Sometimes what that is is simply hop oils that form a slick on the surface and traps rising co2 bubbles..that usually happens when someone dry hops, other times it is a pellicule forming to protect the beer beneath from an infection. A lot of people who brew sour or wild beers with brett or lacto do that on purpose.
You should ever just "consider scrapping" a batch of beer without tasting it a seeing. If it taste badly sour, like vinegar or smells like a dirty diaper, THEN consider dumping it. Otherwise you could be dumping out a perfectly good, if not great batch of beer.
It may be slightly tart and complex, or it may be perfectly fine under that layer.
Since there is nothing beer that can harm you, no know pathogens can exist in beer...you should never fear tasting it.
It it tastes oaky enough for you, and gravity is table, you might want to bottle it or keg it...OR you could rack under it to another sanitized vessel and continue to age it....but if it's ready to go, then get it into bottles or kegs.
Those of you (usually new brewers) who have the words "dumping beer" in your vocabulary should consider reading the stories in here...Many times people dump out perfectly good beers, where if they simply waited may turn into great beers. Bottling or kegging (see the beer through ALL steps in the process, then leaving it alone, IS OFTEN the cure for a supposedly bad beer.)
https://www.homebrewtalk.com/f39/ne...e-time-heals-all-things-even-beer-73254//url]
