piku: A Python repository from johntellsall

The tiniest Heroku/CloudFoundry-like PaaS you've ever seen.

piku, inspired by dokku, allows you do git push deployments to your own servers.

Documentation: Using | Install | Procfile | ENV | Examples | Roadmap | Contributing

Goals and Motivation

I kept finding myself wanting an Heroku/CloudFoundry-like way to deploy stuff on a few remote ARM boards and my Raspberry Pi cluster, but since dokku didn't work on ARM at the time and even docker can be overkill sometimes, I decided to roll my own.

Core values

Runs on low end devices.
Accessible to hobbyists and K-12 schools.
~1000 lines readable code.
Functional code style.
Few (single?) dependencies
12 factor app.
Simplify user experience.
Cover 80% of common use cases.
Sensible defaults.
Leverage distro packages in Raspbian/Debian/Ubuntu (Alpine and RHEL support is WIP)
Leverage standard tooling (git, ssh, uwsgi, nginx).
Preserve backwards compatibility where possible

Using `piku`

piku supports a Heroku-like workflow, like so:

Create a git SSH remote pointing to your piku server with the app name as repo name. git remote add piku piku@yourserver:appname.
Push your code: git push piku master.
piku determines the runtime and installs the dependencies for your app (building whatever's required).
- For Python, it segregates each app's dependencies into a virtualenv.
- For Go, it defines a separate GOPATH for each app.
- For Node, it installs whatever is in package.json into node_modules.
- For Java, it builds your app depending on either pom.xml or build.gradle file.
It then looks at a Procfile which is documented here and starts the relevant workers using uWSGI as a generic process manager.
You can optionally also specify a release worker which is run once when the app is deployed.
You can then remotely change application settings (config:set) or scale up/down worker processes (ps:scale).
You can also bake application settings into a file called ENV which is documented here.
A static worker type, with the root path as the argument, can be used to deploy a gh-pages style static site.

Install

To use piku you need a VPS, Raspberry Pi, or other server bootstrapped with piku's requirements. You can use a single server to run multiple piku apps.

Warning: You should use a fresh server or VPS instance without anything important running on it already, as piku-bootstrap will make changes to configuration files, running services, etc.

Once you've got a fresh server, download the piku-bootstrap shell script onto your local machine and run it:

curl https://piku.github.io/get | sh

The first time it is run piku-bootstrap will install itself into ~/.piku-bootstrap on your local machine and set up a virtualenv there with the dependencies it requires. It will only need to do this once.

The script will display a usage message and you can then bootstrap your server:

./piku-bootstrap root@yourserver.net

If you put the piku-bootstrap script on your PATH somewhere, you can use it again to provision other servers in the future.

See below for instructions on installing other custom dependencies that your apps might need like a database etc.

`piku` client

To make life easier you can also install the piku helper CLI. Install it into your path e.g. ~/bin to run it from anywhere.

./piku-bootstrap install-cli ~/bin

This shell script makes working with piku remotes a bit simpler. If you have a git remote called piku in the current folder it will infer the remote server and app name and insert those into the remote piku commands. This allows you to execute commands like the following on your running remote app:

$ piku logs
$ piku config:set MYVAR=12
$ piku stop
$ piku deploy
$ piku destroy
$ piku # <- will show help for the remote app

You can pass flags through to the underlying SSH command, for example -t to run interactive commands remotely, and -A to proxy authentication credentials in order to do remote git pulls.

Here is an example of using the -t flag to obtain a bash shell in the app directory of one of your Piku apps:

$ piku -t run bash
Piku remote operator.
Server: piku@cloud.mccormickit.com
App: dashboard

piku@piku:~/.piku/apps/dashboard$ ls
data  ENV  index.html  package.json  package-lock.json  Procfile  server.wisp

Tip: If you put this piku script on your PATH you can use the piku command across multiple apps on your local.

Installing other dependencies

piku-bootstrap uses Ansible internally and it comes with several extra built-in playbooks which you can use to bootstrap common components onto your piku server.

Use piku-bootstrap list-playbooks to show a list of built-in playbooks, and then to install one add it as an argument to the bootstrap command.

For example, to deploy nodeenv onto your server:

piku-bootstrap root@yourserver.net nodeenv.yml

You can also use piku-bootstrap to run your own Ansible playbooks like this:

piku-bootstrap root@yourserver.net ./myplaybook.yml

Virtual Hosts

If you are on a LAN and are accessing piku from macOS/iOS/Linux clients, you can try using piku/avahi-aliases to announce different hosts via Avahi/mDNS/Bonjour.

Supported Platforms

piku is intended to work in any POSIX-like environment where you have Python, uWSGI and SSH, i.e.: Linux, FreeBSD, Cygwin and the Windows Subsystem for Linux.

As a baseline, it began its development on an original, 256MB Rasbperry Pi Model B, and still runs reliably on it.

Since I have an ODROID-U2, a bunch of Pi 2s and a few more ARM boards on the way, it is often tested on a number of places where running x64 binaries is unfeasible.

But there are already a few folk using piku on vanilla x64 Linux without any issues whatsoever, so yes, you can use it as a micro-PaaS for 'real' stuff. Your mileage may vary.

Supported Runtimes

piku currently supports deploying apps (and dependencies) written in Python, with Go, Clojure (Java) and Node (see above) in the works. But if it can be invoked from a shell, it can be run inside piku.

johntellsall/piku