
+
+	for _, kv := range selectedAttrs {
+		if len(kv.Key) > 0 {
+			attrs += fmt.Sprintf("\t%s = %s\n", string(kv.Key), kv.Value.AsString())
+		}
+	}
+
+	formattedSpanString := fmt.Sprintf(
+		"%s\n%s",
+		console_fmt.Bold(console_fmt.SeverityLevelToColor(lvl)+fmt.Sprintf("[%s][Event] ", lvl.String())+event.Name),
+		attrs,
+	)
+
+	return formattedSpanString, nil
+}

pkg/exporters/exporters.go

@@ -0,0 +1,76 @@
+package exporters
+
+import (
+	"context"
+	"git.ma-al.com/maal-libraries/observer/pkg/exporters/console_exporter"
+	gelf_exporter "git.ma-al.com/maal-libraries/observer/pkg/exporters/gelf_exporter"
+	otlphttp_exporter "go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp"
+	sdktrace "go.opentelemetry.io/otel/sdk/trace"
+)
+
+// Private type preventing implementation of TraceProcessor by external packages.
+type traceProviderOpt sdktrace.TracerProviderOption
+
+type TraceExporter interface {
+	IntoTraceProviderOption() traceProviderOpt
+}
+
+func NewFromSpanExporter(exporter sdktrace.SpanExporter) ExporterWithOptions {
+	return ExporterWithOptions{
+		exporter: exporter,
+	}
+}
+
+// Sneaky wrapper that makes it so that the TraceExporter can be created from SpanProcessor.
+type proc struct {
+	sdktrace.SpanProcessor
+}
+
+func (p proc) IntoTraceProviderOption() traceProviderOpt {
+	return sdktrace.WithSpanProcessor(p)
+}
+
+func NewFromSpanProcessor(processor sdktrace.SpanProcessor) TraceExporter {
+	return TraceExporter(proc{
+		SpanProcessor: processor,
+	})
+}
+
+// Combined exporter with batch processor config
+type ExporterWithOptions struct {
+	exporter sdktrace.SpanExporter
+	opts     []sdktrace.BatchSpanProcessorOption
+}
+
+func (ecfg ExporterWithOptions) AddOption(opt sdktrace.BatchSpanProcessorOption) ExporterWithOptions {
+	ecfg.opts = append(ecfg.opts, opt)
+	return ecfg
+}
+
+func (ecfg ExporterWithOptions) IntoTraceProviderOption() traceProviderOpt {
+	return sdktrace.WithBatcher(ecfg.exporter, ecfg.opts...)
+}
+
+// An exporter printing to console with very small delay
+func DevConsoleExporter(opts ...console_exporter.ProcessorOptions) TraceExporter {
+	var exporter TraceExporter
+	if len(opts) > 0 {
+		exporter = NewFromSpanProcessor(console_exporter.NewProcessor(opts[0]))
+	} else {
+		exporter = NewFromSpanProcessor(console_exporter.DefaultConsoleExportProcessor())
+	}
+	return TraceExporter(exporter)
+}
+
+// Default exporter to Graylog.
+func GelfExporter(opts ...gelf_exporter.Option) (ExporterWithOptions, error) {
+	gelfExp, err := gelf_exporter.New(opts...)
+	return NewFromSpanExporter(gelfExp), err
+}
+
+// Exporter for traces over HTTP. Can be used with Jaeger.
+// See documentation of [otlhttp_exporter] for details.
+func OtlpHTTPExporter(opts ...otlphttp_exporter.Option) (ExporterWithOptions, error) {
+	otlpExp, err := otlphttp_exporter.New(context.Background(), opts...)
+	return NewFromSpanExporter(otlpExp), err
+}

pkg/exporters/gelf_exporter/gelf.go

@@ -1,12 +1,11 @@
 package gelfexporter
 
 import (
-	"fmt"
 	"log"
 
 	"time"
 
-	"git.ma-al.com/gora_filip/observer/pkg/level"
+	"git.ma-al.com/maal-libraries/observer/pkg/syslog"
 	"gopkg.in/Graylog2/go-gelf.v2/gelf"
 )
 
