Gondolin during the Angband Siege?

[Hisoka Morrow]

Were there any JRRT's or his authorized stuff mention that Gondolin's activities involving to the war-zone during the Angband Siege? Such as did it provide logistic support, keeping it's intellectual agents to keep an eye to the front to secure if there're weapons powerful enough to destroy it's defenses, or so forth.
Forget Hurin brothers, they're ordered to keep Gondolin classified. Interactions between the heads, such as Captain, King or Lord-classes personnel are included, such as Turgon and Fingon if there're such cases.