From 09ef1893cdb13de354d3fe7a57fe43b8389ec7a7 Mon Sep 17 00:00:00 2001
From: Emily Ye <emilyye@google.com>
Date: Tue, 7 Jan 2020 21:27:30 -0800
Subject: [PATCH] add mutex to peering create

---
 .../resource_compute_network_peering.go.erb   | 33 ++++++++++++++-----
 1 file changed, 25 insertions(+), 8 deletions(-)

diff --git a/third_party/terraform/resources/resource_compute_network_peering.go.erb b/third_party/terraform/resources/resource_compute_network_peering.go.erb
index 17a3a0b50ef9..b4e318f13a26 100644
--- a/third_party/terraform/resources/resource_compute_network_peering.go.erb
+++ b/third_party/terraform/resources/resource_compute_network_peering.go.erb
@@ -89,10 +89,22 @@ func resourceComputeNetworkPeeringCreate(d *schema.ResourceData, meta interface{
 	if err != nil {
 		return err
 	}
+	peerNetworkFieldValue, err := ParseNetworkFieldValue(d.Get("peer_network").(string), d, config)
+	if err != nil {
+		return err
+	}
 
 	request := &computeBeta.NetworksAddPeeringRequest{}
 	request.NetworkPeering = expandNetworkPeering(d)
 
+	// Only one peering operation at a time can be performed for a given network.
+	// Lock on both networks, sorted so we don't deadlock for A <--> B peering pairs.
+	peeringLockNames := sortedNetworkPeeringMutexKeys(networkFieldValue, peerNetworkFieldValue)
+	for _, kn := range peeringLockNames {
+		mutexKV.Lock(kn)
+		defer mutexKV.Unlock(kn)
+	}
+
 	addOp, err := config.clientComputeBeta.Networks.AddPeering(networkFieldValue.Project, networkFieldValue.Name, request).Do()
 	if err != nil {
 		return fmt.Errorf("Error adding network peering: %s", err)
@@ -159,10 +171,13 @@ func resourceComputeNetworkPeeringDelete(d *schema.ResourceData, meta interface{
 		Name: name,
 	}
 
-	// Only one delete peering operation at a time can be performed inside any peered VPCs.
-	peeringLockName := getNetworkPeeringLockName(networkFieldValue.Name, peerNetworkFieldValue.Name)
-	mutexKV.Lock(peeringLockName)
-	defer mutexKV.Unlock(peeringLockName)
+	// Only one peering operation at a time can be performed for a given network.
+	// Lock on both networks, sorted so we don't deadlock for A <--> B peering pairs.
+	peeringLockNames := sortedNetworkPeeringMutexKeys(networkFieldValue, peerNetworkFieldValue)
+	for _, kn := range peeringLockNames {
+		mutexKV.Lock(kn)
+		defer mutexKV.Unlock(kn)
+	}
 
 	removeOp, err := config.clientCompute.Networks.RemovePeering(networkFieldValue.Project, networkFieldValue.Name, request).Do()
 	if err != nil {
@@ -201,13 +216,15 @@ func expandNetworkPeering(d *schema.ResourceData) *computeBeta.NetworkPeering {
 	}
 }
 
-func getNetworkPeeringLockName(networkName, peerNetworkName string) string {
+func sortedNetworkPeeringMutexKeys(networkName, peerNetworkName *GlobalFieldValue) []string {
 	// Whether you delete the peering from network A to B or the one from B to A, they
 	// cannot happen at the same time.
-	networks := []string{networkName, peerNetworkName}
+	networks := []string{
+		fmt.Sprintf("%s/peerings", networkName.RelativeLink()),
+		fmt.Sprintf("%s/peerings", peerNetworkName.RelativeLink()),
+	}
 	sort.Strings(networks)
-
-	return fmt.Sprintf("network_peering/%s/%s", networks[0], networks[1])
+	return networks
 }
 
 func resourceComputeNetworkPeeringImport(d *schema.ResourceData, meta interface{}) ([]*schema.ResourceData, error) {