Add support of client-go credential plugins in auth (#396)

kubernetes/provider.go

@@ -101,6 +101,34 @@ func Provider() terraform.ResourceProvider {
 				DefaultFunc: schema.EnvDefaultFunc("KUBE_LOAD_CONFIG_FILE", true),
 				Description: "Load local kubeconfig.",
 			},
+			"exec": {
+				Type:     schema.TypeList,
+				Optional: true,
+				MaxItems: 1,
+				Elem: &schema.Resource{
+					Schema: map[string]*schema.Schema{
+						"api_version": {
+							Type:     schema.TypeString,
+							Required: true,
+						},
+						"command": {
+							Type:     schema.TypeString,
+							Required: true,
+						},
+						"env": {
+							Type:     schema.TypeMap,
+							Optional: true,
+							Elem:     &schema.Schema{Type: schema.TypeString},
+						},
+						"args": {
+							Type:     schema.TypeList,
+							Optional: true,
+							Elem:     &schema.Schema{Type: schema.TypeString},
+						},
+					},
+				},
+				Description: "",
+			},
 		},
 
 		DataSourcesMap: map[string]*schema.Resource{
@@ -181,6 +209,21 @@ func providerConfigure(d *schema.ResourceData) (interface{}, error) {
 		cfg.BearerToken = v.(string)
 	}
 
+	if v, ok := d.GetOk("exec"); ok {
+		exec := &clientcmdapi.ExecConfig{}
+		if spec, ok := v.([]interface{})[0].(map[string]interface{}); ok {
+			exec.APIVersion = spec["api_version"].(string)
+			exec.Command = spec["command"].(string)
+			exec.Args = expandStringSlice(spec["args"].([]interface{}))
+			for kk, vv := range spec["env"].(map[string]interface{}) {
+				exec.Env = append(exec.Env, clientcmdapi.ExecEnvVar{Name: kk, Value: vv.(string)})
+			}
+		} else {
+			return nil, fmt.Errorf("Failed to parse exec")
+		}
+		cfg.ExecProvider = exec
+	}
+
 	k, err := kubernetes.NewForConfig(cfg)
 	if err != nil {
 		return nil, fmt.Errorf("Failed to configure: %s", err)

website/docs/index.html.markdown

@@ -109,4 +109,8 @@ The following arguments are supported:
 * `config_context_cluster` - (Optional) Cluster context of the kube config (name of the kubeconfig cluster, `--cluster` flag in `kubectl`). Can be sourced from `KUBE_CTX_CLUSTER`.
 * `token` - (Optional) Token of your service account.  Can be sourced from `KUBE_TOKEN`.
 * `load_config_file` - (Optional) By default the local config (~/.kube/config) is loaded when you use this provider. This option at false disable this behaviour. Can be sourced from `KUBE_LOAD_CONFIG_FILE`.
-
+* `exec` - (Optional) Configuration block to use an [exec-based credential plugin] (https://kubernetes.io/docs/reference/access-authn-authz/authentication/#client-go-credential-plugins), e.g. call an external command to receive user credentials.
+  * `api_version` - (Required) API version to use when decoding the ExecCredentials resource, e.g. `client.authentication.k8s.io/v1beta1`.
+  * `command` - (Required) Command to execute.
+  * `args` - (Optional) List of arguments to pass when executing the plugin.
+  * `env` - (Optional) Map of environment variables to set when executing the plugin.