deepvariant: Building DockerFile fails at Stage 'Install CLIF binary''

**Have you checked the FAQ? https://github.com/google/deepvariant/blob/r1.2/docs/FAQ.md**: yes

Describe the issue: I am building the deep variant Dockerfile (v1.2) off the Databricks Runtime base image (Ubuntu 18.04). Run into issues at Stage ‘Install CLIF binary’, I get the error,

ModuleNotFoundError: No module named 'apt_pkg'

I see in the build-prereq.sh script this comment,

Build clif binary from scratch. Might not be ideal because it installs a bunch of dependencies, but this works fine when we used this in a Dockerfile because we don't do build-prereq.sh in the final image.

Please advise how to get around this when building your own Docker Image

Cheers,

William

Setup

• Operating system: Ununtu 18.04
• DeepVariant version: 1.2
• Installation method (Docker, built from source, etc.): Docker
• Type of data: (sequencing instrument, reference genome, anything special that is unlike the case studies?)

Steps to reproduce:

• Command:
• Error trace: (if applicable)

Does the quick start test work on your system? Please test with https://github.com/google/deepvariant/blob/r0.10/docs/deepvariant-quick-start.md. Is there any way to reproduce the issue by using the quick start?

Any additional context: