lnav script to mark error messages and an immediately preceding "good" message

mark-error.lnav

#
# @synopsis: mark-error "GoodMsg" "BadMsg"
# @description: Find instances of "BadMsg", then bookmark it and the preceding "GoodMsg"
# 

;WITH badlines AS (
    -- Select the bad and good line numbers from the for the "BadMsg" log messages
    -- that were found
    SELECT badline, goodline FROM (
        -- Find the log messages that contain "GoodMsg" or "BadMsg"
        SELECT log_body, log_line AS badline,
            -- Window function to find the preceding "GoodMsg"
            max(log_line)
                FILTER (WHERE log_body LIKE '%' || $1 || '%')
                OVER (ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW EXCLUDE CURRENT ROW)
                AS goodline
            FROM all_logs
            WHERE log_body LIKE '%' || $1 || '%' OR
                  log_body LIKE '%' || $2 || '%')
        WHERE log_body like '%' || $2 || '%')
    -- Bookmark the bad and immediately preceding good log messages
    UPDATE all_logs SET log_mark = 1
        WHERE log_line IN (SELECT badline FROM badlines UNION ALL
                           SELECT goodline FROM badlines)