Implement Fargate cluster and client

providers/aws/fargate/client.go

@@ -0,0 +1,48 @@
+package fargate
+
+import (
+	"log"
+
+	"github.com/aws/aws-sdk-go/aws"
+	"github.com/aws/aws-sdk-go/aws/session"
+	"github.com/aws/aws-sdk-go/service/ecs"
+	"github.com/aws/aws-sdk-go/service/ecs/ecsiface"
+)
+
+// Client communicates with the regional AWS Fargate service.
+type Client struct {
+	region string
+	svc    *ecs.ECS
+	api    ecsiface.ECSAPI
+}
+
+var client *Client
+
+// NewClient creates a new Fargate client in the given region.
+func newClient(region string) (*Client, error) {
+	var client Client
+
+	// Initialize client session configuration.
+	config := aws.NewConfig()
+	config.Region = aws.String(region)
+
+	session, err := session.NewSessionWithOptions(
+		session.Options{
+			Config:            *config,
+			SharedConfigState: session.SharedConfigEnable,
+		},
+	)
+
+	if err != nil {
+		return nil, err
+	}
+
+	// Create the Fargate service client.
+	client.region = region
+	client.svc = ecs.New(session)
+	client.api = client.svc
+
+	log.Println("Created Fargate service client.")
+
+	return &client, nil
+}

providers/aws/fargate/cluster.go

@@ -0,0 +1,134 @@
+package fargate
+
+import (
+	"fmt"
+	"log"
+	"strings"
+	"sync"
+
+	"github.com/aws/aws-sdk-go/aws"
+	"github.com/aws/aws-sdk-go/service/ecs"
+)
+
+// ClusterConfig contains a Fargate cluster's configurable parameters.
+type ClusterConfig struct {
+	Region                  string
+	Name                    string
+	NodeName                string
+	Subnets                 []string
+	SecurityGroups          []string
+	AssignPublicIPv4Address bool
+	PlatformVersion         string
+}
+
+// Cluster represents a Fargate cluster.
+type Cluster struct {
+	region                  string
+	name                    string
+	nodeName                string
+	arn                     string
+	subnets                 []string
+	securityGroups          []string
+	assignPublicIPv4Address bool
+	platformVersion         string
+	sync.RWMutex
+}
+
+// NewCluster creates a new Cluster object.
+func NewCluster(config *ClusterConfig) (*Cluster, error) {
+	var err error
+
+	// Cluster name cannot contain '_' as it is used as a separator in task tags.
+	if strings.Contains(config.Name, "_") {
+		return nil, fmt.Errorf("cluster name should not contain the '_' character")
+	}
+
+	// Check if Fargate is available in the given region.
+	if !FargateRegions.Include(config.Region) {
+		return nil, fmt.Errorf("Fargate is not available in region %s", config.Region)
+	}
+
+	// Create the client to the regional Fargate service.
+	client, err = newClient(config.Region)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create Fargate client: %v", err)
+	}
+
+	// Initialize the cluster.
+	cluster := &Cluster{
+		region:                  config.Region,
+		name:                    config.Name,
+		nodeName:                config.NodeName,
+		subnets:                 config.Subnets,
+		securityGroups:          config.SecurityGroups,
+		assignPublicIPv4Address: config.AssignPublicIPv4Address,
+		platformVersion:         config.PlatformVersion,
+	}
+
+	// Check if the cluster already exists.
+	err = cluster.describe()
+	if err != nil {
+		return nil, err
+	}
+
+	// If not, try to create it.
+	// This might fail if the role doesn't have the necessary permission.
+	if cluster.arn == "" {
+		err = cluster.create()
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	return cluster, nil
+}
+
+// Create creates a new Fargate cluster.
+func (c *Cluster) create() error {
+	api := client.api
+
+	input := &ecs.CreateClusterInput{
+		ClusterName: aws.String(c.name),
+	}
+
+	log.Printf("Creating Fargate cluster %s in region %s", c.name, c.region)
+
+	output, err := api.CreateCluster(input)
+	if err != nil {
+		err = fmt.Errorf("failed to create cluster: %v", err)
+		log.Println(err)
+		return err
+	}
+
+	c.arn = *output.Cluster.ClusterArn
+	log.Printf("Created Fargate cluster %s in region %s", c.name, c.region)
+
+	return nil
+}
+
+// Describe loads information from an existing Fargate cluster.
+func (c *Cluster) describe() error {
+	api := client.api
+
+	input := &ecs.DescribeClustersInput{
+		Clusters: aws.StringSlice([]string{c.name}),
+	}
+
+	log.Printf("Looking for Fargate cluster %s in region %s.", c.name, c.region)
+
+	output, err := api.DescribeClusters(input)
+	if err != nil || len(output.Clusters) > 1 {
+		err = fmt.Errorf("failed to describe cluster: %v", err)
+		log.Println(err)
+		return err
+	}
+
+	if len(output.Clusters) == 0 {
+		log.Printf("Fargate cluster %s in region %s does not exist.", c.name, c.region)
+	} else {
+		log.Printf("Found Fargate cluster %s in region %s.", c.name, c.region)
+		c.arn = *output.Clusters[0].ClusterArn
+	}
+
+	return nil
+}