feat(codestarconnection): add fromCodestartConnectionArn static method (#10)

* feat(codestarconnection): add fromCodestartConnectionArn static method

with this method, we can create a codestar connection class from an exising arn

* docs(codestarconnection): fix js-doc documentation

the name of the imported resource arn was wrong. This comes from a comment in code review

ISSUES CLOSED: 7

Author: antonio-marquez-perez

API.md

@@ -426,6 +426,28 @@ export interface CodeStarConnectionProps {
  *   }
  */
 export class CodeStarConnection extends CodeStarConnectionBase {
+  /**
+   * Import an externally defined Code Star Connection using its ARN.
+   *
+   * @param scope  the construct that will "own" the imported key.
+   * @param id     the id of the imported code star conection in the construct tree.
+   * @param codestarConnectionArn the ARN of an existing Code Star Connection.
+   */
+  public static fromCodeStarConnectionArn(
+    scope: Construct,
+    id: string,
+    codestarConnectionArn: string
+  ): ICodeStarConnection {
+    class Import extends CodeStarConnectionBase {
+      public connectionName = '';
+      public connectionArn = codestarConnectionArn;
+    }
+
+    return new Import(scope, id, {
+      environmentFromArn: codestarConnectionArn,
+    });
+  }
+
   public readonly connectionName: string;
   public readonly connectionArn: string;
 

src/code-star-connection.ts

@@ -225,3 +225,36 @@ describe('Grants permisions', () => {
     });
   });
 });
+
+describe('Static methods', () => {
+  it('should return a instance of code star connection and use the grantUse method', () => {
+    // GIVEN
+    const app = new App();
+    const stack = new Stack(app, 'TestStack');
+
+    // WHEN
+    const codestarConnection = CodeStarConnection.fromCodeStarConnectionArn(
+      stack,
+      'CodeStarConnectionFromArn',
+      'arn:aws:codestar-connections:eu-west-1:123456789012:connection/8c86942e-a7ca-4a4a-8b63-e2f7f5efaeee'
+    );
+
+    const role = new Role(stack, 'Role', {
+      assumedBy: new AnyPrincipal(),
+    });
+
+    codestarConnection.grantUse(role);
+
+    Template.fromStack(stack).hasResourceProperties('AWS::IAM::Policy', {
+      PolicyDocument: {
+        Statement: [
+          {
+            Action: CodeStarConnectionPolicyActions.USE_CONNECTION,
+            Effect: 'Allow',
+            Resource: codestarConnection.connectionArn,
+          },
+        ],
+      },
+    });
+  });
+});