Merge pull request #73 from cdr/opencensus

Remove direct coupling of opencensus

Author: nhooyr

README.md

@@ -26,8 +26,8 @@ go get cdr.dev/slog
 - [Stdlib](https://godoc.org/cdr.dev/slog#Stdlib) log adapter
 - Skip caller frames with [slog.Helper](https://godoc.org/cdr.dev/slog#Helper)
 - Encodes values as if with `json.Marshal`
-- Transparently log [opencensus](https://godoc.org/go.opencensus.io/trace) trace and span IDs
-- [Single dependency](https://godoc.org/cdr.dev/slog?imports) on go.opencensus.io
+- Transparently log [opencensus](https://godoc.org/go.opencensus.io/trace) span's from the passed context
+- [Zero dependencies](https://godoc.org/cdr.dev/slog?imports)
 - Log to multiple sinks
 
 ## Example

internal/entryhuman/entry.go

@@ -49,7 +49,7 @@ func c(w io.Writer, attrs ...color.Attribute) *color.Color {
 // We also do not indent the fields as go's test does that automatically
 // for extra lines in a log so if we did it here, the fields would be indented
 // twice in test logs. So the Stderr logger indents all the fields itself.
-func Fmt(w io.Writer, ent slog.SinkEntry) string {
+func Fmt(w io.Writer, ent slog.SinkEntry, sc trace.SpanContext) string {
 	var ents string
 	ts := ent.Time.Format(TimeFormat)
 	ents += ts + " "
@@ -79,10 +79,10 @@ func Fmt(w io.Writer, ent slog.SinkEntry) string {
 	msg = quote(msg)
 	ents += msg
 
-	if ent.SpanContext != (trace.SpanContext{}) {
+	if sc != (trace.SpanContext{}) {
 		ent.Fields = append(slog.M(
-			slog.F("trace", ent.SpanContext.TraceID),
-			slog.F("span", ent.SpanContext.SpanID),
+			slog.F("trace", sc.TraceID),
+			slog.F("span", sc.SpanID),
 		), ent.Fields...)
 	}
 

internal/entryhuman/entry_test.go

@@ -14,11 +14,11 @@ import (
 
 var kt = time.Date(2000, time.February, 5, 4, 4, 4, 4, time.UTC)
 
-func TestEntry(t *testing.T) {
+func TestFmt(t *testing.T) {
 	t.Parallel()
 
-	test := func(t *testing.T, in slog.SinkEntry, exp string) {
-		act := entryhuman.Fmt(ioutil.Discard, in)
+	test := func(t *testing.T, in slog.SinkEntry, sc trace.SpanContext, exp string) {
+		act := entryhuman.Fmt(ioutil.Discard, in, sc)
 		assert.Equal(t, exp, act, "entry")
 	}
 
@@ -33,7 +33,7 @@ func TestEntry(t *testing.T) {
 			File: "myfile",
 			Line: 100,
 			Func: "ignored",
-		}, `2000-02-05 04:04:04.000 [DEBUG]	<myfile:100>	"wowowow\tizi"`)
+		}, trace.SpanContext{}, `2000-02-05 04:04:04.000 [DEBUG]	<myfile:100>	"wowowow\tizi"`)
 	})
 
 	t.Run("multilineMessage", func(t *testing.T) {
@@ -42,7 +42,7 @@ func TestEntry(t *testing.T) {
 		test(t, slog.SinkEntry{
 			Message: "line1\nline2",
 			Level:   slog.LevelInfo,
-		}, `0001-01-01 00:00:00.000 [INFO]	<.:0>	...
+		}, trace.SpanContext{}, `0001-01-01 00:00:00.000 [INFO]	<.:0>	...
 "msg": line1
 line2`)
 	})
@@ -53,18 +53,17 @@ line2`)
 		test(t, slog.SinkEntry{
 			Level:       slog.LevelWarn,
 			LoggerNames: []string{"named", "meow"},
-		}, `0001-01-01 00:00:00.000 [WARN]	(named.meow)	<.:0>	""`)
+		}, trace.SpanContext{}, `0001-01-01 00:00:00.000 [WARN]	(named.meow)	<.:0>	""`)
 	})
 
 	t.Run("trace", func(t *testing.T) {
 		t.Parallel()
 
 		test(t, slog.SinkEntry{
 			Level: slog.LevelError,
-			SpanContext: trace.SpanContext{
-				SpanID:  trace.SpanID{0, 1, 2, 3, 4, 5, 6, 7},
-				TraceID: trace.TraceID{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15},
-			},
+		}, trace.SpanContext{
+			SpanID:  trace.SpanID{0, 1, 2, 3, 4, 5, 6, 7},
+			TraceID: trace.TraceID{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15},
 		}, `0001-01-01 00:00:00.000 [ERROR]	<.:0>	""	{"trace": "000102030405060708090a0b0c0d0e0f", "span": "0001020304050607"}`)
 	})
 
@@ -76,7 +75,7 @@ line2`)
 			Fields: slog.M(
 				slog.F("hey", "hi"),
 			),
-		})
+		}, trace.SpanContext{})
 		assert.Equal(t, "0001-01-01 00:00:00.000 \x1b[91m[CRITICAL]\x1b[0m\t\x1b[36m<.:0>\x1b[0m\t\"\"\t{\x1b[34m\"hey\"\x1b[0m: \x1b[32m\"hi\"\x1b[0m}", act, "entry")
 	})
 }

slog.go

@@ -17,8 +17,6 @@ import (
 	"runtime"
 	"sync"
 	"time"
-
-	"go.opencensus.io/trace"
 )
 
