feat: add warmup plugin (#57)

* feat: add warmup plugin

* fix: remove old configs

* docs: update readme

* docs: update readme

* docs: update readme

Author: JadTermsani

README.md

@@ -42,10 +42,6 @@ functions:
       - http:
           path: hello
           method: get
-      # Ping every 5 minutes to avoid cold starts
-      - schedule:
-          rate: rate(5 minutes)
-          enabled: true
 ```
 
 Ignoring the scheduling event, you can see here that we're setting up a function named `hello` with a handler at `src/hello.js` (the `.default` piece is just indicating that the function to run will be the default export from that file). The `http` event says that this function will run when an http event is triggered (on AWS, this happens via API Gateway).
@@ -108,27 +104,27 @@ Lambda functions will go "cold" if they haven't been invoked for a certain perio
 A frequently running function won't have this problem, but you can keep your function running hot by scheduling a regular ping to your lambda function. Here's what that looks like in your `serverless.yml`:
 
 ```yaml
-functions:
-  myFunc:
-    handler: src/myFunc.default
-    timeout: 10
-    memorySize: 256
+custom:
+  warmup:
+    enabled: true
     events:
-      # ...other config happening up here and then...
-      # Ping every 5 minutes to avoid cold starts
-      - schedule:
-          rate: rate(5 minutes)
-          enabled: true
+      - schedule: rate(5 minutes)
+    prewarm: true
+    concurrency: 2
 ```
 
+The above config would keep all of your deployed lambda functions running warm. The `prewarm` flag will ensure your function is warmed immediately after deploys (so you don't have to wait five minutes for the first scheduled event). And by setting the `concurrency` to `2`, we're keeping two instances warm for each deployed function.
+
+Under `custom.warmup`, you can set project-wide warmup behaviors. On the other hand, if you want to set function-specific behaviours, you should use the `warmup` key under the select functions. You can browse all the options [here](https://www.npmjs.com/package/serverless-plugin-warmup#configuration).
+
 Your handler function can then handle this event like so:
 
 ```javascript
 const myFunc = (event, context, callback) => {
   // Detect the keep-alive ping from CloudWatch and exit early. This keeps our
   // lambda function running hot.
-  if (event.source === 'aws.events') {
-    // aws.events is the source for Scheduled events
+  if (event.source === 'serverless-plugin-warmup') {
+    // serverless-plugin-warmup is the source for Scheduled events
     return callback(null, 'pinged');
   }
 

package.json

@@ -16,8 +16,7 @@
     "test": "jest",
     "test:watch": "jest --watch",
     "build": "serverless webpack",
-    "watch:hello": "serverless invoke local --watch --function hello --path fixtures/event.json",
-    "watch:warm": "serverless invoke local --watch --function hello --path fixtures/scheduled.json"
+    "watch:hello": "serverless invoke local --watch --function hello --path fixtures/event.json"
   },
   "devDependencies": {
     "@babel/core": "7.3.3",
@@ -41,9 +40,10 @@
     "lint-staged": "^8.0.0",
     "nodemon": "^1.18.9",
     "prettier": "^1.14.2",
-    "serverless": "^1.32.0",
+    "serverless": "^1.40.0",
     "serverless-dotenv-plugin": "^2.0.1",
     "serverless-offline": "^4.0.0",
+    "serverless-plugin-warmup": "^4.5.3-rc.1",
     "serverless-webpack": "^5.2.0",
     "ts-jest": "^24.0.0",
     "ts-loader": "^5.3.1",

serverless.yml

@@ -31,12 +31,23 @@ provider:
   # you can overwrite defaults here
   #  stage: dev
   #  region: us-east-1
+  iamRoleStatements:
+    - Effect: 'Allow'
+      Action:
+        - 'lambda:InvokeFunction'
+      Resource: '*'
 
 custom:
   webpackIncludeModules: true
   webpack:
     webpackConfig: ./webpack.config.js
     packager: 'yarn' # Packager that will be used to package your external modules
+  warmup:
+    enabled: true
+    events:
+      - schedule: rate(5 minutes)
+    prewarm: true
+    concurrency: 1
 
 # you can add statements to the Lambda function's IAM Role here
 #  iamRoleStatements:
@@ -73,20 +84,12 @@ functions:
       - http:
           path: hello-typescript
           method: get
-      # Ping every 5 minutes to avoid cold starts
-      - schedule:
-          rate: rate(5 minutes)
-          enabled: true
   hello:
     handler: src/hello.default
     events:
       - http:
           path: hello
           method: get
-      # Ping every 5 minutes to avoid cold starts
-      - schedule:
-          rate: rate(5 minutes)
-          enabled: true
 
 #    The following are a few example events you can configure
 #    NOTE: Please make sure to change your handler code to work with those events
@@ -119,4 +122,5 @@ functions:
 plugins:
   - serverless-webpack
   - serverless-offline
+  - serverless-plugin-warmup
   - serverless-dotenv-plugin

src/utils/run-warm.ts

@@ -5,7 +5,7 @@ const runWarm = (lambdaFunc: AWSLambda.Handler): AWSLambda.Handler => (
 ) => {
   // Detect the keep-alive ping from CloudWatch and exit early. This keeps our
   // lambda function running hot.
-  if (event.source === 'aws.events') {
+  if (event.source === 'serverless-plugin-warmup') {
     return callback(null, 'pinged');
   }