docker: failed to compute cache key: "/requirements.txt" not found: not found

Question

I tried to build a docker image with the following command:

docker build -< Dockerfile

I did it in the mail directory of the app. I found this command somewhere in a documentation "how to build a docker image". However the build failed with failure:

failed to compute cache key: "/requirements.txt" not found: not found

My test-app structure looks like:

.
+-- src
|   +-- static
|   +-- templates
|   +-- app.py
+-- Dockerfile
+-- requirements.txt

I'm not a docker expert and there are several instructions out there. It's somehow frustrating. Other stack overflow questions did not solve my issue.

What am I doing wrong?

Answer 1

After some investigation and try out i found the following solution:

The command docker build -> Dockerfile was somehow wrong. Don't know if it is outdated or incomplete.

However i used the following command and it worked:

docker build --tag docker_example .

Very important is the dot at the and. Without this it will not work. It tells Docker which Dockerfile to use.