Listen to Advanced Oracle Queue (AQ) - go

Question

I'm checking Go ability to migrate an existing C++ application.
One of the main task is to listen actively (no polling) an Advanced Oracle Queue.
In Java and C++ there are existing libraries supporting it since a long time.
I could not find anything similar in Go (libraries & examples).
Could you help me with that?

Answer 1

I have an implementation whereby I'm using the "gopkg.in/goracle.v2" package to connect to Oracle, along with the generic Go library "database/sql".
The way I did it, I have the code to read from the AQ in a PL/SQL procedure which I'm calling from my Go code. Although this is not the best approach - and I'm actually going to change it so that it doesn't rely on a stored oracle procedure - it works. The code looks something like the following:
Oracle PL/SQL proc:
PROCEDURE GetAQMessage ( out_content OUT VARCHAR2, in_acknowledge IN VARCHAR2 DEFAULT 'N' )
IS
dyn_sql VARCHAR2(32000);
l_content VARCHAR2(4000);
BEGIN
dyn_sql := '
DECLARE
l_payload MESSAGE_TYPE := MESSAGE_TYPE (NULL);
l_msg_id RAW(16);
l_dequeue_options DBMS_AQ.DEQUEUE_OPTIONS_T;
l_message_properties DBMS_AQ.MESSAGE_PROPERTIES_T;
BEGIN
DBMS_AQ.DEQUEUE(
queue_name => '''|| v_queue_name ||''',
dequeue_options => l_dequeue_options,
message_properties => l_message_properties,
payload => l_payload,
msgid => l_msg_id
);
:b_output := l_payload.message;
END;';
EXECUTE IMMEDIATE dyn_sql USING OUT l_content;
-- Return the content to the OUT parameter
out_content := l_content;
-- Permanently removes the message from the Queue
IF in_acknowledge = 'Y' THEN
COMMIT;
END IF;
END GetAQMessage;
Go code:
func GetAQMessage(transaction *sql.Tx) (string, error) {
var outResult string
var resErr error
var debug int
configuration = conf.Read()
//Run the command
_, resErr = transaction.Exec(`BEGIN CONSENT.GETAQMESSAGE(:1,:2) ; END;`, sql.Out{Dest: &outResult}, "N")
return outResult, resErr
}