[lambda] Function.currentVersion only updates for framework assets

[rix0rrr]

This code seems to assume that the Function's CloudFormation representation is good enough to determine the full source hash, which is not true as soon as indirection ​through a { Ref } or something comes into play:

https://github.com/aws/aws-cdk/blob/master/packages/@aws-cdk/aws-lambda/lib/function-hash.ts

The Code class needs a way to mix in another value in there, so that if the Code comes from an asset, even if that asset is referenced through { Ref }s or whatever, it still has an opportunity to mix in a sourceHash of some sort to cause the Version to be updated.

• It works for new-style assets because the asset sourceHash has been hardcoded into the CFN template fragment.

• It works for old-style assets because the asset sourceHash has been hardcoded into the parameter name (so the template fragment looks like { Ref: AssetObjectKey035fcdc6941252eb150bf31facc9dc4e }.

• It does not work for custom assets (such as the ones used to integrate with Amazon's internal build system) which reference parameters that look like { Ref: SomeNameThatsTheSameEveryTime }.

The correct solution is to explicitly work the asset.sourceHash into the content hash somewhere, and not rely on the CloudFormation template fragment alone.

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This is 🐛 Bug Report

[nija-at]

Can you provide an example?

[rix0rrr]

Yes, but not publicly.

[eladb]

Why not just use environment variables as a way to include additional info in the hash?

[flemjame-at-amazon]

Why not just use environment variables as a way to include additional info in the hash?

That is what we have been doing to work around this. It's not elegant, but it's functional.

[eladb]

Why not just use environment variables as a way to include additional info in the hash?

That is what we have been doing to work around this. It's not elegant, but it's functional.

We can add some "formal" way to salt the version if that feels better. What do you think?

[rehos]

Is it an idea to use currentVersionOptions.codeSha256 as the formal way to salt the version?

[flemjame-at-amazon]

Why not just use environment variables as a way to include additional info in the hash?

That is what we have been doing to work around this. It's not elegant, but it's functional.

We can add some "formal" way to salt the version if that feels better. What do you think?

Sorry to necro the thread -- yes I think that would be a reasonable approach. Having something in the documentation that mentions this workaround would also be helpful

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