Etcd remote state backend

state/remote/etcd.go

@@ -0,0 +1,78 @@
+package remote
+
+import (
+	"crypto/md5"
+	"fmt"
+	"strings"
+
+	"github.com/coreos/etcd/Godeps/_workspace/src/golang.org/x/net/context"
+	etcdapi "github.com/coreos/etcd/client"
+)
+
+func etcdFactory(conf map[string]string) (Client, error) {
+	path, ok := conf["path"]
+	if !ok {
+		return nil, fmt.Errorf("missing 'path' configuration")
+	}
+
+	endpoints, ok := conf["endpoints"]
+	if !ok || endpoints == "" {
+		return nil, fmt.Errorf("missing 'endpoints' configuration")
+	}
+
+	config := etcdapi.Config{
+		Endpoints: strings.Split(endpoints, " "),
+	}
+	if username, ok := conf["username"]; ok && username != "" {
+		config.Username = username
+	}
+	if password, ok := conf["password"]; ok && password != "" {
+		config.Password = password
+	}
+
+	client, err := etcdapi.New(config)
+	if err != nil {
+		return nil, err
+	}
+
+	return &EtcdClient{
+		Client: client,
+		Path:   path,
+	}, nil
+}
+
+// EtcdClient is a remote client that stores data in etcd.
+type EtcdClient struct {
+	Client etcdapi.Client
+	Path   string
+}
+
+func (c *EtcdClient) Get() (*Payload, error) {
+	resp, err := etcdapi.NewKeysAPI(c.Client).Get(context.Background(), c.Path, &etcdapi.GetOptions{Quorum: true})
+	if err != nil {
+		if err, ok := err.(etcdapi.Error); ok && err.Code == etcdapi.ErrorCodeKeyNotFound {
+			return nil, nil
+		}
+		return nil, err
+	}
+	if resp.Node.Dir {
+		return nil, fmt.Errorf("path is a directory")
+	}
+
+	data := []byte(resp.Node.Value)
+	md5 := md5.Sum(data)
+	return &Payload{
+		Data: data,
+		MD5:  md5[:],
+	}, nil
+}
+
+func (c *EtcdClient) Put(data []byte) error {
+	_, err := etcdapi.NewKeysAPI(c.Client).Set(context.Background(), c.Path, string(data), nil)
+	return err
+}
+
+func (c *EtcdClient) Delete() error {
+	_, err := etcdapi.NewKeysAPI(c.Client).Delete(context.Background(), c.Path, nil)
+	return err
+}

state/remote/etcd_test.go

@@ -0,0 +1,38 @@
+package remote
+
+import (
+	"fmt"
+	"os"
+	"testing"
+	"time"
+)
+
+func TestEtcdClient_impl(t *testing.T) {
+	var _ Client = new(EtcdClient)
+}
+
+func TestEtcdClient(t *testing.T) {
+	endpoint := os.Getenv("ETCD_ENDPOINT")
+	if endpoint == "" {
+		t.Skipf("skipping; ETCD_ENDPOINT must be set")
+	}
+
+	config := map[string]string{
+		"endpoints": endpoint,
+		"path":      fmt.Sprintf("tf-unit/%s", time.Now().String()),
+	}
+
+	if username := os.Getenv("ETCD_USERNAME"); username != "" {
+		config["username"] = username
+	}
+	if password := os.Getenv("ETCD_PASSWORD"); password != "" {
+		config["password"] = password
+	}
+
+	client, err := etcdFactory(config)
+	if err != nil {
+		t.Fatalf("Error for valid config: %s", err)
+	}
+
+	testClient(t, client)
+}

state/remote/remote.go

@@ -38,6 +38,7 @@ func NewClient(t string, conf map[string]string) (Client, error) {
 var BuiltinClients = map[string]Factory{
 	"atlas":  atlasFactory,
 	"consul": consulFactory,
+	"etcd":   etcdFactory,
 	"http":   httpFactory,
 	"s3":     s3Factory,
 	"swift":  swiftFactory,

website/source/docs/commands/remote-config.html.markdown

@@ -50,6 +50,11 @@ The following backends are supported:
   variables can optionally be provided. Address is assumed to be the
   local agent if not provided.
 
+* Etcd - Stores the state in etcd at a given path.
+  Requires the `path` and `endpoints` variables. The `username` and `password`
+  variables can optionally be provided. `endpoints` is assumed to be a
+  space-separated list of etcd endpoints.
+
 * S3 - Stores the state as a given key in a given bucket on Amazon S3.
   Requires the `bucket` and `key` variables. Supports and honors the standard
   AWS environment variables `AWS_ACCESS_KEY_ID`, `AWS_SECRET_ACCESS_KEY`