What blessing is said upon seeing a rainbow?

Greetings and blessings

According to the Levush and the Orach Chaim, Siman 229

In Paragraph 1
The one who sees the rainbow says, "Blessed are You, Hashem, our God, King of the universe, who remembers the covenant, is faithful to His covenant, and keeps His word," 

ברוך אתה ה' אלהינו מלך העולם זוכר הברית נאמן בבריתו וקיים במאמרו

meaning the covenant that Hashem made with Noah not to bring another flood of waters upon the earth. Furthermore, one should not look at it too much, for it is an image of the glory of Hashem, as it is written [Ezekiel 1:28], "The appearance of the rainbow is the image of the glory of Hashem," and one who gazes too much at it is as if he does not care for the glory of his Creator—meaning he is as if he has diminished His honor. This prohibition specifically refers to a manner of staring and contemplating at it excessively, for this is seen as brazen and diminishing towards the honor of the Holy King, blessed be He. However, looking at it in a casual manner is permitted, therefore it is permissible to see it during the blessing in a casual glance.

Blessings,

Benjamin Shmueli