veryroundbird.house
1package log
2
3import (
4 "context"
5 "log/slog"
6 "os"
7)
8
9// NewHandler sets up a new slog.Handler with the service name
10// as an attribute
11func NewHandler(name string) slog.Handler {
12 handler := slog.NewTextHandler(os.Stdout, &slog.HandlerOptions{})
13
14 var attrs []slog.Attr
15 attrs = append(attrs, slog.Attr{Key: "service", Value: slog.StringValue(name)})
16 handler.WithAttrs(attrs)
17 return handler
18}
19
20func New(name string) *slog.Logger {
21 return slog.New(NewHandler(name))
22}
23
24func NewContext(ctx context.Context, name string) context.Context {
25 return IntoContext(ctx, New(name))
26}
27
28type ctxKey struct{}
29
30// IntoContext adds a logger to a context. Use FromContext to
31// pull the logger out.
32func IntoContext(ctx context.Context, l *slog.Logger) context.Context {
33 return context.WithValue(ctx, ctxKey{}, l)
34}
35
36// FromContext returns a logger from a context.Context;
37// if the passed context is nil, we return the default slog
38// logger.
39func FromContext(ctx context.Context) *slog.Logger {
40 if ctx != nil {
41 v := ctx.Value(ctxKey{})
42 if v == nil {
43 return slog.Default()
44 }
45 return v.(*slog.Logger)
46 }
47
48 return slog.Default()
49}