Improve elastic/open search error handling (#166)

* Improve elastic/open search error handling

Signed-off-by: Nathan LeRoy <nleroy917@users.noreply.github.com>

* chore: Lint

Signed-off-by: Anush008 <anushshetty90@gmail.com>

---------

Signed-off-by: Nathan LeRoy <nleroy917@users.noreply.github.com>
Signed-off-by: Anush008 <anushshetty90@gmail.com>
Co-authored-by: Nathan LeRoy <nleroy917@users.noreply.github.com>
Co-authored-by: Anush008 <anushshetty90@gmail.com>

Author: nleroy917

cmd/migrate_from_elasticsearch.go

@@ -139,9 +139,13 @@ func (r *MigrateFromElasticsearchCmd) countElasticsearchDocuments(ctx context.Co
 		return 0, fmt.Errorf("failed to decode count response: %w", err)
 	}
 
+	if res.IsError() {
+		return 0, handleElasticOpenSearchHTTPError(res.StatusCode, result, "Elasticsearch")
+	}
+
 	count, ok := result["count"].(float64)
 	if !ok {
-		return 0, fmt.Errorf("invalid count response format")
+		return 0, fmt.Errorf("invalid count response format - expected 'count' field, got: %v", result)
 	}
 
 	return int64(count), nil
@@ -432,6 +436,10 @@ func (r *MigrateFromElasticsearchCmd) searchWithPagination(ctx context.Context,
 		return nil, fmt.Errorf("failed to decode search response: %w", err)
 	}
 
+	if res.IsError() {
+		return nil, handleElasticOpenSearchHTTPError(res.StatusCode, searchResp, "Elasticsearch")
+	}
+
 	hitsContainer, ok := searchResp["hits"].(map[string]any)
 	if !ok {
 		return nil, fmt.Errorf("invalid response format: missing hits container")

cmd/migrate_from_opensearch.go

@@ -136,9 +136,13 @@ func (r *MigrateFromOpenSearchCmd) countOpenSearchDocuments(ctx context.Context,
 		return 0, fmt.Errorf("failed to decode count response: %w", err)
 	}
 
+	if res.StatusCode >= 400 {
+		return 0, handleElasticOpenSearchHTTPError(res.StatusCode, result, "OpenSearch")
+	}
+
 	count, ok := result["count"].(float64)
 	if !ok {
-		return 0, fmt.Errorf("invalid count response format")
+		return 0, fmt.Errorf("invalid count response format - expected 'count' field, got: %v", result)
 	}
 
 	return int64(count), nil
@@ -410,6 +414,10 @@ func (r *MigrateFromOpenSearchCmd) searchWithPagination(ctx context.Context, cli
 		return nil, fmt.Errorf("OpenSearch error: %v", errorInfo)
 	}
 
+	if res.StatusCode >= 400 {
+		return nil, handleElasticOpenSearchHTTPError(res.StatusCode, searchResp, "OpenSearch")
+	}
+
 	hitsContainer, ok := searchResp["hits"].(map[string]any)
 	if !ok {
 		return nil, fmt.Errorf("invalid response format: missing hits container")

cmd/utils.go

@@ -147,3 +147,17 @@ func arbitraryIDToUUID(id string) *qdrant.PointId {
 	deterministicUUID := uuid.NewSHA1(uuid.NameSpaceURL, []byte(id))
 	return qdrant.NewIDUUID(deterministicUUID.String())
 }
+
+// Provides helpful error messages for HTTP responses from ElasticSearch/OpenSearch.
+func handleElasticOpenSearchHTTPError(statusCode int, responseBody map[string]any, source string) error {
+	if statusCode == 401 {
+		return fmt.Errorf("failed to authenticate with %s (status 401): please verify your credentials (username, password, or API key)", source)
+	}
+
+	// Check if response contains error details
+	if errorInfo, ok := responseBody["error"]; ok {
+		return fmt.Errorf("%s returned error (status %d): %v", source, statusCode, errorInfo)
+	}
+
+	return fmt.Errorf("%s request failed with status %d", source, statusCode)
+}