Canada, as a NATO country, has an obligation under Article 5 to consider an armed attack against one member state to be an armed attack against them all. There is no armed attack against the US and Iran is not a NATO country.
The US seems to be looking for the "weapon of mass destruction" in Iran, In My Opinion. In 2003, the US was looking for the "weapon of mass destruction" in Iraq. Canada's role in Iraq was peacekeeping/policing/training. Carney has said that Canada supports the United States acting to prevent Iran from obtaining nuclear weapons and to prevent its regime from further threatening international peace and security.
Again, in my opinion, until there is evidence that Israel and the US are taking specific actions to prevent development of nuclear weapons, Canada will stay out of it. Even if and when there is evidence of actions to prevent development of nuclear weapons, I don't see any role for Canadians in peacekeepers and training roles.
In my opinion, Canada is safe, and removed, from aggression by the US and Israel against Iran and Shia Muslims.