package main
import (
"context"
"net/http"
"github.com/chanxuehong/log"
"github.com/chanxuehong/log/trace"
)
// set defaults if necessary.
// normal at the moment of load config.
func init() {
log.SetFormatter(log.TextFormatter)
log.SetLevelString(log.DebugLevelString)
log.SetDefaultOptions([]log.Option{
log.WithFormatter(log.TextFormatter),
log.WithLevelString(log.DebugLevelString),
})
}
type mockResponseWriter struct {
http.ResponseWriter
header http.Header
}
func (w *mockResponseWriter) Header() http.Header {
return w.header
}
func main() {
w := &mockResponseWriter{
header: make(http.Header),
}
req, _ := http.NewRequest(http.MethodGet, "http://www.example.com", nil)
httpHandler(w, req)
}
func httpHandler(w http.ResponseWriter, req *http.Request) {
defer func() {
log.Debug("debug", "trace_id", w.Header().Get(trace.TraceIdHeaderKey))
}()
// In general, it is a middleware
{
// gets traceId from request header, if not exists, generates it.
traceId, ok := trace.FromRequest(req)
if !ok {
traceId = trace.NewTraceId()
req.Header.Set(trace.TraceIdHeaderKey, traceId)
}
// sets traceId to response header
w.Header().Set(trace.TraceIdHeaderKey, traceId)
// adds traceId to request.Context
req = req.WithContext(trace.NewContext(req.Context(), traceId))
// adds log.Logger to request.Context
req = req.WithContext(log.NewContext(req.Context(), log.New(log.WithTraceId(traceId))))
}
l := log.MustFromRequest(req)
l.Info("1.info message")
l.Info("2.info message", "key1", 1, "key2", 2)
l = l.WithField("key3", 3)
l = l.WithFields("key4", 4, "key5", 5)
l.Info("3.info message")
ctx := log.NewContext(req.Context(), l)
fn1(ctx)
}
func fn1(ctx context.Context) {
l := log.MustFromContext(ctx)
l.Info("4.info message")
l.Info("5.info message", "key6", 6)
l = l.WithField("key7", 7)
ctx = log.NewContext(ctx, l)
fn2(ctx)
}
func fn2(ctx context.Context) {
l := log.MustFromContext(ctx)
l.Info("6.info message", "key8", 8)
fn3(ctx)
}
func fn3(ctx context.Context) {
l := log.MustFromContext(ctx)
l.Info("7.info message", "key9", 9)
}
time=2018-05-25 23:59:16.066, level=info, request_id=934d159e603411e8a1cab4d5bdb21e16, location=main.httpHandler(test1/main.go:61), msg=1.info message
time=2018-05-25 23:59:16.066, level=info, request_id=934d159e603411e8a1cab4d5bdb21e16, location=main.httpHandler(test1/main.go:62), msg=2.info message, key1=1, key2=2
time=2018-05-25 23:59:16.066, level=info, request_id=934d159e603411e8a1cab4d5bdb21e16, location=main.httpHandler(test1/main.go:66), msg=3.info message, key3=3, key4=4, key5=5
time=2018-05-25 23:59:16.066, level=info, request_id=934d159e603411e8a1cab4d5bdb21e16, location=main.fn1(test1/main.go:74), msg=4.info message, key3=3, key4=4, key5=5
time=2018-05-25 23:59:16.066, level=info, request_id=934d159e603411e8a1cab4d5bdb21e16, location=main.fn1(test1/main.go:75), msg=5.info message, key3=3, key4=4, key5=5, key6=6
time=2018-05-25 23:59:16.067, level=info, request_id=934d159e603411e8a1cab4d5bdb21e16, location=main.fn2(test1/main.go:84), msg=6.info message, key3=3, key4=4, key5=5, key7=7, key8=8
time=2018-05-25 23:59:16.067, level=info, request_id=934d159e603411e8a1cab4d5bdb21e16, location=main.fn3(test1/main.go:91), msg=7.info message, key3=3, key4=4, key5=5, key7=7, key9=9
time=2018-05-25 23:59:16.067, level=debug, request_id=, location=main.httpHandler.func1(test1/main.go:41), msg=debug, trace_id=934d159e603411e8a1cab4d5bdb21e16