terraform/plugins: add libvirt, aws, ignition, openstack to KnownPlugins

`KnownPlugins` maps the plugin name (`terraform-provider-<name>`) to a function that runs the plugin

pkg/terraform/exec/plugins/aws.go

@@ -0,0 +1,15 @@
+package plugins
+
+import (
+	"github.com/hashicorp/terraform/plugin"
+	"github.com/terraform-providers/terraform-provider-aws/aws"
+)
+
+func init() {
+	exec := func() {
+		plugin.Serve(&plugin.ServeOpts{
+			ProviderFunc: aws.Provider,
+		})
+	}
+	KnownPlugins["terraform-provider-aws"] = exec
+}

pkg/terraform/exec/plugins/ignition.go

@@ -0,0 +1,15 @@
+package plugins
+
+import (
+	"github.com/hashicorp/terraform/plugin"
+	"github.com/terraform-providers/terraform-provider-ignition/ignition"
+)
+
+func init() {
+	exec := func() {
+		plugin.Serve(&plugin.ServeOpts{
+			ProviderFunc: ignition.Provider,
+		})
+	}
+	KnownPlugins["terraform-provider-ignition"] = exec
+}

pkg/terraform/exec/plugins/libvirt.go

@@ -0,0 +1,19 @@
+// +build libvirt_destroy
+
+package plugins
+
+import (
+	"github.com/dmacvicar/terraform-provider-libvirt/libvirt"
+	"github.com/hashicorp/terraform/plugin"
+)
+
+func init() {
+	exec := func() {
+		defer libvirt.CleanupLibvirtConnections()
+
+		plugin.Serve(&plugin.ServeOpts{
+			ProviderFunc: libvirt.Provider,
+		})
+	}
+	KnownPlugins["terraform-provider-libvirt"] = exec
+}

pkg/terraform/exec/plugins/openstack.go

@@ -0,0 +1,15 @@
+package plugins
+
+import (
+	"github.com/hashicorp/terraform/plugin"
+	"github.com/terraform-providers/terraform-provider-openstack/openstack"
+)
+
+func init() {
+	exec := func() {
+		plugin.Serve(&plugin.ServeOpts{
+			ProviderFunc: openstack.Provider,
+		})
+	}
+	KnownPlugins["terraform-provider-openstack"] = exec
+}

pkg/terraform/exec/plugins/plugins.go

@@ -0,0 +1,5 @@
+// Package plugins is collection of all the terraform plugins that are used/required by installer.
+package plugins
+
+// KnownPlugins is a map of all the known plugin names to their exec functions.
+var KnownPlugins = map[string]func(){}