provider/scaleway: fix scaleway_volume_attachment with count > 1 (#9493)

* provider/scaleway: fix scaleway_volume_attachment with count > 1

since scaleway requires servers to be powered off to attach volumes to, we need
to make sure that we don't power down a server twice, or power up a server while
it's supposed to be modified.

sadly terraform doesn't seem to sport serialization primitives for usecases like
this, but putting the code in question behind a `sync.Mutex` does the trick, too

fixes #9417

* provider/scaleway: use mutexkv to lock per-resource

following  @dcharbonnier  suggestion. thanks!

* provider/scaleway: cleanup waitForServerState signature

* provider/scaleway: store serverID in var

* provider/scaleway: correct imports

* provider/scaleway: increase timeouts

builtin/providers/scaleway/helpers.go

@@ -2,7 +2,6 @@ package scaleway
 
 import (
 	"fmt"
-	"log"
 	"time"
 
 	"github.com/hashicorp/terraform/helper/resource"
@@ -33,7 +32,7 @@ func deleteRunningServer(scaleway *api.ScalewayAPI, server *api.ScalewayServer)
 		return err
 	}
 
-	return resource.Retry(5*time.Minute, func() *resource.RetryError {
+	return resource.Retry(20*time.Minute, func() *resource.RetryError {
 		_, err := scaleway.GetServer(server.Identifier)
 
 		if err == nil {
@@ -68,26 +67,18 @@ func deleteStoppedServer(scaleway *api.ScalewayAPI, server *api.ScalewayServer)
 // NOTE copied from github.com/scaleway/scaleway-cli/pkg/api/helpers.go
 // the helpers.go file pulls in quite a lot dependencies, and they're just convenience wrappers anyway
 
-func waitForServerState(s *api.ScalewayAPI, serverID string, targetState string) error {
+func waitForServerState(scaleway *api.ScalewayAPI, serverID, targetState string) error {
-	var server *api.ScalewayServer
+	return resource.Retry(20*time.Minute, func() *resource.RetryError {
-	var err error
+		s, err := scaleway.GetServer(serverID)
 
-	var currentState string
-
-	for {
-		server, err = s.GetServer(serverID)
 		if err != nil {
-			return err
+			return resource.NonRetryableError(err)
 		}
-		if currentState != server.State {
-			log.Printf("[DEBUG] Server changed state to %q\n", server.State)
-			currentState = server.State
-		}
-		if server.State == targetState {
-			break
-		}
-		time.Sleep(1 * time.Second)
-	}
 
-	return nil
+		if s.State != targetState {
+			return resource.RetryableError(fmt.Errorf("Waiting for server to enter %q state", targetState))
+		}
+
+		return nil
+	})
 }

builtin/providers/scaleway/provider.go

@@ -1,6 +1,7 @@
 package scaleway
 
 import (
+	"github.com/hashicorp/terraform/helper/mutexkv"
 	"github.com/hashicorp/terraform/helper/schema"
 	"github.com/hashicorp/terraform/terraform"
 )
@@ -47,6 +48,8 @@ func Provider() terraform.ResourceProvider {
 	}
 }
 
+var scalewayMutexKV = mutexkv.NewMutexKV()
+
 func providerConfigure(d *schema.ResourceData) (interface{}, error) {
 	config := Config{
 		Organization: d.Get("organization").(string),

builtin/providers/scaleway/resource_scaleway_volume_attachment.go

@@ -32,7 +32,13 @@ func resourceScalewayVolumeAttachmentCreate(d *schema.ResourceData, m interface{
 	scaleway := m.(*Client).scaleway
 
