Merge pull request #55 from c3os-io/feature/cluster-provider

Abstract Cluster Provisioning with Cluster Plugins

sdk/clusterplugin/plugin.go

@@ -0,0 +1,83 @@
+package clusterplugin
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+
+	"github.com/c3os-io/c3os/sdk/bus"
+	"github.com/mudler/go-pluggable"
+	yip "github.com/mudler/yip/pkg/schema"
+	"gopkg.in/yaml.v2"
+)
+
+const clusterProviderCloudConfigFile = "/usr/local/cloud-config/cluster.c3os.yaml"
+
+// ClusterProvider returns a yip configuration that configures a Kubernetes engine.  The yip config may use any elemental
+// stages after initramfs.
+type ClusterProvider func(cluster Cluster) yip.YipConfig
+
+// ClusterPlugin creates a cluster plugin from a `ClusterProvider`.  It calls the cluster provider at the appropriate events
+// and ensures it configuration is written where it will be executed.
+type ClusterPlugin struct {
+	Provider ClusterProvider
+}
+
+func (p ClusterPlugin) onBoot(event *pluggable.Event) pluggable.EventResponse {
+	var payload bus.EventPayload
+	var config Config
+	var response pluggable.EventResponse
+
+	// parse the boot payload
+	if err := json.Unmarshal([]byte(event.Data), &payload); err != nil {
+		response.Error = fmt.Sprintf("failed to parse boot event: %s", err.Error())
+		return response
+	}
+
+	// parse config from boot payload
+	if err := yaml.Unmarshal([]byte(payload.Config), &config); err != nil {
+		response.Error = fmt.Sprintf("failed to parse config from boot event: %s", err.Error())
+		return response
+	}
+
+	if config.Cluster == nil {
+		return response
+	}
+
+	// request the cloud configuration of the provider
+	cc := p.Provider(*config.Cluster)
+
+	// open our cloud configuration file for writing
+	f, err := filesystem.OpenFile(clusterProviderCloudConfigFile, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, 0600)
+	if err != nil {
+		response.Error = fmt.Sprintf("failed to parse boot event: %s", err.Error())
+		return response
+	}
+
+	defer f.Close()
+
+	// write the cloud configuration header
+	_, err = f.WriteString("#cloud-config\n")
+	if err != nil {
+		response.Error = fmt.Sprintf("failed to parse boot event: %s", err.Error())
+		return response
+	}
+
+	// encode the provider's configuration
+	err = yaml.NewEncoder(f).Encode(cc)
+	if err != nil {
+		response.Error = fmt.Sprintf("failed to parse boot event: %s", err.Error())
+		return response
+	}
+
+	return response
+}
+
+func (p ClusterPlugin) Run() error {
+	return pluggable.NewPluginFactory(
+		pluggable.FactoryPlugin{
+			EventType:     bus.EventBoot,
+			PluginHandler: p.onBoot,
+		},
+	).Run(pluggable.EventType(os.Args[1]), os.Stdin, os.Stdout)
+}