@@ -20,7 +19,7 @@ type GELFMessage struct {
 	// Timestamp in Unix
 	Timestamp time.Time `json:"timestamp"`
 	// Severity level matching Syslog standard.
-	Level level.SyslogLevel `json:"level"`
+	Level syslog.SyslogLevel `json:"level"`
 
 	// All additional field names must start with an underline.
 	ExtraFields map[string]interface{} `json:"extrafields,omitempty"`
@@ -32,7 +31,6 @@ func Log(writer *gelf.UDPWriter, msg GELFMessage) {
 		if err != nil {
 			log.Println(err)
 		}
-		fmt.Printf("msg: %v sent\n", msg)
 	}
 }
 

pkg/exporters/gelf_exporter/trace.go

@@ -4,7 +4,9 @@ import (
 	"context"
 	"sync"
 
-	"git.ma-al.com/gora_filip/observer/pkg/level"
+	"git.ma-al.com/maal-libraries/observer/pkg/attr"
+	"git.ma-al.com/maal-libraries/observer/pkg/level"
+	"git.ma-al.com/maal-libraries/observer/pkg/syslog"
 	"go.opentelemetry.io/otel/attribute"
 	"go.opentelemetry.io/otel/sdk/trace"
 	"go.opentelemetry.io/otel/sdk/trace/tracetest"
@@ -63,30 +65,34 @@ func (e *Exporter) ExportSpans(ctx context.Context, spans []trace.ReadOnlySpan)
 			attributes[string(attr.Key)] = GetByType(attr.Value)
 		}
 
-		attributes["from"] = "test"
-
 		for i := range stub.Events {
 			event := stub.Events[i]
 
 			var gelf GELFMessage = GELFMessage{
-				Host:         "salego",
+				Host:         e.appName,
 				ShortMessage: event.Name,
 				Timestamp:    stub.StartTime,
-				Level:        level.DEBUG,
+				// Defaults to ALERT since we consider lack of the level a serious error that should be fixed ASAP.
-				ExtraFields:  attributes,
+				// Otherwise some dangerous unexpected behaviour could go unnoticed.
+				Level:       syslog.ALERT,
+				ExtraFields: attributes,
 			}
-			for _, attr := range event.Attributes {
+			for _, attrKV := range event.Attributes {
-				if attr.Key == "long_message_" {
+				if attrKV.Key == attr.LogMessageLongKey {
-					gelf.LongMessage = attr.Value.AsString()
+					gelf.LongMessage = attrKV.Value.AsString()
+					continue
+				}
+				if attrKV.Key == attr.LogMessageShortKey {
+					gelf.ShortMessage = attrKV.Value.AsString()
 					continue
 				}
 
-				if attr.Key == "level_" {
+				if attrKV.Key == attr.SeverityLevelKey {
-					gelf.Level = level.SyslogLevel(attr.Value.AsInt64())
+					gelf.Level = level.FromString(attrKV.Value.AsString()).IntoSyslogLevel()
 					continue
 				}
 
-				attributes[string(attr.Key)] = GetByType(attr.Value)
+				attributes[string(attrKV.Key)] = GetByType(attrKV.Value)
 			}
 
 			Log(e.gelfWriter, gelf)

