Make plugin compatible with Serverless v0.5

[joostfarla]

• Fix broken functionality
• Leverage Serverless features, introduced in v0.5
• Release plugin v0.4.0

[joostfarla]

Progress can be followed here:

https://github.com/joostfarla/serverless-cors-plugin/tree/v0.4

Big thanks to @ac360! 👍

[joostfarla]

@ac360 upgrade is almost finished and ready for release. However, I'm having one problem with the new way objects can be populated. The endpointDeployPre hook (addPreflightRequests) does not seem to receive the stage and region. They are both null, so I'm getting warnings on missing template variables. Do you want to take a look at this? Would appreciate!

[minibikini]

@joostfarla @ac360 @eahefnawy - Hey, guys!

The problem is that the stage and region are not required parameters by EndpointDeploy, it will prompt the user if those are missing.

Ideally we need to somehow run the CORS plugin right after EndpointDeploy._validateAndPrepare().

Since we don't have hooks between pre and post I can see the only way to hook up to _validateAndPrepare() is to use prototypes, instead of S.addHook() mechanism. Something like this:

const _validateAndPrepare = S.classes.EndpointDeploy.prototype._validateAndPrepare;

S.classes.EndpointDeploy.prototype._validateAndPrepare = function() {
  return _validateAndPrepare.call(this).then(() => {
    const cors = new ServerlessCors();
    return cors.addPreflightRequests(this.evt);
  });
};

What do you think?

[joostfarla]

@minibikini thanks for the input!

You're right in the fact that the problem occurs because the pre hook is fired before the region and stage are being determined or entered. However, this does not hold the plugin from doing its job. In fact, the plugin works perfectly, only some warnings on non-used parameters are being outputted. I'm thinking about just releasing the plugin as-is now and try to find a way to ignore certain parameters or suppress the warnings at a later time.

[joostfarla]

I've already released the new version, but will keep this issue open until we get rid of the warnings.

[joostfarla]

One solution could be to let the framework support “partial populations” by passing an array of JSONPath expressions to the toObjectPopulated method. At the moment, the plugin populates the full endpoint configuration and stores it back. However, this full population is in my opinion not a task of this plugin, but of the eventual deployment action in the framework. /cc @ac360

[joostfarla]

After thinking about this for a while, I think the most simple and logical solution would be:

• Merge in templates instantly on project loading. I cannot think of a reason why this should be done at a later time. In this specific case, I only need the templates to be populated.
• Use toObjectPopulated to just populate the environment variables.

This would remove the need to do population from plugins in general. As said before, it's probably unwanted to let plugins populate the environment variables.

@ac360 what do you think?

[joostfarla]

Just created an issue on the Serverless project (serverless/serverless#1134), which will potentially solve the remaining issue.