Add structured logging to documentStore methods

To troubleshoot reported issues, we add more debugging outputs in
the logging. This includes detailed, structured logs in the Create
and FindID methods to provide better traceability and debuggability.

These changes help diagnose issues by providing detailed context in
the logs, which should improve the ability to identify and resolve
problems.

See also: #9

stores/memory/documents.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 
 	"github.com/oklog/ulid/v2"
+	"github.com/sirupsen/logrus"
 )
 
 var savedDocuments = make(map[string]core.Document)
@@ -18,14 +19,23 @@ func NewDocumentStore() core.DocumentStore {
 }
 
 func (s *documentStore) FindID(ctx context.Context, id string) (*core.Document, error) {
+	log := logrus.WithField("document_id", id)
 	if val, ok := savedDocuments[id]; ok {
+		log.Info("Document retrieved successfully")
 		return &val, nil
 	}
+	log.WithField("error", "document not found").Warn("Document with specified ID not found")
 	return nil, fmt.Errorf("document with id %s not found", id)
 }
 
 func (s *documentStore) Create(ctx context.Context, document *core.Document) (string, error) {
 	id := ulid.Make().String()
 	savedDocuments[id] = *document
+	log := logrus.WithFields(logrus.Fields{
+		"document_id": id,
+		"data_length": len(document.Data.Bytes()),
+	})
+	log.Info("Document created successfully")
+
 	return id, nil
 }