From 0b80d4feaafaef76e7973df2fd1a4bb4759fb9ec Mon Sep 17 00:00:00 2001
From: yyforyongyu <yy2452@columbia.edu>
Date: Thu, 23 Sep 2021 18:34:51 +0800
Subject: [PATCH] tor: add logging to tor controller

---
 log.go            |  2 ++
 tor/controller.go |  9 +++++++++
 tor/log.go        | 26 ++++++++++++++++++++++++++
 3 files changed, 37 insertions(+)
 create mode 100644 tor/log.go

diff --git a/log.go b/log.go
index 61d3b3ca3..68b592bb4 100644
--- a/log.go
+++ b/log.go
@@ -40,6 +40,7 @@ import (
 	"github.com/lightningnetwork/lnd/rpcperms"
 	"github.com/lightningnetwork/lnd/signal"
 	"github.com/lightningnetwork/lnd/sweep"
+	"github.com/lightningnetwork/lnd/tor"
 	"github.com/lightningnetwork/lnd/watchtower"
 	"github.com/lightningnetwork/lnd/watchtower/wtclient"
 )
@@ -161,6 +162,7 @@ func SetupLoggers(root *build.RotatingLogWriter, interceptor signal.Interceptor)
 	AddSubLogger(root, funding.Subsystem, interceptor, funding.UseLogger)
 	AddSubLogger(root, cluster.Subsystem, interceptor, cluster.UseLogger)
 	AddSubLogger(root, rpcperms.Subsystem, interceptor, rpcperms.UseLogger)
+	AddSubLogger(root, tor.Subsystem, interceptor, tor.UseLogger)
 }
 
 // AddSubLogger is a helper method to conveniently create and register the
diff --git a/tor/controller.go b/tor/controller.go
index 5e24ae20d..9ec3f15a8 100644
--- a/tor/controller.go
+++ b/tor/controller.go
@@ -122,6 +122,8 @@ func (c *Controller) Start() error {
 		return nil
 	}
 
+	log.Info("Starting tor controller")
+
 	conn, err := textproto.Dial("tcp", c.controlAddr)
 	if err != nil {
 		return fmt.Errorf("unable to connect to Tor server: %v", err)
@@ -138,6 +140,8 @@ func (c *Controller) Stop() error {
 		return nil
 	}
 
+	log.Info("Stopping tor controller")
+
 	return c.conn.Close()
 }
 
@@ -151,7 +155,12 @@ func (c *Controller) sendCommand(command string) (int, string, error) {
 	// We'll use ReadResponse as it has built-in support for multi-line
 	// text protocol responses.
 	code, reply, err := c.conn.Reader.ReadResponse(success)
+	log.Tracef("sendCommand: %v got <code:%v>, <reply:%v>",
+		command, code, reply)
+
 	if err != nil {
+		log.Debugf("sendCommand:%s got err:%v, reply:%v",
+			command, err, reply)
 		return code, reply, err
 	}
 
diff --git a/tor/log.go b/tor/log.go
new file mode 100644
index 000000000..9fe5b8aab
--- /dev/null
+++ b/tor/log.go
@@ -0,0 +1,26 @@
+package tor
+
+import (
+	"github.com/btcsuite/btclog"
+)
+
+// Subsystem defines the logging code for this subsystem.
+const Subsystem = "TORC" // TORC as in Tor Controller.
+
+// log is a logger that is initialized with no output filters.  This
+// means the package will not perform any logging by default until the caller
+// requests it.
+var log = btclog.Disabled
+
+// DisableLog disables all library log output.  Logging output is disabled
+// by default until UseLogger is called.
+func DisableLog() {
+	UseLogger(btclog.Disabled)
+}
+
+// UseLogger uses a specified Logger to output package logging info.
+// This should be used in preference to SetLogWriter if the caller is also
+// using btclog.
+func UseLogger(logger btclog.Logger) {
+	log = logger
+}