How to log in supabase

logging_supabase.sql

CREATE OR REPLACE FUNCTION example (num INT DEFAULT 10) RETURNS TEXT AS $$
DECLARE
    var1 INT := 20;
    var2 TEXT;
BEGIN
    -- Logging a variable from a SELECT query
    SELECT col_1 FROM some_table INTO var1;
    RAISE LOG 'logging a variable (%)', var1;
    -- It is also possible to avoid using variables, by returning the values of your query to the log
    RAISE LOG 'logging a query with a single return value(%)', (SELECT some_message_value FROM some_table LIMIT 1);
    -- If necessary, you can even log an entire row as JSON
    RAISE LOG 'logging an entire row as JSON (%)', (SELECT to_jsonb(table_name.*) FROM table_name LIMIT 1);
      
    -- When using INSERT or UPDATE, the NEWLY created or updated values can be returned 
    -- into a variable
    -- When using DELETE, the deleted value can be returned.
    -- All three statement types use "RETURNING var INTO" syntax
    INSERT INTO some_table (col_2)
    VALUES('new val')
    RETURNING col_2 INTO var2;
    
    RAISE LOG 'logging a value from an INSERT (could also have been a DELETE or UPDATE) (%)', var2;

    -- Besides logging, returning the variables is the only way to see their
    -- values in PostgreSQL.
    -- The following line concatenates the values into a string so all the variables can be returned as a single value.
    -- Instead of returning variables as strings, you could create and return a composite data type, such as a Temporary table, a
    -- Record type, custom type, array, or a JSON/JSONB type. 
    RETURN var1 || ',' || var2;
EXCEPTION
    -- Handle exceptions here if needed
    WHEN others THEN
        RAISE EXCEPTION 'An error occurred: %', SQLERRM;
        -- ALTERNATIVELY, you could use RAISE LOG 
        -- with the SQLERRM, e.g.: RAISE LOG 'An error occurred: %, SQLERRM;
        -- The benefit of using RAISE LOG in the handler is that it will 
        -- allow you to write an exception that commits. It will essentially allow
        -- the error handler section to behave as an independent transaction.
        -- So you could execute cleanup code or INSERT values into an error management table.
        -- You could even use PG_NET to send a failure message to an external 
        -- API: https://github.com/supabase/pg_net
        -- But, once again, this is only if you use RAISE LOG instead of RAISE EXCEPTION
        -- The tradeoff is that RAISE LOG will not be recognized as an error in the
        -- the Dashboard's logs. 
        -- If you RAISE LOG in this section, you will have to RETURN 
        -- a value or the error handler will
        -- fail
END;
$$ LANGUAGE plpgsql;

SELECT example(12222);