I was wondering if it is possible to write a MySQL User Defined Function (UDF) in Go.   So I tried and I got a very basic UDF working. mysql> SELECT udf_fileexists_go("/etc/hosts"); +---------------------------------+ | udf_fileexists_go("/etc/hosts") | +---------------------------------+ | 1 | +---------------------------------+ 1 row in set (0.00 sec) mysql> SELECT udf_fileexists_go("/nonexistend"); +-----------------------------------+ | udf_fileexists_go("/nonexistend") | +-----------------------------------+ | 0 | +-----------------------------------+ 1 row in set (0.00 sec) This is nowhere near production quality, so be careful. The code is here: https://github.com/dveeden/udf_fileexists_go/blob/master/udf_fileexists_go.go .

Use DNS directly from your database mysql> SELECT lookup('localhost'); +---------------------+ | lookup('localhost') | +---------------------+ | 127.0.0.1 | +---------------------+ 1 row in set (0.00 sec) mysql> SELECT reverse_lookup('127.0.0.1'); +-----------------------------+ | reverse_lookup('127.0.0.1') | +-----------------------------+ | localhost | +-----------------------------+ 1 row in set (0.00 sec) This is how you install these functions. Build udf_example.so which is in your mysql source. ( make udf_example.so ) Copy the udf_example.so file from your build directory to your plugin_dir. Create the lookup and reverse_lookup functions mysql> CREATE FUNCTION lookup RETURNS STRING SONAME 'udf_example.so'; Query OK, 0 rows affected (0.00 sec) mysql> CREATE FUNCTION reverse_lookup RETURNS STRING SONAME 'udf_example.so'; Query OK, 0 rows affected (0.00 sec) I've created a feature ...