feat: added CloudWatchEvents client

Closes getndazn#135

packages/lambda-powertools-cloudwatchevents-client/README.md

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+# lambda-powertools-cloudwatchevents-client
+
+CloudWatchEvents client wrapper that knows how to forward correlation IDs (captured via `@dazn/lambda-powertools-correlation-ids`).
+
+Main features:
+
+* auto-injects correlation IDs into the CloudWatchEvents events when you call `putEvents`
+
+* direct replacement for `AWS.CloudWatchEvents` client
+
+## Getting Started
+
+Install from NPM: `npm install @dazn/lambda-powertools-cloudwatchevents-client`
+
+## API
+
+It's exactly the same as the CloudWatchEvents client from the AWS SDK.
+
+```js
+const CloudWatchEvents = require('@dazn/lambda-powertools-cloudwatchevents-client')
+
+const publishEvents = async () => {
+  const putEventsReq = {
+    Entries: [
+      {
+        Source: "my-source",
+        "Detail-Type": "my-type",
+        Detail: JSON.stringify({ message: 'hello cloudwatchevents' })
+      },
+      {
+        Source: "my-source",
+        "Detail-Type": "my-type",
+        Detail: JSON.stringify({ message: 'hello lambda-powertools' })
+      }
+    ]
+  }
+
+  await CloudWatchEvents.putEvents(putEventsReq).promise()
+}
+```

packages/lambda-powertools-cloudwatchevents-client/__tests__/index.js

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+const AWS = require('aws-sdk')
+
+const mockPutEvents = jest.fn()
+AWS.CloudWatchEvents.prototype.putEvents = mockPutEvents
+
+global.console.log = jest.fn()
+
+const CloudWatchEvents = require('../index')
+const CorrelationIds = require('@dazn/lambda-powertools-correlation-ids')
+
+beforeEach(() => {
+  mockPutEvents.mockReturnValueOnce({
+    promise: async () => Promise.resolve()
+  })
+})
+
+afterEach(() => {
+  mockPutEvents.mockClear()
+
+  CorrelationIds.clearAll()
+})
+
+const verifyPutEventsContext = async (f) => {
+  const eventTypes = [
+    'wrote_test',
+    'ran_test',
+    'pass_test'
+  ]
+  const entries = eventTypes
+    .map(eventType => {
+      const data = { eventType, username: 'theburningmonk' }
+      return {
+        Source: 'test',
+        DetailType: 'test',
+        Detail: JSON.stringify(data)
+      }
+    })
+  const params = {
+    Entries: entries
+  }
+  await CloudWatchEvents.putEvents(params).promise()
+
+  expect(mockPutEvents).toBeCalled()
+  const actualParams = mockPutEvents.mock.calls[0][0]
+  actualParams.Entries.forEach(entry => {
+    const actualDetail = JSON.parse(entry.Detail)
+    f(actualDetail.__context__)
+  })
+}
+
+const verifyPutEventsWithCorrelationIdsContext = async (correlationIds, f) => {
+  const eventTypes = [
+    'wrote_test',
+    'ran_test',
+    'pass_test'
+  ]
+  const entries = eventTypes
+    .map(eventType => {
+      const data = { eventType, username: 'theburningmonk' }
+      return {
+        Source: 'test',
+        DetailType: 'test',
+        Detail: JSON.stringify(data)
+      }
+    })
+  const params = {
+    Entries: entries
+  }
+  await CloudWatchEvents.putEventsWithCorrelationIds(correlationIds, params).promise()
+
+  expect(mockPutEvents).toBeCalled()
+  const actualParams = mockPutEvents.mock.calls[0][0]
+  actualParams.Entries.forEach(entry => {
+    const actualDetail = JSON.parse(entry.Detail)
+    f(actualDetail.__context__)
+  })
+}
+
+describe('CloudWatchEvents client', () => {
+  describe('.putEvents', () => {
+    describe('when there are no correlation IDs', () => {
+      it('sends empty __context__ ', async () => {
+        await verifyPutEventsContext(x => expect(x).toEqual({}))
+      })
+    })
+
+    describe('when there are global correlationIds', () => {
+      it('forwards them in __context__', async () => {
+        const correlationIds = {
+          'x-correlation-id': 'id',
+          'debug-log-enabled': 'true'
+        }
+        CorrelationIds.replaceAllWith(correlationIds)
+
+        await verifyPutEventsContext(x => {
+          expect(x).toEqual({
+            'x-correlation-id': 'id',
+            'debug-log-enabled': 'true'
+          })
+        })
+      })
+    })
+  })
+
+  describe('.putEventsWithCorrelationIds', () => {
+    it('forwards given correlationIds in __context__ field', async () => {
+      const correlationIds = new CorrelationIds({
+        'x-correlation-id': 'child-id',
+        'debug-log-enabled': 'true'
+      })
+
+      await verifyPutEventsWithCorrelationIdsContext(correlationIds, x => {
+        expect(x).toEqual({
+          'x-correlation-id': 'child-id',
+          'debug-log-enabled': 'true'
+        })
+      })
+    })
+  })
+})