 	var startServerAgain = false
-	server, err := scaleway.GetServer(d.Get("server").(string))
+
+	// guard against server shutdown/ startup race conditiond
+	serverID := d.Get("server").(string)
+	scalewayMutexKV.Lock(serverID)
+	defer scalewayMutexKV.Unlock(serverID)
+
+	server, err := scaleway.GetServer(serverID)
 	if err != nil {
 		fmt.Printf("Failed getting server: %q", err)
 		return err
@@ -45,10 +51,9 @@ func resourceScalewayVolumeAttachmentCreate(d *schema.ResourceData, m interface{
 		if err := scaleway.PostServerAction(server.Identifier, "poweroff"); err != nil {
 			return err
 		}
-
+	}
-		if err := waitForServerState(scaleway, server.Identifier, "stopped"); err != nil {
+	if err := waitForServerState(scaleway, server.Identifier, "stopped"); err != nil {
-			return err
+		return err
-		}
 	}
 
 	volumes := make(map[string]api.ScalewayVolume)
@@ -78,21 +83,20 @@ func resourceScalewayVolumeAttachmentCreate(d *schema.ResourceData, m interface{
 	var req = api.ScalewayServerPatchDefinition{
 		Volumes: &volumes,
 	}
-	if err := scaleway.PatchServer(d.Get("server").(string), req); err != nil {
+	if err := scaleway.PatchServer(serverID, req); err != nil {
 		return fmt.Errorf("Failed attaching volume to server: %q", err)
 	}
 
 	if startServerAgain {
-		if err := scaleway.PostServerAction(d.Get("server").(string), "poweron"); err != nil {
+		if err := scaleway.PostServerAction(serverID, "poweron"); err != nil {
 			return err
 		}
-
+		if err := waitForServerState(scaleway, serverID, "running"); err != nil {
-		if err := waitForServerState(scaleway, d.Get("server").(string), "running"); err != nil {
 			return err
 		}
 	}
 
-	d.SetId(fmt.Sprintf("scaleway-server:%s/volume/%s", d.Get("server").(string), d.Get("volume").(string)))
+	d.SetId(fmt.Sprintf("scaleway-server:%s/volume/%s", serverID, d.Get("volume").(string)))
 
 	return resourceScalewayVolumeAttachmentRead(d, m)
 }
@@ -140,7 +144,12 @@ func resourceScalewayVolumeAttachmentDelete(d *schema.ResourceData, m interface{
 	scaleway := m.(*Client).scaleway
 	var startServerAgain = false
 
-	server, err := scaleway.GetServer(d.Get("server").(string))
+	// guard against server shutdown/ startup race conditiond
+	serverID := d.Get("server").(string)
+	scalewayMutexKV.Lock(serverID)
+	defer scalewayMutexKV.Unlock(serverID)
+
+	server, err := scaleway.GetServer(serverID)
 	if err != nil {
 		return err
 	}
@@ -148,14 +157,12 @@ func resourceScalewayVolumeAttachmentDelete(d *schema.ResourceData, m interface{
 	// volumes can only be modified when the server is powered off
 	if server.State != "stopped" {
 		startServerAgain = true
-
 		if err := scaleway.PostServerAction(server.Identifier, "poweroff"); err != nil {
 			return err
 		}
-
+	}
-		if err := waitForServerState(scaleway, server.Identifier, "stopped"); err != nil {
+	if err := waitForServerState(scaleway, server.Identifier, "stopped"); err != nil {
-			return err
+		return err
-		}
 	}
 
 	volumes := make(map[string]api.ScalewayVolume)
@@ -181,16 +188,15 @@ func resourceScalewayVolumeAttachmentDelete(d *schema.ResourceData, m interface{
 	var req = api.ScalewayServerPatchDefinition{
 		Volumes: &volumes,
 	}
-	if err := scaleway.PatchServer(d.Get("server").(string), req); err != nil {
+	if err := scaleway.PatchServer(serverID, req); err != nil {
 		return err
 	}
 
 	if startServerAgain {
-		if err := scaleway.PostServerAction(d.Get("server").(string), "poweron"); err != nil {
+		if err := scaleway.PostServerAction(serverID, "poweron"); err != nil {
 			return err
 		}
-
+		if err := waitForServerState(scaleway, serverID, "running"); err != nil {
-		if err := waitForServerState(scaleway, d.Get("server").(string), "running"); err != nil {
 			return err
 		}
 	}