updated README

Author: abailly

README.md

@@ -21,7 +21,7 @@ This repository contains code and directions to run Haskell executables over [AW
     docker run -ti -v $(pwd):/build -w /build --name=haskell-build haskell-centos stack build --allow-different-user
     ...
     CONTAINER_ID=$(docker ps -a | grep haskell-centos | head -1 | cut -d ' ' -f 1)
-    docker run -t --volumes-from=$CONTAINER_ID busybox dd if=/build/.stack-work/install/x86_64-linux/ghc-7.10.3/7.10.3/bin/main > main
+    docker run --volumes-from=$CONTAINER_ID busybox dd if=/build/.stack-work/install/x86_64-linux/ghc-7.10.3/7.10.3/bin/main > main
     ```
 
 * Build zip file containing Javascript wrapper and main app
@@ -33,12 +33,38 @@ This repository contains code and directions to run Haskell executables over [AW
 * Create function on Lambda:
 
     ```
-    aws lambda create-function --function-name hello-test --runtime nodejs --zip-file fileb://./aws-lambda.zip  --handler run.handle --role arn:aws:iam::259394719635:role/lambda
+    $ aws lambda create-function --function-name hello-test --runtime nodejs4.3 --zip-file fileb://./aws-lambda.zip  --handler run.handle --role arn:aws:iam::259394719635:role/lambda
+    {
+        "CodeSha256": "QYKOebaDN/fqEzb1nmaV3ByNDZK3JvD0kWX6YQnPpjE=", 
+        "FunctionName": "hello-test", 
+        "CodeSize": 265356, 
+        "MemorySize": 128, 
+        "FunctionArn": "arn:aws:lambda:eu-west-1:259394719635:function:hello-test", 
+        "Version": "$LATEST", 
+        "Role": "arn:aws:iam::259394719635:role/lambda", 
+        "Timeout": 20, 
+        "LastModified": "2016-05-23T10:32:38.126+0000", 
+        "Handler": "run.handle", 
+        "Runtime": "nodejs4.3", 
+        "Description": ""
+    }
     ```
 
 * Run function on Lambda:
 
+    ```
+    $ aws lamdba invoke-function --function-name hello-test
+    {
+        "StatusCode": 200
+    }
+    $ cat test
+    "child process exited with code 0"
+    ```
 
+The provided `main.hs` simply output its input to its output. There should be an execution trace in the logs hosted on CloudWatch:
+
+![](cloudwatch.png)
+    
 ## Manifest
 
 * `ghc-centos`: Docker container for building Haskell binaries compatible with [Amazon's Linux AMI](http://docs.aws.amazon.com/lambda/latest/dg/current-supported-versions.html). Does not seem to be a good idea in general as there are quite a few differences between CentOS and Linux AMI.

cloudwatch.png

@@ -1,38 +1,35 @@
-process.env[‘PATH’] = process.env[‘PATH’] + ‘:’ + process.env[‘LAMBDA_TASK_ROOT’]
-
 const spawn = require('child_process').spawn;
-const main = spawn('./main');
-
-main.stdout.on('data', (data) => {
-  console.log(`stdout: ${data}`);
-});
-
-main.stderr.on('data', (data) => {
-  console.log(`stderr: ${data}`);
-});
+const main = spawn('./main', { stdio: ['pipe', 'pipe', process.stderr] });
 
-main.on('error', (err) => {
-    console.error(`error: ${err}`);
-    process.exit(1);
+main.stdout.on('data', function(data) {
+    console.log('stdout: ' + data);
 });
 
-main.on('close', (code) => {
-   console.log(`child process pipes closed with code ${code}`);
-});
-
-main.on('exit', (code) => {
-    console.log(`child process exited with code ${code}`);
-    process.exit(code);
+main.on('close', function(code) {
+    console.log('child process pipes closed with code '+ code);
 });
 
 var ctx;
 
 /**
  * handler for AWS Lambda
  */
-exports.handle = function(event, context) {
+exports.handle = function(event, context, callback) {
+    process.env['PATH'] = process.env['PATH'] + ':' + process.env['LAMBDA_TASK_ROOT']
     ctx = context
+
+    console.log("sending data to main:\n" + JSON.stringify(event));
+    console.log("main pid is " + main.pid);
 
+    main.on('exit', function(code){
+        callback(null, 'child process exited with code ' + code); 
+    });
+
+    main.on('error', function(err) {
+        console.error('error: ' + err);
+        callback(err, 'child process exited with error: ' + err); 
+    });
+
     main.stdin.write(JSON.stringify({
         'event': event,
         'context': context