fix mlog-ing before initialized (#8753)

Dump mlog to STDOUT before initialized, to allow for logging failures
that occur due to config parsing, etc.

Fix file logging to honour logger.FileJson instead of copying the
logger.ConsoleJson setting.

1 files changed, 50 insertions, 0 deletions

diff --git a/mlog/default.go b/mlog/default.go
new file mode 100644
index 000000000..366d22f88
--- /dev/null
+++ b/mlog/default.go
@@ -0,0 +1,50 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See License.txt for license information.
+
+package mlog
+
+import (
+	"encoding/json"
+	"fmt"
+)
+
+// defaultLog manually encodes the log to STDOUT, providing a basic, default logging implementation
+// before mlog is fully configured.
+func defaultLog(level, msg string, fields ...Field) {
+	log := struct {
+		Level   string  `json:"level"`
+		Message string  `json:"msg"`
+		Fields  []Field `json:"fields,omitempty"`
+	}{
+		level,
+		msg,
+		fields,
+	}
+
+	if b, err := json.Marshal(log); err != nil {
+		fmt.Printf(`{"level":"error","msg":"failed to encode log message"}%s`, "\n")
+	} else {
+		fmt.Printf("%s\n", b)
+	}
+}
+
+func defaultDebugLog(msg string, fields ...Field) {
+	defaultLog("debug", msg, fields...)
+}
+
+func defaultInfoLog(msg string, fields ...Field) {
+	defaultLog("info", msg, fields...)
+}
+
+func defaultWarnLog(msg string, fields ...Field) {
+	defaultLog("warn", msg, fields...)
+}
+
+func defaultErrorLog(msg string, fields ...Field) {
+	defaultLog("error", msg, fields...)
+}
+
+func defaultCriticalLog(msg string, fields ...Field) {
+	// We map critical to error in zap, so be consistent.
+	defaultLog("error", msg, fields...)
+}