pkg/fiber_tracing/fiber_tracing.go

@@ -0,0 +1,96 @@
+package fiber_tracing
+
+import (
+	"context"
+	"log"
+
+	"git.ma-al.com/maal-libraries/observer/pkg/exporters"
+	"github.com/gofiber/fiber/v2"
+	"go.opentelemetry.io/otel"
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/sdk/resource"
+	trc "go.opentelemetry.io/otel/sdk/trace"
+	semconv "go.opentelemetry.io/otel/semconv/v1.25.0"
+	trace "go.opentelemetry.io/otel/trace"
+)
+
+var (
+	TracingError error = nil
+	TP           trc.TracerProvider
+)
+
+type Config struct {
+	AppName string
+	Version string
+	// Name of an organization providing the service
+	ServiceProvider string
+	Exporters       []exporters.TraceExporter
+}
+
+func newResource(config Config) *resource.Resource {
+	r := resource.NewWithAttributes(
+		semconv.SchemaURL,
+		semconv.ServiceNameKey.String(config.AppName),
+		semconv.ServiceVersionKey.String(config.Version),
+		attribute.String("service.provider", config.ServiceProvider),
+	)
+	return r
+}
+
+// NOTE: You can use [trace.WithAttributes] as a parameter to opts argument
+func Start(ctx context.Context, spanName string, opts ...trace.SpanStartOption) (context.Context, trace.Span) {
+	return Tracer.Start(ctx, spanName, opts...)
+}
+
+// NOTE: You can use [trace.WithAttributes] as a parameter to opts argument
+// Returns [c.UserContext] as [context.Context]
+func FStart(c *fiber.Ctx, opts ...trace.SpanStartOption) (context.Context, trace.Span) {
+	return Tracer.Start(c.UserContext(), c.Method()+" "+c.Route().Path, opts...)
+}
+
+// Just like [FStart] but makes it possible to assign custom span name.
+func FStartRenamed(c *fiber.Ctx, spanName string, opts ...trace.SpanStartOption) (context.Context, trace.Span) {
+	return Tracer.Start(c.UserContext(), spanName, opts...)
+}
+
+// Retrieve span using [fiber.Ctx]
+func SpanFromContext(c *fiber.Ctx) trace.Span {
+	return trace.SpanFromContext(c.UserContext())
+}
+
+func NewMiddleware(config Config) func(*fiber.Ctx) error {
+	var tracerProviders []trc.TracerProviderOption
+
+	for _, exp := range config.Exporters {
+		tracerProviders = append(tracerProviders, exp.IntoTraceProviderOption())
+	}
+	tracerProviders = append(tracerProviders, trc.WithResource(newResource(config)))
+
+	TP = *trc.NewTracerProvider(tracerProviders...)
+
+	otel.SetTracerProvider(&TP)
+	otel.SetErrorHandler(otel.ErrorHandlerFunc(func(err error) {
+		if err != TracingError {
+			TracingError = err
+			log.Println(err)
+		}
+	}))
+
+	tracer := TP.Tracer("_maal-fiber-otel_")
+
+	return new(
+		middlewareConfig{
+			Tracer: tracer,
+			TracerStartAttributes: []trace.SpanStartOption{
+				trace.WithSpanKind(trace.SpanKindServer),
+				trace.WithNewRoot(),
+			},
+		},
+	)
+}
+
+func ShutdownTracer() {
+	if err := TP.Shutdown(context.Background()); err != nil {
+		log.Fatal(err)
+	}
+}

