feat: support aliases

README.md

@@ -54,9 +54,9 @@ If you're using `async/await`, you can `await` the result of Lambda Warmer and `
 ```javascript
 const warmer = require('lambda-warmer')
 
-exports.handler = async (event) => {
+exports.handler = async (event, context) => {
   // if a warming event
-  if (await warmer(event)) return 'warmed'
+  if (await warmer(event, {/* lambda warmer config here */}, context)) return 'warmed'
   // else proceed with handler logic
   return 'Hello from Lambda'
 }
@@ -69,7 +69,7 @@ const warmer = require('lambda-warmer')
 
 exports.handler = (event, context, callback) => {
   // Start a promise chain
-  warmer(event).then(isWarmer => {
+  warmer(event, {/* lambda warmer config here */}, context).then(isWarmer => {
     // if a warming event
     if (isWarmer) {
       callback(null,'warmed')
@@ -81,6 +81,19 @@ exports.handler = (event, context, callback) => {
 }
 ```
 
+### Passing the `context` Parameter
+
+When your Lambda function is invoked using an **alias** (e.g., `stable`, `prod`, etc.), you need to pass the `context` object to `lambda-warmer` so it can accurately determine if the function is invoking itself.
+
+```javascript
+exports.handler = async (event, context) => {
+  if (await warmer(event, {}, context)) return 'warmed'
+  // Your handler logic
+}
+```
+
+By passing context, `lambda-warmer` can extract the alias from `context`.invokedFunctionArn and properly handle warming invocations.
+
 ## Configuration Options
 
 You can send in a configuration object as the second parameter to change Lambda Warmer's default behavior. All of the settings are optional. Here is a sample configuration object.
@@ -122,7 +135,7 @@ Example passing a configuration:
 ```javascript
 exports.handler = async (event, context) => {
   // if a warming event
-  if (await warmer(event, { correlationId: context.awsRequestId, delay: 50 })) return 'warmed'
+  if (await warmer(event, { correlationId: context.awsRequestId, delay: 50 }, context)) return 'warmed'
   // else proceed with handler logic
   return 'Hello from Lambda'
 }
@@ -209,6 +222,21 @@ myFunction:
             target: myOtherFunction3
 ```
 
+## Support for Lambda Function Aliases
+
+Starting from version `2.1.0`, `lambda-warmer` supports warming Lambda functions invoked via aliases.
+
+### How to Use Alias Support
+
+When invoking your Lambda function using an alias, pass the `context` object to `lambda-warmer`:
+
+```javascript
+exports.handler = async (event, context) => {
+  if (await warmer(event, {/* lambda warmer config here */}, context)) return 'warmed'
+  // Your handler logic
+}
+```
+
 ## Logs
 
 Logs are automatically generated unless the `log` configuration option is set to `false`. Logs contain useful information beyond just invocation data. The `warm` field indicates whether or not the Lambda function was already warm when invoked. The `lastAccessed` field is the timestamp (in milliseconds) of the last time the function was accessed by a non-warming event. Similarly, the `lastAccessedSeconds` gives you a counter (in seconds) of how long it's been since it has been accessed. These can be used to determine if your concurrency can be lowered.

index.js

@@ -19,7 +19,7 @@ const funcVersion = process.env.AWS_LAMBDA_FUNCTION_VERSION
 
 const delay = ms => new Promise(res => setTimeout(res, ms))
 
-const handleEvent = (event, config) => {
+const handleEvent = (event, context, config) => {
   const isWarmerPing = event && event[config.flag]
   if (isWarmerPing) {
     let concurrency =
@@ -68,8 +68,11 @@ const handleEvent = (event, config) => {
     warm = true
     lastAccess = Date.now()
 
+    const currentFunctionAlias = context && context.invokedFunctionArn ? context.invokedFunctionArn.split(':').pop() : funcVersion
+
     // Check whether this lambda is invoking a different lambda
     let isDifferentTarget = !(target === `${funcName}:${funcVersion}` ||
+      target === `${funcName}:${currentFunctionAlias}` ||
       (target === funcName && funcVersion === '$LATEST'))
 
     // Fan out if concurrency is set higher than 1
@@ -115,7 +118,7 @@ const handleEvent = (event, config) => {
   }
 }
 
-module.exports = (event, cfg = {}) => {
+module.exports = (event, cfg = {}, context) => {
   let config = Object.assign(
     {},
     {
@@ -134,12 +137,12 @@ module.exports = (event, cfg = {}) => {
     let i = 0
     const handleNext = () => {
       if (i < event.length) {
-        return handleEvent(event[i++], config).then(handleNext)
+        return handleEvent(event[i++], context, config).then(handleNext)
       }
       return Promise.resolve(event.some((e) => e[config.flag]))
     }
     return handleNext()
   } else {
-    return handleEvent(event, config)
+    return handleEvent(event, context, config)
   }
 } // end module

test/target.js

@@ -49,6 +49,18 @@ describe('Target Tests', function () {
       })
     })
 
+    it('should do nothing if there is a target in the event with the same function name and alias', function (done) {
+      let warmer = rewire('../index')
+      stub.returns(true)
+
+      let event = { warmer: true, concurrency: 1, target: 'test-function:stable' }
+      warmer(event, { log: false }, {invokedFunctionArn: 'arn:aws:lambda:us-west-2:123456789:function:test-function:stable'}).then(out => {
+        expect(stub.callCount).to.equal(0)
+        expect(out).to.equal(true)
+        done()
+      })
+    })
+
     it(
       'should invoke the same lambda if there is no target in the event and the concurrency is more than 1',
       function (done) {
@@ -95,7 +107,7 @@ describe('Target Tests', function () {
         })
       })
 
-      it('if the current function is not $LATEST and the target is with no alias (i.e. $LATEST)', function (done) {
+      it('if the current function is not $LATEST and the target is with no version (i.e. $LATEST)', function (done) {
         process.env.AWS_LAMBDA_FUNCTION_VERSION = '1'
         let warmer = rewire('../index')
         stub.returns(true)
@@ -109,6 +121,21 @@ describe('Target Tests', function () {
           done()
         })
       })
+
+      it('if the current function has an alias that is not the same as the target version', function (done) {
+        process.env.AWS_LAMBDA_FUNCTION_VERSION = '1'
+        let warmer = rewire('../index')
+        stub.returns(true)
+
+        let event = { warmer: true, concurrency: 1, target: 'test-function:2' }
+        warmer(event, { log: false }, {invokedFunctionArn: 'arn:aws:lambda:us-west-2:123456789:function:test-function:1'}).then(out => {
+          expect(stub.callCount).to.equal(1)
+          expect(stub.args[0][0].InvocationType).to.equal('RequestResponse')
+          expect(stub.args[0][0].FunctionName).to.equal('test-function:2')
+          expect(out).to.equal(true)
+          done()
+        })
+      })
     })
 
     it('should return true with two lambda invocations', function (done) {