# Kubereq
Used by [`kubegen`](https://github.com/mruoss/kubegen) to build Resource based
Kubernetes API clients using Req with `kubereq`.
[](https://hex.pm/packages/kubereq)
[](https://github.com/mruoss/kubereq/commits/main)
[](https://hexdocs.pm/kubereq/)
[](https://hex.pm/packages/kubereq)
[](https://github.com/mruoss/kubereq/blob/main/LICENSE.md)
While this library can be used directly, it is easier to let
[`kubegen`](https://github.com/mruoss/kubegen) generate the API client modules
for you. The resulting clients are then using `kubereq` to get the prepared
`Req.Request` struct and make the requests to the Kubernetes API Server.
## Installation
The package can be installed by adding `kubereq` to your list of dependencies in
`mix.exs`:
```elixir
def deps do
[
{:kubereq, "~> 0.1.0"}
]
end
```
The docs can be found at <https://hexdocs.pm/kubereq>.
## Usage with [`kubegen`](https://github.com/mruoss/kubegen)
Unless you want to build your clients yourself, you can use
[`kubegen`](https://github.com/mruoss/kubegen) to generate clients for each
resource kind you need. Check out [`kubegen`](https://github.com/mruoss/kubegen).
## Build your own clients
### Define how to load the Kubernetes Config
In order to get started quickly, you can just use the default pipeline
(`Kubereq.Kubeconfig.Default`) which tries to load the Kubernetes configuration
one-by-one from well-known sources.
If you need more sophisticated rules, you can build your own Kubeconfig loader
pipeline by creating a module `use`-ing [`Pluggable.StepBuilder`](https://hexdocs.pm/pluggable/Pluggable.StepBuilder.html)
and adding `Pluggable` steps defined by this module. The mechanism is exactly
the same as you know from the `Plug` library.
In fact, the default pipeline mentioned above is implemented defining a set of
steps.
```ex
defmodule Kubereq.Kubeconfig.Default do
use Pluggable.StepBuilder
step Kubereq.Kubeconfig.ENV
step Kubereq.Kubeconfig.File, path: ".kube/config", relative_to_home?: true
step Kubereq.Kubeconfig.ServiceAccount
end
```
### Load the Kubernetes Config
With the pipeline defined or implemented, you can now call
`Kubereq.Kubeconfig.load/1` to load the config:
```ex
Kubereq.Kubeconfig.load(Kubereq.Kubeconfig.Default)
```
If your pipelines requires options, you can pass a tuple to
`Kubereq.Kubeconfig.load/1`:
```ex
Kubereq.Kubeconfig.load({Kubereq.Kubeconfig.File, path: ".kube/config", relative_to_home?: true})
```
Instead of creating a new module, you can also pass a list of steps to
`Kubereq.Kubeconfig.load/1`:
```ex
Kubereq.Kubeconfig.load([
Kubereq.Kubeconfig.ENV,
{Kubereq.Kubeconfig.File, path: ".kube/config", relative_to_home?: true},
Kubereq.Kubeconfig.ServiceAccount
])
```
### Building the `Req.Request` struct
Once you have loaded the, you can pass it to `Kubereq.new/2` to get a
`%Req.Request{}` struct which is prepared to make requests to the Kubernetes
API Server for **a specific resource kind**. It expects the `kubeconf` as first
argument and the `path` to the resource as second argument. The path should
contain placeholders for `:namespace` and `:name` which are filled once you make
a request to a specific resource.
The following example builds a `%Req.Request{}` which acts as client for running
operations on `ConfigMaps`:
```ex
kubeconfig = Kubereq.Kubeconfig.load(Kubereq.Kubeconfig.Default)
req = Kubereq.new(kubeconfig, "api/v1/namespaces/:namespace/configmaps/:name")
```
### Running Operations
With the `req` built above, you can now use the other functions defined by
`Kubereq` to run operations - in this example on `ConfigMaps`.
```ex
kubeconfig = Kubereq.Kubeconfig.load(Kubereq.Kubeconfig.Default)
req = Kubereq.new(kubeconfig, "api/v1/namespaces/:namespace/configmaps/:name")
{:ok, resp} = Kubereq.get(req, "my-namespace", "my-config-map")
```
`resp` is a `Req.Response.t()` and you can check for `req.status` and get
`req.body` etc.