pkg/fiber_tracing/middleware.go

@@ -0,0 +1,90 @@
+package fiber_tracing
+
+// This was copied from "github.com/psmarcin/fiber-opentelemetry/pkg/fiber-otel"
+// and slighltly modified but this piece of code is yet to be fully integrated
+// into the package.
+
+import (
+	"git.ma-al.com/maal-libraries/observer/pkg/attr"
+	"github.com/gofiber/fiber/v2"
+	"go.opentelemetry.io/otel"
+	semconv "go.opentelemetry.io/otel/semconv/v1.25.0"
+	"go.opentelemetry.io/otel/trace"
+)
+
+var Tracer = otel.Tracer("fiber_tracing_middleware")
+
+// Config defines the config for middleware.
+type middlewareConfig struct {
+	Tracer                trace.Tracer
+	TracerStartAttributes []trace.SpanStartOption
+}
+
+// ConfigDefault is the default config
+var configDefault = middlewareConfig{
+	Tracer: Tracer,
+	TracerStartAttributes: []trace.SpanStartOption{
+		trace.WithNewRoot(),
+	},
+}
+
+// Helper function to set default values
+func configDefaults(config ...middlewareConfig) middlewareConfig {
+	// Return default config if nothing provided
+	if len(config) < 1 {
+		return configDefault
+	}
+
+	// Override default config
+	cfg := config[0]
+
+	if len(cfg.TracerStartAttributes) == 0 {
+		cfg.TracerStartAttributes = configDefault.TracerStartAttributes
+	}
+
+	return cfg
+}
+
+func new(config ...middlewareConfig) fiber.Handler {
+	// Set default config
+	cfg := configDefaults(config...)
+
+	// Return new handler
+	return func(c *fiber.Ctx) error {
+		spanStartAttributes := []attr.KeyValue{
+			semconv.HTTPMethod(c.Method()),
+			semconv.HTTPTarget(string(c.Request().RequestURI())),
+			semconv.HTTPRoute(c.Route().Path),
+			semconv.HTTPURL(c.OriginalURL()),
+			semconv.HTTPUserAgent(string(c.Request().Header.UserAgent())),
+			semconv.HTTPRequestContentLength(c.Request().Header.ContentLength()),
+			semconv.HTTPScheme(c.Protocol()),
+			semconv.NetTransportTCP,
+		}
+		spanStartAttributes = append(spanStartAttributes, attr.ProcessStart()...)
+
+		opts := []trace.SpanStartOption{
+			trace.WithAttributes(spanStartAttributes...),
+			trace.WithSpanKind(trace.SpanKindServer),
+		}
+		opts = append(opts, cfg.TracerStartAttributes...)
+
+		otelCtx, span := Tracer.Start(
+			c.UserContext(),
+			c.Method()+" "+c.OriginalURL(),
+			opts...,
+		)
+
+		c.SetUserContext(otelCtx)
+		defer span.End()
+
+		err := c.Next()
+
+		statusCode := c.Response().StatusCode()
+		attrs := semconv.HTTPResponseStatusCode(statusCode)
+
+		span.SetAttributes(attrs)
+
+		return err
+	}
+}

pkg/level/level.go

@@ -1,60 +1,67 @@
 package level
 
 import (
+	"git.ma-al.com/maal-libraries/observer/pkg/syslog"
 	"go.opentelemetry.io/otel/attribute"
-	"go.opentelemetry.io/otel/trace"
 )
 
-type SyslogLevel uint8
+type SeverityLevel uint8
 
 const (
-	EMERG SyslogLevel = iota
+	// A magical zero value.
+	// WARN: DO NOT USE IN LOGS OR BASICALLY EVER
+	unset SeverityLevel = iota
+	// This event requires an immediate action. If you suspect that occurence of an event may signal that the
+	// data will get lost, corrupted, or that the application will change its behaviour following the event in
+	// an undesired way, select the ALERT level.
 	ALERT
+	// A critical error has occured. Critical errors are such which can be tough to fix or made the users
+	// experience significantly worse but unlike errors that trigger ALERT they can be fixed at any moment.
 	CRIT
+	// An error has occured but it is not expected to cause any serious issues. These will be often
+	// `Internal Server Error` responses from an HTTP server.
 	ERR
-	WARNING
+	// Signals that something suspicious has happened, for example, a query took too long to execute, gaining access
-	NOTICE
+	// to a resource took multiple attempts, a conflict was automatically resolved, etc.
+	WARN
+	// Used to inform about standard, expected events of an application, like creation of a new object or a new
+	// log-in from a user. Information that could be:
+	// - used to audit the application,
+	// - resolve customer's complaints,
+	// - track history of significant changes,
+	// - calculate valuable statistics;
+	// should be collected and logged at this level.
 	INFO
+	// Verbose information that is useful and meaningful to application developers and system administrators.
 	DEBUG
+	// Extremely verbose information that can be used to investigate performance of specific parts of an application.
+	// It is transled to [syslog.DEBUG] by [IntoSyslogLevel].
+	TRACE
 )
 
-// Level 	Keyword 	Description
+func (l SeverityLevel) String() string {
-// 0 	emergencies 	System is unusable
-// 1 	alerts 			Immediate action is needed
-// 2 	critical 		Critical conditions exist
-// 3 	errors 			Error conditions exist
-// 4 	warnings 		Warning conditions exist
-// 5 	notification 	Normal, but significant, conditions exist
-// 6 	informational 	Informational messages
-// 7 	debugging 		Debugging messages
-
-func (l SyslogLevel) String() string {
 	switch l {
-	case EMERG:
-		return "EMERG"
 	case ALERT:
 		return "ALERT"
 	case CRIT:
 		return "CRIT"
 	case ERR:
 		return "ERR"
-	case WARNING:
+	case WARN:
 		return "WARN"
-	case NOTICE:
-		return "NOTICE"
 	case INFO:
 		return "INFO"
 	case DEBUG:
 		return "DEBUG"
+	case TRACE:
+		return "TRACE"
 	default:
 		return "CRIT"
 	}
 }
 
