Fence gate locks are usually simple locks that can only be opened from one side. There are times, however, when you wish you could just open the gate from outside instead of opening the main door to your house and then walking all the way to open the gate from the inside. One popular two-sided gate lock is YardLock. It’s a keyless gate lock that costs $55 on Amazon.
Another option is to install a traditional keyed deadbolt lock. You can also get one that allows rekeying the lock so that you can use the same key as you have for your main door like this one from Kwikset which costs $35.
To prevent water from getting into the lock and to make it difficult for intruders from reaching over the fence to unlock the door, you can install a weatherproof 2 gang outdoor outlet cover like this one for $18.
Of course, you’d also need to drill 3 holes for the lock and the bolt like you would for a traditional door. Here’s an example of an attempt at this approach. The photos below show how the lock looks from the outside. For weather protection, I just cover the lock a piece of fence wood attached to a door hinge. Instead of a fancy knob, I just screwed a metal clamp into it.
The photos below show how the lock looks from the inside.
It’s not as elegant of a solution as the Yardlock although it can be made to look elegant. It does have the advantage of being more secure than the Yardlock.