Tip - Offload docker image building to Google Container Builder

Want fast docker builds without maintaining costly server(s)? You can offload your build process to Google with their Container Builder service.

Quickstart with the Google Cloud Platform is always a pain (but maybe it's because I'm so used to AWS), but once you're past the initial project setup and the gcloud command line install (doc), building a docker image is as simple as:

gcloud container builds submit --tag 'gcr.io/pullpreview/openproject:test' .

The docker build output will be streamed to your terminal, and then you'll see a quick recap showing how long it took:

DONE
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

ID                                    CREATE_TIME                DURATION  SOURCE                                               IMAGES                              STATUS
3ea83cca-e13d-4e46-b500-a3a2cc2cb667  2017-06-26T20:11:47+00:00  7M34S     gs://pullpreview_cloudbuild/source/1498507902.79.gz  gcr.io/pullpreview/openproject:test  SUCCESS

Success indeed! Based on my tests the machines used are quite fast (the example above is for a really big Rails/NodeJS project), and you get 120min for free per month (but the pricing is ridiculously low anyway). Big caveat though: you can't run more than one build at a time.