-func LevelFromString(level string) SyslogLevel {
+func FromString(level string) SeverityLevel {
 	switch level {
-	case "EMERG":
-		return EMERG
 	case "ALERT":
 		return ALERT
 	case "CRIT":
@@ -62,23 +69,39 @@ func LevelFromString(level string) SyslogLevel {
 	case "ERR":
 		return ERR
 	case "WARN":
-		return WARNING
+		return WARN
-	case "NOTICE":
-		return NOTICE
 	case "INFO":
 		return INFO
 	case "DEBUG":
 		return DEBUG
+	case "TRACE":
+		return TRACE
 	default:
-		return CRIT
+		return unset
 	}
 }
 
-func (lvl SyslogLevel) SetAttribute(att ...attribute.KeyValue) trace.SpanStartEventOption {
+func (lvl SeverityLevel) IntoTraceAttribute() attribute.KeyValue {
-
+	return attribute.String("level", lvl.String())
-	att = append(att, attribute.Int("level", int(lvl)))
+}
-
+
-	return trace.WithAttributes(
+func (lvl SeverityLevel) IntoSyslogLevel() syslog.SyslogLevel {
-		att...,
+	switch lvl {
-	)
+	case ALERT:
+		return syslog.ALERT
+	case CRIT:
+		return syslog.CRIT
+	case ERR:
+		return syslog.ERR
+	case WARN:
+		return syslog.WARNING
+	case INFO:
+		return syslog.INFO
+	case DEBUG:
+		return syslog.DEBUG
+	case TRACE:
+		return syslog.DEBUG
+	default:
+		return syslog.EMERG
+	}
 }

pkg/syslog/syslog.go

@@ -0,0 +1,84 @@
+package syslog
+
+import (
+	"go.opentelemetry.io/otel/attribute"
+)
+
+type SyslogLevel uint8
+
+type IntoSyslogLevel interface {
+	IntoSyslogLevel() SyslogLevel
+}
+
+const (
+	// System is unusable
+	EMERG SyslogLevel = iota
+	// Immediate action is needed
+	ALERT
+	// Critical condition exists
+	CRIT
+	// An error condition has occured
+	ERR
+	// A suspicious behaviour has been observed
+	WARNING
+	// Significant but acceptable event has occured
+	NOTICE
+	// Informational details
+	INFO
+	// Data useful during debugging
+	DEBUG
+)
+
+func (l SyslogLevel) String() string {
+	switch l {
+	case EMERG:
+		return "EMERG"
+	case ALERT:
+		return "ALERT"
+	case CRIT:
+		return "CRIT"
+	case ERR:
+		return "ERR"
+	case WARNING:
+		return "WARN"
+	case NOTICE:
+		return "NOTICE"
+	case INFO:
+		return "INFO"
+	case DEBUG:
+		return "DEBUG"
+	default:
+		return "CRIT"
+	}
+}
+
+func LevelFromString(level string) SyslogLevel {
+	switch level {
+	case "EMERG":
+		return EMERG
+	case "ALERT":
+		return ALERT
+	case "CRIT":
+		return CRIT
+	case "ERR":
+		return ERR
+	case "WARN":
+		return WARNING
+	case "NOTICE":
+		return NOTICE
+	case "INFO":
+		return INFO
+	case "DEBUG":
+		return DEBUG
+	default:
+		return CRIT
+	}
+}
+
+func (lvl SyslogLevel) IntoTraceAttribute() attribute.KeyValue {
+	return attribute.String("level", lvl.String())
+}
+
+func (lvl SyslogLevel) IntoSyslogLevel() SyslogLevel {
+	return lvl
+}

