fix: Improved the error messages and comments

errors.go

@@ -3,30 +3,29 @@ package sturdyc
 import "errors"
 
 var (
-	// ErrStoreMissingRecord should be returned from FetchFn to indicate that we
-	// want to store the record with a cooldown. This only applies to the FetchFn,
-	// for the BatchFetchFn you should enable the functionality through options,
-	// and simply return a map without the record being present.
-	ErrStoreMissingRecord = errors.New("record not found")
-	// ErrMissingRecord is returned by client.GetFetch when
-	// a record has been stored as a missing record.
-	ErrMissingRecord = errors.New("record is missing")
-	// ErrOnlyCachedRecords is returned by sturdyc.GetFetchBatch when we have
-	// some of the requested records in the cache, but the call to fetch the
-	// remaining records failed. The consumer can then choose if they want to
-	// proceed with the cached records or retry the operation.
-	ErrOnlyCachedRecords = errors.New("failed to fetch the records that we did not have cached")
+	// ErrStoreMissingRecord should be returned from a FetchFn to indicate that a record is
+	// to be marked as missing by the cache. This will prevent continuous outgoing requests
+	// to the source. The record will still be refreshed like any other record, and if your
+	// FetchFn returns a value for it, the record will no longer be considered missing.
+	// Please note that this only applies to client.GetFetch and client.Passthrough. For
+	// client.GetFetchBatch and client.PassthroughBatch, this works implicitly if you return
+	// a map without the ID, and have store missing records enabled.
+	ErrStoreMissingRecord = errors.New("the record will be marked as missing in the cache")
+	// ErrMissingRecord is returned by client.GetFetch and client.Passthrough when a record has been marked
+	// as missing. The cache will still try to refresh the record in the background if it's being requested.
+	ErrMissingRecord = errors.New("the record has been marked as missing in the cache")
+	// ErrOnlyCachedRecords is returned by client.GetFetchBatch and client.PassthroughBatch
+	// when some of the requested records are available in the cache, but the attempt to
+	// fetch the remaining records failed. As the consumer, you can then decide whether to
+	// proceed with the cached records or if the entire batch is necessary.
+	ErrOnlyCachedRecords = errors.New("failed to fetch the records that were not in the cache")
 	// ErrInvalidType is returned when you try to use one of the generic
-	// package level functions, and the type assertion fails.
+	// package level functions but the type assertion fails.
 	ErrInvalidType = errors.New("invalid response type")
-	// ErrDeletedRecord should be returned by the function that is passed to
-	// client.GetFetch if you wan't to have a record deleted by a refresh.
-	ErrDeleteRecord = errors.New("record has been deleted at source")
+	// ErrDeletedRecord should be returned by the FetchFn that is passed to client.GetFetch
+	// and client.Passthrough if you wan't to have a record deleted by a refresh. This is
+	// not needed for client.GetFetchBatch and client.PassthroughBatch as the cache will
+	// delete the record automatically if stampede protection is enabled and store missing
+	// records is set to false.
+	ErrDeleteRecord = errors.New("the record has been deleted at the data source")
 )
-
-func ErrIsStoreMissingRecordOrMissingRecord(err error) bool {
-	if err == nil {
-		return false
-	}
-	return errors.Is(err, ErrStoreMissingRecord) || errors.Is(err, ErrMissingRecord)
-}