#5 prepare linux file tailer for multiple log file support

grok_exporter.go

@@ -23,6 +23,7 @@ import (
 	"github.com/fstab/grok_exporter/oniguruma"
 	"github.com/fstab/grok_exporter/tailer"
 	"github.com/prometheus/client_golang/prometheus"
+	"github.com/sirupsen/logrus"
 	"net/http"
 	"os"
 	"time"
@@ -269,13 +270,15 @@ func startServer(cfg v2.ServerConfig, handler http.Handler) chan error {
 }
 
 func startTailer(cfg *v2.Config) (tailer.Tailer, error) {
+	logger := logrus.New()
+	logger.Level = logrus.WarnLevel
 	var tail tailer.Tailer
 	switch {
 	case cfg.Input.Type == "file":
 		if cfg.Input.PollInterval == 0 {
-			tail = tailer.RunFseventFileTailer(cfg.Input.Path, cfg.Input.Readall, cfg.Input.FailOnMissingLogfile, nil)
+			tail = tailer.RunFseventFileTailer(cfg.Input.Path, cfg.Input.Readall, cfg.Input.FailOnMissingLogfile, logger)
 		} else {
-			tail = tailer.RunPollingFileTailer(cfg.Input.Path, cfg.Input.Readall, cfg.Input.FailOnMissingLogfile, cfg.Input.PollInterval, nil)
+			tail = tailer.RunPollingFileTailer(cfg.Input.Path, cfg.Input.Readall, cfg.Input.FailOnMissingLogfile, cfg.Input.PollInterval, logger)
 		}
 	case cfg.Input.Type == "stdin":
 		tail = tailer.RunStdinTailer()

tailer/fileTailer.go

@@ -16,6 +16,7 @@ package tailer
 
 import (
 	"fmt"
+	"github.com/sirupsen/logrus"
 	"io"
 	"os"
 	"path/filepath"
@@ -44,16 +45,18 @@ func (f *fileTailer) Errors() chan Error {
 	return f.errors
 }
 
-func RunPollingFileTailer(path string, readall bool, failOnMissingFile bool, pollIntervall time.Duration, logger simpleLogger) Tailer {
+func RunPollingFileTailer(path string, readall bool, failOnMissingFile bool, pollIntervall time.Duration, logger logrus.FieldLogger) Tailer {
 	makeWatcher := func(abspath string, _ *File) (Watcher, error) {
 		return NewPollingWatcher(abspath, pollIntervall)
 	}
 	return runFileTailer(path, readall, failOnMissingFile, logger, makeWatcher)
 }
 
-func runFileTailer(path string, readall bool, failOnMissingFile bool, logger simpleLogger, makeWatcher func(string, *File) (Watcher, error)) Tailer {
+func runFileTailer(path string, readall bool, failOnMissingFile bool, logger logrus.FieldLogger, makeWatcher func(string, *File) (Watcher, error)) Tailer {
 	if logger == nil {
-		logger = &nilLogger{}
+		log := logrus.New()
+		log.Level = logrus.WarnLevel
+		logger = log
 	}
 
 	lines := make(chan string)
@@ -199,11 +202,3 @@ func writeError(errors chan Error, done chan struct{}, cause error, format strin
 	case <-done:
 	}
 }
-
-type simpleLogger interface {
-	Debug(format string, a ...interface{})
-}
-
-type nilLogger struct{}
-
-func (_ *nilLogger) Debug(_ string, _ ...interface{}) {}

tailer/fileTailerLegacyImplWrapper.go → tailer/fileTailerLegacyImplWrapper_windows.go

@@ -12,11 +12,13 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-// +build !darwin
+// +build !darwin,!linux
 
 package tailer
 
+import "github.com/sirupsen/logrus"
+
 // old implementation, darwin is already switched to the new implementation, the other OSes will follow
-func RunFseventFileTailer(path string, readall bool, failOnMissingFile bool, logger simpleLogger) Tailer {
+func RunFseventFileTailer(path string, readall bool, failOnMissingFile bool, logger logrus.FieldLogger) Tailer {
 	return runFileTailer(path, readall, failOnMissingFile, logger, NewFseventWatcher)
 }

tailer/fileTailerNewImplWrapper_darwin.go → tailer/fileTailerNewImplWrapper.go

@@ -16,8 +16,12 @@ package tailer
 
 import (
 	"github.com/fstab/grok_exporter/tailer/fswatcher"
+	"github.com/fstab/grok_exporter/tailer/glob"
+	"github.com/sirupsen/logrus"
 )
 
+// TODO: This wrapper will be removed when all OSs are migrated to the new fswatcher, supporting multiple log files.
+
 type tailerWrapper struct {
 	lines  chan string
 	errors chan Error
@@ -38,14 +42,21 @@ func (t *tailerWrapper) Errors() chan Error {
 
 // Switch to the new file tailer implementation which supports watching multiple files.
 // Once we switched for all supported operating systems, we can remove the old implementation and the wrapper.
-func RunFseventFileTailer(path string, readall bool, failOnMissingFile bool, _ interface{}) Tailer {
+func RunFseventFileTailer(path string, readall bool, failOnMissingFile bool, logger logrus.FieldLogger) Tailer {
 	result := &tailerWrapper{
 		lines:  make(chan string),
 		errors: make(chan Error),
 		done:   make(chan struct{}),
 	}
 
-	newTailer, err := fswatcher.Run([]string{path}, readall, failOnMissingFile)
+	pathAsGlob, err := glob.Parse(path)
+	if err != nil {
+		go func() {
+			result.errors <- newError("failed to initialize file system watcher", err)
+		}()
+		return result
+	}
+	newTailer, err := fswatcher.Run([]glob.Glob{pathAsGlob}, readall, failOnMissingFile, logger)
 	if err != nil {
 		go func() {
 			result.errors <- newError("failed to initialize file system watcher", err)