Write log also to a file.

alert/log.go

@@ -1,7 +1,7 @@
 package alert
 
 import (
-	"github.com/tendermint/log15"
+	"github.com/tendermint/tendermint/logger"
 )
 
-var log = log15.New("module", "alert")
+var log = logger.New("module", "alert")

binary/log.go

@@ -1,19 +1,17 @@
 package binary
 
 import (
-	"os"
-
 	"github.com/tendermint/log15"
+	"github.com/tendermint/tendermint/logger"
 )
 
-var log = log15.New("module", "binary")
+var log = logger.New("module", "binary")
 
 func init() {
 	log.SetHandler(
 		log15.LvlFilterHandler(
 			log15.LvlWarn,
-			//log15.LvlDebug,
-			log15.StreamHandler(os.Stderr, log15.LogfmtFormat()),
+			logger.RootHandler(),
 		),
 	)
 }

block/log.go

@@ -1,7 +1,7 @@
 package block
 
 import (
-	"github.com/tendermint/log15"
+	"github.com/tendermint/tendermint/logger"
 )
 
-var log = log15.New("module", "block")
+var log = logger.New("module", "block")

cmd/log.go

@@ -1,7 +1,7 @@
 package main
 
 import (
-	"github.com/tendermint/log15"
+	"github.com/tendermint/tendermint/logger"
 )
 
-var log = log15.New("module", "main")
+var log = logger.New("module", "main")

config/log.go

@@ -1,6 +1,8 @@
 package config
 
 import (
+	// We can't use github.com/tendermint/tendermint/logger
+	// because that would create a dependency cycle.
 	"github.com/tendermint/log15"
 )
 

consensus/log.go

@@ -1,7 +1,7 @@
 package consensus
 
 import (
-	"github.com/tendermint/log15"
+	"github.com/tendermint/tendermint/logger"
 )
 
-var log = log15.New("module", "consensus")
+var log = logger.New("module", "consensus")

logger/log.go

@@ -0,0 +1,51 @@
+package logger
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/tendermint/log15"
+	"github.com/tendermint/tendermint/config"
+)
+
+var rootHandler log15.Handler
+
+func init() {
+	handlers := []log15.Handler{}
+
+	// By default, there's a stdout terminal format handler.
+	handlers = append(handlers, log15.LvlFilterHandler(
+		log15.LvlDebug,
+		log15.StreamHandler(os.Stdout, log15.TerminalFormat()),
+	))
+
+	// Maybe also write to a file.
+	if config.App.GetString("Log.Dir") != "" {
+		// Create log dir if it doesn't exist
+		err := os.MkdirAll(config.App.GetString("Log.Dir"), 0700)
+		if err != nil {
+			fmt.Printf("Could not create directory: %v", err)
+			os.Exit(1)
+		}
+		// File handler
+		handlers = append(handlers, log15.LvlFilterHandler(
+			log15.LvlDebug,
+			log15.Must.FileHandler(config.App.GetString("Log.Dir")+"/tendermint.log", log15.LogfmtFormat()),
+		))
+	}
+
+	// Set rootHandler.
+	rootHandler = log15.MultiHandler(handlers...)
+
+	// By setting handlers on the root, we handle events from all loggers.
+	log15.Root().SetHandler(rootHandler)
+}
+
+// See binary/log for an example of usage.
+func RootHandler() log15.Handler {
+	return rootHandler
+}
+
+func New(ctx ...interface{}) log15.Logger {
+	return log15.Root().New(ctx...)
+}

mempool/log.go

@@ -1,7 +1,7 @@
 package mempool
 
 import (
-	"github.com/tendermint/log15"
+	"github.com/tendermint/tendermint/logger"
 )
 
-var log = log15.New("module", "mempool")
+var log = logger.New("module", "mempool")

p2p/log.go

@@ -1,7 +1,7 @@
 package p2p
 
 import (
-	"github.com/tendermint/log15"
+	"github.com/tendermint/tendermint/logger"
 )
 
-var log = log15.New("module", "p2p")
+var log = logger.New("module", "p2p")

p2p/upnp/log.go

@@ -1,7 +1,7 @@
 package upnp
 
 import (
-	"github.com/tendermint/log15"
+	"github.com/tendermint/tendermint/logger"
 )
 
-var log = log15.New("module", "upnp")
+var log = logger.New("module", "upnp")

state/log.go

@@ -1,7 +1,7 @@
 package state
 
 import (
-	"github.com/tendermint/log15"
+	"github.com/tendermint/tendermint/logger"
 )
 
-var log = log15.New("module", "state")
+var log = logger.New("module", "state")