Redis bug bash (#49)

* fix IDs, use cluster name
* simplify acornfile info, fix IDs with empty prefix
* add subnet group as replication group dependency
* add ID validation test
* add automatic snapshots with 1 day of retention
* add snapshot on delete with arg to disable, remove example gettingstarted.md
* move info and run formatter

elasticache/common.go

@@ -1,8 +1,9 @@
 package elasticache
 
 import (
+	"crypto/md5"
+	"encoding/hex"
 	"os"
-	"strings"
 
 	"github.com/aws/aws-cdk-go/awscdk/v2/awsec2"
 	"github.com/aws/aws-cdk-go/awscdk/v2/awselasticache"
@@ -11,15 +12,19 @@ import (
 )
 
 // ResourceID returns an ID that can be used to uniquely identify resources built with the given prefix
-func ResourceID(prefix string) string {
-	id := os.Getenv("ACORN_EXTERNAL_ID")
-	id = strings.ReplaceAll(id, ".", "")
-
-	if len(id) > 40 {
-		return id[:40]
-	} else {
-		return id
+func ResourceID(clusterName string, prefix string) *string {
+	externalIdHash := md5.Sum([]byte(os.Getenv("ACORN_EXTERNAL_ID")))
+	clusterName = clusterName + "-" + hex.EncodeToString(externalIdHash[:])
+
+	if prefix != "" {
+		clusterName = prefix + "-" + clusterName
+	}
+
+	if len(clusterName) > 40 {
+		clusterName = clusterName[:40]
 	}
+
+	return jsii.String(clusterName)
 }
 
 // GetPrivateSubnetGroup returns a new subnet group for the given elasticache stack
@@ -31,7 +36,7 @@ func GetPrivateSubnetGroup(scope constructs.Construct, name *string, vpc awsec2.
 	}
 
 	subnetGroup := awselasticache.NewCfnSubnetGroup(scope, name, &awselasticache.CfnSubnetGroupProps{
-		CacheSubnetGroupName: jsii.String(ResourceID("Sg")),
+		CacheSubnetGroupName: name,
 		Description:          jsii.String("Acorn created Elasticache subnet group."),
 		SubnetIds:            &privateSubnetIDs,
 	})

elasticache/common_test.go

@@ -0,0 +1,23 @@
+package elasticache
+
+import (
+	"os"
+	"testing"
+)
+
+func TestResourceID(t *testing.T) {
+	err := os.Setenv("ACORN_EXTERNAL_ID", "totally-real-and-cool-external-id-123")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	id := ResourceID("Redis", "Sng")
+	if len(*id) == 0 || len(*id) > 40 {
+		t.Errorf("invalid ID %s", *id)
+	}
+
+	idAgain := ResourceID("Redis", "Sng")
+	if *id != *idAgain {
+		t.Error("expected matching IDs")
+	}
+}

elasticache/redis/Acornfile

@@ -1,29 +1,10 @@
 name:        "AWS Elasticache Redis"
 description: "Amazon's Redis compatible Elasticache cluster"
 info:        "\(localData.info)"
-readme: 		 "./README.md"
-
-localData: info: """
-		## How To Use ([examples](https://github.com/acorn-io/aws/tree/main/elasticache/redis/examples))
-
-		1) Link your app with this acorn via an `external` service named "redis".
-
-		```typescript
-				 services: redis: {
-						external: "@{acorn.name}"
-				 }
-				 containers: app: {
-						build: context: "./"
-						ports: publish: ["8080/http"]
-						env: {
-								REDIS_URL: "redis://:@{@{service.}redis.secrets.admin.token}@{@{service.}redis.address}:@{@{service.}redis.port}/0"
-						 }
-				 }
-		```
-		"""
+readme:      "./README.md"
 
 args: {
-	// Name assigned to the cluster during creation. Default value is "RedisCluster".
+	// Name assigned to the cluster during creation alongside a unique ID. Default value is "Redis".
 	clusterName: "Redis"
 
 	// Key value pairs to apply to all resources.
@@ -37,6 +18,9 @@ args: {
 
 	// The number of cache nodes used in the elasticache cluster. Default value is 1. Automatic failover is enabled for values >1. Cluster mode is disabled so its a single primary with read replicas.
 	numNodes: 1
+
+	// Do not take a final snapshot on delete or update and replace operations. Default value is false. If skip is enabled your data since last snapshot will be gone forever if deleted or replaced.
+	skipSnapshotOnDelete: false
 }
 
 services: admin: {
@@ -113,3 +97,24 @@ secrets: "aws-context": {
 		"aws-region": ""
 	}
 }
+
+localData: info: """
+	## How To Use ([examples](https://github.com/acorn-io/aws/tree/main/elasticache/redis/examples))
+
+	1) Link your app with this acorn via an `external` service named "redis".
+
+	```typescript
+			 services: redis: {
+					external: "@{acorn.name}"
+			 }
+			 containers: app: {
+					build: context: "./"
+					ports: publish: ["8080/http"]
+					env: {
+							REDIS_HOST: "@{@{service.}redis.address}"
+							REDIS_PORT: "@{@{service.}redis.data.port}"
+							REDIS_PASSWORD: "@{@{service.}redis.secrets.admin.token}"
+					 }
+			 }
+	```
+	"""

elasticache/redis/examples/echo-app/Acornfile

@@ -1,22 +1,16 @@
 services: redis: build: {
-	context: "../../"
+	context:   "../../"
 	acornfile: "../../Acornfile"
 }
 
