tvl-depot/ops/kontemplate/README.md
Vincent Ambo db30770101 fix(kontemplate): Make build compatible with readTree
The kontemplate build will keep using `buildGoPackage` for now until
I've had the time to add tests to //nix/buildGo
2019-12-20 22:19:52 +00:00

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Kontemplate - A simple Kubernetes templater
===========================================
[Kontemplate][] is a simple CLI tool that can take sets of Kubernetes resource
files with placeholders and insert values per environment.
This tool was made because in many cases all I want in terms of Kubernetes
configuration is simple value interpolation per environment (i.e. Kubernetes
cluster), but with the same deployment files.
In my experience this is often enough and more complex solutions such as
[Helm][] are not required.
Check out a Kontemplate setup example and the feature list below!
<!-- markdown-toc start - Don't edit this section. Run M-x markdown-toc-refresh-toc -->
**Table of Contents**
- [Kontemplate - A simple Kubernetes templater](#kontemplate---a-simple-kubernetes-templater)
- [Features](#features)
- [Example](#example)
- [Installation](#installation)
- [Homebrew](#homebrew)
- [Arch Linux](#arch-linux)
- [Building repeatably from source](#building-repeatably-from-source)
- [Building from source](#building-from-source)
- [Usage](#usage)
- [Contributing](#contributing)
<!-- markdown-toc end -->
## Features
* [Simple, yet powerful templates](docs/templates.md)
* [Clean cluster configuration files](docs/cluster-config.md)
* [Resources organised as simple resource sets](docs/resource-sets.md)
* Integration with pass
* Integration with kubectl
## Example
Kontemplate lets you describe resources as you normally would in a simple folder structure:
```
.
├── prod-cluster.yaml
└── some-api
├── deployment.yaml
└── service.yaml
```
This example has all resources belonging to `some-api` (no file naming conventions enforced at all!) in the `some-api`
folder and the configuration for the cluster `prod-cluster` in the corresponding file.
Lets take a short look at `prod-cluster.yaml`:
```yaml
---
context: k8s.prod.mydomain.com
global:
globalVar: lizards
include:
- name: some-api
values:
version: 1.0-0e6884d
importantFeature: true
apiPort: 4567
```
Those values are then templated into the resource files of `some-api`. That's it!
You can also set up more complicated folder structures for organisation, for example:
```
.
├── api
│   ├── image-api
│   │   └── deployment.yaml
│   └── music-api
│   └── deployment.yaml
│   │   └── default.json
├── frontend
│   ├── main-app
│   │   ├── deployment.yaml
│   │   └── service.yaml
│   └── user-page
│   ├── deployment.yaml
│   └── service.yaml
├── prod-cluster.yaml
└── test-cluster.yaml
```
And selectively template or apply resources with a command such as
`kontemplate apply test-cluster.yaml --include api --include frontend/user-page`
to only update the `api` resource sets and the `frontend/user-page` resource set.
## Installation
It is recommended to install Kontemplate from the signed binary releases available on the
[releases page][]. Release binaries are available for Linux, OS X, FreeBSD and Windows.
### Homebrew
OS X users with Homebrew installed can "tap" Kontemplate like such:
```sh
brew tap tazjin/kontemplate https://github.com/tazjin/kontemplate
brew install kontemplate
```
### NixOS
Kontemplate has been included in [NixOS](https://nixos.org/) since version 17.09.
It is available as `kontemplate` from the default Nix package set.
### Arch Linux
An [AUR package][] is available for Arch Linux and other `pacman`-based distributions.
### Building from source
Assuming you have Go configured correctly, you can simply `go get github.com/tazjin/kontemplate/...`.
## Usage
You must have `kubectl` installed to use Kontemplate effectively.
```
usage: kontemplate [<flags>] <command> [<args> ...]
simple Kubernetes resource templating
Flags:
-h, --help Show context-sensitive help (also try --help-long and --help-man).
-i, --include=INCLUDE ... Resource sets to include explicitly
-e, --exclude=EXCLUDE ... Resource sets to exclude explicitly
Commands:
help [<command>...]
Show help.
template <file>
Template resource sets and print them
apply [<flags>] <file>
Template resources and pass to 'kubectl apply'
replace <file>
Template resources and pass to 'kubectl replace'
delete <file>
Template resources and pass to 'kubectl delete'
create <file>
Template resources and pass to 'kubectl create'
```
Examples:
```
# Look at output for a specific resource set and check to see if it's correct ...
kontemplate template example/prod-cluster.yaml -i some-api
# ... maybe do a dry-run to see what kubectl would do:
kontemplate apply example/prod-cluster.yaml --dry-run
# And actually apply it if you like what you see:
kontemplate apply example/prod-cluster.yaml
```
Check out the feature list and the individual feature documentation above. Then you should be good to go!
## Contributing
Feel free to contribute pull requests, file bugs and open issues with feature suggestions!
Kontemplate is licensed under the GPLv3, a copy of the license and its terms can be found
in the `LICENSE` file.
Please follow the [code of conduct](CODE_OF_CONDUCT.md).
[Kontemplate]: http://kontemplate.works
[Helm]: https://helm.sh/
[releases page]: https://github.com/tazjin/kontemplate/releases
[AUR package]: https://aur.archlinux.org/packages/kontemplate-git/
[Repeatr]: http://repeatr.io/