Lint checks phase 2 (#1747)

* Log 3 unchecked errors

Rather than ignore errors, log them at
the WARNING log level.

The server has been functioning without these, so assume they are not at
the ERROR level.

* Log errors in concurrency test

If we can't initialize the configuration, treat the test as a failure.

* Undo the errcheck on configurations for now.

* Handle unchecked errors in pkg/manager

* Resolve unchecked errors

* Handle DLNA/DMS unchecked errors

* Handle error checking in concurrency test

Generalize config initialization, so we can initialize a configuration
without writing it to disk.

Use this in the test case, since otherwise the test fails to write.

* Handle the remaining unchecked errors

* Heed gosimple in update test

* Use one-line if-initializer statements

While here, fix a wrong variable capture error.

* testing.T doesn't support %w

use %v instead which is supported.

* Remove unused query builder functions

The Int/String criterion handler functions are now generalized.

Thus, there's no need to keep these functions around anymore.

* Mark filterBuilder.addRecursiveWith nolint

The function is useful in the future and no other refactors are looking
nice.

Keep the function around, but tell the linter to ignore it.

* Remove utils.Btoi

There are no users of this utility function

* Return error on scan failure

If we fail to scan the row when looking for the
unique checksum index, then report the error upwards.

* Fix comments on exported functions

* Fix typos

* Fix startup error

pkg/manager/manager.go

@@ -110,11 +110,15 @@ func Initialize() *singleton {
 			logger.Warnf("config file %snot found. Assuming new system...", cfgFile)
 		}
 
-		initFFMPEG()
+		if err = initFFMPEG(); err != nil {
+			logger.Warnf("could not initialize FFMPEG subsystem: %v", err)
+		}
 
 		// if DLNA is enabled, start it now
 		if instance.Config.GetDLNADefaultEnabled() {
-			instance.DLNAService.Start(nil)
+			if err := instance.DLNAService.Start(nil); err != nil {
+				logger.Warnf("could not start DLNA service: %v", err)
+			}
 		}
 	})
 
@@ -134,7 +138,9 @@ func initProfiling(cpuProfilePath string) {
 	logger.Infof("profiling to %s", cpuProfilePath)
 
 	// StopCPUProfile is defer called in main
-	pprof.StartCPUProfile(f)
+	if err = pprof.StartCPUProfile(f); err != nil {
+		logger.Warnf("could not start CPU profiling: %v", err)
+	}
 }
 
 func initFFMPEG() error {
@@ -182,7 +188,9 @@ func initLog() {
 // configuration has been set. Should only be called if the configuration
 // is valid.
 func (s *singleton) PostInit() error {
-	s.Config.SetInitialConfig()
+	if err := s.Config.SetInitialConfig(); err != nil {
+		logger.Warnf("could not set initial configuration: %v", err)
+	}
 
 	s.Paths = paths.NewPaths(s.Config.GetGeneratedPath())
 	s.RefreshConfig()
@@ -201,8 +209,12 @@ func (s *singleton) PostInit() error {
 		const deleteTimeout = 1 * time.Second
 
 		utils.Timeout(func() {
-			utils.EmptyDir(instance.Paths.Generated.Downloads)
-			utils.EmptyDir(instance.Paths.Generated.Tmp)
+			if err := utils.EmptyDir(instance.Paths.Generated.Downloads); err != nil {
+				logger.Warnf("could not empty Downloads directory: %v", err)
+			}
+			if err := utils.EmptyDir(instance.Paths.Generated.Tmp); err != nil {
+				logger.Warnf("could not empty Tmp directory: %v", err)
+			}
 		}, deleteTimeout, func(done chan struct{}) {
 			logger.Info("Please wait. Deleting temporary files...") // print
 			<-done                                                  // and wait for deletion
@@ -236,11 +248,21 @@ func (s *singleton) RefreshConfig() {
 	s.Paths = paths.NewPaths(s.Config.GetGeneratedPath())
 	config := s.Config
 	if config.Validate() == nil {
-		utils.EnsureDir(s.Paths.Generated.Screenshots)
-		utils.EnsureDir(s.Paths.Generated.Vtt)
-		utils.EnsureDir(s.Paths.Generated.Markers)
-		utils.EnsureDir(s.Paths.Generated.Transcodes)
-		utils.EnsureDir(s.Paths.Generated.Downloads)
+		if err := utils.EnsureDir(s.Paths.Generated.Screenshots); err != nil {
+			logger.Warnf("could not create directory for Screenshots: %v", err)
+		}
+		if err := utils.EnsureDir(s.Paths.Generated.Vtt); err != nil {
+			logger.Warnf("could not create directory for VTT: %v", err)
+		}
+		if err := utils.EnsureDir(s.Paths.Generated.Markers); err != nil {
+			logger.Warnf("could not create directory for Markers: %v", err)
+		}
+		if err := utils.EnsureDir(s.Paths.Generated.Transcodes); err != nil {
+			logger.Warnf("could not create directory for Transcodes: %v", err)
+		}
+		if err := utils.EnsureDir(s.Paths.Generated.Downloads); err != nil {
+			logger.Warnf("could not create directory for Downloads: %v", err)
+		}
 	}
 }
 
@@ -304,7 +326,9 @@ func (s *singleton) Setup(input models.SetupInput) error {
 
 	s.Config.FinalizeSetup()
 
-	initFFMPEG()
+	if err := initFFMPEG(); err != nil {
+		return fmt.Errorf("error initializing FFMPEG subsystem: %v", err)
+	}
 
 	return nil
 }