logger: allow logging HTTP traffic enabling all logs

When using SNAPD_DEBUG_HTTP, it was also necessary to set SNAPD_DEBUG
for the HTTP traffic to be logged. So it was impossible to log the HTTP
traffic without logging everything. This commit changes that so that
setting the former logs the HTTP traffic and setting SNAPD_DEBUG
enables the debug logs in the rest of snapd.

Signed-off-by: Miguel Pires <miguel.pires@canonical.com>

httputil/logger.go

@@ -64,14 +64,14 @@ func (tr *LoggedTransport) RoundTrip(req *http.Request) (*http.Response, error)
 
 	if flags.debugRequest() {
 		buf, _ := httputil.DumpRequestOut(req, tr.body && flags.debugBody())
-		logger.Debugf("> %q", buf)
+		logger.NoGuardDebugf("> %q", buf)
 	}
 
 	rsp, err := tr.Transport.RoundTrip(req)
 
 	if err == nil && flags.debugResponse() {
 		buf, _ := httputil.DumpResponse(rsp, tr.body && flags.debugBody())
-		logger.Debugf("< %q", buf)
+		logger.NoGuardDebugf("< %q", buf)
 	}
 
 	return rsp, err

httputil/logger_test.go

@@ -46,12 +46,10 @@ type loggerSuite struct {
 var _ = check.Suite(&loggerSuite{})
 
 func (s *loggerSuite) TearDownTest(c *check.C) {
-	os.Unsetenv("SNAPD_DEBUG")
 	s.restoreLogger()
 }
 
 func (s *loggerSuite) SetUpTest(c *check.C) {
-	os.Setenv("SNAPD_DEBUG", "true")
 	s.logbuf = bytes.NewBuffer(nil)
 	s.logbuf, s.restoreLogger = logger.MockLogger()
 }

logger/logger.go

@@ -37,6 +37,9 @@ type Logger interface {
 	Notice(msg string)
 	// Debug is for messages that the user should be able to find if they're debugging something
 	Debug(msg string)
+	// NoGuardDebug is for messages that we always want to print (e.g., configurations
+	// were checked by the caller, etc)
+	NoGuardDebug(msg string)
 }
 
 const (
@@ -46,8 +49,9 @@ const (
 
 type nullLogger struct{}
 
-func (nullLogger) Notice(string) {}
-func (nullLogger) Debug(string)  {}
+func (nullLogger) Notice(string)       {}
+func (nullLogger) Debug(string)        {}
+func (nullLogger) NoGuardDebug(string) {}
 
 // NullLogger is a logger that does nothing
 var NullLogger = nullLogger{}
@@ -88,6 +92,16 @@ func Debugf(format string, v ...interface{}) {
 	logger.Debug(msg)
 }
 
+// NoGuardDebugf records something in the debug log
+func NoGuardDebugf(format string, v ...interface{}) {
+	msg := fmt.Sprintf(format, v...)
+
+	lock.Lock()
+	defer lock.Unlock()
+
+	logger.NoGuardDebug(msg)
+}
+
 // MockLogger replaces the exiting logger with a buffer and returns
 // the log buffer and a restore function.
 func MockLogger() (buf *bytes.Buffer, restore func()) {
@@ -129,7 +143,7 @@ type Log struct {
 // Debug only prints if SNAPD_DEBUG is set
 func (l *Log) Debug(msg string) {
 	if l.debug || osutil.GetenvBool("SNAPD_DEBUG") {
-		l.log.Output(3, "DEBUG: "+msg)
+		l.NoGuardDebug(msg)
 	}
 }
 
@@ -138,6 +152,12 @@ func (l *Log) Notice(msg string) {
 	l.log.Output(3, msg)
 }
 
+// NoGuardDebug always prints the message, w/o gating it based on environment
+// variables or other configurations.
+func (l *Log) NoGuardDebug(msg string) {
+	l.log.Output(3, "DEBUG: "+msg)
+}
+
 // New creates a log.Logger using the given io.Writer and flag.
 func New(w io.Writer, flag int) (Logger, error) {
 	logger := &Log{

logger/logger_test.go

@@ -131,6 +131,19 @@ func (s *LogSuite) TestWithLoggerLock(c *C) {
 	c.Check(called, Equals, true)
 }
 
+func (s *LogSuite) TestNoGuardDebug(c *C) {
+	debugValue, ok := os.LookupEnv("SNAPD_DEBUG")
+	if ok {
+		defer func() {
+			os.Setenv("SNAPD_DEBUG", debugValue)
+		}()
+		os.Unsetenv("SNAPD_DEBUG")
+	}
+
+	logger.NoGuardDebugf("xyzzy")
+	c.Check(s.logbuf.String(), testutil.Contains, `DEBUG: xyzzy`)
+}
+
 func (s *LogSuite) TestIntegrationDebugFromKernelCmdline(c *C) {
 	// must enable actually checking the command line, because by default the
 	// logger package will skip checking for the kernel command line parameter