For the time being, it appears that no one at Facebook nor Google have added Facebook tracking pixel into amp-analytics yet.
Does anybody here knows how to do it ? sample code or github is preferred.
thank you very much
This should work
<amp-pixel src="https://www.facebook.com/tr?id=YOUR_ID&ev=PageView&noscript=1"
layout="nodisplay"></amp-pixel>
You will need to change YOUR_ID
to the ID you can find in Facebook's tracking code.
I created this by adopting the noscript src from their sample script for use in amp-pixel. More advanced usages would be possible, but ideally Facebook would provide the respective documentation.