feat(events-targets): add CloudWatch LogGroup Target

packages/@aws-cdk/aws-events-targets/README.md

@@ -23,7 +23,48 @@ Currently supported are:
 * Queue a Batch job
 * Make an AWS API call
 * Put a record to a Kinesis stream
+* Log an event into a LogGroup
 
 See the README of the `@aws-cdk/aws-events` library for more information on
 EventBridge.
 
+## LogGroup
+
+Use the `LogGroup` target to log your events in a CloudWatch LogGroup.
+
+The LogGroup name must start with `/aws/events/`.
+
+```ts
+const rule = new Rule(this, 'rule', {
+  eventPattern: {
+    source: [stack.account],
+  },
+});
+
+const logGroup = new LogGroup(this, 'MyLogGroup', {
+  logGroupName: '/aws/events/MyLogGroup',
+});
+
+rule.addTarget(targets.LogGroup(logGroup));
+```
+
+You can also use an [InputTransformer](https://docs.aws.amazon.com/eventbridge/latest/APIReference/API_InputTransformer.html).
+
+```ts
+const rule = new Rule(this, 'rule', {
+  eventPattern: {
+    source: [stack.account],
+  },
+});
+
+const logGroup = new LogGroup(this, 'MyLogGroup', {
+  logGroupName: '/aws/events/MyLogGroup',
+});
+
+rule.addTarget(new targets.LogGroup(logGroup, {
+  event: events.RuleTargetInput.fromObject({
+    status: events.EventField.fromPath('$.detail.status'),
+    instanceId: events.EventField.fromPath('$.detail.instance-id'),
+  })
+}));
+```

packages/@aws-cdk/aws-events-targets/lib/index.ts

@@ -9,3 +9,4 @@ export * from './ecs-task-properties';
 export * from './ecs-task';
 export * from './state-machine';
 export * from './kinesis-stream';
+export * from './log-group';

packages/@aws-cdk/aws-events-targets/lib/log-group.ts

@@ -0,0 +1,40 @@
+import * as events from '@aws-cdk/aws-events';
+import * as logs from '@aws-cdk/aws-logs';
+import { Token } from '@aws-cdk/core';
+/**
+ * Customize the CloudWatch LogGroup Event Target
+ */
+export interface LogGroupProps {
+  /**
+   * The event to send to the CloudWatch LogGroup
+   *
+   * This will be the event logged into the CloudWatch LogGroup
+   *
+   * @default - the entire EventBridge event
+   */
+  readonly event?: events.RuleTargetInput;
+}
+
+/**
+ * Use an AWS CloudWatch LogGroup as an event rule target.
+ *
+ * The LogGroup name must start with /aws/events/.
+ */
+export class LogGroup implements events.IRuleTarget {
+  constructor(private readonly logGroup: logs.ILogGroup, private readonly props: LogGroupProps = {}) {}
+
+  /**
+   * Returns a RuleTarget that can be used to log an event into a CloudWatch LogGroup
+   */
+  public bind(_rule: events.IRule, _id?: string): events.RuleTargetConfig {
+    if (!Token.isUnresolved(this.logGroup.logGroupName) && !this.logGroup.logGroupName.startsWith('/aws/events/')) {
+      throw new Error('Target LogGroup name must start with "/aws/events/"');
+    }
+
+    return {
+      id: '',
+      arn: `arn:aws:logs:${this.logGroup.stack.region}:${this.logGroup.stack.account}:log-group:${this.logGroup.logGroupName}`,
+      input: this.props.event,
+    };
+  }
+}

