Builders POC

[soltysh]

As a follow up discussions from #115 and #140 I'm creating this issue to gather requirements and ideas regarding our builder scripts.

Overview

Currently builder images (see docker-builder and sti-builder) contain single script responsible for doing builds. The build process itself consists of the following steps:

1. Check if docker is available.
2. Build the image.
3. Optionally push the result image to repository.

Requirements

By now we've identified a couple of requirements to make this mechanism more reliable and what's more important, user friendly:

• reliable more than bash and curl (see current solution)
• easy to modify & extend, production ready
• validate context URL for docker build before starting actual build (see Docker build sourceURI with https:// hangs #115)
• provide readable logs describing validation and build process

Possible solutions

For now I'm proposing to use something similar to what we already have in kube-deploy. Rationale for this being go language with docker client, already used in the project.

[smarterclayton]

Is this now complete with #347?

[soltysh]

From what I review PR it is, but please @csrwng can you confirm that?

[csrwng]

@soltysh yes it is