Errcheck phase 1 (#1715)

* Avoid redundant logging in migrations

Return the error and let the caller handle the logging of the error if
needed.

While here, defer m.Close() to the function boundary.

* Treat errors as values

Use %v rather than %s and pass the errors directly.

* Generate a wrapped error on stat-failure

* 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.

* Propagate errors upward

Failure in path generation was ignored. Propagate the errors upward the
call stack, so it can be handled at the level of orchestration.

* Warn on errors

Log errors rather than quenching them.

Errors are logged at the Warn-level for now.

* Check error when creating test databases

Use the builtin log package and stop the program fatally on error.

* Add warnings to uncheck task errors

Focus on the task system in a single commit, logging unchecked
errors as warnings.

* Warn-on-error in API routes

Look through the API routes, and make sure errors are being logged if
they occur. Prefer the Warn-log-level because none of these has proven
to be fatal in the system up until now.

* Propagate error when adding Util API

* Propagate error on adding util API

* Return unhandled error

* JS log API: propagate and log errors

* JS Plugins: log GQL addition failures.

* Warn on failure to write to stdin

* Warn on failure to stop task

* Wrap viper.BindEnv

The current viper code only errors if no name is provided, so it should
never fail. Rewrite the code flow to factor through a panic-function.

This removes error warnings from this part of the code.

* Log errors in concurrency test

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

* Warn on errors in configuration code

* Plug an unchecked error in gallery zip walking

* Warn on screenshot serving failure

* Warn on encoder screenshot failure

* Warn on errors in path-handling code

* Undo the errcheck on configurations for now.

* Use one-line initializers where applicable

rather than using

  err := f()
  if err!= nil { ..

prefer the shorter

  if err := f(); err != nil { ..

If f() isn't too long of a name, or wraps a function with a body.

pkg/manager/task_export.go

@@ -126,7 +126,7 @@ func (t *ExportTask) Start(wg *sync.WaitGroup) {
 
 	paths.EnsureJSONDirs(t.baseDir)
 
-	t.txnManager.WithReadTxn(context.TODO(), func(r models.ReaderRepository) error {
+	txnErr := t.txnManager.WithReadTxn(context.TODO(), func(r models.ReaderRepository) error {
 		// include movie scenes and gallery images
 		if !t.full {
 			// only include movie scenes if includeDependencies is also set
@@ -154,6 +154,9 @@ func (t *ExportTask) Start(wg *sync.WaitGroup) {
 
 		return nil
 	})
+	if txnErr != nil {
+		logger.Warnf("error while running export transaction: %v", txnErr)
+	}
 
 	if err := t.json.saveMappings(t.Mappings); err != nil {
 		logger.Errorf("[mappings] failed to save json: %s", err.Error())
@@ -202,17 +205,24 @@ func (t *ExportTask) zipFiles(w io.Writer) error {
 		return err
 	}
 
-	filepath.Walk(t.json.json.Tags, t.zipWalkFunc(u.json.Tags, z))
-	filepath.Walk(t.json.json.Galleries, t.zipWalkFunc(u.json.Galleries, z))
-	filepath.Walk(t.json.json.Performers, t.zipWalkFunc(u.json.Performers, z))
-	filepath.Walk(t.json.json.Studios, t.zipWalkFunc(u.json.Studios, z))
-	filepath.Walk(t.json.json.Movies, t.zipWalkFunc(u.json.Movies, z))
-	filepath.Walk(t.json.json.Scenes, t.zipWalkFunc(u.json.Scenes, z))
-	filepath.Walk(t.json.json.Images, t.zipWalkFunc(u.json.Images, z))
+	walkWarn(t.json.json.Tags, t.zipWalkFunc(u.json.Tags, z))
+	walkWarn(t.json.json.Galleries, t.zipWalkFunc(u.json.Galleries, z))
+	walkWarn(t.json.json.Performers, t.zipWalkFunc(u.json.Performers, z))
+	walkWarn(t.json.json.Studios, t.zipWalkFunc(u.json.Studios, z))
+	walkWarn(t.json.json.Movies, t.zipWalkFunc(u.json.Movies, z))
+	walkWarn(t.json.json.Scenes, t.zipWalkFunc(u.json.Scenes, z))
+	walkWarn(t.json.json.Images, t.zipWalkFunc(u.json.Images, z))
 
 	return nil
 }
 
+// like filepath.Walk but issue a warning on error
+func walkWarn(root string, fn filepath.WalkFunc) {
+	if err := filepath.Walk(root, fn); err != nil {
+		logger.Warnf("error walking structure %v: %v", root, err)
+	}
+}
+
 func (t *ExportTask) zipWalkFunc(outDir string, z *zip.Writer) filepath.WalkFunc {
 	return func(path string, info os.FileInfo, err error) error {
 		if err != nil {