pkg/tracer/event.go

@@ -1,32 +0,0 @@
-package tracer
-
-import (
-	"encoding/json"
-
-	"git.ma-al.com/gora_filip/observer/pkg/level"
-	"go.opentelemetry.io/otel/attribute"
-	"go.opentelemetry.io/otel/codes"
-	"go.opentelemetry.io/otel/trace"
-)
-
-func LongMessage(message string) attribute.KeyValue {
-	return attribute.KeyValue{Key: "long_message_", Value: attribute.StringValue(message)}
-}
-
-func Level(level level.SyslogLevel) attribute.KeyValue {
-	return attribute.KeyValue{Key: "level_", Value: attribute.Int64Value(int64(level))}
-}
-
-func JsonAttr(key string, jsonEl map[string]interface{}) attribute.KeyValue {
-
-	jsonStr, _ := json.Marshal(jsonEl)
-	return attribute.KeyValue{Key: attribute.Key(key), Value: attribute.StringValue(string(jsonStr))}
-
-}
-
-func RecordError(span trace.Span, err error) error {
-	span.SetStatus(codes.Error, err.Error())
-	span.RecordError(err)
-
-	return nil
-}

pkg/tracer/middleware.go

@@ -1,202 +0,0 @@
-package tracer
-
-import (
-	"context"
-	"fmt"
-	"log"
-	"os"
-	"runtime"
-
-	gelfexporter "git.ma-al.com/gora_filip/observer/pkg/gelf_exporter"
-	"github.com/gofiber/fiber/v2"
-	fiberOpentelemetry "github.com/psmarcin/fiber-opentelemetry/pkg/fiber-otel"
-	"go.opentelemetry.io/otel"
-	"go.opentelemetry.io/otel/attribute"
-	"go.opentelemetry.io/otel/codes"
-	"go.opentelemetry.io/otel/exporters/otlp/otlptrace"
-	"go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp"
-	"go.opentelemetry.io/otel/exporters/stdout/stdouttrace"
-	"go.opentelemetry.io/otel/sdk/resource"
-	trc "go.opentelemetry.io/otel/sdk/trace"
-	semconv "go.opentelemetry.io/otel/semconv/v1.4.0"
-	trace "go.opentelemetry.io/otel/trace"
-)
-
-var (
-	TracingError error = nil
-	TP           trc.TracerProvider
-)
-
-type CustomExporter struct {
-	jaeger      *otlptrace.Exporter
-	stdouttrace *stdouttrace.Exporter
-}
-
-type Config struct {
-	AppName   string
-	JaegerUrl string
-	GelfUrl   string
-	Version   string
-}
-
-func NewCustomExporter(jaegerUrl string) (trc.SpanExporter, error) {
-	var jaeg *otlptrace.Exporter
-	var outrace *stdouttrace.Exporter
-	var err error
-
-	outrace, err = stdouttrace.New(
-		stdouttrace.WithWriter(os.Stdout),
-		stdouttrace.WithPrettyPrint(),
-		stdouttrace.WithoutTimestamps(),
-	)
-	if err != nil {
-		return &CustomExporter{}, err
-	}
-
-	if len(jaegerUrl) > 0 {
-		jaeg = otlptracehttp.NewUnstarted(otlptracehttp.WithEndpointURL(jaegerUrl))
-	}
-
-	return &CustomExporter{
-		jaeger:      jaeg,
-		stdouttrace: outrace,
-	}, nil
-
-}
-
-func (e *CustomExporter) ExportSpans(ctx context.Context, spans []trc.ReadOnlySpan) error {
-	if TracingError == nil {
-		if e.jaeger != nil {
-			err := e.jaeger.ExportSpans(ctx, spans)
-			return err
-		} else {
-			return e.printOnlyOnError(ctx, spans)
-		}
-	}
-	return nil
-}
-
-func (e *CustomExporter) printOnlyOnError(ctx context.Context, spans []trc.ReadOnlySpan) error {
-	var err error
-	for _, s := range spans {
-		if s.Status().Code == codes.Error {
-			err = e.stdouttrace.ExportSpans(ctx, spans)
-			break
-		}
-	}
-	return err
-}
-