packages/@aws-cdk/aws-events-targets/package.json

@@ -81,39 +81,41 @@
     "pkglint": "0.0.0"
   },
   "dependencies": {
+    "@aws-cdk/aws-batch": "0.0.0",
     "@aws-cdk/aws-codebuild": "0.0.0",
     "@aws-cdk/aws-codepipeline": "0.0.0",
     "@aws-cdk/aws-ec2": "0.0.0",
     "@aws-cdk/aws-ecs": "0.0.0",
     "@aws-cdk/aws-events": "0.0.0",
     "@aws-cdk/aws-iam": "0.0.0",
+    "@aws-cdk/aws-kinesis": "0.0.0",
     "@aws-cdk/aws-lambda": "0.0.0",
+    "@aws-cdk/aws-logs": "0.0.0",
     "@aws-cdk/aws-sns": "0.0.0",
     "@aws-cdk/aws-sns-subscriptions": "0.0.0",
     "@aws-cdk/aws-sqs": "0.0.0",
     "@aws-cdk/aws-stepfunctions": "0.0.0",
-    "@aws-cdk/aws-batch": "0.0.0",
-    "@aws-cdk/aws-kinesis": "0.0.0",
     "@aws-cdk/core": "0.0.0",
     "constructs": "^3.0.4"
   },
   "homepage": "https://github.com/aws/aws-cdk",
   "peerDependencies": {
+    "@aws-cdk/aws-batch": "0.0.0",
     "@aws-cdk/aws-codebuild": "0.0.0",
     "@aws-cdk/aws-codepipeline": "0.0.0",
     "@aws-cdk/aws-ec2": "0.0.0",
     "@aws-cdk/aws-ecs": "0.0.0",
     "@aws-cdk/aws-events": "0.0.0",
     "@aws-cdk/aws-iam": "0.0.0",
+    "@aws-cdk/aws-kinesis": "0.0.0",
     "@aws-cdk/aws-lambda": "0.0.0",
+    "@aws-cdk/aws-logs": "0.0.0",
     "@aws-cdk/aws-sns": "0.0.0",
     "@aws-cdk/aws-sns-subscriptions": "0.0.0",
     "@aws-cdk/aws-sqs": "0.0.0",
     "@aws-cdk/aws-stepfunctions": "0.0.0",
-    "@aws-cdk/aws-batch": "0.0.0",
     "@aws-cdk/core": "0.0.0",
-    "constructs": "^3.0.4",
-    "@aws-cdk/aws-kinesis": "0.0.0"
+    "constructs": "^3.0.4"
   },
   "engines": {
     "node": ">= 10.13.0 <13 || >=13.7.0"

packages/@aws-cdk/aws-events-targets/test/logs/integ.log-group.expected.json

@@ -0,0 +1,81 @@
+{
+  "Resources": {
+    "loggroupB02AAEB1": {
+      "Type": "AWS::Logs::LogGroup",
+      "Properties": {
+        "LogGroupName": "/aws/events/MyLogGroupName",
+        "RetentionInDays": 731
+      },
+      "UpdateReplacePolicy": "Retain",
+      "DeletionPolicy": "Retain"
+    },
+    "TimerBF6F831F": {
+      "Type": "AWS::Events::Rule",
+      "Properties": {
+        "ScheduleExpression": "rate(1 minute)",
+        "State": "ENABLED",
+        "Targets": [
+          {
+            "Arn": {
+              "Fn::Join": [
+                "",
+                [
+                  "arn:aws:logs:",
+                  {
+                    "Ref": "AWS::Region"
+                  },
+                  ":",
+                  {
+                    "Ref": "AWS::AccountId"
+                  },
+                  ":log-group:",
+                  {
+                    "Ref": "loggroupB02AAEB1"
+                  }
+                ]
+              ]
+            },
+            "Id": "Target0"
+          }
+        ]
+      }
+    },
+    "Timer2B6F162E9": {
+      "Type": "AWS::Events::Rule",
+      "Properties": {
+        "ScheduleExpression": "rate(2 minutes)",
+        "State": "ENABLED",
+        "Targets": [
+          {
+            "Arn": {
+              "Fn::Join": [
+                "",
+                [
+                  "arn:aws:logs:",
+                  {
+                    "Ref": "AWS::Region"
+                  },
+                  ":",
+                  {
+                    "Ref": "AWS::AccountId"
+                  },
+                  ":log-group:",
+                  {
+                    "Ref": "loggroupB02AAEB1"
+                  }
+                ]
+              ]
+            },
+            "Id": "Target0",
+            "InputTransformer": {
+              "InputPathsMap": {
+                "f1": "$"
+              },
+              "InputTemplate": "{\"data\":<f1>}"
+            }
+          }
+        ]
+      }
+    }
+  }
+}

packages/@aws-cdk/aws-events-targets/test/logs/integ.log-group.ts

@@ -0,0 +1,29 @@
+import * as events from '@aws-cdk/aws-events';
+import * as logs from '@aws-cdk/aws-logs';
+import * as cdk from '@aws-cdk/core';
+import * as targets from '../../lib';
+
+const app = new cdk.App();
+
+const stack = new cdk.Stack(app, 'log-group-events');
+
+const logGroup = new logs.LogGroup(stack, 'log-group', {
+  logGroupName: '/aws/events/MyLogGroupName',
+});
+
+const timer = new events.Rule(stack, 'Timer', {
+  schedule: events.Schedule.rate(cdk.Duration.minutes(1)),
+});
+timer.addTarget(new targets.LogGroup(logGroup));
+
+const timer2 = new events.Rule(stack, 'Timer2', {
+  schedule: events.Schedule.rate(cdk.Duration.minutes(2)),
+});
+timer2.addTarget(new targets.LogGroup(logGroup, {
+  event: events.RuleTargetInput.fromObject({
+    data: events.EventField.fromPath('$'),
+  }),
+}));
+
+app.synth();
+

