feat(cli): write stack outputs to a file

packages/aws-cdk/README.md

@@ -162,6 +162,60 @@ $ cdk deploy --parameters "ParametersStack:TopicNameParam=blahagain" --force
 
 ⚠️ Parameters do not propagate to NestedStacks. These must be sent with the constructor. See Nested Stack [documentation](https://docs.aws.amazon.com/cdk/api/latest/docs/@aws-cdk_aws-cloudformation.NestedStack.html)
 
+##### Outputs
+
+Write stack outputs from deployments into a file. When your stack finishes deploying, all stack outputs will be written to the output file as JSON.
+
+Usage of output in a CDK stack
+```typescript
+const fn = new lambda.Function(this, "fn", {
+      handler: "index.handler",
+      code: lambda.Code.fromInline(`exports.handler = \${handler.toString()}`),
+      runtime: lambda.Runtime.NODEJS_10_X
+    });
+
+    new cdk.CfnOutput(this, 'FunctionArn', {
+      value: fn.functionArn,
+    });
+```
+
+Specify an outputs file to write to by supplying the `--outputs-file` parameter
+
+```console
+$ cdk deploy --outputs-file "/Users/code/myproject/outputs.json"
+```
+
+When the stack finishes deployment, `outputs.json` would look like.
+```json
+{
+  "MyStack": {
+    "FunctionArn": "arn:aws:lambda:us-east-1:123456789012:function:MyStack-fn5FF616E3-G632ITHSP5HK"
+  }
+}
+```
+
+⚠️ The `key` of the outputs corresponds to the logical ID.
+Read more about identifiers in the CDK [here](https://docs.aws.amazon.com/cdk/latest/guide/identifiers.html)
+
+If multiple stacks are being deployed or the wild card `*` is used to deploy all stacks, all outputs are written to the same output file where each stack artifact ID is a key in the JSON file
+
+
+```console
+$ cdk deploy '*' --outputs-file "/Users/code/myproject/outputs.json"
+```
+
+Example `outputs.json` after deployment of multiple stacks
+```json
+{
+  "MyStack": {
+    "FunctionArn": "arn:aws:lambda:us-east-1:123456789012:function:MyStack-fn5FF616E3-G632ITHSP5HK"
+  },
+  "AnotherStack": {
+    "VPCId": "vpc-z0mg270fee16693f"
+  }  
+}
+```
+
 #### `cdk destroy`
 Deletes a stack from it's environment. This will cause the resources in the stack to be destroyed (unless they were
 configured with a `DeletionPolicy` of `Retain`). During the stack destruction, the command will output progress

packages/aws-cdk/bin/cdk.ts

@@ -71,6 +71,7 @@ async function parseCommandLineArguments() {
       .option('execute', { type: 'boolean', desc: 'Whether to execute ChangeSet (--no-execute will NOT execute the ChangeSet)', default: true })
       .option('force', { alias: 'f', type: 'boolean', desc: 'Always deploy stack even if templates are identical', default: false })
       .option('parameters', { type: 'array', desc: 'Additional parameters passed to CloudFormation at deploy time (STACK:KEY=VALUE)', nargs: 1, requiresArg: true, default: {} })
+      .option('outputs-file', { type: 'string', alias: 'O', desc: 'Path to file where stack outputs will be written as JSON', requiresArg: true })
     )
     .command('destroy [STACKS..]', 'Destroy the stack(s) named STACKS', yargs => yargs
       .option('exclusively', { type: 'boolean', alias: 'e', desc: 'Only destroy requested stacks, don\'t include dependees' })
@@ -238,7 +239,8 @@ async function initCommandLine() {
           sdk: aws,
           execute: args.execute,
           force: args.force,
-          parameters: parameterMap
+          parameters: parameterMap,
+          outputsFile: args.outputsFile
         });
 
       case 'destroy':

