feat: Add JSON logging

Signed-off-by: Julien Riou <julien@riou.xyz>

base/session.go

@@ -1,20 +1,21 @@
 package base
 
 import (
+	"encoding/json"
 	"fmt"
 	"strings"
 )
 
 // Session represents a PostgreSQL backend
 type Session struct {
-	Pid             int64
-	User            string
-	Db              string
-	Client          string
-	State           string
-	Query           string
-	StateDuration   float64
-	ApplicationName string
+	Pid             int64   `json:"pid"`
+	User            string  `json:"user"`
+	Db              string  `json:"database"`
+	Client          string  `json:"client"`
+	State           string  `json:"state"`
+	Query           string  `json:"query"`
+	StateDuration   float64 `json:"state_duration"`
+	ApplicationName string  `json:"application_name"`
 }
 
 // NewSession instanciates a Session
@@ -53,6 +54,12 @@ func (s *Session) Format(format string) string {
 	return output
 }
 
+// JSON returns a Session marshaled as a JSON string
+func (s *Session) JSON() string {
+	b, _ := json.Marshal(s)
+	return string(b)
+}
+
 // IsIdle returns true when a session is doing nothing
 func (s *Session) IsIdle() bool {
 	if s.State == "idle" || s.State == "idle in transaction" || s.State == "idle in transaction (aborted)" {

base/session_test.go

@@ -1,9 +1,32 @@
 package base
 
 import (
+	"encoding/json"
 	"testing"
 )
 
+func TestSessionJSON(t *testing.T) {
+	session := &Session{
+		Pid:             1,
+		User:            "test",
+		Db:              "db",
+		Client:          "127.0.0.1:5432",
+		State:           "active",
+		Query:           "select 1",
+		StateDuration:   1.5,
+		ApplicationName: "psql",
+	}
+
+	var got Session
+	if err := json.Unmarshal([]byte(session.JSON()), &got); err != nil {
+		t.Fatalf("invalid JSON: %v", err)
+	}
+
+	if got != *session {
+		t.Errorf("got %+v; want %+v", got, *session)
+	}
+}
+
 func TestSessionEqual(t *testing.T) {
 	tests := []struct {
 		name   string