logger: add missing tests and fix crash when syslog is not available (thanks John!)

2 files changed, 41 insertions, 6 deletions

diff --git a/logger/logger.go b/logger/logger.go
index 0bb0e70f34..0fce8d091d 100644
--- a/logger/logger.go
+++ b/logger/logger.go
@@ -20,6 +20,7 @@ package logger
 import (
	"fmt"
	"io"
+	"io/ioutil"
	"log"
	"log/syslog"
	"os"
@@ -112,14 +113,22 @@ func (l *ConsoleLog) Notice(msg string) {
	l.log.Output(3, msg)
 }
 
+// variable to allow mocking the syslog.NewLogger call in the tests
+var newSyslog = newSyslogImpl
+
+func newSyslogImpl() (*log.Logger, error) {
+	return syslog.NewLogger(SyslogPriority, SyslogFlags)
+}
+
 // NewConsoleLog creates a ConsoleLog with a log.Logger using the given
 // io.Writer and flag, and a syslog.Writer.
 func NewConsoleLog(w io.Writer, flag int) (*ConsoleLog, error) {
	clog := log.New(w, "", flag)
 
-	sys, err := syslog.NewLogger(SyslogPriority, SyslogFlags)
+	sys, err := newSyslog()
	if err != nil {
	clog.Output(3, "WARNING: can not create syslog logger")
+	sys = log.New(ioutil.Discard, "", flag)
	}
 
	return &ConsoleLog{
diff --git a/logger/logger_test.go b/logger/logger_test.go
index 209393a49c..af311ab75e 100644
--- a/logger/logger_test.go
+++ b/logger/logger_test.go
@@ -19,8 +19,9 @@ package logger
 
 import (
	"bytes"
+	"fmt"
+	"io/ioutil"
	"log"
-	"log/syslog"
	"testing"
 
	. "launchpad.net/gocheck"
@@ -36,15 +37,17 @@ type LogSuite struct{}
 func (s *LogSuite) SetUpTest(c *C) {
	c.Assert(logger, Equals, NullLogger)
 
-	// sbuild environments do not allow talking to /dev/log
-	_, err := syslog.NewLogger(SyslogPriority, SyslogFlags)
-	if err != nil {
-	c.Skip("/dev/log can not be accessed")
+	// we do not want to pollute syslog in our tests (and sbuild
+	// will also not let us do that)
+	newSyslog = func() (*log.Logger, error) {
+	l := log.New(ioutil.Discard, "discarded-log-msg", 0)
+	return l, nil
	}
 }
 
 func (s *LogSuite) TearDownTest(c *C) {
	SetLogger(NullLogger)
+	newSyslog = newSyslogImpl
 }
 
 func (s *LogSuite) TestDefault(c *C) {
@@ -109,3 +112,26 @@ func (s *LogSuite) TestPanicf(c *C) {
	c.Check(sysbuf.String(), Matches, `(?m).*logger_test\.go:\d+: PANIC xyzzy`)
	c.Check(logbuf.String(), Matches, `(?m).*logger_test\.go:\d+: PANIC xyzzy`)
 }
+
+func (s *LogSuite) TestSyslogFails(c *C) {
+	var logbuf bytes.Buffer
+
+	// pretend syslog is not available (e.g. because of no /dev/log in
+	// a chroot or something)
+	newSyslog = func() (*log.Logger, error) {
+	return nil, fmt.Errorf("nih! nih!")
+	}
+
+	// ensure a warning is displayed
+	l, err := NewConsoleLog(&logbuf, DefaultFlags)
+	c.Assert(err, IsNil)
+	c.Check(logbuf.String(), Matches, `(?m).*:\d+: WARNING: can not create syslog logger`)
+
+	// ensure that even without a syslog the console log works and we
+	// do not crash
+	logbuf.Reset()
+	SetLogger(l)
+	Noticef("I do not want to crash")
+	c.Check(logbuf.String(), Matches, `(?m).*logger_test\.go:\d+: I do not want to crash`)
+
+}