-func (e *CustomExporter) Shutdown(ctx context.Context) error {
-	if e.jaeger != nil {
-		e.stdouttrace.Shutdown(ctx)
-		return e.jaeger.Shutdown(ctx)
-	} else {
-		return e.stdouttrace.Shutdown(ctx)
-	}
-}
-
-func newResource(config Config) *resource.Resource {
-	r := resource.NewWithAttributes(
-		semconv.SchemaURL,
-		semconv.ServiceNameKey.String(config.AppName),
-		semconv.ServiceVersionKey.String(config.Version),
-		attribute.String("service.provider", "maal"),
-	)
-	return r
-}
-
-func NewTracer(config Config) func(*fiber.Ctx) error {
-	l := log.New(os.Stdout, "", 0)
-
-	var tracerProviders []trc.TracerProviderOption
-
-	otlpExporter := otlptracehttp.NewUnstarted(otlptracehttp.WithEndpointURL(config.JaegerUrl))
-
-	gelfExporter, err := gelfexporter.New(
-		gelfexporter.WithGelfUrl(config.GelfUrl),
-		gelfexporter.WithAppName("salego"),
-	)
-	if err != nil {
-		l.Fatal(err)
-	}
-	tracerProviders = append(tracerProviders, trc.WithBatcher(otlpExporter))
-	tracerProviders = append(tracerProviders, trc.WithBatcher(gelfExporter))
-	tracerProviders = append(tracerProviders, trc.WithResource(newResource(config)))
-
-	TP = *trc.NewTracerProvider(tracerProviders...)
-
-	otel.SetTracerProvider(&TP)
-	otel.SetErrorHandler(otel.ErrorHandlerFunc(func(err error) {
-		if err != TracingError {
-			TracingError = err
-			log.Println(err)
-		}
-	}))
-
-	tracer := TP.Tracer("fiber-otel-router")
-
-	return fiberOpentelemetry.New(
-		fiberOpentelemetry.Config{
-			Tracer:   tracer,
-			SpanName: "{{ .Method }} {{ .Path }}",
-			TracerStartAttributes: []trace.SpanStartOption{
-				trace.WithSpanKind(trace.SpanKindServer),
-				trace.WithNewRoot(),
-			},
-		},
-	)
-}
-
-func ShutdownTracer() {
-	if err := TP.Shutdown(context.Background()); err != nil {
-		log.Fatal(err)
-	}
-}
-
-func Handler(fc *fiber.Ctx) (context.Context, trace.Span) {
-	spanName := fmt.Sprint(fc.OriginalURL())
-	simpleCtx, span := fiberOpentelemetry.Tracer.Start(fc.UserContext(), spanName)
-
-	fc.SetUserContext(simpleCtx)
-
-	_, file, line, _ := runtime.Caller(1)
-	span.SetAttributes(
-		attribute.String("service.layer", "handler"),
-		attribute.String("file", file),
-		attribute.String("line", fmt.Sprintf("%d", line)),
-	)
-
-	return simpleCtx, span
-}
-
-func Service(c context.Context, spanName string) (context.Context, trace.Span) {
-	simpleCtx, span := fiberOpentelemetry.Tracer.Start(c, spanName)
-	var attribs []attribute.KeyValue
-
-	_, file, line, _ := runtime.Caller(1)
-	attribs = append(
-		attribs,
-		attribute.String("service.layer", "service"),
-		attribute.String("file", file),
-		attribute.String("line", fmt.Sprintf("%d", line)),
-	)
-
-	span.SetAttributes(attribs...)
-
-	return simpleCtx, span
-}
-
-func Repository(c context.Context, spanName string) (context.Context, trace.Span) {
-	ctx2, span := fiberOpentelemetry.Tracer.Start(c, spanName)
-	var attribs []attribute.KeyValue
-
-	_, file, line, _ := runtime.Caller(1)
-	attribs = append(attribs,
-		attribute.String("file", file),
-		attribute.String("line", fmt.Sprintf("%d", line)),
-	)
-	span.SetAttributes(attribs...)
-
-	return ctx2, span
-}