[bug] curling a nodejs function produces: "TypeError: Cannot read property 'info' of undefined"

[alanfx]

Describe the bug
Created a nodejs function, ran it locally, and curling the loclhost:8080 endpoint produces an error.

To Reproduce
Steps to reproduce the behavior:

1. kn faas init -l node
2. npm run local
3. curl -X POST -d '{"hello": "world"}' -H'Content-type: application/json' -H'Ce-id: 1' -H'Ce-source: cloud-event-example' -H'Ce-type: dev.knative.example' -H'Ce-specversion: 1.0' http://localhost:8080

Result: {"statusMessage":"Cannot read property 'info' of undefined"}

TypeError: Cannot read property 'info' of undefined
    at invoke (/home/afield/Development/go/bin/func1/index.js:30:15)
    at invokeFunction (/home/afield/.npm/_npx/1178569/lib/node_modules/faas-js-runtime/lib/invoker.js:21:34)
    at Object.doPost (/home/afield/.npm/_npx/1178569/lib/node_modules/faas-js-runtime/lib/request-handler.js:18:28)
    at preHandlerCallback (/home/afield/.npm/_npx/1178569/lib/node_modules/faas-js-runtime/node_modules/fastify/lib/handleRequest.js:124:28)
    at next (/home/afield/.npm/_npx/1178569/lib/node_modules/faas-js-runtime/node_modules/fastify/lib/hooks.js:158:7)
    at Object.<anonymous> (/home/afield/.npm/_npx/1178569/lib/node_modules/faas-js-runtime/lib/event-handler.js:26:5)
    at hookIterator (/home/afield/.npm/_npx/1178569/lib/node_modules/faas-js-runtime/node_modules/fastify/lib/hooks.js:221:10)
    at next (/home/afield/.npm/_npx/1178569/lib/node_modules/faas-js-runtime/node_modules/fastify/lib/hooks.js:162:20)
    at Object.<anonymous> (/home/afield/.npm/_npx/1178569/lib/node_modules/faas-js-runtime/index.js:32:5)
    at hookIterator (/home/afield/.npm/_npx/1178569/lib/node_modules/faas-js-runtime/node_modules/fastify/lib/hooks.js:221:10)

Expected behavior
The CloudEvent is delivered to the function without error.

[matejvasek]

@alanfx Thanks for the feedback!
I think that when using CloudEvents the function should be initialized by kn faas init -l node -t events.
Otherwise plain HTTP is assumed. With plain HTTP the function signature is different.

[matejvasek]

When the runtime receives CE it expects that the user function accepts two parameters, but HTTP template has only one.

[matejvasek]

@lance Maybe it would be better to pass CloudEvent as second parameter, not the first.

Also if it's possible in JS, the runtime could check function arity and return Bad request if signature doesn't match.

[matejvasek]

@lance I mean something like this. Beware I didn't try to run code below.

diff --git a/lib/invoker.js b/lib/invoker.js
index ef8f83a..3ab2d15 100644
--- a/lib/invoker.js
+++ b/lib/invoker.js
@@ -18,11 +18,25 @@ module.exports = function invoker(func) {
       if (context.cloudevent && context.cloudevent.data) {
         // If there is a cloud event, provide the data
         // as the first parameter
-        payload.response = await func(context.cloudevent.data, context);
+        if (func.length === 2) {
+          payload.response = await func(context.cloudevent.data, context);
+        } else {
+          payload.response = {
+            statusCode: 400,
+            statusMessage: 'Received CloudEvent but handler is plain HTTP handler.'
+          };
+        }
       } else {
         // Invoke with context
         // TODO: Should this actually just get the Node.js request object?
-        payload.response = await func(context);
+        if (func.length === 1) {
+          payload.response = await func(context);
+        } else {
+          payload.response = {
+            statusCode: 400,
+            statusMessage: 'Received plain HTTP but handler is CloudEvent handler.'
+          };
+        }
       }
     } catch (err) {
       log.error(err);

[alanfx]

@matejvasek you are exactly right! I was confused by the output of the npm run local command:

go/bin/func1 is 📦 v0.1.0 via ⬢ v12.19.0 on ☁️  us-west-1 took 15s 
❯ npm run local

> http-handler@0.1.0 local /home/afield/Development/go/bin/func1
> npx faas-js-runtime ./index.js

{"level":30,"time":1603999818473,"pid":1189464,"hostname":"afield-lenovo","msg":"Server listening at http://0.0.0.0:8080"}

The server has started.

You can use curl to POST an event to the endpoint:

curl -X POST -d '{"hello": "world"}' \
    -H'Content-type: application/json' \
    -H'Ce-id: 1' \
    -H'Ce-source: cloud-event-example' \
    -H'Ce-type: dev.knative.example' \
    -H'Ce-specversion: 1.0' \
    http://localhost:8080

Maybe the text should also mention that curl http://localhost:8080 will work for HTTP endpoints?