 // Sink is the destination of a Logger.
@@ -147,11 +145,10 @@ func (l Logger) log(ctx context.Context, level Level, msg string, fields Map) {
 
 func (l Logger) entry(ctx context.Context, level Level, msg string, fields Map) SinkEntry {
 	ent := SinkEntry{
-		Time:        time.Now().UTC(),
-		Level:       level,
-		Message:     msg,
-		Fields:      fieldsFromContext(ctx).append(fields),
-		SpanContext: trace.FromContext(ctx).SpanContext(),
+		Time:    time.Now().UTC(),
+		Level:   level,
+		Message: msg,
+		Fields:  fieldsFromContext(ctx).append(fields),
 	}
 	ent = ent.fillLoc(l.skip + 3)
 	return ent
@@ -275,8 +272,6 @@ type SinkEntry struct {
 	File string
 	Line int
 
-	SpanContext trace.SpanContext
-
 	Fields Map
 }
 

slog_test.go

@@ -6,8 +6,6 @@ import (
 	"runtime"
 	"testing"
 
-	"go.opencensus.io/trace"
-
 	"cdr.dev/slog"
 	"cdr.dev/slog/internal/assert"
 )
@@ -74,7 +72,7 @@ func TestLogger(t *testing.T) {
 
 			File: slogTestFile,
 			Func: "cdr.dev/slog_test.TestLogger.func2",
-			Line: 66,
+			Line: 64,
 
 			Fields: slog.M(
 				slog.F("ctx", 1024),
@@ -90,8 +88,7 @@ func TestLogger(t *testing.T) {
 		l = l.Named("hello")
 		l = l.Named("hello2")
 
-		ctx, span := trace.StartSpan(bg, "trace")
-		ctx = slog.With(ctx, slog.F("ctx", io.EOF))
+		ctx := slog.With(bg, slog.F("ctx", io.EOF))
 		l = l.With(slog.F("with", 2))
 
 		l.Info(ctx, "meow", slog.F("hi", "xd"))
@@ -107,9 +104,7 @@ func TestLogger(t *testing.T) {
 
 			File: slogTestFile,
 			Func: "cdr.dev/slog_test.TestLogger.func3",
-			Line: 97,
-
-			SpanContext: span.SpanContext(),
+			Line: 94,
 
 			Fields: slog.M(
 				slog.F("with", 2),

sloggers/sloghuman/sloghuman.go

@@ -7,6 +7,8 @@ import (
 	"io"
 	"strings"
 
+	"go.opencensus.io/trace"
+
 	"cdr.dev/slog"
 	"cdr.dev/slog/internal/entryhuman"
 	"cdr.dev/slog/internal/syncwriter"
@@ -30,7 +32,7 @@ type humanSink struct {
 }
 
 func (s humanSink) LogEntry(ctx context.Context, ent slog.SinkEntry) {
-	str := entryhuman.Fmt(s.w2, ent)
+	str := entryhuman.Fmt(s.w2, ent, trace.FromContext(ctx).SpanContext())
 	lines := strings.Split(str, "\n")
 
 	// We need to add 4 spaces before every field line for readability.

sloggers/slogjson/slogjson.go

@@ -57,10 +57,11 @@ func (s jsonSink) LogEntry(ctx context.Context, ent slog.SinkEntry) {
 		m = append(m, slog.F("logger_names", ent.LoggerNames))
 	}
 
-	if ent.SpanContext != (trace.SpanContext{}) {
+	sc := trace.FromContext(ctx).SpanContext()
+	if sc != (trace.SpanContext{}) {
 		m = append(m,
-			slog.F("trace", ent.SpanContext.TraceID),
-			slog.F("span", ent.SpanContext.SpanID),
+			slog.F("trace", sc.TraceID),
+			slog.F("span", sc.SpanID),
 		)
 	}
 

sloggers/slogstackdriver/slogstackdriver.go

@@ -54,11 +54,12 @@ func (s stackdriverSink) LogEntry(ctx context.Context, ent slog.SinkEntry) {
 		}))
 	}
 
-	if ent.SpanContext != (trace.SpanContext{}) {
+	sc := trace.FromContext(ctx).SpanContext()
+	if sc != (trace.SpanContext{}) {
 		e = append(e,
-			slog.F("logging.googleapis.com/trace", s.traceField(ent.SpanContext.TraceID)),
-			slog.F("logging.googleapis.com/spanId", ent.SpanContext.SpanID.String()),
-			slog.F("logging.googleapis.com/trace_sampled", ent.SpanContext.IsSampled()),
+			slog.F("logging.googleapis.com/trace", s.traceField(sc.TraceID)),
+			slog.F("logging.googleapis.com/spanId", sc.SpanID.String()),
+			slog.F("logging.googleapis.com/trace_sampled", sc.IsSampled()),
 		)
 	}
 

sloggers/slogtest/t.go

@@ -11,6 +11,8 @@ import (
 	"os"
 	"testing"
 
+	"go.opencensus.io/trace"
+
 	"cdr.dev/slog"
 	"cdr.dev/slog/internal/entryhuman"
 	"cdr.dev/slog/sloggers/sloghuman"
@@ -49,7 +51,7 @@ type testSink struct {
 
 func (ts testSink) LogEntry(ctx context.Context, ent slog.SinkEntry) {
 	// The testing package logs to stdout and not stderr.
-	s := entryhuman.Fmt(os.Stdout, ent)
+	s := entryhuman.Fmt(os.Stdout, ent, trace.FromContext(ctx).SpanContext())
 
 	switch ent.Level {
 	case slog.LevelDebug, slog.LevelInfo, slog.LevelWarn: