slog: use middle dot for TextHandler groups/scopes
Use a Unicode middle dot 'ยท' as the separator between group/scope names
and keys in the TextHandler, instead of an ordinary dot '.'.
Although both dot and middle-dot may appear in a user-supplied
attribute key, making unambiguous parsing into groups impossible,
middle-dot is expected to be much less common, thus reducing the
frequency of ambiguity. If a user wants to escape, they can use
ReplaceAttr.
Alternative encodings that unambiguously preserve the group/key
separation would make parsing more complicated than simply calling
strconv.Unquote.
Change-Id: I6951ced8bb64dcb340c16372e0c27f49c861d88c
Reviewed-on: https://go-review.googlesource.com/c/exp/+/442355
Run-TryBot: Jonathan Amsterdam <jba@google.com>
Reviewed-by: Alan Donovan <adonovan@google.com>
diff --git a/slog/handler.go b/slog/handler.go
index c00e5c9..d10d2d0 100644
--- a/slog/handler.go
+++ b/slog/handler.go
@@ -308,6 +308,11 @@
}
}
+// Separator for group/scope names and keys.
+// We use the uncommon character middle-dot rather than an ordinary dot
+// to reduce the likelihood of ambiguous group structure.
+const keyComponentSep = "·" // Unicode middle dot
+
// openGroup starts a new group of attributes
// with the given name.
// A group can arise from a scope, or from an Attr with a GroupKind value.
@@ -317,9 +322,8 @@
s.buf.WriteByte('{')
s.sep = ""
} else {
- // TODO: fix escaping to make it easy to recover the original.
- s.prefix.WriteString(escapeDots(name))
- s.prefix.WriteByte('.')
+ s.prefix.WriteString(name)
+ s.prefix.WriteString(keyComponentSep)
}
}
@@ -328,7 +332,7 @@
if s.h.json {
s.buf.WriteByte('}')
} else {
- (*s.prefix) = (*s.prefix)[:len(*s.prefix)-len(name)-1]
+ (*s.prefix) = (*s.prefix)[:len(*s.prefix)-len(name)-len(keyComponentSep)]
}
s.sep = s.h.attrSep()
}
@@ -364,11 +368,12 @@
func (s *handleState) appendKey(key string) {
s.buf.WriteString(s.sep)
- // TODO: make sure the entire prefix+key is quoted if any part of it needs to be.
if s.prefix != nil {
- s.buf.Write(*s.prefix)
+ // TODO: optimize by avoiding allocation.
+ s.appendString(string(*s.prefix) + key)
+ } else {
+ s.appendString(key)
}
- s.appendString(key)
if s.h.json {
s.buf.WriteByte(':')
} else {
diff --git a/slog/handler_test.go b/slog/handler_test.go
index 7275f9e..ae0d70c 100644
--- a/slog/handler_test.go
+++ b/slog/handler_test.go
@@ -49,13 +49,13 @@
Int("d", 4)),
Int("e", 5),
},
- want: "INFO message a=1 g.b=2 g.h.c=3 g.d=4 e=5",
+ want: "INFO message a=1 g·b=2 g·h·c=3 g·d=4 e=5",
},
{
name: "scope",
with: func(h Handler) Handler { return h.With(preAttrs).WithScope("s") },
attrs: attrs,
- want: "INFO message pre=0 s.a=1 s.b=two",
+ want: "INFO message pre=0 s·a=1 s·b=two",
},
{
name: "preformatted scopes",
@@ -66,7 +66,7 @@
WithScope("s2")
},
attrs: attrs,
- want: "INFO message p1=1 s1.p2=2 s1.s2.a=1 s1.s2.b=two",
+ want: "INFO message p1=1 s1·p2=2 s1·s2·a=1 s1·s2·b=two",
},
{
name: "two scopes",
@@ -76,7 +76,7 @@
WithScope("s2")
},
attrs: attrs,
- want: "INFO message p1=1 s1.s2.a=1 s1.s2.b=two",
+ want: "INFO message p1=1 s1·s2·a=1 s1·s2·b=two",
},
} {
t.Run(test.name, func(t *testing.T) {
@@ -204,17 +204,29 @@
Int("d", 4)),
Int("e", 5),
},
- wantText: "msg=message a=1 g.b=2 g.h.c=3 g.d=4 e=5",
+ wantText: "msg=message a=1 g·b=2 g·h·c=3 g·d=4 e=5",
wantJSON: `{"msg":"message","a":1,"g":{"b":2,"h":{"c":3},"d":4},"e":5}`,
},
{
name: "empty group",
replace: removeKeys(timeKey, levelKey),
attrs: []Attr{Group("g"), Group("h", Int("a", 1))},
- wantText: "msg=message h.a=1",
+ wantText: "msg=message h·a=1",
wantJSON: `{"msg":"message","g":{},"h":{"a":1}}`,
},
{
+ name: "escapes",
+ replace: removeKeys(timeKey, levelKey),
+ attrs: []Attr{
+ String("a b", "x\t\n\000y"),
+ Group(" b.c=\"\\x2E\t",
+ String("d=e", "f.g\""),
+ Int("m·d", 1)), // middle dot is not escaped
+ },
+ wantText: `msg=message "a b"="x\t\n\x00y" " b.c=\"\\x2E\t·d=e"="f.g\"" " b.c=\"\\x2E\t·m·d"=1`,
+ wantJSON: `{"msg":"message","a b":"x\t\n\u0000y"," b.c=\"\\x2E\t":{"d=e":"f.g\"","m·d":1}}`,
+ },
+ {
name: "LogValuer",
replace: removeKeys(timeKey, levelKey),
attrs: []Attr{
@@ -222,7 +234,7 @@
Any("name", logValueName{"Ren", "Hoek"}),
Int("b", 2),
},
- wantText: "msg=message a=1 name.first=Ren name.last=Hoek b=2",
+ wantText: "msg=message a=1 name·first=Ren name·last=Hoek b=2",
wantJSON: `{"msg":"message","a":1,"name":{"first":"Ren","last":"Hoek"},"b":2}`,
},
{
@@ -230,7 +242,7 @@
replace: removeKeys(timeKey, levelKey),
with: func(h Handler) Handler { return h.With(preAttrs).WithScope("s") },
attrs: attrs,
- wantText: "msg=message pre=3 x=y s.a=one s.b=2",
+ wantText: "msg=message pre=3 x=y s·a=one s·b=2",
wantJSON: `{"msg":"message","pre":3,"x":"y","s":{"a":"one","b":2}}`,
},
{
@@ -243,7 +255,7 @@
WithScope("s2")
},
attrs: attrs,
- wantText: "msg=message p1=1 s1.p2=2 s1.s2.a=one s1.s2.b=2",
+ wantText: "msg=message p1=1 s1·p2=2 s1·s2·a=one s1·s2·b=2",
wantJSON: `{"msg":"message","p1":1,"s1":{"p2":2,"s2":{"a":"one","b":2}}}`,
},
{
@@ -255,7 +267,7 @@
WithScope("s2")
},
attrs: attrs,
- wantText: "msg=message p1=1 s1.s2.a=one s1.s2.b=2",
+ wantText: "msg=message p1=1 s1·s2·a=one s1·s2·b=2",
wantJSON: `{"msg":"message","p1":1,"s1":{"s2":{"a":"one","b":2}}}`,
},
} {
diff --git a/slog/text_handler.go b/slog/text_handler.go
index 2268f76..152445a 100644
--- a/slog/text_handler.go
+++ b/slog/text_handler.go
@@ -8,7 +8,6 @@
"encoding"
"fmt"
"io"
- "strings"
"unicode"
"unicode/utf8"
)
@@ -71,6 +70,12 @@
// Keys and values are quoted if they contain Unicode space characters,
// non-printing characters, '"' or '='.
//
+// Keys inside groups and scopes consist of components (keys or scope names)
+// separated by the Unicode middle dot character, '·'. No further escaping is
+// performed. If it is necessary to reconstruct the group structure of a key
+// even in the presence of middle dots inside components, use
+// [HandlerOptions.ReplaceAttr] to escape the keys.
+//
// Each call to Handle results in a single serialized call to
// io.Writer.Write.
func (h *TextHandler) Handle(r Record) error {
@@ -100,13 +105,6 @@
return nil
}
-// escapeDots replaces all '.' runes in s with the equivalent hex escape code.
-// This allows the scope/group structure to be retrieved from the dot-separated
-// components of a key.
-func escapeDots(s string) string {
- return strings.ReplaceAll(s, ".", `\x2E`)
-}
-
func needsQuoting(s string) bool {
for i := 0; i < len(s); {
b := s[i]
