diff options
| -rw-r--r-- | core/dnsserver/server.go | 2 | ||||
| -rw-r--r-- | plugin.md | 12 | ||||
| -rw-r--r-- | plugin/pkg/log/log.go | 69 | ||||
| -rw-r--r-- | plugin/pkg/log/log_test.go | 61 |
4 files changed, 140 insertions, 4 deletions
diff --git a/core/dnsserver/server.go b/core/dnsserver/server.go index 2bbd8f8d3..04aaadf21 100644 --- a/core/dnsserver/server.go +++ b/core/dnsserver/server.go @@ -11,6 +11,7 @@ import ( "github.com/coredns/coredns/plugin" "github.com/coredns/coredns/plugin/metrics/vars" "github.com/coredns/coredns/plugin/pkg/edns" + "github.com/coredns/coredns/plugin/pkg/log" "github.com/coredns/coredns/plugin/pkg/rcode" "github.com/coredns/coredns/plugin/pkg/trace" "github.com/coredns/coredns/request" @@ -60,6 +61,7 @@ func NewServer(addr string, group []*Config) (*Server, error) { for _, site := range group { if site.Debug { s.debug = true + log.D = true } // set the config per zone s.zones[site.Zone] = site @@ -35,11 +35,15 @@ See a couple of blog posts on how to write and add plugin to CoreDNS: ## Logging -If your plugin needs to output a log line you should use the `log` package. CoreDNS does not -implement log levels. The standard way of outputing is: `log.Printf("[LEVEL] ...")`, and LEVEL -can be: `INFO`, `WARNING` or `ERROR`. +If your plugin needs to output a log line you should use the `plugin/pkg/log` package. This package +implements log levels. The standard way of outputting is: `log.Info` for info level messages. The +levels available are `log.Info`, `log.Warning`, `log.Error`, `log.Debug`. Each of these also has +a `f` variant. + In general, logging should be left to the higher layers by returning an error. However, if there is -a reason to consume the error but notify the user, then logging in the plugin can be acceptable. +a reason to consume the error and notify the user, then logging in the plugin itself can be +acceptable. The `Debug*` functions only output something when the *debug* plugin is loaded in the +server. ## Metrics diff --git a/plugin/pkg/log/log.go b/plugin/pkg/log/log.go new file mode 100644 index 000000000..6594f593d --- /dev/null +++ b/plugin/pkg/log/log.go @@ -0,0 +1,69 @@ +// Package log implements a small wrapper around the std lib log package. +// It implements log levels by prefixing the logs with [INFO], [DEBUG], +// [WARNING] or [ERROR]. +// Debug logging is available and enabled if the *debug* plugin is used. +// +// log.Info("this is some logging"), will log on the Info level. +// +// log.Debug("this is debug output"), will log in the Debug level. +package log + +import ( + "fmt" + golog "log" +) + +// D controls whether we should ouput debug logs. If true, we do. +var D bool + +// logf calls log.Printf prefixed with level. +func logf(level, format string, v ...interface{}) { + s := level + fmt.Sprintf(format, v...) + golog.Print(s) +} + +// log calls log.Print prefixed with level. +func log(level string, v ...interface{}) { s := level + fmt.Sprint(v...); golog.Print(s) } + +// Debug is equivalent to log.Print(), but prefixed with "[DEBUG] ". It only outputs something +// if D is true. +func Debug(v ...interface{}) { + if !D { + return + } + log(debug, v...) +} + +// Debugf is equivalent to log.Printf(), but prefixed with "[DEBUG] ". It only outputs something +// if D is true. +func Debugf(format string, v ...interface{}) { + if !D { + return + } + logf(debug, format, v...) +} + +// Info is equivalent to log.Print, but prefixed with "[INFO] ". +func Info(v ...interface{}) { log(info, v...) } + +// Infof is equivalent to log.Printf, but prefixed with "[INFO] ". +func Infof(format string, v ...interface{}) { logf(info, format, v...) } + +// Warning is equivalent to log.Print, but prefixed with "[WARNING] ". +func Warning(v ...interface{}) { log(warning, v...) } + +// Warningf is equivalent to log.Printf, but prefixed with "[WARNING] ". +func Warningf(format string, v ...interface{}) { logf(warning, format, v...) } + +// Error is equivalent to log.Print, but prefixed with "[ERROR] ". +func Error(v ...interface{}) { log(err, v...) } + +// Errorf is equivalent to log.Printf, but prefixed with "[ERROR] ". +func Errorf(format string, v ...interface{}) { logf(err, format, v...) } + +const ( + debug = "[DEBUG] " + err = "[ERROR] " + warning = "[WARNING] " + info = "[INFO] " +) diff --git a/plugin/pkg/log/log_test.go b/plugin/pkg/log/log_test.go new file mode 100644 index 000000000..c9ead7604 --- /dev/null +++ b/plugin/pkg/log/log_test.go @@ -0,0 +1,61 @@ +package log + +import ( + "bytes" + golog "log" + "strings" + "testing" +) + +func TestDebug(t *testing.T) { + var f bytes.Buffer + golog.SetOutput(&f) + + // D == false + Debug("debug") + if x := f.String(); x != "" { + t.Errorf("Expected no debug logs, got %s", x) + } + + D = true + Debug("debug") + if x := f.String(); !strings.Contains(x, debug+"debug") { + t.Errorf("Expected debug log to be %s, got %s", debug+"debug", x) + } +} + +func TestDebugx(t *testing.T) { + var f bytes.Buffer + golog.SetOutput(&f) + + D = true + + Debugf("%s", "debug") + if x := f.String(); !strings.Contains(x, debug+"debug") { + t.Errorf("Expected debug log to be %s, got %s", debug+"debug", x) + } + + Debug("debug") + if x := f.String(); !strings.Contains(x, debug+"debug") { + t.Errorf("Expected debug log to be %s, got %s", debug+"debug", x) + } +} + +func TestLevels(t *testing.T) { + var f bytes.Buffer + const ts = "test" + golog.SetOutput(&f) + + Info(ts) + if x := f.String(); !strings.Contains(x, info+ts) { + t.Errorf("Expected log to be %s, got %s", info+ts, x) + } + Warning(ts) + if x := f.String(); !strings.Contains(x, warning+ts) { + t.Errorf("Expected log to be %s, got %s", warning+ts, x) + } + Error(ts) + if x := f.String(); !strings.Contains(x, err+ts) { + t.Errorf("Expected log to be %s, got %s", err+ts, x) + } +} |