link logs to traces

Author: mxmeinhold

backend/config.yaml

@@ -1,3 +1,4 @@
 tracing:
   enabled: false
 environment: "local"
+version: "local-dev"

backend/log/context.go

@@ -3,6 +3,7 @@ package log
 import (
 	"context"
 
+	"github.com/DataDog/dd-trace-go/v2/ddtrace/tracer"
 	"go.uber.org/zap"
 
 	"csh/cluesheet/config"
@@ -38,8 +39,22 @@ func ContextWithLogger(ctx context.Context, logger *zap.Logger) context.Context
 
 func FromContext(ctx context.Context) *zap.Logger {
 	l := ctx.Value(contextKey)
+	var logger *zap.Logger
 	if l == nil {
-		return zap.L()
+		logger = zap.L()
+	} else {
+		logger = l.(*zap.Logger)
+	}
+
+	config := config.FromContext(ctx)
+	if span, ok := tracer.SpanFromContext(ctx); ok {
+		spanContext := span.Context()
+		logger = logger.With(
+			zap.String("dd.trace_id", spanContext.TraceID()),
+			zap.Uint64("dd.span_id", spanContext.SpanID()),
+			zap.String("dd.version", config.GetString("version")),
+			zap.String("dd.env", config.GetString("environment")),
+		)
 	}
-	return l.(*zap.Logger)
+	return logger
 }

backend/main.go

@@ -286,7 +286,7 @@ func main() {
 		tx, err := conn.Begin(r.Context())
 		if err != nil {
 			http.Error(rw, "failed to store clue", 500)
-			fmt.Printf(err.Error())
+			fmt.Println(err.Error())
 			return
 		}
 		defer tx.Rollback(r.Context())
@@ -303,7 +303,7 @@ func main() {
 		)
 		if err != nil {
 			http.Error(rw, "failed to store clue", 500)
-			fmt.Printf(err.Error())
+			fmt.Println(err.Error())
 			return
 		}
 
@@ -323,25 +323,25 @@ func main() {
 			_, err = tx.Exec(r.Context(), `insert into clue_relation(id, parent_id, child_id) values ($1, $2, $3)`, cr.Id, cr.Parent_id, cr.Child_id)
 			if err != nil {
 				http.Error(rw, "failed to store clue parent", 500)
-				fmt.Printf(err.Error())
+				fmt.Println(err.Error())
 				return
 			}
 		}
 
 		err = tx.Commit(r.Context())
 		if err != nil {
 			http.Error(rw, "failed to store clue with parent", 500)
-			fmt.Printf(err.Error())
+			fmt.Println(err.Error())
 			return
 		}
 
 		data, err := json.Marshal(struct {
 			Clue         Clue
-			ClueRelation *ClueRelation `json:,omitempty,omitzero`
+			ClueRelation *ClueRelation `json:",omitempty,omitzero"`
 		}{Clue: newClue, ClueRelation: cr})
 		if err != nil {
 			http.Error(rw, "Failed to marshal data", 500)
-			fmt.Printf(err.Error())
+			fmt.Println(err.Error())
 			return
 		}
 

backend/model.go

@@ -28,7 +28,7 @@ type Cluesheet struct {
 	Visibility string     /* TODO: int key? or defined enum? I think SQL enums are difficult to work with in migrations */
 	Owners     []string
 	Groups     []string
-	Clues      *[]Clue
+	Clues      *[]Clue `json:",omitzero"`
 }
 
 type Clue struct {
@@ -42,7 +42,7 @@ type Clue struct {
 	Edited_by   string
 	Edited_at   time.Time
 	Tags        []string
-	Children    []*Clue
+	Children    []*Clue `json:",omitzero"`
 }
 
 type ClueRelation struct {