package ln import ( "context" "os" "time" "github.com/pkg/errors" ) // Logger holds the current priority and list of filters type Logger struct { Filters []Filter } // DefaultLogger is the default implementation of Logger var DefaultLogger *Logger func init() { var defaultFilters []Filter // Default to STDOUT for logging, but allow LN_OUT to change it. out := os.Stdout if os.Getenv("LN_OUT") == "" { out = os.Stderr } defaultFilters = append(defaultFilters, NewWriterFilter(out, nil)) DefaultLogger = &Logger{ Filters: defaultFilters, } } // F is a key-value mapping for structured data. type F map[string]interface{} // Extend concatentates one F with one or many Fer instances. func (f F) Extend(other ...Fer) { for _, ff := range other { for k, v := range ff.F() { f[k] = v } } } // F makes F an Fer func (f F) F() F { return f } // Fer allows any type to add fields to the structured logging key->value pairs. type Fer interface { F() F } // Event represents an event type Event struct { Time time.Time Data F Message string } // Log is the generic logging method. func (l *Logger) Log(ctx context.Context, xs ...Fer) { event := Event{Time: time.Now()} addF := func(bf F) { if event.Data == nil { event.Data = bf } else { for k, v := range bf { event.Data[k] = v } } } for _, f := range xs { addF(f.F()) } ctxf, ok := FFromContext(ctx) if ok { addF(ctxf) } if os.Getenv("LN_DEBUG_ALL_EVENTS") == "1" { frame := callersFrame() if event.Data == nil { event.Data = make(F) } event.Data["_lineno"] = frame.lineno event.Data["_function"] = frame.function event.Data["_filename"] = frame.filename } l.filter(ctx, event) } func (l *Logger) filter(ctx context.Context, e Event) { for _, f := range l.Filters { if !f.Apply(ctx, e) { return } } } // Error logs an error and information about the context of said error. func (l *Logger) Error(ctx context.Context, err error, xs ...Fer) { data := F{} frame := callersFrame() data["_lineno"] = frame.lineno data["_function"] = frame.function data["_filename"] = frame.filename data["err"] = err cause := errors.Cause(err) if cause != nil { data["cause"] = cause.Error() } xs = append(xs, data) l.Log(ctx, xs...) } // Fatal logs this set of values, then exits with status code 1. func (l *Logger) Fatal(ctx context.Context, xs ...Fer) { xs = append(xs, F{"fatal": true}) l.Log(ctx, xs...) os.Exit(1) } // FatalErr combines Fatal and Error. func (l *Logger) FatalErr(ctx context.Context, err error, xs ...Fer) { xs = append(xs, F{"fatal": true}) data := F{} frame := callersFrame() data["_lineno"] = frame.lineno data["_function"] = frame.function data["_filename"] = frame.filename data["err"] = err cause := errors.Cause(err) if cause != nil { data["cause"] = cause.Error() } xs = append(xs, data) l.Log(ctx, xs...) os.Exit(1) } // Default Implementation // Log is the generic logging method. func Log(ctx context.Context, xs ...Fer) { DefaultLogger.Log(ctx, xs...) } // Error logs an error and information about the context of said error. func Error(ctx context.Context, err error, xs ...Fer) { DefaultLogger.Error(ctx, err, xs...) } // Fatal logs this set of values, then exits with status code 1. func Fatal(ctx context.Context, xs ...Fer) { DefaultLogger.Fatal(ctx, xs...) } // FatalErr combines Fatal and Error. func FatalErr(ctx context.Context, err error, xs ...Fer) { DefaultLogger.FatalErr(ctx, err, xs...) }