UDFs: Functions with Handler Code That Reads Files from a Stage Execute in the Owner’s Context¶
This behavior change is in the 2023_03 bundle.
For the current status of the bundle, refer to Bundle History.
UDFs whose handler code reads files from a stage will execute in the owner’s context. A caller must pass the file location as a scoped URL, whether the handler code is in a UDF or procedure and regardless of whether they are running with caller’s or owner’s rights:
When Java code in a UDF handler reads a file from a stage, it does so using the caller’s context.
A caller may pass the file’s location to the function using a form such as
Handler code receives the stage URL and reads the file with
SnowflakeFile.getInputStreamor receives the file as a
SnowflakeFile sfFile = SnowflakeFile.newInstance(file_url); InputStream is = sfFile.getInputStream();
Files read by handler code may be on an external stage or on a user or named internal stage.
When Java code in a UDF handler reads a file from a stage, it will do so using the owner’s context.
For both UDFs and procedures, a caller must pass the file’s location in a scoped URL by using the BUILD_SCOPED_FILE_URL function, as in the following function example:
select my_func(build_scoped_file_url(@my_stage, 'filename.txt'));
Handler code receives the scoped URL and reads the file as before.
SnowflakeFile sfFile = SnowflakeFile.newInstance(scopedFileUrl); InputStream is = sfFile.getInputStream();
For files whose locations are specified within handler code (not as scoped URLs passed in by a caller), you can read the staged file in one of two ways: handler code can call the newInstance method with a boolean value for a new requireScopedUrl parameter; or handler code must use a scoped URL when creating an InputStream from the file path.
The following example uses
String filename = “@my_stage/filename.txt”; SnowflakeFile sfFile = SnowflakeFile.newInstance(filename, require_scoped_url = false).
In addition, user stages are no longer supported as locations for files read by a handler. Files read by handler code must be on an external stage or on a named internal stage.