[exporter/elasticsearch] use validation for batcher (#38072)

<!--Ex. Fixing a bug - Describe the bug and how this fixes the issue.
Ex. Adding a feature - Explain what this achieves.-->
#### Description

This PR fixes the validation for batcher. 
- We create our own batcher struct and embed it, instead of using
`exporterbatcher.Config` (for backward compatibility). We ignore key
validations done in [exporterbatcher's
validate](https://github.com/open-telemetry/opentelemetry-collector/blob/56fbf4c2c19ec2a3be8390b84046293f69f5028e/exporter/exporterbatcher/config.go#L46-L60).

<!--Describe what testing was performed and which tests were added.-->
#### Testing
Added

<!--Describe the documentation added.-->
#### Documentation

<!--Please delete paragraphs that you did not use before submitting.-->

---------

Co-authored-by: Carson Ip <[email protected]>
Co-authored-by: Pablo Baeyens <[email protected]>

Author: 3 people

.chloggen/elasticexporte-batcher.yaml

@@ -0,0 +1,27 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: bug_fix
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: elasticsearchexporter
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Validate batcher config for exporter
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [38072]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:
+
+# If your change doesn't affect end users or the exported elements of any package,
+# you should instead start your pull request title with [chore] or use the "Skip Changelog" label.
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: []

exporter/elasticsearchexporter/config.go

@@ -274,6 +274,11 @@ func (cfg *Config) Validate() error {
 	if cfg.Retry.MaxRetries < 0 {
 		return errors.New("retry::max_retries should be non-negative")
 	}
+	if batcherCfg, ok := cfg.exporterbatcherConfig(); ok {
+		if err := batcherCfg.Validate(); err != nil {
+			return fmt.Errorf("invalid batcher config: %w", err)
+		}
+	}
 
 	return nil
 }
@@ -314,6 +319,18 @@ func (cfg *Config) endpoints() ([]string, error) {
 	return endpoints, nil
 }
 
+func (cfg *Config) exporterbatcherConfig() (exporterbatcher.Config, bool) {
+	if cfg.Batcher.Enabled == nil {
+		return exporterbatcher.Config{}, false
+	}
+	return exporterbatcher.Config{
+		Enabled:       *cfg.Batcher.Enabled,
+		FlushTimeout:  cfg.Batcher.FlushTimeout,
+		MinSizeConfig: cfg.Batcher.MinSizeConfig,
+		MaxSizeConfig: cfg.Batcher.MaxSizeConfig,
+	}, true
+}
+
 func validateEndpoint(endpoint string) error {
 	if endpoint == "" {
 		return errConfigEmptyEndpoint

exporter/elasticsearchexporter/config_test.go

@@ -425,6 +425,16 @@ func TestConfig_Validate(t *testing.T) {
 			}),
 			err: `must not specify both retry::max_requests and retry::max_retries`,
 		},
+		"batcher max_size_items less than min_size_items": {
+			config: withDefaultConfig(func(cfg *Config) {
+				cfg.Endpoints = []string{"http://test:9200"}
+				cfg.Batcher.MaxSizeItems = 1000
+				cfg.Batcher.MinSizeItems = 2000
+				enableBatcher := true
+				cfg.Batcher.Enabled = &enableBatcher
+			}),
+			err: `max_size_items must be greater than or equal to min_size_items`,
+		},
 	}
 
 	for name, tt := range tests {

exporter/elasticsearchexporter/factory.go

@@ -203,14 +203,8 @@ func exporterhelperOptions(
 		exporterhelper.WithShutdown(shutdown),
 		exporterhelper.WithQueue(cfg.QueueSettings),
 	}
-	if cfg.Batcher.Enabled != nil {
-		batcherConfig := exporterbatcher.Config{
-			Enabled:       *cfg.Batcher.Enabled,
-			FlushTimeout:  cfg.Batcher.FlushTimeout,
-			MinSizeConfig: cfg.Batcher.MinSizeConfig,
-			MaxSizeConfig: cfg.Batcher.MaxSizeConfig,
-		}
-		opts = append(opts, exporterhelper.WithBatcher(batcherConfig))
+	if batcherCfg, ok := cfg.exporterbatcherConfig(); ok {
+		opts = append(opts, exporterhelper.WithBatcher(batcherCfg))
 
 		// Effectively disable timeout_sender because timeout is enforced in bulk indexer.
 		//