Add wait_for_steady_state

aws/resource_aws_ecs_service.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"log"
 	"regexp"
+	"strconv"
 	"strings"
 	"time"
 
@@ -115,6 +116,7 @@ func resourceAwsEcsService() *schema.Resource {
 				},
 				Set: resourceAwsEcsLoadBalancerHash,
 			},
+
 			"network_configuration": {
 				Type:     schema.TypeList,
 				Optional: true,
@@ -136,6 +138,7 @@ func resourceAwsEcsService() *schema.Resource {
 					},
 				},
 			},
+
 			"placement_strategy": {
 				Type:     schema.TypeSet,
 				Optional: true,
@@ -197,6 +200,12 @@ func resourceAwsEcsService() *schema.Resource {
 					},
 				},
 			},
+
+			"wait_for_steady_state": {
+				Type:     schema.TypeBool,
+				Optional: true,
+				Default:  false,
+			},
 		},
 	}
 }
@@ -523,6 +532,22 @@ func resourceAwsEcsServiceUpdate(d *schema.ResourceData, meta interface{}) error
 		return err
 	}
 
+	if d.Get("wait_for_steady_state").(bool) {
+		log.Println("[INFO] Waiting for service to reach a steady state")
+
+		steadyStateConf := &resource.StateChangeConf{
+			Pending:    []string{"false"},
+			Target:     []string{"true"},
+			Refresh:    resourceAwsEcsServiceIsSteadyStateFunc(d, meta),
+			Timeout:    10 * time.Minute,
+			MinTimeout: 1 * time.Second,
+		}
+
+		if _, err := steadyStateConf.WaitForState(); err != nil {
+			return err
+		}
+	}
+
 	return resourceAwsEcsServiceRead(d, meta)
 }
 
@@ -668,3 +693,44 @@ func validateAwsEcsServiceHealthCheckGracePeriodSeconds(v interface{}, k string)
 	}
 	return
 }
+
+// Returns a StateRefreshFunc for a given service. That function will return "true" if the service is in a
+// steady state, "false" if the service is running but not in a steady state, and an error otherwise.
+func resourceAwsEcsServiceIsSteadyStateFunc(d *schema.ResourceData, meta interface{}) resource.StateRefreshFunc {
+	return func() (interface{}, string, error) {
+		conn := meta.(*AWSClient).ecsconn
+		in := &ecs.DescribeServicesInput{
+			Services: []*string{aws.String(d.Id())},
+			Cluster:  aws.String(d.Get("cluster").(string)),
+		}
+
+		out, err := conn.DescribeServices(in)
+		if err != nil {
+			return nil, "", err
+		}
+
+		if len(out.Services) < 1 {
+			return nil, "", fmt.Errorf(
+				"Service %v disappeared while waiting for it to reach a steady state",
+				d.Id())
+		}
+
+		service := out.Services[0]
+
+		// A service is in a steady state if:
+		// 1. It is not INACTIVE or DRAINING
+		// 2. There is only one deployment, which will be PRIMARY
+		// 3. The count of running tasks matches the desired count
+		// ref: https://github.com/boto/botocore/blob/3ac0dd53/botocore/data/ecs/2014-11-13/waiters-2.json#L42-L72
+		if *service.Status == "INACTIVE" || *service.Status == "DRAINING" {
+			return nil, "", fmt.Errorf(
+				"Service %v can't reach steady state because its status is %v",
+				d.Id(), *service.Status)
+		}
+
+		isSteadyState := len(service.Deployments) == 1 &&
+			*service.RunningCount == *service.DesiredCount
+
+		return service, strconv.FormatBool(isSteadyState), nil
+	}
+}

website/docs/r/ecs_service.html.markdown

@@ -63,6 +63,7 @@ into consideration during task placement. The maximum number of
 * `placement_constraints` - (Optional) rules that are taken into consideration during task placement. Maximum number of
 `placement_constraints` is `10`. Defined below.
 * `network_configuration` - (Optional) The network configuration for the service. This parameter is required for task definitions that use the awsvpc network mode to receive their own Elastic Network Interface, and it is not supported for other network modes.
+* `wait_for_steady_state` - (Optional) If `true`, Terraform will wait for the service to reach a steady state (like [`aws ecs wait services-stable`](https://docs.aws.amazon.com/cli/latest/reference/ecs/wait/services-stable.html)) before continuing. Default `false`.
 
 -> **Note:** As a result of an AWS limitation, a single `load_balancer` can be attached to the ECS service at most. See [related docs](https://docs.aws.amazon.com/AmazonECS/latest/developerguide/service-load-balancing.html#load-balancing-concepts).