Add CDB_Username() function

scripts-available/CDB_Username.sql

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+-- Function returning the username of the provided user
+CREATE OR REPLACE FUNCTION _CDB_Username(pg_user TEXT)
+RETURNS text
+AS $$
+  SELECT CDB_Conf_GetConf(CONCAT('api_keys_', pg_user))->>'username';
+$$ LANGUAGE SQL STRICT IMMUTABLE PARALLEL SAFE SECURITY DEFINER;
+
+-- Function returning the username of the current user
+CREATE OR REPLACE FUNCTION CDB_Username()
+RETURNS text
+AS $$
+  SELECT _CDB_Username(current_user);
+$$ LANGUAGE SQL STABLE PARALLEL SAFE;

scripts-enabled/920-CDB_Username.sql

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+../scripts-available/CDB_Username.sql

test/CDB_Username.sql

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+SELECT current_user; -- postgres
+SELECT CDB_Username(); -- (NULL)
+
+-- Connect with admin
+\set QUIET on
+\o log/test.log
+SELECT current_database() AS current_database;
+\gset
+SELECT SUBSTRING (:'current_database', 19, 36) AS user_id;
+\gset
+SELECT rolname AS admin_user FROM pg_roles where rolname LIKE ('%' || :'user_id');
+\gset
+\c :current_database :admin_user
+\o
+\set QUIET off
+
+SELECT CDB_Username(); -- admin

test/CDB_Username_expect

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+postgres
+
+admin