fix: updated CDK examples to remove old references & improve comments

[dreamorosi]

Description of your changes

This PR sets up #425 and aims at:

• Updating references to old parameters/implementations (i.e. Docs: CDK examples (metrics & tracer) have outdated references #435)
• Improving consistency with examples in docs
• Improving comments in Tracer examples
• Adding full kitchen sink examples that use all three utilities for manual, middy middleware, class decorator based functions

How to verify this change

After #416 has been merged, checkout the branch, go to examples/cdk & run cdk deploy.

Related issues, RFCs

#435
#425

PR status

Is this ready for review?: YES
Is it a breaking change?: NO

Checklist

• My changes meet the tenets criteria
• I have performed a self-review of my own code
• I have commented my code where necessary, particularly in areas that should be flagged with a TODO, or hard-to-understand areas
• My changes generate no new warnings
• The code coverage hasn't decreased
• New and existing unit tests pass locally and in Github Actions
• Any dependent changes have been merged and published in downstream module
• The PR title follows the conventional commit semantics

Breaking change checklist

N/A

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[ijemmy]

The only major one is that we have try/catch without throwing an error. I am willing approve if that is addressed.

The rest are either minor/nit.

[ijemmy]

Same as above. Why try/catch without throw?

[dreamorosi]

See this comment.

[dreamorosi]

This one has the throw at L57.

[ijemmy]

(minor) I am not aware of this. O.o

AFAI see, this is not mentioned in the documentation. Can we add it to the list in this section . Another PR is fine.

[dreamorosi]

The actual example, in this file, is from L4 to L11 since this example wants to demonstrate how to instrument an AWS SDK v2 client.

What I wanted to say with this comment is that even though this example uses manual instrumentation, you don't need to use this method specifically over others (Middy middleware, decorator). Essentially, as long as you instrument the AWS SDK client with tracer.capture* it'll be traced & appear as custom subsegment on X-Ray no matter how you write your function.

That's why in the docs the AWS SDK patching example only has these lines.

I included a function in the example just because otherwise the lines above alone wouldn't run as a Lambda function and the lines from L15 onwards are similar to manual method in the section you linked.

[michaelbrewer]

As CDK V2 is GA, would it make sense to just start using it from the get go @dreamorosi ?

[dreamorosi]

As CDK V2 is GA, would it make sense to just start using it from the get go @dreamorosi ?

Would love to, but at the moment we are relying on some classes that are not exported in v2, see this issue I've opened on the CDK repo.