From 22991dc46df8f9833b311477474e8dd7ce562cb4 Mon Sep 17 00:00:00 2001
From: Mitja T <mitjat@oasislabs.com>
Date: Wed, 31 Jan 2024 21:28:00 -0800
Subject: [PATCH] logging: Pogreb now logs into our logger, not stderr

---
 cmd/common/common.go |  6 ++++++
 log/log.go           | 33 +++++++++++++++++++++++++++++++++
 2 files changed, 39 insertions(+)

diff --git a/cmd/common/common.go b/cmd/common/common.go
index c6572336c..a5cbd9e99 100644
--- a/cmd/common/common.go
+++ b/cmd/common/common.go
@@ -4,8 +4,10 @@ package common
 import (
 	"fmt"
 	"io"
+	stdLog "log"
 	"os"
 
+	"github.com/akrylysov/pogreb"
 	coreLogging "github.com/oasisprotocol/oasis-core/go/common/logging"
 
 	"github.com/oasisprotocol/nexus/config"
@@ -50,6 +52,10 @@ func Init(cfg *config.Config) error {
 		return err
 	}
 
+	// Initialize pogreb logging.
+	pogrebLogger := RootLogger().WithModule("pogreb").WithCallerUnwind(7)
+	pogreb.SetLogger(stdLog.New(log.WriterIntoLogger(*pogrebLogger), "", 0))
+
 	// Initialize Prometheus service.
 	if cfg.Metrics != nil {
 		promServer, err := metrics.NewPullService(cfg.Metrics.PullEndpoint, rootLogger)
diff --git a/log/log.go b/log/log.go
index 6a1939b48..d0fbbeb54 100644
--- a/log/log.go
+++ b/log/log.go
@@ -112,7 +112,40 @@ func (l *Logger) WithModule(module string) *Logger {
 	}
 }
 
+// WithCallerUnwind returns a clone of the logger where the `caller`
+// value will show the n-th entry on the call stack at the time of logging.
+func (l *Logger) WithCallerUnwind(n int) *Logger {
+	return &Logger{
+		logger: log.With(l.logger, "caller", log.Caller(n)),
+		level:  l.level,
+		module: l.module,
+	}
+}
+
 // Level is the logging level.
 func (l *Logger) Level() Level {
 	return l.level
 }
+
+// An io.Writer impl that writes every string to the backing logger `l` at Info level.
+type writerIntoLoggerImpl struct {
+	Logger
+}
+
+var _ io.Writer = (*writerIntoLoggerImpl)(nil)
+
+func (l *writerIntoLoggerImpl) Write(msg []byte) (n int, err error) {
+	// Strip trailing newlines from message.
+	origLen := len(msg)
+	for len(msg) > 0 && msg[len(msg)-1] == '\n' {
+		msg = msg[:len(msg)-1]
+	}
+
+	// Write message to backing logger.
+	l.Info(string(msg))
+	return origLen, nil
+}
+
+func WriterIntoLogger(l Logger) io.Writer {
+	return &writerIntoLoggerImpl{l}
+}