packages/aws-cdk/lib/cdk-toolkit.ts

@@ -100,6 +100,9 @@ export class CdkToolkit {
       }
     }
 
+    const stackOutputs: {[key: string]: any } = {};
+    const outputsFile = options.outputsFile;
+
     for (const stack of stacks) {
       if (stacks.length !== 1) { highlight(stack.displayName); }
       if (!stack.environment) {
@@ -170,6 +173,8 @@ export class CdkToolkit {
 
         if (Object.keys(result.outputs).length > 0) {
           print('\nOutputs:');
+
+          stackOutputs[stack.stackName] = result.outputs;
         }
 
         for (const name of Object.keys(result.outputs)) {
@@ -183,6 +188,17 @@ export class CdkToolkit {
       } catch (e) {
         error('\n ❌  %s failed: %s', colors.bold(stack.displayName), e);
         throw e;
+      } finally {
+        // If an outputs file has been specified, create the file path and write stack outputs to it once.
+        // Outputs are written after all stacks have been deployed. If a stack deployment fails,
+        // all of the outputs from successfully deployed stacks before the failure will still be written.
+        if (outputsFile) {
+          fs.ensureFileSync(outputsFile);
+          fs.writeJson(outputsFile, stackOutputs, {
+            spaces: 2,
+            encoding: 'utf8'
+          });
+        }
       }
     }
   }
@@ -337,6 +353,12 @@ export interface DeployOptions {
    * @default {}
    */
   parameters?: { [name: string]: string | undefined };
+
+  /**
+   * Path to file where stack outputs will be written after a successful deploy as JSON
+   * @default - Outputs are not written to any file
+   */
+  outputsFile?: string;
 }
 
 export interface DestroyOptions {

packages/aws-cdk/test/integ/cli/app/app.js

@@ -61,6 +61,34 @@ class OtherParameterStack extends cdk.Stack {
   }
 }
 
+class OutputsStack extends cdk.Stack {
+  constructor(parent, id, props) {
+    super(parent, id, props);
+
+    const topic =  new sns.Topic(this, 'MyOutput', {
+      topicName: 'MyTopic'
+    });
+
+    new cdk.CfnOutput(this, 'TopicName', {
+      value: topic.topicName
+    })
+  }
+}
+
+class AnotherOutputsStack extends cdk.Stack {
+  constructor(parent, id, props) {
+    super(parent, id, props);
+
+    const topic = new sns.Topic(this, 'MyOtherOutput', {
+      topicName: 'MyOtherTopic'
+    });
+
+    new cdk.CfnOutput(this, 'TopicName', {
+      value: topic.topicName
+    });
+  }
+}
+
 class IamStack extends cdk.Stack {
   constructor(parent, id, props) {
     super(parent, id, props);
@@ -208,6 +236,9 @@ new YourStack(app, `${stackPrefix}-test-2`);
 // Deploy wildcard with parameters does ${stackPrefix}-param-test-*
 new ParameterStack(app, `${stackPrefix}-param-test-1`);
 new OtherParameterStack(app, `${stackPrefix}-param-test-2`);
+// Deploy stack with outputs does ${stackPrefix}-outputs-test-*
+new OutputsStack(app, `${stackPrefix}-outputs-test-1`);
+new AnotherOutputsStack(app, `${stackPrefix}-outputs-test-2`);
 // Not included in wildcard
 new IamStack(app, `${stackPrefix}-iam-test`);
 const providing = new ProvidingStack(app, `${stackPrefix}-order-providing`);

packages/aws-cdk/test/integ/cli/cdk-deploy-wildcard-with-outputs-expected.json

@@ -0,0 +1,8 @@
+{
+  "cdk-toolkit-integration-outputs-test-1": {
+    "TopicName": "MyTopic"
+  },
+  "cdk-toolkit-integration-outputs-test-2": {
+    "TopicName": "MyOtherTopic"
+  }
+}

