feat: add support for debug logs

This is a port of
GoogleCloudPlatform/cloud-sql-proxy#2107.

cmd/root.go

@@ -322,6 +322,14 @@ Localhost Admin Server
   /quitquitquit. The admin server exits gracefully when it receives a POST
   request at /quitquitquit.
 
+Debug logging
+
+  On occasion, it can help to enable debug logging which will report on
+  internal certificate refresh operations. To enable debug logging, use:
+
+      ./cloud-sql-proxy <INSTANCE_CONNECTION_NAME> --debug-logs
+
+
 Waiting for Startup
 
   See the wait subcommand's help for details.
@@ -509,6 +517,8 @@ Instead prefer Application Default Credentials
 the Proxy will then pick-up automatically.`)
 	localFlags.BoolVarP(&c.conf.StructuredLogs, "structured-logs", "l", false,
 		"Enable structured logs using the LogEntry format")
+	localFlags.BoolVar(&c.conf.DebugLogs, "debug-logs", false,
+		"Enable debug logging")
 	localFlags.Uint64Var(&c.conf.MaxConnections, "max-connections", 0,
 		`Limits the number of connections by refusing any additional connections.
 When this flag is not set, there is no limit.`)

cmd/root_test.go

@@ -464,6 +464,14 @@ func TestNewCommandArguments(t *testing.T) {
 				RunConnectionTest: true,
 			}),
 		},
+		{
+			desc: "using the debug logs flag",
+			args: []string{"--debug-logs",
+				"projects/proj/locations/region/clusters/clust/instances/inst"},
+			want: withDefaults(&proxy.Config{
+				DebugLogs: true,
+			}),
+		},
 	}
 
 	for _, tc := range tcs {

go.mod

@@ -3,7 +3,7 @@ module github.com/GoogleCloudPlatform/alloydb-auth-proxy
 go 1.22
 
 require (
-	cloud.google.com/go/alloydbconn v1.7.0
+	cloud.google.com/go/alloydbconn v1.7.1-0.20240311180616-a9b8557ffb4e
 	contrib.go.opencensus.io/exporter/prometheus v0.4.2
 	contrib.go.opencensus.io/exporter/stackdriver v0.13.14
 	github.com/coreos/go-systemd/v22 v22.5.0
@@ -84,7 +84,7 @@ require (
 	google.golang.org/genproto/googleapis/api v0.0.0-20240205150955-31a09d347014 // indirect
 	google.golang.org/genproto/googleapis/rpc v0.0.0-20240213162025-012b6fc9bca9 // indirect
 	google.golang.org/grpc v1.61.1 // indirect
-	google.golang.org/protobuf v1.32.0 // indirect
+	google.golang.org/protobuf v1.33.0 // indirect
 	gopkg.in/ini.v1 v1.67.0 // indirect
 	gopkg.in/yaml.v2 v2.4.0 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect

go.sum

@@ -35,6 +35,10 @@ cloud.google.com/go/alloydb v1.8.1 h1:H7bNDEoqc9IvtxCiA1oOJqoAAsVFB4BXPZ//6Qp/v7
 cloud.google.com/go/alloydb v1.8.1/go.mod h1:GTzEf72qrkivvTH1GNkCe9lkJp8zXOZyoC6Zjy1SG/s=
 cloud.google.com/go/alloydbconn v1.7.0 h1:gKK2Ky355yP6wxd7yDKvY5MSsGqk2R6X4YGH3Wo7Khk=
 cloud.google.com/go/alloydbconn v1.7.0/go.mod h1:JcGl5vwN9ndUOqbmmNKrFs/Wlw8c2Bwmz+jHzShGAJc=
+cloud.google.com/go/alloydbconn v1.7.1-0.20240311014225-6ca502909c02 h1:Mgn60Ou4Ufut751Noe5YgyKp+yS11OrN/LxAsLaDQCU=
+cloud.google.com/go/alloydbconn v1.7.1-0.20240311014225-6ca502909c02/go.mod h1:JcGl5vwN9ndUOqbmmNKrFs/Wlw8c2Bwmz+jHzShGAJc=
+cloud.google.com/go/alloydbconn v1.7.1-0.20240311180616-a9b8557ffb4e h1:3SglE3sq2Bf2Oy1cJbuDh8k2vPZxpR1nuxYdnssaHD4=
+cloud.google.com/go/alloydbconn v1.7.1-0.20240311180616-a9b8557ffb4e/go.mod h1:jt41sRKNEgy2LmQwH/1QOe2zOEmqLbdjtvYJ8EthA7k=
 cloud.google.com/go/bigquery v1.0.1/go.mod h1:i/xbL2UlR5RvWAURpBYZTtm/cXjCha9lbfbpx4poX+o=
 cloud.google.com/go/bigquery v1.3.0/go.mod h1:PjpwJnslEMmckchkHFfq+HTD2DmtT67aNFKH1/VBDHE=
 cloud.google.com/go/bigquery v1.4.0/go.mod h1:S8dzgnTigyfTmLBfrtrhyYhwRxG72rYxvftPBK2Dvzc=
@@ -1813,6 +1817,8 @@ google.golang.org/protobuf v1.28.0/go.mod h1:HV8QOd/L58Z+nl8r43ehVNZIU/HEI6OcFqw
 google.golang.org/protobuf v1.28.1/go.mod h1:HV8QOd/L58Z+nl8r43ehVNZIU/HEI6OcFqwMG9pJV4I=
 google.golang.org/protobuf v1.32.0 h1:pPC6BG5ex8PDFnkbrGU3EixyhKcQ2aDuBS36lqK/C7I=
 google.golang.org/protobuf v1.32.0/go.mod h1:c6P6GXX6sHbq/GpV6MGZEdwhWPcYBgnhAHhKbcUYpos=
+google.golang.org/protobuf v1.33.0 h1:uNO2rsAINq/JlFpSdYEKIZ0uKD/R9cpdv0T+yoGwGmI=
+google.golang.org/protobuf v1.33.0/go.mod h1:c6P6GXX6sHbq/GpV6MGZEdwhWPcYBgnhAHhKbcUYpos=
 gopkg.in/airbrake/gobrake.v2 v2.0.9/go.mod h1:/h5ZAUhDkGaJfjzjKLSjv6zCL6O0LLBxU4K+aSYdM/U=
 gopkg.in/alecthomas/kingpin.v2 v2.2.6/go.mod h1:FMv+mEhP44yOT+4EoQTLFTRgOQ1FBLkstjWtayDeSgw=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=

internal/log/log.go

@@ -28,15 +28,17 @@ import (
 // logs.
 type StdLogger struct {
 	infoLog *llog.Logger
+	debugLog *llog.Logger
 	errLog  *llog.Logger
 }
 
 // NewStdLogger create a Logger that uses out and err for informational and
 // error messages.
 func NewStdLogger(out, err io.Writer) alloydb.Logger {
 	return &StdLogger{
-		infoLog: llog.New(out, "", llog.LstdFlags),
-		errLog:  llog.New(err, "", llog.LstdFlags),
+		infoLog:  llog.New(out, "", llog.LstdFlags),
+		debugLog: llog.New(out, "", llog.LstdFlags),
+		errLog:   llog.New(err, "", llog.LstdFlags),
 	}
 }
 
@@ -52,7 +54,7 @@ func (l *StdLogger) Errorf(format string, v ...interface{}) {
 
 // Debugf logs debug messages.
 func (l *StdLogger) Debugf(format string, v ...interface{}) {
-	l.infoLog.Printf(format, v...)
+	l.debugLog.Printf(format, v...)
 }
 
 // StructuredLogger writes log messages in JSON.
@@ -72,7 +74,7 @@ func (l *StructuredLogger) Errorf(format string, v ...interface{}) {
 
 // Debugf logs debug messages.
 func (l *StructuredLogger) Debugf(format string, v ...interface{}) {
-	l.logger.Infof(format, v...)
+	l.logger.Debugf(format, v...)
 }
 
 // NewStructuredLogger creates a Logger that logs messages using JSON.

internal/proxy/proxy.go

@@ -142,6 +142,10 @@ type Config struct {
 	// See https://cloud.google.com/logging/docs/reference/v2/rest/v2/LogEntry
 	StructuredLogs bool
 
+	// DebugLogs enables debug logging and is useful when diagnosing surprising
+	// Proxy behavior.
+	DebugLogs bool
+
 	// Quiet controls whether only error messages are logged.
 	Quiet bool
 
@@ -306,6 +310,10 @@ func (c *Config) DialerOptions(l alloydb.Logger) ([]alloydbconn.Option, error) {
 		opts = append(opts, alloydbconn.WithIAMAuthN())
 	}
 
+    if c.DebugLogs {
+        opts = append(opts, alloydbconn.WithDebugLogger(l))
+    }
+
 	return opts, nil
 }