feat: implement experimental BackScanner for reading files backward and add tests for various scenarios

internal/net/gphttp/accesslog/rotate_test.go

@@ -0,0 +1,86 @@
+package accesslog_test
+
+import (
+	"fmt"
+	"testing"
+	"time"
+
+	. "github.com/yusing/go-proxy/internal/net/gphttp/accesslog"
+	"github.com/yusing/go-proxy/internal/task"
+	"github.com/yusing/go-proxy/internal/utils/strutils"
+	. "github.com/yusing/go-proxy/internal/utils/testing"
+)
+
+func TestParseLogTime(t *testing.T) {
+	tests := []string{
+		`{"foo":"bar","time":"%s","bar":"baz"}`,
+		`example.com 192.168.1.1 - - [%s] "GET / HTTP/1.1" 200 1234`,
+	}
+	testTime := time.Date(2024, 1, 2, 3, 4, 5, 0, time.UTC)
+	testTimeStr := testTime.Format(LogTimeFormat)
+
+	for i, test := range tests {
+		tests[i] = fmt.Sprintf(test, testTimeStr)
+	}
+
+	for _, test := range tests {
+		t.Run(test, func(t *testing.T) {
+			actual := ParseLogTime([]byte(test))
+			ExpectTrue(t, actual.Equal(testTime))
+		})
+	}
+}
+
+func TestRetentionCommonFormat(t *testing.T) {
+	var file MockFile
+	logger := NewAccessLogger(task.RootTask("test", false), &file, &Config{
+		Format:     FormatCommon,
+		BufferSize: 1024,
+	})
+	for range 10 {
+		logger.Log(req, resp)
+	}
+	logger.Flush()
+	// test.Finish(nil)
+
+	ExpectEqual(t, logger.Config().Retention, nil)
+	ExpectTrue(t, file.Len() > 0)
+	ExpectEqual(t, file.LineCount(), 10)
+
+	t.Run("keep last", func(t *testing.T) {
+		logger.Config().Retention = strutils.MustParse[*Retention]("last 5")
+		ExpectEqual(t, logger.Config().Retention.Days, 0)
+		ExpectEqual(t, logger.Config().Retention.Last, 5)
+		ExpectNoError(t, logger.Rotate())
+		ExpectEqual(t, file.LineCount(), 5)
+	})
+
+	_ = file.Truncate(0)
+
+	timeNow := time.Now()
+	for i := range 10 {
+		logger.Formatter.(*CommonFormatter).GetTimeNow = func() time.Time {
+			return timeNow.AddDate(0, 0, -10+i)
+		}
+		logger.Log(req, resp)
+	}
+	logger.Flush()
+	ExpectEqual(t, file.LineCount(), 10)
+
+	t.Run("keep days", func(t *testing.T) {
+		logger.Config().Retention = strutils.MustParse[*Retention]("3 days")
+		ExpectEqual(t, logger.Config().Retention.Days, 3)
+		ExpectEqual(t, logger.Config().Retention.Last, 0)
+		ExpectNoError(t, logger.Rotate())
+		ExpectEqual(t, file.LineCount(), 3)
+		rotated := string(file.Content())
+		_ = file.Truncate(0)
+		for i := range 3 {
+			logger.Formatter.(*CommonFormatter).GetTimeNow = func() time.Time {
+				return timeNow.AddDate(0, 0, -3+i)
+			}
+			logger.Log(req, resp)
+		}
+		ExpectEqual(t, rotated, string(file.Content()))
+	})
+}