Kubernetes GCP Python Starter App

Install

OSX system requirements:

• pyenv - brew install pyenv
• docker - brew install --cask docker
• httpie - brew install httpie

These are listed individually to avoid polluting your global installation unknowingly.

After installing the above, you can run the following command to setup your local dependencies. It sets up on a virtualenv for you.

make install

You should run this command every time your python dependencies change.

Development

The development workflow involves using one or two terminal windows, depending on the type of work you are doing.

All of our python commands use inv / invoke eg pyinvoke, a makefile replacement written in python. This allows us a degree of flexibility and comfort with our dev time tooling.

For the context of this API, all of the work you do should be able to be covered by 100% unit test coverage. Also, the primary mechanism of testing development work should be pytest-watch.

When testing via a more "hands on" approach, we use a combination of flask run (via invoke) and httpie. httpie is used as a UX friendly alternative to curl, although we do utilize curl to confirm that we are aligned with the project spec.

Pytest

$ source ./venv/bin/activate
$ invoke test

Pytest Watch

$ source ./venv/bin/activate
$ invoke test-watch

This terminal will now watch for changes, and automatically re-run the tests when it finds them.

The majority of our tests were written in this way.

httpie

# first terminal
$ source ./venv/bin/activate
$ invoke flask

# second terminal
$ http :8080/api/healthcheck
> HTTP/1.1 200 OK

curl

# first terminal
$ source ./venv/bin/activate
$ invoke flask

# second terminal
$ curl http://0.0.0.0:8080/api/healthcheck
> OK

Updating Dependencies

You can update dependencies via the following commands:

$ source ./venv/bin/activate
$ pipenv install < some package >
$ make upgrade

Deployment

This deployment command assumes you are locally installed to gcloud and kubectl, in addition to all the other above installations

Note that, during the deploy process, you will likely need to enable several google APIs. Do so when prompted, then run the deploy again. This will show up as messages like:

googleapi: Error 403: $API has not been used in project $PROECT before or it is disabled. Enable it by visiting...

These instructions all assume you are starting from the top level directory, whenever a $SHELL command is given.

0. Name your project

Open config.yml and modify the "Project configuration" section

1. Create a new project

Create a new project via https://console.cloud.google.com/, then set its name in config.yml

# config.yml
project: dotted-hope-405813

Then you should run the following commands once, replacing $PROJECT with your actual project ID.

# $SHELL
$ gcloud config set project $PROJECT
$ gcloud auth application-default login --project $PROJECT

2. Create a terraform state bucket

Create a terraform state bucket via https://console.cloud.google.com/, then set its name in config.yml

# config.yml
bucket: coilysiren-k8s-gpc-tfstate-3

Then you must set its name manually in every state.tf file. Open every state.tf file in the repo. You will see a block like this:

terraform {
  backend "gcs" {
    bucket = "coilysiren-k8s-gpc-tfstate-3"
    prefix = "terraform/state"
  }
}

You should modify the bucket = ... line with your bucket name, same as in config.yml.

Finally, import you import the bucket into terraform.

# $SHELL
$ cd infrastructure/foundation/
$ terraform init
$ terraform import google_storage_bucket.default coilysiren-k8s-gpc-tfstate-3

Note that, when you deploy in the next step, you might have to modify the state bucket's region. The goal is to avoid replacing the state bucket.

3. Deploy

Run the deploy script

# $SHELL
$ source ./venv/bin/activate
$ invoke deploy # see tasks.py for source code