feat: adding HandleInlineHandler and InlineHandler (#25)

* feat: adding HandleInlineHandler and InlineHandler

* doc: adding HandleInlineHandler and InlineHandler

Author: samber

README.md

@@ -363,6 +363,35 @@ The example above uses:
 
 Note: `WithAttrs` and `WithGroup` methods of custom middleware must return a new instance, instead of `this`.
 
+#### Inline handler
+
+An "inline handler" (aka. lambda), is a shortcut to handler implement, that hooks a single method and proxies others.
+
+```go
+mdw := slogmulti.NewHandleInlineHandler(
+    // simulate "Handle()"
+    func(ctx context.Context, groups []string, attrs []slog.Attr, record slog.Record) error {
+        // [...]
+        return nil
+    },
+)
+```
+
+```go
+mdw := slogmulti.NewInlineHandler(
+    // simulate "Enabled()"
+    func(ctx context.Context, groups []string, attrs []slog.Attr, level slog.Level) bool {
+        // [...]
+        return true
+    },
+    // simulate "Handle()"
+    func(ctx context.Context, groups []string, attrs []slog.Attr, record slog.Record) error {
+        // [...]
+        return nil
+    },
+)
+```
+
 #### Inline middleware
 
 An "inline middleware" (aka. lambda), is a shortcut to middleware implementation, that hooks a single method and proxies others.

go.work.sum

@@ -5,6 +5,7 @@ github.com/kr/pretty v0.1.0/go.mod h1:dAy3ld7l9f0ibDNOQOHHMYYIIbhfbHSm3C4ZsoJORN
 github.com/stretchr/objx v0.5.0 h1:1zr/of2m5FGMsad5YfcqgdqdWrIhu+EBEJRhR1U7z/c=
 github.com/yuin/goldmark v1.4.13 h1:fVcFKWvrslecOb/tg+Cc05dkeYx540o0FuFt3nUVDoE=
 github.com/yuin/goldmark v1.4.13/go.mod h1:6yULJ656Px+3vBD8DxQVa3kxgyrAnzto9xy5taEt/CY=
+golang.org/x/exp v0.0.0-20220303212507-bbda1eaf7a17/go.mod h1:lgLbSvA5ygNOMpwM/9anMpWVlVJ7Z+cHWq/eFuinpGE=
 golang.org/x/mod v0.6.0/go.mod h1:4mET923SAdbXp2ki8ey+zGs1SLqsuM2Y0uvdZR/fUNI=
 golang.org/x/mod v0.11.0 h1:bUO06HqtnRcc/7l71XBe4WcqTZ+3AH1J59zWDDwLKgU=
 golang.org/x/mod v0.11.0/go.mod h1:iBbtSCu2XBx23ZKBPSOrRkjjQPZFPuis4dIYUhu/chs=
@@ -18,8 +19,6 @@ golang.org/x/sys v0.1.0 h1:kunALQeHf1/185U1i0GOB/fy1IPRDDpuoOOqRReG57U=
 golang.org/x/sys v0.1.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.20.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/telemetry v0.0.0-20240228155512-f48c80bd79b2/go.mod h1:TeRTkGYfJXctD9OcfyVLyj2J3IxLnKwHJR8f4D8a3YE=
-golang.org/x/text v0.16.0 h1:a94ExnEXNtEwYLGJSIUxnWoxoRz/ZcCsV63ROupILh4=
-golang.org/x/text v0.16.0/go.mod h1:GhwF1Be+LQoKShO3cGOHzqOgRrGaYc9AvblQOmPVHnI=
 golang.org/x/tools v0.2.0 h1:G6AHpWxTMGY1KyEYoAQ5WTtIekUUvDNjan3ugu60JvE=
 golang.org/x/tools v0.2.0/go.mod h1:y4OqIKeOV/fWJetJ8bXPU1sEVniLMIyDAZWeHdV+NTA=
 golang.org/x/tools v0.13.0/go.mod h1:HvlwmtVNQAhOuCjW7xxvovg8wbNq7LwfXh/k7wXUl58=

handler_inline.go

@@ -0,0 +1,71 @@
+package slogmulti
+
+import (
+	"context"
+
+	"log/slog"
+)
+
+// NewInlineHandler is a shortcut to a handler that implements all methods.
+func NewInlineHandler(
+	enabledFunc func(ctx context.Context, groups []string, attrs []slog.Attr, level slog.Level) bool,
+	handleFunc func(ctx context.Context, groups []string, attrs []slog.Attr, record slog.Record) error,
+) slog.Handler {
+	return &InlineHandler{
+		groups:      []string{},
+		attrs:       []slog.Attr{},
+		enabledFunc: enabledFunc,
+		handleFunc:  handleFunc,
+	}
+}
+
+var _ slog.Handler = (*InlineHandler)(nil)
+
+type InlineHandler struct {
+	groups      []string
+	attrs       []slog.Attr
+	enabledFunc func(ctx context.Context, groups []string, attrs []slog.Attr, level slog.Level) bool
+	handleFunc  func(ctx context.Context, groups []string, attrs []slog.Attr, record slog.Record) error
+}
+
+// Implements slog.Handler
+func (h *InlineHandler) Enabled(ctx context.Context, level slog.Level) bool {
+	return h.enabledFunc(ctx, h.groups, h.attrs, level)
+}
+
+// Implements slog.Handler
+func (h *InlineHandler) Handle(ctx context.Context, record slog.Record) error {
+	return h.handleFunc(ctx, h.groups, h.attrs, record)
+}
+
+// Implements slog.Handler
+func (h *InlineHandler) WithAttrs(attrs []slog.Attr) slog.Handler {
+	newAttrs := []slog.Attr{}
+	newAttrs = append(newAttrs, h.attrs...)
+	newAttrs = append(newAttrs, attrs...)
+
+	return &InlineHandler{
+		groups:      h.groups,
+		attrs:       newAttrs,
+		enabledFunc: h.enabledFunc,
+		handleFunc:  h.handleFunc,
+	}
+}
+
+// Implements slog.Handler
+func (h *InlineHandler) WithGroup(name string) slog.Handler {
+	// https://cs.opensource.google/go/x/exp/+/46b07846:slog/handler.go;l=247
+	if name == "" {
+		return h
+	}
+
+	newGroups := []string{}
+	newGroups = append(newGroups, h.groups...)
+	newGroups = append(newGroups, name)
+	return &InlineHandler{
+		groups:      newGroups,
+		attrs:       h.attrs,
+		enabledFunc: h.enabledFunc,
+		handleFunc:  h.handleFunc,
+	}
+}

handler_inline_handle.go

@@ -0,0 +1,66 @@
+package slogmulti
+
+import (
+	"context"
+
+	"log/slog"
+)
+
+// NewHandleInlineHandler is a shortcut to a middleware that implements only the `Handle` method.
+func NewHandleInlineHandler(handleFunc func(ctx context.Context, groups []string, attrs []slog.Attr, record slog.Record) error) Middleware {
+	return func(next slog.Handler) slog.Handler {
+		return &HandleInlineHandler{
+			groups:     []string{},
+			attrs:      []slog.Attr{},
+			handleFunc: handleFunc,
+		}
+	}
+}
+
+var _ slog.Handler = (*HandleInlineHandler)(nil)
+
+type HandleInlineHandler struct {
+	groups     []string
+	attrs      []slog.Attr
+	handleFunc func(ctx context.Context, groups []string, attrs []slog.Attr, record slog.Record) error
+}
+
+// Implements slog.Handler
+func (h *HandleInlineHandler) Enabled(ctx context.Context, level slog.Level) bool {
+	return true
+}
+
+// Implements slog.Handler
+func (h *HandleInlineHandler) Handle(ctx context.Context, record slog.Record) error {
+	return h.handleFunc(ctx, h.groups, h.attrs, record)
+}
+
+// Implements slog.Handler
+func (h *HandleInlineHandler) WithAttrs(attrs []slog.Attr) slog.Handler {
+	newAttrs := []slog.Attr{}
+	newAttrs = append(newAttrs, h.attrs...)
+	newAttrs = append(newAttrs, attrs...)
+
+	return &InlineHandler{
+		groups:     h.groups,
+		attrs:      newAttrs,
+		handleFunc: h.handleFunc,
+	}
+}
+
+// Implements slog.Handler
+func (h *HandleInlineHandler) WithGroup(name string) slog.Handler {
+	// https://cs.opensource.google/go/x/exp/+/46b07846:slog/handler.go;l=247
+	if name == "" {
+		return h
+	}
+
+	newGroups := []string{}
+	newGroups = append(newGroups, h.groups...)
+	newGroups = append(newGroups, name)
+	return &InlineHandler{
+		groups:     newGroups,
+		attrs:      h.attrs,
+		handleFunc: h.handleFunc,
+	}
+}