Report faulting file when config reload fails

CHANGELOG.next.asciidoc

@@ -35,6 +35,7 @@ https://github.com/elastic/beats/compare/v7.0.0-alpha2...master[Check the HEAD d
   info from the cloud.machine.type and cloud.availability_zone. {issue}10968[10968]
 - Empty `meta.json` file will be treated as a missing meta file. {issue}8558[8558]
 - Rename `migration.enabled` config to `migration.6_to_7.enabled`. {pull}11284[11284]
+- Report faulting file when config reload fails. {pull}[11304]11304
 - Beats Xpack now checks for Basic license on connect. {pull}11296[11296]
 
 *Auditbeat*
@@ -174,7 +175,7 @@ https://github.com/elastic/beats/compare/v7.0.0-alpha2...master[Check the HEAD d
 - Add on_failure handler for Zeek ingest pipelines. Fix one field name error for notice and add an additional test case. {issue}11004[11004] {pull}11105[11105]
 - Fix goroutine leak happening when harvesters are dynamically stopped. {pull}11263[11263]
 - Fix issue preventing docker container events to be stored if the container has a network interface without ip address. {issue}11225[11225] {pull}11247[11247]
-- Add on_failure handler for Zeek ingest pipelines. Fix one field name error for notice and add an additional test 
+- Add on_failure handler for Zeek ingest pipelines. Fix one field name error for notice and add an additional test
   case. {issue}11004[11004] {pull}11105[11105]
 - Change URLPATH grok pattern to support brackets. {issue}11135[11135] {pull}11252[11252]
 - Add support for iis log with different address format. {issue}11255[11255] {pull}11256[11256]

libbeat/cfgfile/reload.go

@@ -35,6 +35,7 @@ import (
 )
 
 var (
+	// DefaultDynamicConfig provides default behavior for a Runner.
 	DefaultDynamicConfig = DynamicConfig{
 		Reload: Reload{
 			Period:  10 * time.Second,
@@ -58,16 +59,20 @@ type DynamicConfig struct {
 	Reload Reload `config:"reload"`
 }
 
+// Reload defines reload behavior and frequency
 type Reload struct {
 	Period  time.Duration `config:"period"`
 	Enabled bool          `config:"enabled"`
 }
 
+// RunnerFactory is used for creating of new Runners
 type RunnerFactory interface {
 	Create(p beat.Pipeline, config *common.Config, meta *common.MapStrPointer) (Runner, error)
 	CheckConfig(config *common.Config) error
 }
 
+// Runner is a simple interface providing a simple way to
+// Start and Stop Reloader
 type Runner interface {
 	// We include fmt.Stringer here because we do log debug messages that must print
 	// something for the given Runner. We need Runner implementers to consciously implement a
@@ -220,7 +225,7 @@ func (rl *Reloader) loadConfigs(files []string) ([]*reload.ConfigWithMeta, error
 		configs, err := LoadList(file)
 		if err != nil {
 			errs = append(errs, err)
-			logp.Err("Error loading config: %s", err)
+			logp.Err("Error loading config from file '%s', error %v", file, err)
 			continue
 		}
 

libbeat/template/load.go

@@ -29,13 +29,15 @@ import (
 	"github.com/elastic/beats/libbeat/paths"
 )
 
-// TemplateLoader is a subset of the Elasticsearch client API capable of
+// ESClient is a subset of the Elasticsearch client API capable of
 // loading the template.
 type ESClient interface {
 	Request(method, path string, pipeline string, params map[string]string, body interface{}) (int, []byte, error)
 	GetVersion() common.Version
 }
 
+// Loader is a template loader capable of loading the template using
+// Elasticsearch Client API
 type Loader struct {
 	config    TemplateConfig
 	client    ESClient