ccpaging/nxlog4go

// Copyright (C) 2017, ccpaging <ccpaging@gmail.com>.  All rights reserved.

package driver

import (
    "bytes"
)

// Filter contains:
//  - Enabler, the Enabler interface for filter log Recorder
//  - Layout, the Layout interface for encoding log Recorder
//  - Apps, the slice of the Appender interface
type Filter struct {
    Name string
    Enabler
    Layout
    Apps []Appender
}

// Dispatch filters, encodes a log recorder to bytes, and writes it to all appenders.
//  - Enabler.Enabled, filter log Recorder.
//  - Layout.Encode, encode log Recorder to bytes.Buffer.
//  - Apps[i].Enabled, filter log recorder by appender.
//  - Apps[i].Write, append with log recorder encoded bytes.
func (f *Filter) Dispatch(r *Recorder) {
    if f.Enabler != nil && !f.Enabler.Enabled(r) {
        return
    }

    out := new(bytes.Buffer)
    encoded := false
    for _, a := range f.Apps {
        if a != nil && !a.Enabled(r) {
            continue
        }
        if f.Layout == nil {
            continue
        }
        if !encoded {
            f.Layout.Encode(out, r)
            encoded = true
        }
        a.Write(out.Bytes())
    }
}

// Close closes all log appenders in preparation for exiting the program.
// Calling this is not really imperative, unless you want to
// guarantee that all log messages are written.
//
// Notice: Close() removes all appenders from the filter.
func (f *Filter) Close() {
    for _, a := range f.Apps {
        if a != nil {
            a.Close()
        }
    }
    f.Apps = nil
}