K8s
K8s - Kubernetes API Client for Elixir
Features
- A client API for humans
- Kubernetes resources, groups, and CRDs are autodiscovered at boot time. No swagger file to include or override.
- Client supports standard HTTP calls, async batches, wait on status, and watchers
- Supports multiple clusters
Supports multiple authentication credentials
- serviceaccount
- token
- certificate
- auth-provider
- Supports multiple kubernetes API
- Tested against kubernetes swagger specs: 1.10+ and master
- CRD support
- Kubernetes resource and version helper functions
- Kube config file parsing
- Certificate and service account based auth
- Pluggable auth providers
- Macro free; fast compile & fast startup
Installation
The package can be installed by adding k8s
to your list of dependencies in mix.exs
:
def deps do
[
{:k8s, "~> 0.2"}
]
end
Usage
Check out the Usage Guide for in-depth examples.
Most functions are also written using doctests.
- K8s.Client doctests
- K8s.Cluster doctests
- K8s.Conf doctests
- K8s.Resource doctests
- K8s.Version doctests
Testing K8s
operations in your application
K8s
ships with a K8s.Client.DynamicHTTPProvider
for stubbing HTTP responses to kubernetes API requests.
This provider is used throughout the test suite for mocking HTTP responses.
defmodule MyApp.ResourceTest do
use ExUnit.Case, async: true
defmodule K8sMock do
@base_url "https://localhost:6443"
@namespaces_url @base_url <> "/api/v1/namespaces"
def request(:get, @namespaces_url, _, _, _) do
namespaces = [%{"metadata" => %{"name" => "default"}}]
body = Jason.encode!(namespaces)
{:ok, %HTTPoison.Response{status_code: 200, body: body}}
end
end
setup do
DynamicHTTPProvider.register(self(), __MODULE__.K8sMock)
end
test "gets namespaces" do
operation = K8s.Client.get("v1", :namespaces)
assert {:ok, namespaces} = K8s.Client.run(operation, :default)
assert namespaces == [%{"metadata" => %{"name" => "default"}}]
end
end
To see advanced examples of usage, check out these examples in the test suite:
Contributing
Adding support for a new version of kubernetes
Download the swagger spec for the new version. k8s
doesn't use swagger to define the API, but it is used to drive property tests.
export NEW_VERSION_NUMBER=1.1n
make get/${NEW_VERSION_NUMBER}
make test/${NEW_VERSION_NUMBER}
Mock discovery responses exist to simulate runtime API discovery using the FileDriver
If new resources or APIs were added to kubernetes in the new version you will likely see one of these errors: unsupported_api_version
and unsupported_resource
.
Unsupported API Version errors
This error occurs when a new API is added to kubernetes.
Example: {:error, :unsupported_api_version, "scheduling.k8s.io/v1"}
Add the :unsupported_api_version
to this mock configuration and rerun the test suite.
A config entry looks like:
// ...
{
"groupVersion": "scheduling.k8s.io/v1", // add the api version
"kind": "APIResourceList", // leave as is
"resources": [ // add a list of resources provided by the new `groupVersion`
{
"kind": "PriorityClass", // `kind` name
"name": "priorityclasses", // plural name
"namespaced": false, // namespaced or not
"singularName": "",
"verbs": [ // list of verbs supported by the new API
"create",
"delete",
"deletecollection",
"get",
"list",
"patch",
"update",
"watch"
]
}
]
},
// ...
Unsupported Resource errors
This error occurs when a new resource type is added to an existing API, similar to above you will need to add the resource
to the list of resources
.
The following config is missing runtimeclasses
as a resource.
{
"groupVersion": "node.k8s.io/v1beta1",
"kind": "APIResourceList",
"resources": [
{
"kind": "Node",
"name": "nodes",
"namespaced": false,
"singularName": "",
"verbs": [
"create",
"delete",
"deletecollection",
"get",
"list",
"patch",
"update",
"watch"
]
}
]
},
After mocking:
{
"groupVersion": "node.k8s.io/v1beta1",
"kind": "APIResourceList",
"resources": [
{
"kind": "Node",
"name": "nodes",
"namespaced": false,
"singularName": "",
"verbs": [
"create",
"delete",
"deletecollection",
"get",
"list",
"patch",
"update",
"watch"
]
},
{
"kind": "RuntimeClass",
"name": "runtimeclasses",
"namespaced": false,
"singularName": "",
"verbs": [
"create",
"delete",
"deletecollection",
"get",
"list",
"patch",
"update",
"watch"
]
}
]
},