packages/@aws-cdk/aws-events-targets/test/logs/log-group.test.ts

@@ -0,0 +1,123 @@
+import '@aws-cdk/assert/jest';
+import * as events from '@aws-cdk/aws-events';
+import * as logs from '@aws-cdk/aws-logs';
+import * as cdk from '@aws-cdk/core';
+import * as targets from '../../lib';
+
+
+test('use log group as an event rule target', () => {
+  // GIVEN
+  const stack = new cdk.Stack();
+  const logGroup = new logs.LogGroup(stack, 'MyLogGroup', {
+    logGroupName: '/aws/events/MyLogGroup',
+  });
+  const rule1 = new events.Rule(stack, 'Rule', {
+    schedule: events.Schedule.rate(cdk.Duration.minutes(1)),
+  });
+
+  // WHEN
+  rule1.addTarget(new targets.LogGroup(logGroup));
+
+  // THEN
+  expect(stack).toHaveResource('AWS::Events::Rule', {
+    ScheduleExpression: 'rate(1 minute)',
+    State: 'ENABLED',
+    Targets: [
+      {
+        Arn: {
+          'Fn::Join': [
+            '',
+            [
+              'arn:aws:logs:',
+              {
+                Ref: 'AWS::Region',
+              },
+              ':',
+              {
+                Ref: 'AWS::AccountId',
+              },
+              ':log-group:',
+              {
+                Ref: 'MyLogGroup5C0DAD85',
+              },
+            ],
+          ],
+        },
+        Id: 'Target0',
+      },
+    ],
+  });
+});
+
+
+test.only('log group used as an event rule target must have a name starting with "/aws/events/"', () => {
+  // GIVEN
+  const logGroupName = '/awdss/events/MyLogGroup';
+  const stack = new cdk.Stack();
+
+  const rule1 = new events.Rule(stack, 'Rule', {
+    schedule: events.Schedule.rate(cdk.Duration.minutes(1)),
+  });
+
+  // WHEN
+  let addTargetWrapper = () => {
+    rule1.addTarget(new targets.LogGroup(logs.LogGroup.fromLogGroupName(stack, 'MyLogGroupImported', logGroupName)));
+  };
+
+  // THEN
+  expect(addTargetWrapper).toThrowError('Target LogGroup name must start with "/aws/events/"');
+});
+
+test('use log group as an event rule target with rule target input', () => {
+  // GIVEN
+  const stack = new cdk.Stack();
+  const logGroup = new logs.LogGroup(stack, 'MyLogGroup', {
+    logGroupName: '/aws/events/MyLogGroup',
+  });
+  const rule1 = new events.Rule(stack, 'Rule', {
+    schedule: events.Schedule.rate(cdk.Duration.minutes(1)),
+  });
+
+  // WHEN
+  rule1.addTarget(new targets.LogGroup(logGroup, {
+    event: events.RuleTargetInput.fromObject({
+      data: events.EventField.fromPath('$'),
+    }),
+  }));
+
+  // THEN
+  expect(stack).toHaveResource('AWS::Events::Rule', {
+    ScheduleExpression: 'rate(1 minute)',
+    State: 'ENABLED',
+    Targets: [
+      {
+        Arn: {
+          'Fn::Join': [
+            '',
+            [
+              'arn:aws:logs:',
+              {
+                Ref: 'AWS::Region',
+              },
+              ':',
+              {
+                Ref: 'AWS::AccountId',
+              },
+              ':log-group:',
+              {
+                Ref: 'MyLogGroup5C0DAD85',
+              },
+            ],
+          ],
+        },
+        Id: 'Target0',
+        InputTransformer: {
+          InputPathsMap: {
+            f1: '$',
+          },
+          InputTemplate: '{"data":<f1>}',
+        },
+      },
+    ],
+  });
+});

packages/@aws-cdk/aws-events/README.md

@@ -28,7 +28,7 @@ event when the pipeline changes it's state.
   Service](https://docs.aws.amazon.com/eventbridge/latest/userguide/event-types.html).
 * __Targets__: A target processes events. Targets can include Amazon EC2
   instances, AWS Lambda functions, Kinesis streams, Amazon ECS tasks, Step
-  Functions state machines, Amazon SNS topics, Amazon SQS queues, and built-in
+  Functions state machines, Amazon SNS topics, Amazon SQS queues, Amazon CloudWatch LogGroups, and built-in
   targets. A target receives events in JSON format.
 * __Rules__: A rule matches incoming events and routes them to targets for
   processing. A single rule can route to multiple targets, all of which are