[feature + performance] add JSON logging format (#4355)

# Description

Adds JSON logging as an optional alternative log output format. In the process this moves our log formatting itself into a separate subpkg to make it more easily modular, and improves caller name getting with some calling function name caching.

## Checklist

- [x] I/we have read the [GoToSocial contribution guidelines](https://codeberg.org/superseriousbusiness/gotosocial/src/branch/main/CONTRIBUTING.md).
- [x] I/we have discussed the proposed changes already, either in an issue on the repository, or in the Matrix chat.
- [x] I/we have not leveraged AI to create the proposed changes.
- [x] I/we have performed a self-review of added code.
- [x] I/we have written code that is legible and maintainable by others.
- [x] I/we have commented the added code, particularly in hard-to-understand areas.
- [x] I/we have made any necessary changes to documentation.
- [ ] I/we have added tests that cover new code.
- [x] I/we have run tests and they pass locally with the changes.
- [x] I/we have run `go fmt ./...` and `golangci-lint run`.

Reviewed-on: https://codeberg.org/superseriousbusiness/gotosocial/pulls/4355
Co-authored-by: kim <grufwub@gmail.com>
Co-committed-by: kim <grufwub@gmail.com>

1 files changed, 60 insertions, 0 deletions

diff --git a/internal/log/format/format_test.go b/internal/log/format/format_test.go
new file mode 100644
index 000000000..a8d229eb7
--- /dev/null
+++ b/internal/log/format/format_test.go
@@ -0,0 +1,60 @@
+// GoToSocial
+// Copyright (C) GoToSocial Authors admin@gotosocial.org
+// SPDX-License-Identifier: AGPL-3.0-or-later
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package format_test
+
+import (
+	"testing"
+	"time"
+
+	"code.superseriousbusiness.org/gotosocial/internal/log/format"
+	"codeberg.org/gruf/go-byteutil"
+)
+
+func BenchmarkStampCache(b *testing.B) {
+	var base format.Base
+	base.TimeFormat = `02/01/2006 15:04:05.000`
+
+	b.RunParallel(func(pb *testing.PB) {
+		var buf byteutil.Buffer
+		buf.B = make([]byte, 0, 1024)
+
+		for pb.Next() {
+			base.AppendFormatStamp(&buf, time.Now())
+			buf.B = buf.B[:0]
+		}
+
+		buf.B = buf.B[:0]
+	})
+}
+
+func BenchmarkNoStampCache(b *testing.B) {
+	var base format.Base
+	base.TimeFormat = `02/01/2006 15:04:05.000`
+
+	b.RunParallel(func(pb *testing.PB) {
+		var buf byteutil.Buffer
+		buf.B = make([]byte, 0, 1024)
+
+		for pb.Next() {
+			buf.B = time.Now().AppendFormat(buf.B, base.TimeFormat)
+			buf.B = buf.B[:0]
+		}
+
+		buf.B = buf.B[:0]
+	})
+}