Implement basic resource equivalence #132
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Add a `refactor` command. For now, it only works in dry run mode (`-dry-run` in the command line, or `dryRun: true` to the toolkit). It computes the mappings based on the difference between the deployed stacks and the cloud assembly stacks, and shows them in a table. Example: ``` $ cdk refactor --dry-run --unstable=refactor The following resources were moved or renamed: ┌───────────────────────┬────────────────────────────────────────┬───────────────────────────────────────┐ │ Resource Type │ Old Construct Path │ New Construct Path │ ├───────────────────────┼────────────────────────────────────────┼───────────────────────────────────────┤ │ AWS::IAM::Role │ Consumer/Function/ServiceRole/Resource │ Consumer/NewName/ServiceRole/Resource │ ├───────────────────────┼────────────────────────────────────────┼───────────────────────────────────────┤ │ AWS::Lambda::Function │ Consumer/Function/Resource │ Consumer/NewName/Resource │ └───────────────────────┴────────────────────────────────────────┴───────────────────────────────────────┘ ``` Note that we are launching this feature under unstable mode, which requires the user to acknowledge that by passing the `--unstable=refactor` flag. Closes #132, #133, #141, #134 and #135. --- By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license
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To detect which resources should be refactored, we need to indentify which
resources have only changed their location, but have remained "the same", in
some sense. This can be made precise by defining an equivalence relation on
the set of resources.
Before that, let's define a digest function,
d:where
hashis a cryptographic hash function. In other words, the hashis computed from its type, its own properties (that is, excluding properties
that refer to other resources), and the digests of each of its dependencies.
The digest of a resource, defined recursively this way, remains stable even if
one or more of its dependencies gets renamed. Since the resources in a
CloudFormation template form an acyclic graph, this function is well-defined.
The equivalence relation then follows directly: two resources
r1andr2are equivalent if
d(r1) = d(r2).The text was updated successfully, but these errors were encountered: