function.json

{
  "bindings": [
    {
      "authLevel": "function",
      "type": "httpTrigger",
      "direction": "in",
      "name": "req"
    },
    {
      "type": "http",
      "direction": "out",
      "name": "$return"
    },
    {
      "type": "eventHub",
      "name": "outputEventHubMessage",
      "path": "github-events",
      "connection": "github-events",
      "direction": "out"
    },
    {
      "type": "documentDB",
      "name": "outputDocument",
      "databaseName": "rtyler-github-events",
      "collectionName": "jenkins-infra",
      "createIfNotExists": false,
      "connection": "rtyler-github-events_DOCUMENTDB",
      "direction": "out"
    }
  ],
  "disabled": false
}

index.js

module.exports = function (context, req) {
    context.log('JavaScript HTTP trigger function processed a request.');

    if (req.body) {
        context.log(req.body);

        var gh_event = {
            event: req.body,
            received: new Date().toISOString()    
        };

        context.bindings.outputEventHubMessage = gh_event;
        context.bindings.outputDocument = JSON.stringify(gh_event);
        
        res = {
            // status: 200, /* Defaults to 200 */
            body: "Thanks for the GitHub event"
        };
    }
    context.done(null, res);
};