Expose public/ API as submodule (#23345)

* model -> public/model

* plugin -> public/plugin

* public/model/utils -> public/utils

* platform/shared/mlog -> public/shared/mlog

* platform/shared/i18n -> public/shared/i18n

* platform/shared/markdown -> public/shared/markdown

* platform/services/timezones -> public/shared/timezones

* channels/einterfaces -> einterfaces

* expose public/ submodule

* go mod tidy

* .github: cache-dependency-path, setup-go-work

* modules-tidy for public/ too

* remove old gomodtidy

server/public/shared/mlog/global_test.go

@@ -0,0 +1,138 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package mlog_test
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+	"path/filepath"
+	"regexp"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/mattermost/mattermost-server/server/public/shared/mlog"
+)
+
+func TestLoggingBeforeInitialized(t *testing.T) {
+	require.NotPanics(t, func() {
+		// None of these should segfault before mlog is globally configured
+		mlog.Info("info log")
+		mlog.Debug("debug log")
+		mlog.Warn("warning log")
+		mlog.Error("error log")
+	})
+}
+
+func TestLoggingAfterInitialized(t *testing.T) {
+	testCases := []struct {
+		description  string
+		cfg          mlog.TargetCfg
+		expectedLogs []string
+	}{
+		{
+			"file logging, json, debug",
+			mlog.TargetCfg{
+				Type:          "file",
+				Format:        "json",
+				FormatOptions: json.RawMessage(`{"enable_caller":true}`),
+				Levels:        []mlog.Level{mlog.LvlError, mlog.LvlWarn, mlog.LvlInfo, mlog.LvlDebug},
+			},
+			[]string{
+				`{"timestamp":0,"level":"debug","msg":"real debug log","caller":"mlog/global_test.go:0"}`,
+				`{"timestamp":0,"level":"info","msg":"real info log","caller":"mlog/global_test.go:0"}`,
+				`{"timestamp":0,"level":"warn","msg":"real warning log","caller":"mlog/global_test.go:0"}`,
+				`{"timestamp":0,"level":"error","msg":"real error log","caller":"mlog/global_test.go:0"}`,
+			},
+		},
+		{
+			"file logging, json, error",
+			mlog.TargetCfg{
+				Type:          "file",
+				Format:        "json",
+				FormatOptions: json.RawMessage(`{"enable_caller":true}`),
+				Levels:        []mlog.Level{mlog.LvlError},
+			},
+			[]string{
+				`{"timestamp":0,"level":"error","msg":"real error log","caller":"mlog/global_test.go:0"}`,
+			},
+		},
+		{
+			"file logging, non-json, debug",
+			mlog.TargetCfg{
+				Type:          "file",
+				Format:        "plain",
+				FormatOptions: json.RawMessage(`{"delim":" | ", "enable_caller":true}`),
+				Levels:        []mlog.Level{mlog.LvlError, mlog.LvlWarn, mlog.LvlInfo, mlog.LvlDebug},
+			},
+			[]string{
+				`debug | TIME | real debug log | caller="mlog/global_test.go:0"`,
+				`info | TIME | real info log | caller="mlog/global_test.go:0"`,
+				`warn | TIME | real warning log | caller="mlog/global_test.go:0"`,
+				`error | TIME | real error log | caller="mlog/global_test.go:0"`,
+			},
+		},
+		{
+			"file logging, non-json, error",
+			mlog.TargetCfg{
+				Type:          "file",
+				Format:        "plain",
+				FormatOptions: json.RawMessage(`{"delim":" | ", "enable_caller":true}`),
+				Levels:        []mlog.Level{mlog.LvlError},
+			},
+			[]string{
+				`error | TIME | real error log | caller="mlog/global_test.go:0"`,
+			},
+		},
+	}
+
+	for _, testCase := range testCases {
+		t.Run(testCase.description, func(t *testing.T) {
+			var filePath string
+			if testCase.cfg.Type == "file" {
+				tempDir, err := os.MkdirTemp(os.TempDir(), "TestLoggingAfterInitialized")
+				require.NoError(t, err)
+				defer os.Remove(tempDir)
+
+				filePath = filepath.Join(tempDir, "file.log")
+				testCase.cfg.Options = json.RawMessage(fmt.Sprintf(`{"filename": "%s"}`, filePath))
+			}
+
+			logger, _ := mlog.NewLogger()
+			err := logger.ConfigureTargets(map[string]mlog.TargetCfg{testCase.description: testCase.cfg}, nil)
+			require.NoError(t, err)
+
+			mlog.InitGlobalLogger(logger)
+
+			mlog.Debug("real debug log")
+			mlog.Info("real info log")
+			mlog.Warn("real warning log")
+			mlog.Error("real error log")
+
+			logger.Shutdown()
+
+			if testCase.cfg.Type == "file" {
+				logs, err := os.ReadFile(filePath)
+				require.NoError(t, err)
+
+				actual := strings.TrimSpace(string(logs))
+
+				if testCase.cfg.Format == "json" {
+					reTs := regexp.MustCompile(`"timestamp":"[0-9\.\-\+\:\sZ]+"`)
+					reCaller := regexp.MustCompile(`"caller":"([^"]+):[0-9\.]+"`)
+					actual = reTs.ReplaceAllString(actual, `"timestamp":0`)
+					actual = reCaller.ReplaceAllString(actual, `"caller":"$1:0"`)
+				} else {
+					reTs := regexp.MustCompile(`\[\d\d\d\d-\d\d-\d\d\s[0-9\:\.\s\-\+Z]+\]`)
+					reCaller := regexp.MustCompile(`caller="([^"]+):[0-9\.]+"`)
+					actual = reTs.ReplaceAllString(actual, "TIME")
+					actual = reCaller.ReplaceAllString(actual, `caller="$1:0"`)
+				}
+				require.ElementsMatch(t, testCase.expectedLogs, strings.Split(actual, "\n"))
+			}
+		})
+	}
+}