Docker has a cache, which is great, but all I see in the "docker build" output is either:
---> Using cache
or the output of the command (which implies it's not using the cache).
After one step in my Dockerfile (a COPY), it clearly doesn't use the cache. But I'm fairly certain nothing has changed in the folder that it's copying. (It's our application, and I run into the no-cache case even when I deploy twice in a row, for example.)
Is there any way to get Docker to tell me what it thinks changed?
I know Docker used to check timestamps for this, but that was fixed in Docker 1.8, and I'm on Docker 1.9.x here.