packages/aws-cdk/test/integ/cli/cdk-deploy-with-outputs-expected.json

@@ -0,0 +1,5 @@
+{
+  "cdk-toolkit-integration-outputs-test-1": {
+    "TopicName": "MyTopic"
+  }
+}

packages/aws-cdk/test/integ/cli/common.bash

@@ -93,6 +93,8 @@ function cleanup() {
   cleanup_stack ${STACK_NAME_PREFIX}-test-2
   cleanup_stack ${STACK_NAME_PREFIX}-iam-test
   cleanup_stack ${STACK_NAME_PREFIX}-with-nested-stack
+  cleanup_stack ${STACK_NAME_PREFIX}-outputs-test-1
+  cleanup_stack ${STACK_NAME_PREFIX}-outputs-test-2
 }
 
 function setup() {

packages/aws-cdk/test/integ/cli/test-cdk-deploy-wildcard-with-outputs.sh

@@ -0,0 +1,28 @@
+#!/bin/bash
+set -euo pipefail
+scriptdir=$(cd $(dirname $0) && pwd)
+source ${scriptdir}/common.bash
+# ----------------------------------------------------------
+
+setup
+
+outputs_file=${integ_test_dir}/outputs/outputs.json
+expected_outputs=${scriptdir}/cdk-deploy-wildcard-with-outputs-expected.json
+
+# deploy all outputs stacks
+cdk deploy ${STACK_NAME_PREFIX}-outputs-test-\* --outputs-file ${outputs_file}
+echo "Stacks deployed successfully"
+
+# verify generated outputs file
+generated_outputs_file="$(cat ${outputs_file})"
+expected_outputs_file="$(cat ${expected_outputs})"
+if [[ "${generated_outputs_file}" != "${expected_outputs_file}" ]]; then
+    fail "unexpected outputs. Expected: ${expected_outputs_file} Actual: ${generated_outputs_file}"
+fi 
+
+# destroy
+rm ${outputs_file}
+cdk destroy -f ${STACK_NAME_PREFIX}-outputs-test-1
+cdk destroy -f ${STACK_NAME_PREFIX}-outputs-test-2
+
+echo "✅  success"

packages/aws-cdk/test/integ/cli/test-cdk-deploy-with-outputs.sh

@@ -0,0 +1,26 @@
+#!/bin/bash
+set -euo pipefail
+scriptdir=$(cd $(dirname $0) && pwd)
+source ${scriptdir}/common.bash
+# ----------------------------------------------------------
+
+setup
+
+outputs_file=${integ_test_dir}/outputs/outputs.json
+expected_outputs=${scriptdir}/cdk-deploy-with-outputs-expected.json
+
+cdk deploy -v ${STACK_NAME_PREFIX}-outputs-test-1 --outputs-file ${outputs_file}
+echo "Stack deployed successfully"
+
+# verify generated outputs file
+generated_outputs_file="$(cat ${outputs_file})"
+expected_outputs_file="$(cat ${expected_outputs})"
+if [[ "${generated_outputs_file}" != "${expected_outputs_file}" ]]; then
+    fail "unexpected outputs. Expected: ${expected_outputs_file} Actual: ${generated_outputs_file}"
+fi 
+
+# destroy
+rm ${outputs_file}
+cdk destroy -f ${STACK_NAME_PREFIX}-outputs-test-1
+
+echo "✅  success"

packages/aws-cdk/test/integ/cli/test-cdk-ls.sh

@@ -15,6 +15,8 @@ ${STACK_NAME_PREFIX}-iam-test
 ${STACK_NAME_PREFIX}-lambda
 ${STACK_NAME_PREFIX}-missing-ssm-parameter
 ${STACK_NAME_PREFIX}-order-providing
+${STACK_NAME_PREFIX}-outputs-test-1
+${STACK_NAME_PREFIX}-outputs-test-2
 ${STACK_NAME_PREFIX}-param-test-1
 ${STACK_NAME_PREFIX}-param-test-2
 ${STACK_NAME_PREFIX}-test-1