Add roleArn: config, support external IAM role.

src/aws/target.ts

@@ -19,9 +19,18 @@ export default class Target extends Resource {
 
     const nameTarget = this.name.target(this.read)
     const nameRole = this.name.role()
+    const roleArn = this.options.roleArn
     const nameDimension = this.name.dimension(this.read)
 
-    const DependsOn = [ this.options.table, nameRole ].concat(this.dependencies)
+    const DependsOn = [ this.options.table ].concat(this.dependencies)
+
+    let accessRoleArn: any = { 'Fn::GetAtt': [ nameRole, 'Arn' ] }
+
+    if (!!roleArn) {
+      accessRoleArn = `'${roleArn}'`
+    } else {
+      DependsOn.concat(nameRole)
+    }
 
     return {
       [nameTarget]: {
@@ -30,7 +39,7 @@ export default class Target extends Resource {
           MaxCapacity: this.max,
           MinCapacity: this.min,
           ResourceId: { 'Fn::Join': [ '', resource ] },
-          RoleARN: { 'Fn::GetAtt': [ nameRole, 'Arn' ] },
+          RoleARN: accessRoleArn,
           ScalableDimension: nameDimension,
           ServiceNamespace: 'dynamodb'
         },

src/plugin.ts

@@ -106,9 +106,13 @@ class AWSDBAutoScaling {
     )
 
     // Add role to manage Auto Scaling policies
-    const resources: any[] = [
-      new Role(options)
-    ]
+    const resources: any[] = []
+
+    if (!config.roleArn) {
+      resources.push(new Role(options))
+    } else {
+      options.roleArn = config.roleArn
+    }
 
     // Only add Auto Scaling for read capacity if configuration set is available
     if (!!config.read) {

vendor/main.d.ts

@@ -2,6 +2,7 @@ declare interface Capacity {
   table: string | string[]
   index: string | string[]
   indexOnly?: boolean
+  roleArn?: string
   write?: CapacityConfiguration
   read?: CapacityConfiguration
 }
@@ -18,6 +19,7 @@ declare interface Options {
   service: string
   stage: string
   table: string
+  roleArn?: string
 }
 
 /**
@@ -29,4 +31,4 @@ declare namespace Serverless {
       capacities: Capacity[]
     }
   }
-}
+}