packages/lambda-powertools-cloudwatchevents-client/index.js

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+process.env.AWS_NODEJS_CONNECTION_REUSE_ENABLED = '1'
+const CloudWatchEvents = require('aws-sdk/clients/cloudwatchevents')
+const client = new CloudWatchEvents()
+const Log = require('@dazn/lambda-powertools-logger')
+const CorrelationIds = require('@dazn/lambda-powertools-correlation-ids')
+
+function tryJsonParse (data) {
+  if (typeof data !== 'string') {
+    return null
+  }
+
+  try {
+    return JSON.parse(data)
+  } catch (err) {
+    Log.warn('only JSON string data can be modified to insert correlation IDs', null, err)
+    return null
+  }
+}
+
+function addCorrelationIds (correlationIds, data) {
+  // only do this with JSON string data
+  const payload = tryJsonParse(data)
+  if (!payload) {
+    return data
+  }
+
+  const ids = correlationIds.get()
+  const newData = {
+    __context__: ids,
+    ...payload
+  }
+  return JSON.stringify(newData)
+}
+
+client._putEvents = client.putEvents
+
+client.putEvents = (...args) => {
+  return client.putEventsWithCorrelationIds(CorrelationIds, ...args)
+}
+
+client.putEventsWithCorrelationIds = (correlationIds, params, ...args) => {
+  const newEntries = params.Entries.map(entry => {
+    const newDetail = addCorrelationIds(correlationIds, entry.Detail)
+    return {
+      ...entry,
+      Detail: newDetail
+    }
+  })
+
+  const extendedParams = {
+    ...params,
+    Entries: newEntries
+  }
+
+  return client._putEvents(extendedParams, ...args)
+}
+
+module.exports = client

packages/lambda-powertools-cloudwatchevents-client/package.json

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+{
+  "name": "@dazn/lambda-powertools-cloudwatchevents-client",
+  "version": "1.15.6",
+  "description": "CloudWatchEvents client wrapper that knows how to forward correlation IDs (captured via @dazn/lambda-powertools-correlation-ids)",
+  "main": "index.js",
+  "scripts": {
+    "test": "jest"
+  },
+  "dependencies": {
+    "@dazn/lambda-powertools-correlation-ids": "^1.8.2",
+    "@dazn/lambda-powertools-logger": "^1.15.2",
+    "aws-sdk": "^2.540.0"
+  },
+  "license": "MIT",
+  "author": "Yan Cui",
+  "homepage": "https://github.com/getndazn/dazn-lambda-powertools#readme",
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/getndazn/dazn-lambda-powertools.git"
+  },
+  "bugs": {
+    "url": "https://github.com/getndazn/dazn-lambda-powertools/issues"
+  },
+  "publishConfig": {
+    "access": "public"
+  }
+}