-containers: {
-    app: {
-        build: {
-            context: "."
-        }
-        ports: publish: ["5000/http"]
-        if args.dev {
-            dirs: {
-                "/src": "./"
-            }
-        }
-        env: {
-        		REDIS_HOST: "@{service.redis.address}"
-            REDIS_PASSWORD: "@{service.redis.secrets.admin.token}"
-        }
-    }
+containers: app: {
+	build: context: "."
+	ports: publish: ["5000/http"]
+	if args.dev {
+		dirs: "/src": "./"
+	}
+	env: {
+		REDIS_HOST:     "@{service.redis.address}"
+		REDIS_PASSWORD: "@{service.redis.secrets.admin.token}"
+	}
 }

elasticache/redis/redis.go

@@ -14,10 +14,11 @@ import (
 
 type redisStackProps struct {
 	awscdk.StackProps
-	ClusterName string            `json:"clusterName" yaml:"clusterName"`
-	UserTags    map[string]string `json:"tags" yaml:"tags"`
-	NodeType    string            `json:"nodeType" yaml:"nodeType"`
-	NumNodes    int               `json:"numNodes" yaml:"numNodes"`
+	ClusterName          string            `json:"clusterName" yaml:"clusterName"`
+	UserTags             map[string]string `json:"tags" yaml:"tags"`
+	NodeType             string            `json:"nodeType" yaml:"nodeType"`
+	NumNodes             int               `json:"numNodes" yaml:"numNodes"`
+	SkipSnapshotOnDelete bool              `json:"skipSnapshotOnDelete" yaml:"skipSnapshotOnDelete"`
 }
 
 // NewRedisStack creates the new Redis stack
@@ -36,10 +37,10 @@ func NewRedisStack(scope constructs.Construct, id string, props *redisStackProps
 	})
 
 	// get the subnet group
-	subnetGroup := elasticache.GetPrivateSubnetGroup(stack, jsii.String(props.ClusterName+"SubnetGroup"), vpc)
+	subnetGroup := elasticache.GetPrivateSubnetGroup(stack, elasticache.ResourceID(props.ClusterName, "Sng"), vpc)
 
 	// get the security group
-	sg := common.GetAllowAllVPCSecurityGroup(stack, jsii.String(props.ClusterName+"SecurityGroup"), jsii.String("Acorn generated Elasticache security group"), vpc, 6379)
+	sg := common.GetAllowAllVPCSecurityGroup(stack, elasticache.ResourceID(props.ClusterName, "Scg"), jsii.String("Acorn generated Elasticache security group"), vpc, 6379)
 
 	vpcSecurityGroupIDs := make([]*string, 0)
 	vpcSecurityGroupIDs = append(vpcSecurityGroupIDs, sg.SecurityGroupId())
@@ -58,7 +59,7 @@ func NewRedisStack(scope constructs.Construct, id string, props *redisStackProps
 	// it might seem like creating a replication group is not the same as creating a cluster
 	// but actually it creates the cluster and the replication group in one go
 	redisRG := awselasticache.NewCfnReplicationGroup(stack, jsii.String(props.ClusterName), &awselasticache.CfnReplicationGroupProps{
-		ReplicationGroupId:          jsii.String(elasticache.ResourceID("Rg")),
+		ReplicationGroupId:          elasticache.ResourceID(props.ClusterName, ""),
 		ReplicationGroupDescription: jsii.String("Acorn created Redis replication group"),
 		Engine:                      jsii.String("redis"),
 		CacheNodeType:               jsii.String(props.NodeType),
@@ -71,8 +72,20 @@ func NewRedisStack(scope constructs.Construct, id string, props *redisStackProps
 		SecurityGroupIds:         &vpcSecurityGroupIDs,
 		AuthToken:                token.SecretValue().ToString(),
 		Port:                     jsii.Number(6379),
+		SnapshotRetentionLimit:   jsii.Number(1), // how many days to retain snapshots
 	})
 
+	// indicate that the subnet group depends on the cluster
+	// this prevents deletion errors caused by attempted subnet group deletes while the cluster still exists
+	redisRG.AddDependency(subnetGroup)
+
+	if !props.SkipSnapshotOnDelete {
+		// indicate that the cluster should be backed up before deletion
+		redisRG.ApplyRemovalPolicy(awscdk.RemovalPolicy_SNAPSHOT, &awscdk.RemovalPolicyOptions{
+			ApplyToUpdateReplacePolicy: jsii.Bool(true),
+		})
+	}
+
 	// output the cluster details
 	awscdk.NewCfnOutput(stack, jsii.String("clustername"), &awscdk.CfnOutputProps{
 		Value: jsii.String(props.ClusterName),