Merge pull request #287 from alex/rescue

Implement rescue for servers. Fixes #285
diff --git a/openstack/compute/v2/servers/fixtures.go b/openstack/compute/v2/servers/fixtures.go
index e872b07..9ec3def 100644
--- a/openstack/compute/v2/servers/fixtures.go
+++ b/openstack/compute/v2/servers/fixtures.go
@@ -457,3 +457,14 @@
 		fmt.Fprintf(w, response)
 	})
 }
+
+func HandleServerRescueSuccessfully(t *testing.T) {
+	th.Mux.HandleFunc("/servers/1234asdf/action", func(w http.ResponseWriter, r *http.Request) {
+		th.TestMethod(t, r, "POST")
+		th.TestHeader(t, r, "X-Auth-Token", client.TokenID)
+		th.TestJSONRequest(t, r, `{ "rescue": { "adminPass": "1234567890" } }`)
+
+		w.WriteHeader(http.StatusOK)
+		w.Write([]byte(`{ "adminPass": "1234567890" }`))
+	})
+}
diff --git a/openstack/compute/v2/servers/requests.go b/openstack/compute/v2/servers/requests.go
index 6381419..2740a60 100644
--- a/openstack/compute/v2/servers/requests.go
+++ b/openstack/compute/v2/servers/requests.go
@@ -482,7 +482,7 @@
 	FlavorRef string
 }
 
-// ToServerResizeMap formats a ResizeOpts as a map that can be used as a JSON request body to the
+// ToServerResizeMap formats a ResizeOpts as a map that can be used as a JSON request body for the
 // Resize request.
 func (opts ResizeOpts) ToServerResizeMap() (map[string]interface{}, error) {
 	resize := map[string]interface{}{
@@ -543,3 +543,51 @@
 
 	return res
 }
+
+// RescueOptsBuilder is an interface that allows extensions to override the
+// default structure of a Rescue request.
+type RescueOptsBuilder interface {
+	ToServerRescueMap() (map[string]interface{}, error)
+}
+
+// RescueOpts represents the configuration options used to control a Rescue
+// option.
+type RescueOpts struct {
+	// AdminPass is the desired administrative password for the instance in
+	// RESCUE mode. If it's left blank, the server will generate a password.
+	AdminPass string
+}
+
+// ToRescueResizeMap formats a RescueOpts as a map that can be used as a JSON
+// request body for the Rescue request.
+func (opts RescueOpts) ToServerRescueMap() (map[string]interface{}, error) {
+	server := make(map[string]interface{})
+	if opts.AdminPass != "" {
+		server["adminPass"] = opts.AdminPass
+	}
+	return map[string]interface{}{"rescue": server}, nil
+}
+
+// Rescue instructs the provider to place the server into RESCUE mode.
+func Rescue(client *gophercloud.ServiceClient, id string, opts RescueOptsBuilder) RescueResult {
+	var result RescueResult
+
+	if id == "" {
+		result.Err = fmt.Errorf("ID is required")
+		return result
+	}
+	reqBody, err := opts.ToServerRescueMap()
+	if err != nil {
+		result.Err = err
+		return result
+	}
+
+	_, result.Err = perigee.Request("POST", actionURL(client, id), perigee.Options{
+		Results:     &result.Body,
+		ReqBody:     &reqBody,
+		MoreHeaders: client.AuthenticatedHeaders(),
+		OkCodes:     []int{200},
+	})
+
+	return result
+}
diff --git a/openstack/compute/v2/servers/requests_test.go b/openstack/compute/v2/servers/requests_test.go
index 392e2d8..9639702 100644
--- a/openstack/compute/v2/servers/requests_test.go
+++ b/openstack/compute/v2/servers/requests_test.go
@@ -174,3 +174,17 @@
 	res := RevertResize(client.ServiceClient(), "1234asdf")
 	th.AssertNoErr(t, res.Err)
 }
+
+func TestRescue(t *testing.T) {
+	th.SetupHTTP()
+	defer th.TeardownHTTP()
+
+	HandleServerRescueSuccessfully(t)
+
+	res := Rescue(client.ServiceClient(), "1234asdf", RescueOpts{
+		AdminPass: "1234567890",
+	})
+	th.AssertNoErr(t, res.Err)
+	adminPass, _ := res.Extract()
+	th.AssertEquals(t, "1234567890", adminPass)
+}
diff --git a/openstack/compute/v2/servers/results.go b/openstack/compute/v2/servers/results.go
index 53946ba..fec5345 100644
--- a/openstack/compute/v2/servers/results.go
+++ b/openstack/compute/v2/servers/results.go
@@ -54,6 +54,24 @@
 	gophercloud.ErrResult
 }
 
+// RescueResult represents the result of a server rescue operation
+type RescueResult struct {
+	ActionResult
+}
+
+func (r RescueResult) Extract() (string, error) {
+	if r.Err != nil {
+		return "", r.Err
+	}
+
+	var response struct {
+		AdminPass string `mapstructure:"adminPass"`
+	}
+
+	err := mapstructure.Decode(r.Body, &response)
+	return response.AdminPass, err
+}
+
 // Server exposes only the standard OpenStack fields corresponding to a given server on the user's account.
 type Server struct {
 	// ID uniquely identifies this server amongst all other servers, including those not accessible to the current tenant.